From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/namei.c | 2313 +++++++++++++++++++++++++++--------------------------------
1 files changed, 1,059 insertions(+), 1,254 deletions(-)
diff --git a/kernel/fs/namei.c b/kernel/fs/namei.c
index 8492dc6..83ef3d7 100644
--- a/kernel/fs/namei.c
+++ b/kernel/fs/namei.c
@@ -39,7 +39,6 @@
#include <linux/bitops.h>
#include <linux/init_task.h>
#include <linux/uaccess.h>
-#include <linux/build_bug.h>
#include "internal.h"
#include "mount.h"
@@ -134,7 +133,6 @@
struct filename *result;
char *kname;
int len;
- BUILD_BUG_ON(offsetof(struct filename, iname) % sizeof(long) != 0);
result = audit_reusename(filename);
if (result)
@@ -276,7 +274,7 @@
/* no ->get_acl() calls in RCU mode... */
if (is_uncached_acl(acl))
return -ECHILD;
- return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
+ return posix_acl_permission(inode, acl, mask);
}
acl = get_acl(inode, ACL_TYPE_ACCESS);
@@ -293,37 +291,51 @@
}
/*
- * This does the basic permission checking
+ * This does the basic UNIX permission checking.
+ *
+ * Note that the POSIX ACL check cares about the MAY_NOT_BLOCK bit,
+ * for RCU walking.
*/
static int acl_permission_check(struct inode *inode, int mask)
{
unsigned int mode = inode->i_mode;
- if (likely(uid_eq(current_fsuid(), inode->i_uid)))
+ /* Are we the owner? If so, ACL's don't matter */
+ if (likely(uid_eq(current_fsuid(), inode->i_uid))) {
+ mask &= 7;
mode >>= 6;
- else {
- if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
- int error = check_acl(inode, mask);
- if (error != -EAGAIN)
- return error;
- }
+ return (mask & ~mode) ? -EACCES : 0;
+ }
+ /* Do we have ACL's? */
+ if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
+ int error = check_acl(inode, mask);
+ if (error != -EAGAIN)
+ return error;
+ }
+
+ /* Only RWX matters for group/other mode bits */
+ mask &= 7;
+
+ /*
+ * Are the group permissions different from
+ * the other permissions in the bits we care
+ * about? Need to check group ownership if so.
+ */
+ if (mask & (mode ^ (mode >> 3))) {
if (in_group_p(inode->i_gid))
mode >>= 3;
}
- /*
- * If the DACs are ok we don't need any capability check.
- */
- if ((mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
- return 0;
- return -EACCES;
+ /* Bits in 'mode' clear that we require? */
+ return (mask & ~mode) ? -EACCES : 0;
}
/**
* generic_permission - check for access rights on a Posix-like filesystem
* @inode: inode to check access rights for
- * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...)
+ * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC,
+ * %MAY_NOT_BLOCK ...)
*
* Used to check for read/write/execute permissions on a file.
* We use "fsuid" for this, letting us set arbitrary permissions
@@ -382,11 +394,9 @@
* flag in inode->i_opflags, that says "this has not special
* permission function, use the fast case".
*/
-static inline int do_inode_permission(struct vfsmount *mnt, struct inode *inode, int mask)
+static inline int do_inode_permission(struct inode *inode, int mask)
{
if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) {
- if (likely(mnt && inode->i_op->permission2))
- return inode->i_op->permission2(mnt, inode, mask);
if (likely(inode->i_op->permission))
return inode->i_op->permission(inode, mask);
@@ -419,8 +429,7 @@
}
/**
- * inode_permission2 - Check for access rights to a given inode
- * @mnt:
+ * inode_permission - Check for access rights to a given inode
* @inode: Inode to check permission on
* @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
*
@@ -430,7 +439,7 @@
*
* When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
*/
-int inode_permission2(struct vfsmount *mnt, struct inode *inode, int mask)
+int inode_permission(struct inode *inode, int mask)
{
int retval;
@@ -454,7 +463,7 @@
return -EACCES;
}
- retval = do_inode_permission(mnt, inode, mask);
+ retval = do_inode_permission(inode, mask);
if (retval)
return retval;
@@ -462,14 +471,7 @@
if (retval)
return retval;
- retval = security_inode_permission(inode, mask);
- return retval;
-}
-EXPORT_SYMBOL(inode_permission2);
-
-int inode_permission(struct inode *inode, int mask)
-{
- return inode_permission2(NULL, inode, mask);
+ return security_inode_permission(inode, mask);
}
EXPORT_SYMBOL(inode_permission);
@@ -506,7 +508,7 @@
struct path root;
struct inode *inode; /* path.dentry.d_inode */
unsigned int flags;
- unsigned seq, m_seq;
+ unsigned seq, m_seq, r_seq;
int last_type;
unsigned depth;
int total_link_count;
@@ -518,9 +520,10 @@
} *stack, internal[EMBEDDED_LEVELS];
struct filename *name;
struct nameidata *saved;
- struct inode *link_inode;
unsigned root_seq;
int dfd;
+ kuid_t dir_uid;
+ umode_t dir_mode;
} __randomize_layout;
static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
@@ -529,6 +532,8 @@
p->stack = p->internal;
p->dfd = dfd;
p->name = name;
+ p->path.mnt = NULL;
+ p->path.dentry = NULL;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
current->nameidata = p;
@@ -545,52 +550,34 @@
kfree(now->stack);
}
-static int __nd_alloc_stack(struct nameidata *nd)
+static bool nd_alloc_stack(struct nameidata *nd)
{
struct saved *p;
- if (nd->flags & LOOKUP_RCU) {
- p= kmalloc_array(MAXSYMLINKS, sizeof(struct saved),
- GFP_ATOMIC);
- if (unlikely(!p))
- return -ECHILD;
- } else {
- p= kmalloc_array(MAXSYMLINKS, sizeof(struct saved),
- GFP_KERNEL);
- if (unlikely(!p))
- return -ENOMEM;
- }
+ p= kmalloc_array(MAXSYMLINKS, sizeof(struct saved),
+ nd->flags & LOOKUP_RCU ? GFP_ATOMIC : GFP_KERNEL);
+ if (unlikely(!p))
+ return false;
memcpy(p, nd->internal, sizeof(nd->internal));
nd->stack = p;
- return 0;
+ return true;
}
/**
- * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
- * @path: nameidate to verify
+ * path_connected - Verify that a dentry is below mnt.mnt_root
*
* Rename can sometimes move a file or directory outside of a bind
* mount, path_connected allows those cases to be detected.
*/
-static bool path_connected(const struct path *path)
+static bool path_connected(struct vfsmount *mnt, struct dentry *dentry)
{
- struct vfsmount *mnt = path->mnt;
struct super_block *sb = mnt->mnt_sb;
- /* Bind mounts and multi-root filesystems can have disconnected paths */
- if (!(sb->s_iflags & SB_I_MULTIROOT) && (mnt->mnt_root == sb->s_root))
+ /* Bind mounts can have disconnected paths */
+ if (mnt->mnt_root == sb->s_root)
return true;
- return is_subdir(path->dentry, mnt->mnt_root);
-}
-
-static inline int nd_alloc_stack(struct nameidata *nd)
-{
- if (likely(nd->depth != EMBEDDED_LEVELS))
- return 0;
- if (likely(nd->stack != nd->internal))
- return 0;
- return __nd_alloc_stack(nd);
+ return is_subdir(dentry, mnt->mnt_root);
}
static void drop_links(struct nameidata *nd)
@@ -611,24 +598,23 @@
path_put(&nd->path);
for (i = 0; i < nd->depth; i++)
path_put(&nd->stack[i].link);
- if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ if (nd->flags & LOOKUP_ROOT_GRABBED) {
path_put(&nd->root);
- nd->root.mnt = NULL;
+ nd->flags &= ~LOOKUP_ROOT_GRABBED;
}
} else {
nd->flags &= ~LOOKUP_RCU;
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
rcu_read_unlock();
}
nd->depth = 0;
+ nd->path.mnt = NULL;
+ nd->path.dentry = NULL;
}
/* path_put is needed afterwards regardless of success or failure */
-static bool legitimize_path(struct nameidata *nd,
- struct path *path, unsigned seq)
+static bool __legitimize_path(struct path *path, unsigned seq, unsigned mseq)
{
- int res = __legitimize_mnt(path->mnt, nd->m_seq);
+ int res = __legitimize_mnt(path->mnt, mseq);
if (unlikely(res)) {
if (res > 0)
path->mnt = NULL;
@@ -642,9 +628,20 @@
return !read_seqcount_retry(&path->dentry->d_seq, seq);
}
+static inline bool legitimize_path(struct nameidata *nd,
+ struct path *path, unsigned seq)
+{
+ return __legitimize_path(path, seq, nd->m_seq);
+}
+
static bool legitimize_links(struct nameidata *nd)
{
int i;
+ if (unlikely(nd->flags & LOOKUP_CACHED)) {
+ drop_links(nd);
+ nd->depth = 0;
+ return false;
+ }
for (i = 0; i < nd->depth; i++) {
struct saved *last = nd->stack + i;
if (unlikely(!legitimize_path(nd, &last->link, last->seq))) {
@@ -654,6 +651,22 @@
}
}
return true;
+}
+
+static bool legitimize_root(struct nameidata *nd)
+{
+ /*
+ * For scoped-lookups (where nd->root has been zeroed), we need to
+ * restart the whole lookup from scratch -- because set_root() is wrong
+ * for these lookups (nd->dfd is the root, not the filesystem root).
+ */
+ if (!nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED))
+ return false;
+ /* Nothing to do if nd->root is zero or is managed by the VFS user. */
+ if (!nd->root.mnt || (nd->flags & LOOKUP_ROOT))
+ return true;
+ nd->flags |= LOOKUP_ROOT_GRABBED;
+ return legitimize_path(nd, &nd->root, nd->root_seq);
}
/*
@@ -668,17 +681,17 @@
*/
/**
- * unlazy_walk - try to switch to ref-walk mode.
+ * try_to_unlazy - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
- * Returns: 0 on success, -ECHILD on failure
+ * Returns: true on success, false on failure
*
- * unlazy_walk attempts to legitimize the current nd->path and nd->root
+ * try_to_unlazy attempts to legitimize the current nd->path and nd->root
* for ref-walk mode.
* Must be called from rcu-walk context.
- * Nothing should touch nameidata between unlazy_walk() failure and
+ * Nothing should touch nameidata between try_to_unlazy() failure and
* terminate_walk().
*/
-static int unlazy_walk(struct nameidata *nd)
+static bool try_to_unlazy(struct nameidata *nd)
{
struct dentry *parent = nd->path.dentry;
@@ -686,42 +699,37 @@
nd->flags &= ~LOOKUP_RCU;
if (unlikely(!legitimize_links(nd)))
- goto out2;
- if (unlikely(!legitimize_path(nd, &nd->path, nd->seq)))
goto out1;
- if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
- if (unlikely(!legitimize_path(nd, &nd->root, nd->root_seq)))
- goto out;
- }
+ if (unlikely(!legitimize_path(nd, &nd->path, nd->seq)))
+ goto out;
+ if (unlikely(!legitimize_root(nd)))
+ goto out;
rcu_read_unlock();
BUG_ON(nd->inode != parent->d_inode);
- return 0;
+ return true;
-out2:
+out1:
nd->path.mnt = NULL;
nd->path.dentry = NULL;
-out1:
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
out:
rcu_read_unlock();
- return -ECHILD;
+ return false;
}
/**
- * unlazy_child - try to switch to ref-walk mode.
+ * try_to_unlazy_next - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
- * @dentry: child of nd->path.dentry
- * @seq: seq number to check dentry against
- * Returns: 0 on success, -ECHILD on failure
+ * @dentry: next dentry to step into
+ * @seq: seq number to check @dentry against
+ * Returns: true on success, false on failure
*
- * unlazy_child attempts to legitimize the current nd->path, nd->root and dentry
- * for ref-walk mode. @dentry must be a path found by a do_lookup call on
- * @nd. Must be called from rcu-walk context.
- * Nothing should touch nameidata between unlazy_child() failure and
+ * Similar to to try_to_unlazy(), but here we have the next dentry already
+ * picked by rcu-walk and want to legitimize that in addition to the current
+ * nd->path and nd->root for ref-walk mode. Must be called from rcu-walk context.
+ * Nothing should touch nameidata between try_to_unlazy_next() failure and
* terminate_walk().
*/
-static int unlazy_child(struct nameidata *nd, struct dentry *dentry, unsigned seq)
+static bool try_to_unlazy_next(struct nameidata *nd, struct dentry *dentry, unsigned seq)
{
BUG_ON(!(nd->flags & LOOKUP_RCU));
@@ -742,25 +750,16 @@
*/
if (unlikely(!lockref_get_not_dead(&dentry->d_lockref)))
goto out;
- if (unlikely(read_seqcount_retry(&dentry->d_seq, seq))) {
- rcu_read_unlock();
- dput(dentry);
- goto drop_root_mnt;
- }
+ if (unlikely(read_seqcount_retry(&dentry->d_seq, seq)))
+ goto out_dput;
/*
* Sequence counts matched. Now make sure that the root is
* still valid and get it if required.
*/
- if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
- if (unlikely(!legitimize_path(nd, &nd->root, nd->root_seq))) {
- rcu_read_unlock();
- dput(dentry);
- return -ECHILD;
- }
- }
-
+ if (unlikely(!legitimize_root(nd)))
+ goto out_dput;
rcu_read_unlock();
- return 0;
+ return true;
out2:
nd->path.mnt = NULL;
@@ -768,10 +767,11 @@
nd->path.dentry = NULL;
out:
rcu_read_unlock();
-drop_root_mnt:
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
- return -ECHILD;
+ return false;
+out_dput:
+ rcu_read_unlock();
+ dput(dentry);
+ return false;
}
static inline int d_revalidate(struct dentry *dentry, unsigned int flags)
@@ -873,10 +873,36 @@
int status;
if (nd->flags & LOOKUP_RCU) {
- if (!(nd->flags & LOOKUP_ROOT))
+ /*
+ * We don't want to zero nd->root for scoped-lookups or
+ * externally-managed nd->root.
+ */
+ if (!(nd->flags & (LOOKUP_ROOT | LOOKUP_IS_SCOPED)))
nd->root.mnt = NULL;
- if (unlikely(unlazy_walk(nd)))
+ nd->flags &= ~LOOKUP_CACHED;
+ if (!try_to_unlazy(nd))
return -ECHILD;
+ }
+
+ if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) {
+ /*
+ * While the guarantee of LOOKUP_IS_SCOPED is (roughly) "don't
+ * ever step outside the root during lookup" and should already
+ * be guaranteed by the rest of namei, we want to avoid a namei
+ * BUG resulting in userspace being given a path that was not
+ * scoped within the root at some point during the lookup.
+ *
+ * So, do a final sanity-check to make sure that in the
+ * worst-case scenario (a complete bypass of LOOKUP_IS_SCOPED)
+ * we won't silently return an fd completely outside of the
+ * requested root to userspace.
+ *
+ * Userspace could move the path outside the root after this
+ * check, but as discussed elsewhere this is not a concern (the
+ * resolved file was inside the root at some point).
+ */
+ if (!path_is_under(&nd->path, &nd->root))
+ return -EXDEV;
}
if (likely(!(nd->flags & LOOKUP_JUMPED))) {
@@ -901,9 +927,17 @@
return status;
}
-static void set_root(struct nameidata *nd)
+static int set_root(struct nameidata *nd)
{
struct fs_struct *fs = current->fs;
+
+ /*
+ * Jumping to the real root in a scoped-lookup is a BUG in namei, but we
+ * still have to ensure it doesn't happen because it will cause a breakout
+ * from the dirfd.
+ */
+ if (WARN_ON(nd->flags & LOOKUP_IS_SCOPED))
+ return -ENOTRECOVERABLE;
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
@@ -915,30 +949,25 @@
} while (read_seqcount_retry(&fs->seq, seq));
} else {
get_fs_root(fs, &nd->root);
+ nd->flags |= LOOKUP_ROOT_GRABBED;
}
-}
-
-static void path_put_conditional(struct path *path, struct nameidata *nd)
-{
- dput(path->dentry);
- if (path->mnt != nd->path.mnt)
- mntput(path->mnt);
-}
-
-static inline void path_to_nameidata(const struct path *path,
- struct nameidata *nd)
-{
- if (!(nd->flags & LOOKUP_RCU)) {
- dput(nd->path.dentry);
- if (nd->path.mnt != path->mnt)
- mntput(nd->path.mnt);
- }
- nd->path.mnt = path->mnt;
- nd->path.dentry = path->dentry;
+ return 0;
}
static int nd_jump_root(struct nameidata *nd)
{
+ if (unlikely(nd->flags & LOOKUP_BENEATH))
+ return -EXDEV;
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV)) {
+ /* Absolute path arguments to path_init() are allowed. */
+ if (nd->path.mnt != NULL && nd->path.mnt != nd->root.mnt)
+ return -EXDEV;
+ }
+ if (!nd->root.mnt) {
+ int error = set_root(nd);
+ if (error)
+ return error;
+ }
if (nd->flags & LOOKUP_RCU) {
struct dentry *d;
nd->path = nd->root;
@@ -961,14 +990,32 @@
* Helper to directly jump to a known parsed path from ->get_link,
* caller must have taken a reference to path beforehand.
*/
-void nd_jump_link(struct path *path)
+int nd_jump_link(struct path *path)
{
+ int error = -ELOOP;
struct nameidata *nd = current->nameidata;
- path_put(&nd->path);
+ if (unlikely(nd->flags & LOOKUP_NO_MAGICLINKS))
+ goto err;
+
+ error = -EXDEV;
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV)) {
+ if (nd->path.mnt != path->mnt)
+ goto err;
+ }
+ /* Not currently safe for scoped-lookups. */
+ if (unlikely(nd->flags & LOOKUP_IS_SCOPED))
+ goto err;
+
+ path_put(&nd->path);
nd->path = *path;
nd->inode = nd->path.dentry->d_inode;
nd->flags |= LOOKUP_JUMPED;
+ return 0;
+
+err:
+ path_put(path);
+ return error;
}
static inline void put_link(struct nameidata *nd)
@@ -999,35 +1046,28 @@
*
* Returns 0 if following the symlink is allowed, -ve on error.
*/
-static inline int may_follow_link(struct nameidata *nd)
+static inline int may_follow_link(struct nameidata *nd, const struct inode *inode)
{
- const struct inode *inode;
- const struct inode *parent;
- kuid_t puid;
-
if (!sysctl_protected_symlinks)
return 0;
/* Allowed if owner and follower match. */
- inode = nd->link_inode;
if (uid_eq(current_cred()->fsuid, inode->i_uid))
return 0;
/* Allowed if parent directory not sticky and world-writable. */
- parent = nd->inode;
- if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
+ if ((nd->dir_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
return 0;
/* Allowed if parent directory and link owner match. */
- puid = parent->i_uid;
- if (uid_valid(puid) && uid_eq(puid, inode->i_uid))
+ if (uid_valid(nd->dir_uid) && uid_eq(nd->dir_uid, inode->i_uid))
return 0;
if (nd->flags & LOOKUP_RCU)
return -ECHILD;
audit_inode(nd->name, nd->stack[0].link.dentry, 0);
- audit_log_link_denied("follow_link");
+ audit_log_path_denied(AUDIT_ANOM_LINK, "follow_link");
return -EACCES;
}
@@ -1078,7 +1118,7 @@
*
* Returns 0 if successful, -ve on error.
*/
-static int may_linkat(struct path *link)
+int may_linkat(struct path *link)
{
struct inode *inode = link->dentry->d_inode;
@@ -1095,7 +1135,7 @@
if (safe_hardlink_source(inode) || inode_owner_or_capable(inode))
return 0;
- audit_log_link_denied("linkat");
+ audit_log_path_denied(AUDIT_ANOM_LINK, "linkat");
return -EPERM;
}
@@ -1134,64 +1174,13 @@
(dir_mode & 0020 &&
((sysctl_protected_fifos >= 2 && S_ISFIFO(inode->i_mode)) ||
(sysctl_protected_regular >= 2 && S_ISREG(inode->i_mode))))) {
+ const char *operation = S_ISFIFO(inode->i_mode) ?
+ "sticky_create_fifo" :
+ "sticky_create_regular";
+ audit_log_path_denied(AUDIT_ANOM_CREAT, operation);
return -EACCES;
}
return 0;
-}
-
-static __always_inline
-const char *get_link(struct nameidata *nd)
-{
- struct saved *last = nd->stack + nd->depth - 1;
- struct dentry *dentry = last->link.dentry;
- struct inode *inode = nd->link_inode;
- int error;
- const char *res;
-
- if (!(nd->flags & LOOKUP_RCU)) {
- touch_atime(&last->link);
- cond_resched();
- } else if (atime_needs_update(&last->link, inode)) {
- if (unlikely(unlazy_walk(nd)))
- return ERR_PTR(-ECHILD);
- touch_atime(&last->link);
- }
-
- error = security_inode_follow_link(dentry, inode,
- nd->flags & LOOKUP_RCU);
- if (unlikely(error))
- return ERR_PTR(error);
-
- nd->last_type = LAST_BIND;
- res = READ_ONCE(inode->i_link);
- if (!res) {
- const char * (*get)(struct dentry *, struct inode *,
- struct delayed_call *);
- get = inode->i_op->get_link;
- if (nd->flags & LOOKUP_RCU) {
- res = get(NULL, inode, &last->done);
- if (res == ERR_PTR(-ECHILD)) {
- if (unlikely(unlazy_walk(nd)))
- return ERR_PTR(-ECHILD);
- res = get(dentry, inode, &last->done);
- }
- } else {
- res = get(dentry, inode, &last->done);
- }
- if (IS_ERR_OR_NULL(res))
- return res;
- }
- if (*res == '/') {
- if (!nd->root.mnt)
- set_root(nd);
- if (unlikely(nd_jump_root(nd)))
- return ERR_PTR(-ECHILD);
- while (unlikely(*++res == '/'))
- ;
- }
- if (!*res)
- res = NULL;
- return res;
}
/*
@@ -1227,19 +1216,59 @@
}
EXPORT_SYMBOL(follow_up);
+static bool choose_mountpoint_rcu(struct mount *m, const struct path *root,
+ struct path *path, unsigned *seqp)
+{
+ while (mnt_has_parent(m)) {
+ struct dentry *mountpoint = m->mnt_mountpoint;
+
+ m = m->mnt_parent;
+ if (unlikely(root->dentry == mountpoint &&
+ root->mnt == &m->mnt))
+ break;
+ if (mountpoint != m->mnt.mnt_root) {
+ path->mnt = &m->mnt;
+ path->dentry = mountpoint;
+ *seqp = read_seqcount_begin(&mountpoint->d_seq);
+ return true;
+ }
+ }
+ return false;
+}
+
+static bool choose_mountpoint(struct mount *m, const struct path *root,
+ struct path *path)
+{
+ bool found;
+
+ rcu_read_lock();
+ while (1) {
+ unsigned seq, mseq = read_seqbegin(&mount_lock);
+
+ found = choose_mountpoint_rcu(m, root, path, &seq);
+ if (unlikely(!found)) {
+ if (!read_seqretry(&mount_lock, mseq))
+ break;
+ } else {
+ if (likely(__legitimize_path(path, seq, mseq)))
+ break;
+ rcu_read_unlock();
+ path_put(path);
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+ return found;
+}
+
/*
* Perform an automount
* - return -EISDIR to tell follow_managed() to stop and return the path we
* were called with.
*/
-static int follow_automount(struct path *path, struct nameidata *nd,
- bool *need_mntput)
+static int follow_automount(struct path *path, int *count, unsigned lookup_flags)
{
- struct vfsmount *mnt;
- int err;
-
- if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
- return -EREMOTE;
+ struct dentry *dentry = path->dentry;
/* We don't want to mount if someone's just doing a stat -
* unless they're stat'ing a directory and appended a '/' to
@@ -1252,129 +1281,89 @@
* as being automount points. These will need the attentions
* of the daemon to instantiate them before they can be used.
*/
- if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
+ if (!(lookup_flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
- path->dentry->d_inode)
+ dentry->d_inode)
return -EISDIR;
- nd->total_link_count++;
- if (nd->total_link_count >= 40)
+ if (count && (*count)++ >= MAXSYMLINKS)
return -ELOOP;
- mnt = path->dentry->d_op->d_automount(path);
- if (IS_ERR(mnt)) {
- /*
- * The filesystem is allowed to return -EISDIR here to indicate
- * it doesn't want to automount. For instance, autofs would do
- * this so that its userspace daemon can mount on this dentry.
- *
- * However, we can only permit this if it's a terminal point in
- * the path being looked up; if it wasn't then the remainder of
- * the path is inaccessible and we should say so.
- */
- if (PTR_ERR(mnt) == -EISDIR && (nd->flags & LOOKUP_PARENT))
- return -EREMOTE;
- return PTR_ERR(mnt);
- }
-
- if (!mnt) /* mount collision */
- return 0;
-
- if (!*need_mntput) {
- /* lock_mount() may release path->mnt on error */
- mntget(path->mnt);
- *need_mntput = true;
- }
- err = finish_automount(mnt, path);
-
- switch (err) {
- case -EBUSY:
- /* Someone else made a mount here whilst we were busy */
- return 0;
- case 0:
- path_put(path);
- path->mnt = mnt;
- path->dentry = dget(mnt->mnt_root);
- return 0;
- default:
- return err;
- }
-
+ return finish_automount(dentry->d_op->d_automount(path), path);
}
/*
- * Handle a dentry that is managed in some way.
- * - Flagged for transit management (autofs)
- * - Flagged as mountpoint
- * - Flagged as automount point
- *
- * This may only be called in refwalk mode.
- *
- * Serialization is taken care of in namespace.c
+ * mount traversal - out-of-line part. One note on ->d_flags accesses -
+ * dentries are pinned but not locked here, so negative dentry can go
+ * positive right under us. Use of smp_load_acquire() provides a barrier
+ * sufficient for ->d_inode and ->d_flags consistency.
*/
-static int follow_managed(struct path *path, struct nameidata *nd)
+static int __traverse_mounts(struct path *path, unsigned flags, bool *jumped,
+ int *count, unsigned lookup_flags)
{
- struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */
- unsigned managed;
+ struct vfsmount *mnt = path->mnt;
bool need_mntput = false;
int ret = 0;
- /* Given that we're not holding a lock here, we retain the value in a
- * local variable for each dentry as we look at it so that we don't see
- * the components of that value change under us */
- while (managed = READ_ONCE(path->dentry->d_flags),
- managed &= DCACHE_MANAGED_DENTRY,
- unlikely(managed != 0)) {
+ while (flags & DCACHE_MANAGED_DENTRY) {
/* Allow the filesystem to manage the transit without i_mutex
* being held. */
- if (managed & DCACHE_MANAGE_TRANSIT) {
- BUG_ON(!path->dentry->d_op);
- BUG_ON(!path->dentry->d_op->d_manage);
+ if (flags & DCACHE_MANAGE_TRANSIT) {
ret = path->dentry->d_op->d_manage(path, false);
+ flags = smp_load_acquire(&path->dentry->d_flags);
if (ret < 0)
break;
}
- /* Transit to a mounted filesystem. */
- if (managed & DCACHE_MOUNTED) {
+ if (flags & DCACHE_MOUNTED) { // something's mounted on it..
struct vfsmount *mounted = lookup_mnt(path);
- if (mounted) {
+ if (mounted) { // ... in our namespace
dput(path->dentry);
if (need_mntput)
mntput(path->mnt);
path->mnt = mounted;
path->dentry = dget(mounted->mnt_root);
+ // here we know it's positive
+ flags = path->dentry->d_flags;
need_mntput = true;
continue;
}
-
- /* Something is mounted on this dentry in another
- * namespace and/or whatever was mounted there in this
- * namespace got unmounted before lookup_mnt() could
- * get it */
}
- /* Handle an automount point */
- if (managed & DCACHE_NEED_AUTOMOUNT) {
- ret = follow_automount(path, nd, &need_mntput);
- if (ret < 0)
- break;
- continue;
- }
+ if (!(flags & DCACHE_NEED_AUTOMOUNT))
+ break;
- /* We didn't change the current path point */
- break;
+ // uncovered automount point
+ ret = follow_automount(path, count, lookup_flags);
+ flags = smp_load_acquire(&path->dentry->d_flags);
+ if (ret < 0)
+ break;
}
+ if (ret == -EISDIR)
+ ret = 0;
+ // possible if you race with several mount --move
if (need_mntput && path->mnt == mnt)
mntput(path->mnt);
- if (ret == -EISDIR || !ret)
- ret = 1;
- if (need_mntput)
- nd->flags |= LOOKUP_JUMPED;
- if (unlikely(ret < 0))
- path_put_conditional(path, nd);
+ if (!ret && unlikely(d_flags_negative(flags)))
+ ret = -ENOENT;
+ *jumped = need_mntput;
return ret;
+}
+
+static inline int traverse_mounts(struct path *path, bool *jumped,
+ int *count, unsigned lookup_flags)
+{
+ unsigned flags = smp_load_acquire(&path->dentry->d_flags);
+
+ /* fastpath */
+ if (likely(!(flags & DCACHE_MANAGED_DENTRY))) {
+ *jumped = false;
+ if (unlikely(d_flags_negative(flags)))
+ return -ENOENT;
+ return 0;
+ }
+ return __traverse_mounts(path, flags, jumped, count, lookup_flags);
}
int follow_down_one(struct path *path)
@@ -1393,11 +1382,22 @@
}
EXPORT_SYMBOL(follow_down_one);
-static inline int managed_dentry_rcu(const struct path *path)
+/*
+ * Follow down to the covering mount currently visible to userspace. At each
+ * point, the filesystem owning that dentry may be queried as to whether the
+ * caller is permitted to proceed or not.
+ */
+int follow_down(struct path *path)
{
- return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
- path->dentry->d_op->d_manage(path, true) : 0;
+ struct vfsmount *mnt = path->mnt;
+ bool jumped;
+ int ret = traverse_mounts(path, &jumped, NULL, 0);
+
+ if (path->mnt != mnt)
+ mntput(mnt);
+ return ret;
}
+EXPORT_SYMBOL(follow_down);
/*
* Try to skip to top of mountpoint pile in rcuwalk mode. Fail if
@@ -1406,190 +1406,90 @@
static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
struct inode **inode, unsigned *seqp)
{
+ struct dentry *dentry = path->dentry;
+ unsigned int flags = dentry->d_flags;
+
+ if (likely(!(flags & DCACHE_MANAGED_DENTRY)))
+ return true;
+
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV))
+ return false;
+
for (;;) {
- struct mount *mounted;
/*
* Don't forget we might have a non-mountpoint managed dentry
* that wants to block transit.
*/
- switch (managed_dentry_rcu(path)) {
- case -ECHILD:
- default:
- return false;
- case -EISDIR:
- return true;
- case 0:
- break;
+ if (unlikely(flags & DCACHE_MANAGE_TRANSIT)) {
+ int res = dentry->d_op->d_manage(path, true);
+ if (res)
+ return res == -EISDIR;
+ flags = dentry->d_flags;
}
- if (!d_mountpoint(path->dentry))
- return !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT);
-
- mounted = __lookup_mnt(path->mnt, path->dentry);
- if (!mounted)
- break;
- path->mnt = &mounted->mnt;
- path->dentry = mounted->mnt.mnt_root;
- nd->flags |= LOOKUP_JUMPED;
- *seqp = read_seqcount_begin(&path->dentry->d_seq);
- /*
- * Update the inode too. We don't need to re-check the
- * dentry sequence number here after this d_inode read,
- * because a mount-point is always pinned.
- */
- *inode = path->dentry->d_inode;
- }
- return !read_seqretry(&mount_lock, nd->m_seq) &&
- !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT);
-}
-
-static int follow_dotdot_rcu(struct nameidata *nd)
-{
- struct inode *inode = nd->inode;
-
- while (1) {
- if (path_equal(&nd->path, &nd->root))
- break;
- if (nd->path.dentry != nd->path.mnt->mnt_root) {
- struct dentry *old = nd->path.dentry;
- struct dentry *parent = old->d_parent;
- unsigned seq;
-
- inode = parent->d_inode;
- seq = read_seqcount_begin(&parent->d_seq);
- if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq)))
- return -ECHILD;
- nd->path.dentry = parent;
- nd->seq = seq;
- if (unlikely(!path_connected(&nd->path)))
- return -ECHILD;
- break;
- } else {
- struct mount *mnt = real_mount(nd->path.mnt);
- struct mount *mparent = mnt->mnt_parent;
- struct dentry *mountpoint = mnt->mnt_mountpoint;
- struct inode *inode2 = mountpoint->d_inode;
- unsigned seq = read_seqcount_begin(&mountpoint->d_seq);
- if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
- return -ECHILD;
- if (&mparent->mnt == nd->path.mnt)
- break;
- /* we know that mountpoint was pinned */
- nd->path.dentry = mountpoint;
- nd->path.mnt = &mparent->mnt;
- inode = inode2;
- nd->seq = seq;
+ if (flags & DCACHE_MOUNTED) {
+ struct mount *mounted = __lookup_mnt(path->mnt, dentry);
+ if (mounted) {
+ path->mnt = &mounted->mnt;
+ dentry = path->dentry = mounted->mnt.mnt_root;
+ nd->flags |= LOOKUP_JUMPED;
+ *seqp = read_seqcount_begin(&dentry->d_seq);
+ *inode = dentry->d_inode;
+ /*
+ * We don't need to re-check ->d_seq after this
+ * ->d_inode read - there will be an RCU delay
+ * between mount hash removal and ->mnt_root
+ * becoming unpinned.
+ */
+ flags = dentry->d_flags;
+ if (read_seqretry(&mount_lock, nd->m_seq))
+ return false;
+ continue;
+ }
+ if (read_seqretry(&mount_lock, nd->m_seq))
+ return false;
}
+ return !(flags & DCACHE_NEED_AUTOMOUNT);
}
- while (unlikely(d_mountpoint(nd->path.dentry))) {
- struct mount *mounted;
- mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);
- if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
- return -ECHILD;
- if (!mounted)
- break;
- nd->path.mnt = &mounted->mnt;
- nd->path.dentry = mounted->mnt.mnt_root;
- inode = nd->path.dentry->d_inode;
- nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
- }
- nd->inode = inode;
- return 0;
}
-/*
- * Follow down to the covering mount currently visible to userspace. At each
- * point, the filesystem owning that dentry may be queried as to whether the
- * caller is permitted to proceed or not.
- */
-int follow_down(struct path *path)
+static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry,
+ struct path *path, struct inode **inode,
+ unsigned int *seqp)
{
- unsigned managed;
+ bool jumped;
int ret;
- while (managed = READ_ONCE(path->dentry->d_flags),
- unlikely(managed & DCACHE_MANAGED_DENTRY)) {
- /* Allow the filesystem to manage the transit without i_mutex
- * being held.
- *
- * We indicate to the filesystem if someone is trying to mount
- * something here. This gives autofs the chance to deny anyone
- * other than its daemon the right to mount on its
- * superstructure.
- *
- * The filesystem may sleep at this point.
- */
- if (managed & DCACHE_MANAGE_TRANSIT) {
- BUG_ON(!path->dentry->d_op);
- BUG_ON(!path->dentry->d_op->d_manage);
- ret = path->dentry->d_op->d_manage(path, false);
- if (ret < 0)
- return ret == -EISDIR ? 0 : ret;
- }
-
- /* Transit to a mounted filesystem. */
- if (managed & DCACHE_MOUNTED) {
- struct vfsmount *mounted = lookup_mnt(path);
- if (!mounted)
- break;
- dput(path->dentry);
- mntput(path->mnt);
- path->mnt = mounted;
- path->dentry = dget(mounted->mnt_root);
- continue;
- }
-
- /* Don't handle automount points here */
- break;
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ if (nd->flags & LOOKUP_RCU) {
+ unsigned int seq = *seqp;
+ if (unlikely(!*inode))
+ return -ENOENT;
+ if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
+ return 0;
+ if (!try_to_unlazy_next(nd, dentry, seq))
+ return -ECHILD;
+ // *path might've been clobbered by __follow_mount_rcu()
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
}
- return 0;
-}
-EXPORT_SYMBOL(follow_down);
-
-/*
- * Skip to top of mountpoint pile in refwalk mode for follow_dotdot()
- */
-static void follow_mount(struct path *path)
-{
- while (d_mountpoint(path->dentry)) {
- struct vfsmount *mounted = lookup_mnt(path);
- if (!mounted)
- break;
+ ret = traverse_mounts(path, &jumped, &nd->total_link_count, nd->flags);
+ if (jumped) {
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV))
+ ret = -EXDEV;
+ else
+ nd->flags |= LOOKUP_JUMPED;
+ }
+ if (unlikely(ret)) {
dput(path->dentry);
- mntput(path->mnt);
- path->mnt = mounted;
- path->dentry = dget(mounted->mnt_root);
+ if (path->mnt != nd->path.mnt)
+ mntput(path->mnt);
+ } else {
+ *inode = d_backing_inode(path->dentry);
+ *seqp = 0; /* out of RCU mode, so the value doesn't matter */
}
-}
-
-static int path_parent_directory(struct path *path)
-{
- struct dentry *old = path->dentry;
- /* rare case of legitimate dget_parent()... */
- path->dentry = dget_parent(path->dentry);
- dput(old);
- if (unlikely(!path_connected(path)))
- return -ENOENT;
- return 0;
-}
-
-static int follow_dotdot(struct nameidata *nd)
-{
- while(1) {
- if (path_equal(&nd->path, &nd->root))
- break;
- if (nd->path.dentry != nd->path.mnt->mnt_root) {
- int ret = path_parent_directory(&nd->path);
- if (ret)
- return ret;
- break;
- }
- if (!follow_up(&nd->path))
- break;
- }
- follow_mount(&nd->path);
- nd->inode = nd->path.dentry->d_inode;
- return 0;
+ return ret;
}
/*
@@ -1646,14 +1546,12 @@
return dentry;
}
-static int lookup_fast(struct nameidata *nd,
- struct path *path, struct inode **inode,
- unsigned *seqp)
+static struct dentry *lookup_fast(struct nameidata *nd,
+ struct inode **inode,
+ unsigned *seqp)
{
- struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
int status = 1;
- int err;
/*
* Rename seqlock is not required here because in the off chance
@@ -1662,12 +1560,11 @@
*/
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
- bool negative;
dentry = __d_lookup_rcu(parent, &nd->last, &seq);
if (unlikely(!dentry)) {
- if (unlazy_walk(nd))
- return -ECHILD;
- return 0;
+ if (!try_to_unlazy(nd))
+ return ERR_PTR(-ECHILD);
+ return NULL;
}
/*
@@ -1675,9 +1572,8 @@
* the dentry name information from lookup.
*/
*inode = d_backing_inode(dentry);
- negative = d_is_negative(dentry);
if (unlikely(read_seqcount_retry(&dentry->d_seq, seq)))
- return -ECHILD;
+ return ERR_PTR(-ECHILD);
/*
* This sequence count validates that the parent had no
@@ -1687,50 +1583,30 @@
* enough, we can use __read_seqcount_retry here.
*/
if (unlikely(__read_seqcount_retry(&parent->d_seq, nd->seq)))
- return -ECHILD;
+ return ERR_PTR(-ECHILD);
*seqp = seq;
status = d_revalidate(dentry, nd->flags);
- if (likely(status > 0)) {
- /*
- * Note: do negative dentry check after revalidation in
- * case that drops it.
- */
- if (unlikely(negative))
- return -ENOENT;
- path->mnt = mnt;
- path->dentry = dentry;
- if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
- return 1;
- }
- if (unlazy_child(nd, dentry, seq))
- return -ECHILD;
+ if (likely(status > 0))
+ return dentry;
+ if (!try_to_unlazy_next(nd, dentry, seq))
+ return ERR_PTR(-ECHILD);
if (unlikely(status == -ECHILD))
/* we'd been told to redo it in non-rcu mode */
status = d_revalidate(dentry, nd->flags);
} else {
dentry = __d_lookup(parent, &nd->last);
if (unlikely(!dentry))
- return 0;
+ return NULL;
status = d_revalidate(dentry, nd->flags);
}
if (unlikely(status <= 0)) {
if (!status)
d_invalidate(dentry);
dput(dentry);
- return status;
+ return ERR_PTR(status);
}
- if (unlikely(d_is_negative(dentry))) {
- dput(dentry);
- return -ENOENT;
- }
-
- path->mnt = mnt;
- path->dentry = dentry;
- err = follow_managed(path, nd);
- if (likely(err > 0))
- *inode = d_backing_inode(path->dentry);
- return err;
+ return dentry;
}
/* Fast lookup failed, do it the slow way */
@@ -1750,17 +1626,15 @@
if (IS_ERR(dentry))
return dentry;
if (unlikely(!d_in_lookup(dentry))) {
- if (!(flags & LOOKUP_NO_REVAL)) {
- int error = d_revalidate(dentry, flags);
- if (unlikely(error <= 0)) {
- if (!error) {
- d_invalidate(dentry);
- dput(dentry);
- goto again;
- }
+ int error = d_revalidate(dentry, flags);
+ if (unlikely(error <= 0)) {
+ if (!error) {
+ d_invalidate(dentry);
dput(dentry);
- dentry = ERR_PTR(error);
+ goto again;
}
+ dput(dentry);
+ dentry = ERR_PTR(error);
}
} else {
old = inode->i_op->lookup(inode, dentry, flags);
@@ -1788,71 +1662,112 @@
static inline int may_lookup(struct nameidata *nd)
{
if (nd->flags & LOOKUP_RCU) {
- int err = inode_permission2(nd->path.mnt, nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
- if (err != -ECHILD)
+ int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
+ if (err != -ECHILD || !try_to_unlazy(nd))
return err;
- if (unlazy_walk(nd))
- return -ECHILD;
}
- return inode_permission2(nd->path.mnt, nd->inode, MAY_EXEC);
+ return inode_permission(nd->inode, MAY_EXEC);
}
-static inline int handle_dots(struct nameidata *nd, int type)
+static int reserve_stack(struct nameidata *nd, struct path *link, unsigned seq)
{
- if (type == LAST_DOTDOT) {
- if (!nd->root.mnt)
- set_root(nd);
- if (nd->flags & LOOKUP_RCU) {
- return follow_dotdot_rcu(nd);
- } else
- return follow_dotdot(nd);
- }
- return 0;
-}
-
-static int pick_link(struct nameidata *nd, struct path *link,
- struct inode *inode, unsigned seq)
-{
- int error;
- struct saved *last;
- if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {
- path_to_nameidata(link, nd);
+ if (unlikely(nd->total_link_count++ >= MAXSYMLINKS))
return -ELOOP;
- }
- if (!(nd->flags & LOOKUP_RCU)) {
- if (link->mnt == nd->path.mnt)
- mntget(link->mnt);
- }
- error = nd_alloc_stack(nd);
- if (unlikely(error)) {
- if (error == -ECHILD) {
- if (unlikely(!legitimize_path(nd, link, seq))) {
- drop_links(nd);
- nd->depth = 0;
- nd->flags &= ~LOOKUP_RCU;
- nd->path.mnt = NULL;
- nd->path.dentry = NULL;
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
- rcu_read_unlock();
- } else if (likely(unlazy_walk(nd)) == 0)
- error = nd_alloc_stack(nd);
- }
- if (error) {
- path_put(link);
- return error;
- }
- }
+ if (likely(nd->depth != EMBEDDED_LEVELS))
+ return 0;
+ if (likely(nd->stack != nd->internal))
+ return 0;
+ if (likely(nd_alloc_stack(nd)))
+ return 0;
+
+ if (nd->flags & LOOKUP_RCU) {
+ // we need to grab link before we do unlazy. And we can't skip
+ // unlazy even if we fail to grab the link - cleanup needs it
+ bool grabbed_link = legitimize_path(nd, link, seq);
+
+ if (!try_to_unlazy(nd) != 0 || !grabbed_link)
+ return -ECHILD;
+
+ if (nd_alloc_stack(nd))
+ return 0;
+ }
+ return -ENOMEM;
+}
+
+enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};
+
+static const char *pick_link(struct nameidata *nd, struct path *link,
+ struct inode *inode, unsigned seq, int flags)
+{
+ struct saved *last;
+ const char *res;
+ int error = reserve_stack(nd, link, seq);
+
+ if (unlikely(error)) {
+ if (!(nd->flags & LOOKUP_RCU))
+ path_put(link);
+ return ERR_PTR(error);
+ }
last = nd->stack + nd->depth++;
last->link = *link;
clear_delayed_call(&last->done);
- nd->link_inode = inode;
last->seq = seq;
- return 1;
-}
-enum {WALK_FOLLOW = 1, WALK_MORE = 2};
+ if (flags & WALK_TRAILING) {
+ error = may_follow_link(nd, inode);
+ if (unlikely(error))
+ return ERR_PTR(error);
+ }
+
+ if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS) ||
+ unlikely(link->mnt->mnt_flags & MNT_NOSYMFOLLOW))
+ return ERR_PTR(-ELOOP);
+
+ if (!(nd->flags & LOOKUP_RCU)) {
+ touch_atime(&last->link);
+ cond_resched();
+ } else if (atime_needs_update(&last->link, inode)) {
+ if (!try_to_unlazy(nd))
+ return ERR_PTR(-ECHILD);
+ touch_atime(&last->link);
+ }
+
+ error = security_inode_follow_link(link->dentry, inode,
+ nd->flags & LOOKUP_RCU);
+ if (unlikely(error))
+ return ERR_PTR(error);
+
+ res = READ_ONCE(inode->i_link);
+ if (!res) {
+ const char * (*get)(struct dentry *, struct inode *,
+ struct delayed_call *);
+ get = inode->i_op->get_link;
+ if (nd->flags & LOOKUP_RCU) {
+ res = get(NULL, inode, &last->done);
+ if (res == ERR_PTR(-ECHILD) && try_to_unlazy(nd))
+ res = get(link->dentry, inode, &last->done);
+ } else {
+ res = get(link->dentry, inode, &last->done);
+ }
+ if (!res)
+ goto all_done;
+ if (IS_ERR(res))
+ return res;
+ }
+ if (*res == '/') {
+ error = nd_jump_root(nd);
+ if (unlikely(error))
+ return ERR_PTR(error);
+ while (unlikely(*++res == '/'))
+ ;
+ }
+ if (*res)
+ return res;
+all_done: // pure jump
+ put_link(nd);
+ return NULL;
+}
/*
* Do we need to follow links? We _really_ want to be able
@@ -1860,68 +1775,187 @@
* so we keep a cache of "no, this doesn't need follow_link"
* for the common case.
*/
-static inline int step_into(struct nameidata *nd, struct path *path,
- int flags, struct inode *inode, unsigned seq)
-{
- if (!(flags & WALK_MORE) && nd->depth)
- put_link(nd);
- if (likely(!d_is_symlink(path->dentry)) ||
- !(flags & WALK_FOLLOW || nd->flags & LOOKUP_FOLLOW)) {
- /* not a symlink or should not follow */
- path_to_nameidata(path, nd);
- nd->inode = inode;
- nd->seq = seq;
- return 0;
- }
- /* make sure that d_is_symlink above matches inode */
- if (nd->flags & LOOKUP_RCU) {
- if (read_seqcount_retry(&path->dentry->d_seq, seq))
- return -ECHILD;
- }
- return pick_link(nd, path, inode, seq);
-}
-
-static int walk_component(struct nameidata *nd, int flags)
+static const char *step_into(struct nameidata *nd, int flags,
+ struct dentry *dentry, struct inode *inode, unsigned seq)
{
struct path path;
+ int err = handle_mounts(nd, dentry, &path, &inode, &seq);
+
+ if (err < 0)
+ return ERR_PTR(err);
+ if (likely(!d_is_symlink(path.dentry)) ||
+ ((flags & WALK_TRAILING) && !(nd->flags & LOOKUP_FOLLOW)) ||
+ (flags & WALK_NOFOLLOW)) {
+ /* not a symlink or should not follow */
+ if (!(nd->flags & LOOKUP_RCU)) {
+ dput(nd->path.dentry);
+ if (nd->path.mnt != path.mnt)
+ mntput(nd->path.mnt);
+ }
+ nd->path = path;
+ nd->inode = inode;
+ nd->seq = seq;
+ return NULL;
+ }
+ if (nd->flags & LOOKUP_RCU) {
+ /* make sure that d_is_symlink above matches inode */
+ if (read_seqcount_retry(&path.dentry->d_seq, seq))
+ return ERR_PTR(-ECHILD);
+ } else {
+ if (path.mnt == nd->path.mnt)
+ mntget(path.mnt);
+ }
+ return pick_link(nd, &path, inode, seq, flags);
+}
+
+static struct dentry *follow_dotdot_rcu(struct nameidata *nd,
+ struct inode **inodep,
+ unsigned *seqp)
+{
+ struct dentry *parent, *old;
+
+ if (path_equal(&nd->path, &nd->root))
+ goto in_root;
+ if (unlikely(nd->path.dentry == nd->path.mnt->mnt_root)) {
+ struct path path;
+ unsigned seq;
+ if (!choose_mountpoint_rcu(real_mount(nd->path.mnt),
+ &nd->root, &path, &seq))
+ goto in_root;
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV))
+ return ERR_PTR(-ECHILD);
+ nd->path = path;
+ nd->inode = path.dentry->d_inode;
+ nd->seq = seq;
+ if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
+ return ERR_PTR(-ECHILD);
+ /* we know that mountpoint was pinned */
+ }
+ old = nd->path.dentry;
+ parent = old->d_parent;
+ *inodep = parent->d_inode;
+ *seqp = read_seqcount_begin(&parent->d_seq);
+ if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq)))
+ return ERR_PTR(-ECHILD);
+ if (unlikely(!path_connected(nd->path.mnt, parent)))
+ return ERR_PTR(-ECHILD);
+ return parent;
+in_root:
+ if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
+ return ERR_PTR(-ECHILD);
+ if (unlikely(nd->flags & LOOKUP_BENEATH))
+ return ERR_PTR(-ECHILD);
+ return NULL;
+}
+
+static struct dentry *follow_dotdot(struct nameidata *nd,
+ struct inode **inodep,
+ unsigned *seqp)
+{
+ struct dentry *parent;
+
+ if (path_equal(&nd->path, &nd->root))
+ goto in_root;
+ if (unlikely(nd->path.dentry == nd->path.mnt->mnt_root)) {
+ struct path path;
+
+ if (!choose_mountpoint(real_mount(nd->path.mnt),
+ &nd->root, &path))
+ goto in_root;
+ path_put(&nd->path);
+ nd->path = path;
+ nd->inode = path.dentry->d_inode;
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV))
+ return ERR_PTR(-EXDEV);
+ }
+ /* rare case of legitimate dget_parent()... */
+ parent = dget_parent(nd->path.dentry);
+ if (unlikely(!path_connected(nd->path.mnt, parent))) {
+ dput(parent);
+ return ERR_PTR(-ENOENT);
+ }
+ *seqp = 0;
+ *inodep = parent->d_inode;
+ return parent;
+
+in_root:
+ if (unlikely(nd->flags & LOOKUP_BENEATH))
+ return ERR_PTR(-EXDEV);
+ dget(nd->path.dentry);
+ return NULL;
+}
+
+static const char *handle_dots(struct nameidata *nd, int type)
+{
+ if (type == LAST_DOTDOT) {
+ const char *error = NULL;
+ struct dentry *parent;
+ struct inode *inode;
+ unsigned seq;
+
+ if (!nd->root.mnt) {
+ error = ERR_PTR(set_root(nd));
+ if (error)
+ return error;
+ }
+ if (nd->flags & LOOKUP_RCU)
+ parent = follow_dotdot_rcu(nd, &inode, &seq);
+ else
+ parent = follow_dotdot(nd, &inode, &seq);
+ if (IS_ERR(parent))
+ return ERR_CAST(parent);
+ if (unlikely(!parent))
+ error = step_into(nd, WALK_NOFOLLOW,
+ nd->path.dentry, nd->inode, nd->seq);
+ else
+ error = step_into(nd, WALK_NOFOLLOW,
+ parent, inode, seq);
+ if (unlikely(error))
+ return error;
+
+ if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) {
+ /*
+ * If there was a racing rename or mount along our
+ * path, then we can't be sure that ".." hasn't jumped
+ * above nd->root (and so userspace should retry or use
+ * some fallback).
+ */
+ smp_rmb();
+ if (unlikely(__read_seqcount_retry(&mount_lock.seqcount, nd->m_seq)))
+ return ERR_PTR(-EAGAIN);
+ if (unlikely(__read_seqcount_retry(&rename_lock.seqcount, nd->r_seq)))
+ return ERR_PTR(-EAGAIN);
+ }
+ }
+ return NULL;
+}
+
+static const char *walk_component(struct nameidata *nd, int flags)
+{
+ struct dentry *dentry;
struct inode *inode;
unsigned seq;
- int err;
/*
* "." and ".." are special - ".." especially so because it has
* to be able to know about the current root directory and
* parent relationships.
*/
if (unlikely(nd->last_type != LAST_NORM)) {
- err = handle_dots(nd, nd->last_type);
if (!(flags & WALK_MORE) && nd->depth)
put_link(nd);
- return err;
+ return handle_dots(nd, nd->last_type);
}
- err = lookup_fast(nd, &path, &inode, &seq);
- if (unlikely(err <= 0)) {
- if (err < 0)
- return err;
- path.dentry = lookup_slow(&nd->last, nd->path.dentry,
- nd->flags);
- if (IS_ERR(path.dentry))
- return PTR_ERR(path.dentry);
-
- path.mnt = nd->path.mnt;
- err = follow_managed(&path, nd);
- if (unlikely(err < 0))
- return err;
-
- if (unlikely(d_is_negative(path.dentry))) {
- path_to_nameidata(&path, nd);
- return -ENOENT;
- }
-
- seq = 0; /* we are already out of RCU mode */
- inode = d_backing_inode(path.dentry);
+ dentry = lookup_fast(nd, &inode, &seq);
+ if (IS_ERR(dentry))
+ return ERR_CAST(dentry);
+ if (unlikely(!dentry)) {
+ dentry = lookup_slow(&nd->last, nd->path.dentry, nd->flags);
+ if (IS_ERR(dentry))
+ return ERR_CAST(dentry);
}
-
- return step_into(nd, &path, flags, inode, seq);
+ if (!(flags & WALK_MORE) && nd->depth)
+ put_link(nd);
+ return step_into(nd, flags, dentry, inode, seq);
}
/*
@@ -2162,8 +2196,11 @@
*/
static int link_path_walk(const char *name, struct nameidata *nd)
{
+ int depth = 0; // depth <= nd->depth
int err;
+ nd->last_type = LAST_ROOT;
+ nd->flags |= LOOKUP_PARENT;
if (IS_ERR(name))
return PTR_ERR(name);
while (*name=='/')
@@ -2173,6 +2210,7 @@
/* At this point we know we have a real path component. */
for(;;) {
+ const char *link;
u64 hash_len;
int type;
@@ -2222,40 +2260,31 @@
} while (unlikely(*name == '/'));
if (unlikely(!*name)) {
OK:
- /* pathname body, done */
- if (!nd->depth)
+ /* pathname or trailing symlink, done */
+ if (!depth) {
+ nd->dir_uid = nd->inode->i_uid;
+ nd->dir_mode = nd->inode->i_mode;
+ nd->flags &= ~LOOKUP_PARENT;
return 0;
- name = nd->stack[nd->depth - 1].name;
- /* trailing symlink, done */
- if (!name)
- return 0;
+ }
/* last component of nested symlink */
- err = walk_component(nd, WALK_FOLLOW);
+ name = nd->stack[--depth].name;
+ link = walk_component(nd, 0);
} else {
/* not the last component */
- err = walk_component(nd, WALK_FOLLOW | WALK_MORE);
+ link = walk_component(nd, WALK_MORE);
}
- if (err < 0)
- return err;
-
- if (err) {
- const char *s = get_link(nd);
-
- if (IS_ERR(s))
- return PTR_ERR(s);
- err = 0;
- if (unlikely(!s)) {
- /* jumped */
- put_link(nd);
- } else {
- nd->stack[nd->depth - 1].name = name;
- name = s;
- continue;
- }
+ if (unlikely(link)) {
+ if (IS_ERR(link))
+ return PTR_ERR(link);
+ /* a symlink to follow */
+ nd->stack[depth++].name = name;
+ name = link;
+ continue;
}
if (unlikely(!d_can_lookup(nd->path.dentry))) {
if (nd->flags & LOOKUP_RCU) {
- if (unlazy_walk(nd))
+ if (!try_to_unlazy(nd))
return -ECHILD;
}
return -ENOTDIR;
@@ -2266,16 +2295,25 @@
/* must be paired with terminate_walk() */
static const char *path_init(struct nameidata *nd, unsigned flags)
{
+ int error;
const char *s = nd->name->name;
+
+ /* LOOKUP_CACHED requires RCU, ask caller to retry */
+ if ((flags & (LOOKUP_RCU | LOOKUP_CACHED)) == LOOKUP_CACHED)
+ return ERR_PTR(-EAGAIN);
if (!*s)
flags &= ~LOOKUP_RCU;
if (flags & LOOKUP_RCU)
rcu_read_lock();
- nd->last_type = LAST_ROOT; /* if there are only slashes... */
- nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
+ nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;
+
+ nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
+ nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount);
+ smp_rmb();
+
if (flags & LOOKUP_ROOT) {
struct dentry *root = nd->root.dentry;
struct inode *inode = root->d_inode;
@@ -2284,9 +2322,8 @@
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
- nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
nd->root_seq = nd->seq;
- nd->m_seq = read_seqbegin(&mount_lock);
} else {
path_get(&nd->path);
}
@@ -2294,16 +2331,17 @@
}
nd->root.mnt = NULL;
- nd->path.mnt = NULL;
- nd->path.dentry = NULL;
- nd->m_seq = read_seqbegin(&mount_lock);
- if (*s == '/') {
- set_root(nd);
- if (likely(!nd_jump_root(nd)))
- return s;
- return ERR_PTR(-ECHILD);
- } else if (nd->dfd == AT_FDCWD) {
+ /* Absolute pathname -- fetch the root (LOOKUP_IN_ROOT uses nd->dfd). */
+ if (*s == '/' && !(flags & LOOKUP_IN_ROOT)) {
+ error = nd_jump_root(nd);
+ if (unlikely(error))
+ return ERR_PTR(error);
+ return s;
+ }
+
+ /* Relative pathname -- get the starting-point it is relative to. */
+ if (nd->dfd == AT_FDCWD) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
@@ -2318,7 +2356,6 @@
get_fs_pwd(current->fs, &nd->path);
nd->inode = nd->path.dentry->d_inode;
}
- return s;
} else {
/* Caller must check execute permissions on the starting path component */
struct fd f = fdget_raw(nd->dfd);
@@ -2343,58 +2380,35 @@
nd->inode = nd->path.dentry->d_inode;
}
fdput(f);
- return s;
}
+
+ /* For scoped-lookups we need to set the root to the dirfd as well. */
+ if (flags & LOOKUP_IS_SCOPED) {
+ nd->root = nd->path;
+ if (flags & LOOKUP_RCU) {
+ nd->root_seq = nd->seq;
+ } else {
+ path_get(&nd->root);
+ nd->flags |= LOOKUP_ROOT_GRABBED;
+ }
+ }
+ return s;
}
-static const char *trailing_symlink(struct nameidata *nd)
-{
- const char *s;
- int error = may_follow_link(nd);
- if (unlikely(error))
- return ERR_PTR(error);
- nd->flags |= LOOKUP_PARENT;
- nd->stack[0].name = NULL;
- s = get_link(nd);
- return s ? s : "";
-}
-
-static inline int lookup_last(struct nameidata *nd)
+static inline const char *lookup_last(struct nameidata *nd)
{
if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
- nd->flags &= ~LOOKUP_PARENT;
- return walk_component(nd, 0);
+ return walk_component(nd, WALK_TRAILING);
}
static int handle_lookup_down(struct nameidata *nd)
{
- struct path path = nd->path;
- struct inode *inode = nd->inode;
- unsigned seq = nd->seq;
- int err;
-
- if (nd->flags & LOOKUP_RCU) {
- /*
- * don't bother with unlazy_walk on failure - we are
- * at the very beginning of walk, so we lose nothing
- * if we simply redo everything in non-RCU mode
- */
- if (unlikely(!__follow_mount_rcu(nd, &path, &inode, &seq)))
- return -ECHILD;
- } else {
- dget(path.dentry);
- err = follow_managed(&path, nd);
- if (unlikely(err < 0))
- return err;
- inode = d_backing_inode(path.dentry);
- seq = 0;
- }
- path_to_nameidata(&path, nd);
- nd->inode = inode;
- nd->seq = seq;
- return 0;
+ if (!(nd->flags & LOOKUP_RCU))
+ dget(nd->path.dentry);
+ return PTR_ERR(step_into(nd, WALK_NOFOLLOW,
+ nd->path.dentry, nd->inode, nd->seq));
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
@@ -2409,9 +2423,12 @@
s = ERR_PTR(err);
}
- while (!(err = link_path_walk(s, nd))
- && ((err = lookup_last(nd)) > 0)) {
- s = trailing_symlink(nd);
+ while (!(err = link_path_walk(s, nd)) &&
+ (s = lookup_last(nd)) != NULL)
+ ;
+ if (!err && unlikely(nd->flags & LOOKUP_MOUNTPOINT)) {
+ err = handle_lookup_down(nd);
+ nd->flags &= ~LOOKUP_JUMPED; // no d_weak_revalidate(), please...
}
if (!err)
err = complete_walk(nd);
@@ -2428,8 +2445,8 @@
return err;
}
-static int filename_lookup(int dfd, struct filename *name, unsigned flags,
- struct path *path, struct path *root)
+int filename_lookup(int dfd, struct filename *name, unsigned flags,
+ struct path *path, struct path *root)
{
int retval;
struct nameidata nd;
@@ -2447,7 +2464,8 @@
retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path);
if (likely(!retval))
- audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
+ audit_inode(name, path->dentry,
+ flags & LOOKUP_MOUNTPOINT ? AUDIT_INODE_NOEVAL : 0);
restore_nameidata();
putname(name);
return retval;
@@ -2488,7 +2506,7 @@
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
- audit_inode(name, parent->dentry, LOOKUP_PARENT);
+ audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
} else {
putname(name);
name = ERR_PTR(retval);
@@ -2550,8 +2568,8 @@
}
EXPORT_SYMBOL(vfs_path_lookup);
-static int lookup_one_len_common(const char *name, struct vfsmount *mnt,
- struct dentry *base, int len, struct qstr *this)
+static int lookup_one_len_common(const char *name, struct dentry *base,
+ int len, struct qstr *this)
{
this->name = name;
this->len = len;
@@ -2579,7 +2597,7 @@
return err;
}
- return inode_permission2(mnt, base->d_inode, MAY_EXEC);
+ return inode_permission(base->d_inode, MAY_EXEC);
}
/**
@@ -2603,7 +2621,7 @@
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
- err = lookup_one_len_common(name, NULL, base, len, &this);
+ err = lookup_one_len_common(name, base, len, &this);
if (err)
return ERR_PTR(err);
@@ -2622,7 +2640,7 @@
*
* The caller must hold base->i_mutex.
*/
-struct dentry *lookup_one_len2(const char *name, struct vfsmount *mnt, struct dentry *base, int len)
+struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
{
struct dentry *dentry;
struct qstr this;
@@ -2630,18 +2648,12 @@
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
- err = lookup_one_len_common(name, mnt, base, len, &this);
+ err = lookup_one_len_common(name, base, len, &this);
if (err)
return ERR_PTR(err);
dentry = lookup_dcache(&this, base, 0);
return dentry ? dentry : __lookup_slow(&this, base, 0);
-}
-EXPORT_SYMBOL(lookup_one_len2);
-
-struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
-{
- return lookup_one_len2(name, NULL, base, len);
}
EXPORT_SYMBOL(lookup_one_len);
@@ -2664,7 +2676,7 @@
int err;
struct dentry *ret;
- err = lookup_one_len_common(name, NULL, base, len, &this);
+ err = lookup_one_len_common(name, base, len, &this);
if (err)
return ERR_PTR(err);
@@ -2675,30 +2687,49 @@
}
EXPORT_SYMBOL(lookup_one_len_unlocked);
+/*
+ * Like lookup_one_len_unlocked(), except that it yields ERR_PTR(-ENOENT)
+ * on negatives. Returns known positive or ERR_PTR(); that's what
+ * most of the users want. Note that pinned negative with unlocked parent
+ * _can_ become positive at any time, so callers of lookup_one_len_unlocked()
+ * need to be very careful; pinned positives have ->d_inode stable, so
+ * this one avoids such problems.
+ */
+struct dentry *lookup_positive_unlocked(const char *name,
+ struct dentry *base, int len)
+{
+ struct dentry *ret = lookup_one_len_unlocked(name, base, len);
+ if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
+ dput(ret);
+ ret = ERR_PTR(-ENOENT);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(lookup_positive_unlocked);
+
#ifdef CONFIG_UNIX98_PTYS
int path_pts(struct path *path)
{
/* Find something mounted on "pts" in the same directory as
* the input path.
*/
- struct dentry *child, *parent;
- struct qstr this;
- int ret;
+ struct dentry *parent = dget_parent(path->dentry);
+ struct dentry *child;
+ struct qstr this = QSTR_INIT("pts", 3);
- ret = path_parent_directory(path);
- if (ret)
- return ret;
-
- parent = path->dentry;
- this.name = "pts";
- this.len = 3;
+ if (unlikely(!path_connected(path->mnt, parent))) {
+ dput(parent);
+ return -ENOENT;
+ }
+ dput(path->dentry);
+ path->dentry = parent;
child = d_hash_and_lookup(parent, &this);
- if (!child)
+ if (IS_ERR_OR_NULL(child))
return -ENOENT;
path->dentry = child;
dput(parent);
- follow_mount(path);
+ follow_down(path);
return 0;
}
#endif
@@ -2710,151 +2741,6 @@
flags, path, NULL);
}
EXPORT_SYMBOL(user_path_at_empty);
-
-/**
- * mountpoint_last - look up last component for umount
- * @nd: pathwalk nameidata - currently pointing at parent directory of "last"
- *
- * This is a special lookup_last function just for umount. In this case, we
- * need to resolve the path without doing any revalidation.
- *
- * The nameidata should be the result of doing a LOOKUP_PARENT pathwalk. Since
- * mountpoints are always pinned in the dcache, their ancestors are too. Thus,
- * in almost all cases, this lookup will be served out of the dcache. The only
- * cases where it won't are if nd->last refers to a symlink or the path is
- * bogus and it doesn't exist.
- *
- * Returns:
- * -error: if there was an error during lookup. This includes -ENOENT if the
- * lookup found a negative dentry.
- *
- * 0: if we successfully resolved nd->last and found it to not to be a
- * symlink that needs to be followed.
- *
- * 1: if we successfully resolved nd->last and found it to be a symlink
- * that needs to be followed.
- */
-static int
-mountpoint_last(struct nameidata *nd)
-{
- int error = 0;
- struct dentry *dir = nd->path.dentry;
- struct path path;
-
- /* If we're in rcuwalk, drop out of it to handle last component */
- if (nd->flags & LOOKUP_RCU) {
- if (unlazy_walk(nd))
- return -ECHILD;
- }
-
- nd->flags &= ~LOOKUP_PARENT;
-
- if (unlikely(nd->last_type != LAST_NORM)) {
- error = handle_dots(nd, nd->last_type);
- if (error)
- return error;
- path.dentry = dget(nd->path.dentry);
- } else {
- path.dentry = d_lookup(dir, &nd->last);
- if (!path.dentry) {
- /*
- * No cached dentry. Mounted dentries are pinned in the
- * cache, so that means that this dentry is probably
- * a symlink or the path doesn't actually point
- * to a mounted dentry.
- */
- path.dentry = lookup_slow(&nd->last, dir,
- nd->flags | LOOKUP_NO_REVAL);
- if (IS_ERR(path.dentry))
- return PTR_ERR(path.dentry);
- }
- }
- if (d_is_negative(path.dentry)) {
- dput(path.dentry);
- return -ENOENT;
- }
- path.mnt = nd->path.mnt;
- return step_into(nd, &path, 0, d_backing_inode(path.dentry), 0);
-}
-
-/**
- * path_mountpoint - look up a path to be umounted
- * @nd: lookup context
- * @flags: lookup flags
- * @path: pointer to container for result
- *
- * Look up the given name, but don't attempt to revalidate the last component.
- * Returns 0 and "path" will be valid on success; Returns error otherwise.
- */
-static int
-path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path)
-{
- const char *s = path_init(nd, flags);
- int err;
-
- while (!(err = link_path_walk(s, nd)) &&
- (err = mountpoint_last(nd)) > 0) {
- s = trailing_symlink(nd);
- }
- if (!err) {
- *path = nd->path;
- nd->path.mnt = NULL;
- nd->path.dentry = NULL;
- follow_mount(path);
- }
- terminate_walk(nd);
- return err;
-}
-
-static int
-filename_mountpoint(int dfd, struct filename *name, struct path *path,
- unsigned int flags)
-{
- struct nameidata nd;
- int error;
- if (IS_ERR(name))
- return PTR_ERR(name);
- set_nameidata(&nd, dfd, name);
- error = path_mountpoint(&nd, flags | LOOKUP_RCU, path);
- if (unlikely(error == -ECHILD))
- error = path_mountpoint(&nd, flags, path);
- if (unlikely(error == -ESTALE))
- error = path_mountpoint(&nd, flags | LOOKUP_REVAL, path);
- if (likely(!error))
- audit_inode(name, path->dentry, 0);
- restore_nameidata();
- putname(name);
- return error;
-}
-
-/**
- * user_path_mountpoint_at - lookup a path from userland in order to umount it
- * @dfd: directory file descriptor
- * @name: pathname from userland
- * @flags: lookup flags
- * @path: pointer to container to hold result
- *
- * A umount is a special case for path walking. We're not actually interested
- * in the inode in this situation, and ESTALE errors can be a problem. We
- * simply want track down the dentry and vfsmount attached at the mountpoint
- * and avoid revalidating the last component.
- *
- * Returns 0 and populates "path" on success.
- */
-int
-user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags,
- struct path *path)
-{
- return filename_mountpoint(dfd, getname(name), path, flags);
-}
-
-int
-kern_path_mountpoint(int dfd, const char *name, struct path *path,
- unsigned int flags)
-{
- return filename_mountpoint(dfd, getname_kernel(name), path, flags);
-}
-EXPORT_SYMBOL(kern_path_mountpoint);
int __check_sticky(struct inode *dir, struct inode *inode)
{
@@ -2888,7 +2774,7 @@
* 11. We don't allow removal of NFS sillyrenamed files; it's handled by
* nfs_async_unlink().
*/
-static int may_delete(struct vfsmount *mnt, struct inode *dir, struct dentry *victim, bool isdir)
+static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
{
struct inode *inode = d_backing_inode(victim);
int error;
@@ -2905,7 +2791,7 @@
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
- error = inode_permission2(mnt, dir, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
return error;
if (IS_APPEND(dir))
@@ -2937,7 +2823,7 @@
* 4. We should have write and exec permissions on dir
* 5. We can't do it if dir is immutable (done in permission())
*/
-static inline int may_create(struct vfsmount *mnt, struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child)
{
struct user_namespace *s_user_ns;
audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
@@ -2949,7 +2835,7 @@
if (!kuid_has_mapping(s_user_ns, current_fsuid()) ||
!kgid_has_mapping(s_user_ns, current_fsgid()))
return -EOVERFLOW;
- return inode_permission2(mnt, dir, MAY_WRITE | MAY_EXEC);
+ return inode_permission(dir, MAY_WRITE | MAY_EXEC);
}
/*
@@ -2980,8 +2866,8 @@
return p;
}
- inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
- inode_lock_nested(p2->d_inode, I_MUTEX_PARENT2);
+ lock_two_inodes(p1->d_inode, p2->d_inode,
+ I_MUTEX_PARENT, I_MUTEX_PARENT2);
return NULL;
}
EXPORT_SYMBOL(lock_rename);
@@ -2996,17 +2882,74 @@
}
EXPORT_SYMBOL(unlock_rename);
-int vfs_create2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry,
- umode_t mode, bool want_excl)
+/**
+ * mode_strip_umask - handle vfs umask stripping
+ * @dir: parent directory of the new inode
+ * @mode: mode of the new inode to be created in @dir
+ *
+ * Umask stripping depends on whether or not the filesystem supports POSIX
+ * ACLs. If the filesystem doesn't support it umask stripping is done directly
+ * in here. If the filesystem does support POSIX ACLs umask stripping is
+ * deferred until the filesystem calls posix_acl_create().
+ *
+ * Returns: mode
+ */
+static inline umode_t mode_strip_umask(const struct inode *dir, umode_t mode)
{
- int error = may_create(mnt, dir, dentry);
+ if (!IS_POSIXACL(dir))
+ mode &= ~current_umask();
+ return mode;
+}
+
+/**
+ * vfs_prepare_mode - prepare the mode to be used for a new inode
+ * @dir: parent directory of the new inode
+ * @mode: mode of the new inode
+ * @mask_perms: allowed permission by the vfs
+ * @type: type of file to be created
+ *
+ * This helper consolidates and enforces vfs restrictions on the @mode of a new
+ * object to be created.
+ *
+ * Umask stripping depends on whether the filesystem supports POSIX ACLs (see
+ * the kernel documentation for mode_strip_umask()). Moving umask stripping
+ * after setgid stripping allows the same ordering for both non-POSIX ACL and
+ * POSIX ACL supporting filesystems.
+ *
+ * Note that it's currently valid for @type to be 0 if a directory is created.
+ * Filesystems raise that flag individually and we need to check whether each
+ * filesystem can deal with receiving S_IFDIR from the vfs before we enforce a
+ * non-zero type.
+ *
+ * Returns: mode to be passed to the filesystem
+ */
+static inline umode_t vfs_prepare_mode(const struct inode *dir, umode_t mode,
+ umode_t mask_perms, umode_t type)
+{
+ mode = mode_strip_sgid(dir, mode);
+ mode = mode_strip_umask(dir, mode);
+
+ /*
+ * Apply the vfs mandated allowed permission mask and set the type of
+ * file to be created before we call into the filesystem.
+ */
+ mode &= (mask_perms & ~S_IFMT);
+ mode |= (type & S_IFMT);
+
+ return mode;
+}
+
+int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool want_excl)
+{
+ int error = may_create(dir, dentry);
if (error)
return error;
if (!dir->i_op->create)
return -EACCES; /* shouldn't it be ENOSYS? */
- mode &= S_IALLUGO;
- mode |= S_IFREG;
+
+ mode = vfs_prepare_mode(dir, mode, S_IALLUGO, S_IFREG);
error = security_inode_create(dir, dentry, mode);
if (error)
return error;
@@ -3015,21 +2958,14 @@
fsnotify_create(dir, dentry);
return error;
}
-EXPORT_SYMBOL(vfs_create2);
+EXPORT_SYMBOL_NS(vfs_create, ANDROID_GKI_VFS_EXPORT_ONLY);
-int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
- bool want_excl)
-{
- return vfs_create2(NULL, dir, dentry, mode, want_excl);
-}
-EXPORT_SYMBOL(vfs_create);
-
-int vfs_mkobj2(struct vfsmount *mnt, struct dentry *dentry, umode_t mode,
+int vfs_mkobj(struct dentry *dentry, umode_t mode,
int (*f)(struct dentry *, umode_t, void *),
void *arg)
{
struct inode *dir = dentry->d_parent->d_inode;
- int error = may_create(mnt, dir, dentry);
+ int error = may_create(dir, dentry);
if (error)
return error;
@@ -3043,15 +2979,6 @@
fsnotify_create(dir, dentry);
return error;
}
-EXPORT_SYMBOL(vfs_mkobj2);
-
-
-int vfs_mkobj(struct dentry *dentry, umode_t mode,
- int (*f)(struct dentry *, umode_t, void *),
- void *arg)
-{
- return vfs_mkobj2(NULL, dentry, mode, f, arg);
-}
EXPORT_SYMBOL(vfs_mkobj);
bool may_open_dev(const struct path *path)
@@ -3063,7 +2990,6 @@
static int may_open(const struct path *path, int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
- struct vfsmount *mnt = path->mnt;
struct inode *inode = dentry->d_inode;
int error;
@@ -3076,19 +3002,27 @@
case S_IFDIR:
if (acc_mode & MAY_WRITE)
return -EISDIR;
+ if (acc_mode & MAY_EXEC)
+ return -EACCES;
break;
case S_IFBLK:
case S_IFCHR:
if (!may_open_dev(path))
return -EACCES;
- /*FALLTHRU*/
+ fallthrough;
case S_IFIFO:
case S_IFSOCK:
+ if (acc_mode & MAY_EXEC)
+ return -EACCES;
flag &= ~O_TRUNC;
+ break;
+ case S_IFREG:
+ if ((acc_mode & MAY_EXEC) && path_noexec(path))
+ return -EACCES;
break;
}
- error = inode_permission2(mnt, inode, MAY_OPEN | acc_mode);
+ error = inode_permission(inode, MAY_OPEN | acc_mode);
if (error)
return error;
@@ -3123,7 +3057,7 @@
if (!error)
error = security_path_truncate(path);
if (!error) {
- error = do_truncate2(path->mnt, path->dentry, 0,
+ error = do_truncate(path->dentry, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
filp);
}
@@ -3150,7 +3084,7 @@
!kgid_has_mapping(s_user_ns, current_fsgid()))
return -EOVERFLOW;
- error = inode_permission2(dir->mnt, dir->dentry->d_inode, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC);
if (error)
return error;
@@ -3170,17 +3104,13 @@
*
* Returns an error code otherwise.
*/
-static int atomic_open(struct nameidata *nd, struct dentry *dentry,
- struct path *path, struct file *file,
- const struct open_flags *op,
- int open_flag, umode_t mode)
+static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry,
+ struct file *file,
+ int open_flag, umode_t mode)
{
struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
struct inode *dir = nd->path.dentry->d_inode;
int error;
-
- if (!(~open_flag & (O_EXCL | O_CREAT))) /* both O_EXCL and O_CREAT */
- open_flag &= ~O_TRUNC;
if (nd->flags & LOOKUP_DIRECTORY)
open_flag |= O_DIRECTORY;
@@ -3192,19 +3122,10 @@
d_lookup_done(dentry);
if (!error) {
if (file->f_mode & FMODE_OPENED) {
- /*
- * We didn't have the inode before the open, so check open
- * permission here.
- */
- int acc_mode = op->acc_mode;
- if (file->f_mode & FMODE_CREATED) {
- WARN_ON(!(open_flag & O_CREAT));
- fsnotify_create(dir, dentry);
- acc_mode = 0;
+ if (unlikely(dentry != file->f_path.dentry)) {
+ dput(dentry);
+ dentry = dget(file->f_path.dentry);
}
- error = may_open(&file->f_path, acc_mode, open_flag);
- if (WARN_ON(error > 0))
- error = -EINVAL;
} else if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) {
error = -EIO;
} else {
@@ -3212,19 +3133,15 @@
dput(dentry);
dentry = file->f_path.dentry;
}
- if (file->f_mode & FMODE_CREATED)
- fsnotify_create(dir, dentry);
- if (unlikely(d_is_negative(dentry))) {
+ if (unlikely(d_is_negative(dentry)))
error = -ENOENT;
- } else {
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 0;
- }
}
}
- dput(dentry);
- return error;
+ if (error) {
+ dput(dentry);
+ dentry = ERR_PTR(error);
+ }
+ return dentry;
}
/*
@@ -3242,10 +3159,9 @@
*
* An error code is returned on failure.
*/
-static int lookup_open(struct nameidata *nd, struct path *path,
- struct file *file,
- const struct open_flags *op,
- bool got_write)
+static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
+ const struct open_flags *op,
+ bool got_write)
{
struct dentry *dir = nd->path.dentry;
struct inode *dir_inode = dir->d_inode;
@@ -3256,7 +3172,7 @@
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
if (unlikely(IS_DEADDIR(dir_inode)))
- return -ENOENT;
+ return ERR_PTR(-ENOENT);
file->f_mode &= ~FMODE_CREATED;
dentry = d_lookup(dir, &nd->last);
@@ -3264,7 +3180,7 @@
if (!dentry) {
dentry = d_alloc_parallel(dir, &nd->last, &wq);
if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ return dentry;
}
if (d_in_lookup(dentry))
break;
@@ -3280,7 +3196,7 @@
}
if (dentry->d_inode) {
/* Cached positive dentry: will open in f_op->open */
- goto out_no_open;
+ return dentry;
}
/*
@@ -3292,41 +3208,26 @@
* Another problem is returing the "right" error value (e.g. for an
* O_EXCL open we want to return EEXIST not EROFS).
*/
+ if (unlikely(!got_write))
+ open_flag &= ~O_TRUNC;
if (open_flag & O_CREAT) {
- if (!IS_POSIXACL(dir->d_inode))
- mode &= ~current_umask();
- if (unlikely(!got_write)) {
- create_error = -EROFS;
- open_flag &= ~O_CREAT;
- if (open_flag & (O_EXCL | O_TRUNC))
- goto no_open;
- /* No side effects, safe to clear O_CREAT */
- } else {
+ if (open_flag & O_EXCL)
+ open_flag &= ~O_TRUNC;
+ mode = vfs_prepare_mode(dir->d_inode, mode, mode, mode);
+ if (likely(got_write))
create_error = may_o_create(&nd->path, dentry, mode);
- if (create_error) {
- open_flag &= ~O_CREAT;
- if (open_flag & O_EXCL)
- goto no_open;
- }
- }
- } else if ((open_flag & (O_TRUNC|O_WRONLY|O_RDWR)) &&
- unlikely(!got_write)) {
- /*
- * No O_CREATE -> atomicity not a requirement -> fall
- * back to lookup + open
- */
- goto no_open;
+ else
+ create_error = -EROFS;
}
-
+ if (create_error)
+ open_flag &= ~O_CREAT;
if (dir_inode->i_op->atomic_open) {
- error = atomic_open(nd, dentry, path, file, op, open_flag,
- mode);
- if (unlikely(error == -ENOENT) && create_error)
- error = create_error;
- return error;
+ dentry = atomic_open(nd, dentry, file, open_flag, mode);
+ if (unlikely(create_error) && dentry == ERR_PTR(-ENOENT))
+ dentry = ERR_PTR(create_error);
+ return dentry;
}
-no_open:
if (d_in_lookup(dentry)) {
struct dentry *res = dir_inode->i_op->lookup(dir_inode, dentry,
nd->flags);
@@ -3353,84 +3254,62 @@
open_flag & O_EXCL);
if (error)
goto out_dput;
- fsnotify_create(dir_inode, dentry);
}
if (unlikely(create_error) && !dentry->d_inode) {
error = create_error;
goto out_dput;
}
-out_no_open:
- path->dentry = dentry;
- path->mnt = nd->path.mnt;
- return 0;
+ return dentry;
out_dput:
dput(dentry);
- return error;
+ return ERR_PTR(error);
}
-/*
- * Handle the last step of open()
- */
-static int do_last(struct nameidata *nd,
+static const char *open_last_lookups(struct nameidata *nd,
struct file *file, const struct open_flags *op)
{
struct dentry *dir = nd->path.dentry;
- kuid_t dir_uid = nd->inode->i_uid;
- umode_t dir_mode = nd->inode->i_mode;
int open_flag = op->open_flag;
- bool will_truncate = (open_flag & O_TRUNC) != 0;
bool got_write = false;
- int acc_mode = op->acc_mode;
unsigned seq;
struct inode *inode;
- struct path path;
- int error;
+ struct dentry *dentry;
+ const char *res;
- nd->flags &= ~LOOKUP_PARENT;
nd->flags |= op->intent;
if (nd->last_type != LAST_NORM) {
- error = handle_dots(nd, nd->last_type);
- if (unlikely(error))
- return error;
- goto finish_open;
+ if (nd->depth)
+ put_link(nd);
+ return handle_dots(nd, nd->last_type);
}
if (!(open_flag & O_CREAT)) {
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
/* we _can_ be in RCU mode here */
- error = lookup_fast(nd, &path, &inode, &seq);
- if (likely(error > 0))
+ dentry = lookup_fast(nd, &inode, &seq);
+ if (IS_ERR(dentry))
+ return ERR_CAST(dentry);
+ if (likely(dentry))
goto finish_lookup;
- if (error < 0)
- return error;
-
- BUG_ON(nd->inode != dir->d_inode);
BUG_ON(nd->flags & LOOKUP_RCU);
} else {
/* create side of things */
- /*
- * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED
- * has been cleared when we got to the last component we are
- * about to look up
- */
- error = complete_walk(nd);
- if (error)
- return error;
-
- audit_inode(nd->name, dir, LOOKUP_PARENT);
+ if (nd->flags & LOOKUP_RCU) {
+ if (!try_to_unlazy(nd))
+ return ERR_PTR(-ECHILD);
+ }
+ audit_inode(nd->name, dir, AUDIT_INODE_PARENT);
/* trailing slashes? */
if (unlikely(nd->last.name[nd->last.len]))
- return -EISDIR;
+ return ERR_PTR(-EISDIR);
}
if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
- error = mnt_want_write(nd->path.mnt);
- if (!error)
- got_write = true;
+ got_write = !mnt_want_write(nd->path.mnt);
/*
* do _not_ fail yet - we might not need that or fail with
* a different error; let lookup_open() decide; we'll be
@@ -3441,113 +3320,90 @@
inode_lock(dir->d_inode);
else
inode_lock_shared(dir->d_inode);
- error = lookup_open(nd, &path, file, op, got_write);
+ dentry = lookup_open(nd, file, op, got_write);
+ if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED))
+ fsnotify_create(dir->d_inode, dentry);
if (open_flag & O_CREAT)
inode_unlock(dir->d_inode);
else
inode_unlock_shared(dir->d_inode);
- if (error)
- goto out;
+ if (got_write)
+ mnt_drop_write(nd->path.mnt);
- if (file->f_mode & FMODE_OPENED) {
- if ((file->f_mode & FMODE_CREATED) ||
- !S_ISREG(file_inode(file)->i_mode))
- will_truncate = false;
+ if (IS_ERR(dentry))
+ return ERR_CAST(dentry);
- audit_inode(nd->name, file->f_path.dentry, 0);
- goto opened;
+ if (file->f_mode & (FMODE_OPENED | FMODE_CREATED)) {
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+ return NULL;
}
+finish_lookup:
+ if (nd->depth)
+ put_link(nd);
+ res = step_into(nd, WALK_TRAILING, dentry, inode, seq);
+ if (unlikely(res))
+ nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
+ return res;
+}
+
+/*
+ * Handle the last step of open()
+ */
+static int do_open(struct nameidata *nd,
+ struct file *file, const struct open_flags *op)
+{
+ int open_flag = op->open_flag;
+ bool do_truncate;
+ int acc_mode;
+ int error;
+
+ if (!(file->f_mode & (FMODE_OPENED | FMODE_CREATED))) {
+ error = complete_walk(nd);
+ if (error)
+ return error;
+ }
+ if (!(file->f_mode & FMODE_CREATED))
+ audit_inode(nd->name, nd->path.dentry, 0);
+ if (open_flag & O_CREAT) {
+ if ((open_flag & O_EXCL) && !(file->f_mode & FMODE_CREATED))
+ return -EEXIST;
+ if (d_is_dir(nd->path.dentry))
+ return -EISDIR;
+ error = may_create_in_sticky(nd->dir_mode, nd->dir_uid,
+ d_backing_inode(nd->path.dentry));
+ if (unlikely(error))
+ return error;
+ }
+ if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
+ return -ENOTDIR;
+
+ do_truncate = false;
+ acc_mode = op->acc_mode;
if (file->f_mode & FMODE_CREATED) {
/* Don't check for write permission, don't truncate */
open_flag &= ~O_TRUNC;
- will_truncate = false;
acc_mode = 0;
- path_to_nameidata(&path, nd);
- goto finish_open_created;
- }
-
- /*
- * If atomic_open() acquired write access it is dropped now due to
- * possible mount and symlink following (this might be optimized away if
- * necessary...)
- */
- if (got_write) {
- mnt_drop_write(nd->path.mnt);
- got_write = false;
- }
-
- error = follow_managed(&path, nd);
- if (unlikely(error < 0))
- return error;
-
- if (unlikely(d_is_negative(path.dentry))) {
- path_to_nameidata(&path, nd);
- return -ENOENT;
- }
-
- /*
- * create/update audit record if it already exists.
- */
- audit_inode(nd->name, path.dentry, 0);
-
- if (unlikely((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))) {
- path_to_nameidata(&path, nd);
- return -EEXIST;
- }
-
- seq = 0; /* out of RCU mode, so the value doesn't matter */
- inode = d_backing_inode(path.dentry);
-finish_lookup:
- error = step_into(nd, &path, 0, inode, seq);
- if (unlikely(error))
- return error;
-finish_open:
- /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
- error = complete_walk(nd);
- if (error)
- return error;
- audit_inode(nd->name, nd->path.dentry, 0);
- if (open_flag & O_CREAT) {
- error = -EISDIR;
- if (d_is_dir(nd->path.dentry))
- goto out;
- error = may_create_in_sticky(dir_mode, dir_uid,
- d_backing_inode(nd->path.dentry));
- if (unlikely(error))
- goto out;
- }
- error = -ENOTDIR;
- if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
- goto out;
- if (!d_is_reg(nd->path.dentry))
- will_truncate = false;
-
- if (will_truncate) {
+ } else if (d_is_reg(nd->path.dentry) && open_flag & O_TRUNC) {
error = mnt_want_write(nd->path.mnt);
if (error)
- goto out;
- got_write = true;
+ return error;
+ do_truncate = true;
}
-finish_open_created:
error = may_open(&nd->path, acc_mode, open_flag);
- if (error)
- goto out;
- BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */
- error = vfs_open(&nd->path, file);
- if (error)
- goto out;
-opened:
- error = ima_file_check(file, op->acc_mode);
- if (!error && will_truncate)
+ if (!error && !(file->f_mode & FMODE_OPENED))
+ error = vfs_open(&nd->path, file);
+ if (!error)
+ error = ima_file_check(file, op->acc_mode);
+ if (!error && do_truncate)
error = handle_truncate(file);
-out:
if (unlikely(error > 0)) {
WARN_ON(1);
error = -EINVAL;
}
- if (got_write)
+ if (do_truncate)
mnt_drop_write(nd->path.mnt);
return error;
}
@@ -3560,8 +3416,7 @@
int error;
/* we want directory to be writable */
- error = inode_permission2(ERR_PTR(-EOPNOTSUPP), dir,
- MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
goto out_err;
error = -EOPNOTSUPP;
@@ -3571,6 +3426,7 @@
child = d_alloc(dentry, &slash_name);
if (unlikely(!child))
goto out_err;
+ mode = vfs_prepare_mode(dir, mode, mode, mode);
error = dir->i_op->tmpfile(dir, child, mode);
if (error)
goto out_err;
@@ -3583,6 +3439,7 @@
inode->i_state |= I_LINKABLE;
spin_unlock(&inode->i_lock);
}
+ ima_post_create_tmpfile(inode);
return child;
out_err:
@@ -3652,10 +3509,10 @@
} else {
const char *s = path_init(nd, flags);
while (!(error = link_path_walk(s, nd)) &&
- (error = do_last(nd, file, op)) > 0) {
- nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
- s = trailing_symlink(nd);
- }
+ (s = open_last_lookups(nd, file, op)) != NULL)
+ ;
+ if (!error)
+ error = do_open(nd, file, op);
terminate_walk(nd);
}
if (likely(!error)) {
@@ -3815,19 +3672,22 @@
}
EXPORT_SYMBOL(user_path_create);
-int vfs_mknod2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
+int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
{
- int error = may_create(mnt, dir, dentry);
+ bool is_whiteout = S_ISCHR(mode) && dev == WHITEOUT_DEV;
+ int error = may_create(dir, dentry);
if (error)
return error;
- if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
+ if ((S_ISCHR(mode) || S_ISBLK(mode)) && !is_whiteout &&
+ !capable(CAP_MKNOD))
return -EPERM;
if (!dir->i_op->mknod)
return -EPERM;
+ mode = vfs_prepare_mode(dir, mode, mode, mode);
error = devcgroup_inode_mknod(mode, dev);
if (error)
return error;
@@ -3840,12 +3700,6 @@
if (!error)
fsnotify_create(dir, dentry);
return error;
-}
-EXPORT_SYMBOL(vfs_mknod2);
-
-int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
-{
- return vfs_mknod2(NULL, dir, dentry, mode, dev);
}
EXPORT_SYMBOL(vfs_mknod);
@@ -3866,7 +3720,7 @@
}
}
-long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+static long do_mknodat(int dfd, const char __user *filename, umode_t mode,
unsigned int dev)
{
struct dentry *dentry;
@@ -3882,19 +3736,18 @@
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- if (!IS_POSIXACL(path.dentry->d_inode))
- mode &= ~current_umask();
- error = security_path_mknod(&path, dentry, mode, dev);
+ error = security_path_mknod(&path, dentry,
+ mode_strip_umask(path.dentry->d_inode, mode), dev);
if (error)
goto out;
switch (mode & S_IFMT) {
case 0: case S_IFREG:
- error = vfs_create2(path.mnt, path.dentry->d_inode,dentry,mode,true);
+ error = vfs_create(path.dentry->d_inode,dentry,mode,true);
if (!error)
ima_post_path_mknod(dentry);
break;
case S_IFCHR: case S_IFBLK:
- error = vfs_mknod2(path.mnt, path.dentry->d_inode,dentry,mode,
+ error = vfs_mknod(path.dentry->d_inode,dentry,mode,
new_decode_dev(dev));
break;
case S_IFIFO: case S_IFSOCK:
@@ -3921,9 +3774,9 @@
return do_mknodat(AT_FDCWD, filename, mode, dev);
}
-int vfs_mkdir2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry, umode_t mode)
+int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
- int error = may_create(mnt, dir, dentry);
+ int error = may_create(dir, dentry);
unsigned max_links = dir->i_sb->s_max_links;
if (error)
@@ -3932,7 +3785,7 @@
if (!dir->i_op->mkdir)
return -EPERM;
- mode &= (S_IRWXUGO|S_ISVTX);
+ mode = vfs_prepare_mode(dir, mode, S_IRWXUGO | S_ISVTX, 0);
error = security_inode_mkdir(dir, dentry, mode);
if (error)
return error;
@@ -3945,15 +3798,9 @@
fsnotify_mkdir(dir, dentry);
return error;
}
-EXPORT_SYMBOL(vfs_mkdir2);
+EXPORT_SYMBOL_NS(vfs_mkdir, ANDROID_GKI_VFS_EXPORT_ONLY);
-int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
-{
- return vfs_mkdir2(NULL, dir, dentry, mode);
-}
-EXPORT_SYMBOL(vfs_mkdir);
-
-long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
+static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
{
struct dentry *dentry;
struct path path;
@@ -3965,11 +3812,10 @@
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- if (!IS_POSIXACL(path.dentry->d_inode))
- mode &= ~current_umask();
- error = security_path_mkdir(&path, dentry, mode);
+ error = security_path_mkdir(&path, dentry,
+ mode_strip_umask(path.dentry->d_inode, mode));
if (!error)
- error = vfs_mkdir2(path.mnt, path.dentry->d_inode, dentry, mode);
+ error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
@@ -3988,9 +3834,9 @@
return do_mkdirat(AT_FDCWD, pathname, mode);
}
-int vfs_rmdir2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry)
+int vfs_rmdir(struct inode *dir, struct dentry *dentry)
{
- int error = may_delete(mnt, dir, dentry, 1);
+ int error = may_delete(dir, dentry, 1);
if (error)
return error;
@@ -4022,28 +3868,21 @@
inode_unlock(dentry->d_inode);
dput(dentry);
if (!error)
- d_delete(dentry);
+ d_delete_notify(dir, dentry);
return error;
}
-EXPORT_SYMBOL(vfs_rmdir2);
+EXPORT_SYMBOL_NS(vfs_rmdir, ANDROID_GKI_VFS_EXPORT_ONLY);
-int vfs_rmdir(struct inode *dir, struct dentry *dentry)
-{
- return vfs_rmdir2(NULL, dir, dentry);
-}
-EXPORT_SYMBOL(vfs_rmdir);
-
-long do_rmdir(int dfd, const char __user *pathname)
+long do_rmdir(int dfd, struct filename *name)
{
int error = 0;
- struct filename *name;
struct dentry *dentry;
struct path path;
struct qstr last;
int type;
unsigned int lookup_flags = 0;
retry:
- name = filename_parentat(dfd, getname(pathname), lookup_flags,
+ name = filename_parentat(dfd, name, lookup_flags,
&path, &last, &type);
if (IS_ERR(name))
return PTR_ERR(name);
@@ -4076,7 +3915,7 @@
error = security_path_rmdir(&path, dentry);
if (error)
goto exit3;
- error = vfs_rmdir2(path.mnt, path.dentry->d_inode, dentry);
+ error = vfs_rmdir(path.dentry->d_inode, dentry);
exit3:
dput(dentry);
exit2:
@@ -4084,17 +3923,17 @@
mnt_drop_write(path.mnt);
exit1:
path_put(&path);
- putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
+ putname(name);
return error;
}
SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
{
- return do_rmdir(AT_FDCWD, pathname);
+ return do_rmdir(AT_FDCWD, getname(pathname));
}
/**
@@ -4115,10 +3954,10 @@
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
*/
-int vfs_unlink2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
+int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
{
struct inode *target = dentry->d_inode;
- int error = may_delete(mnt, dir, dentry, 0);
+ int error = may_delete(dir, dentry, 0);
if (error)
return error;
@@ -4146,20 +3985,16 @@
inode_unlock(target);
/* We don't d_delete() NFS sillyrenamed files--they still exist. */
- if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
+ if (!error && dentry->d_flags & DCACHE_NFSFS_RENAMED) {
+ fsnotify_unlink(dir, dentry);
+ } else if (!error) {
fsnotify_link_count(target);
- d_delete(dentry);
+ d_delete_notify(dir, dentry);
}
return error;
}
-EXPORT_SYMBOL(vfs_unlink2);
-
-int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
-{
- return vfs_unlink2(NULL, dir, dentry, delegated_inode);
-}
-EXPORT_SYMBOL(vfs_unlink);
+EXPORT_SYMBOL_NS(vfs_unlink, ANDROID_GKI_VFS_EXPORT_ONLY);
/*
* Make sure that the actual truncation of the file will occur outside its
@@ -4204,7 +4039,7 @@
error = security_path_unlink(&path, dentry);
if (error)
goto exit2;
- error = vfs_unlink2(path.mnt, path.dentry->d_inode, dentry, &delegated_inode);
+ error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode);
exit2:
dput(dentry);
}
@@ -4244,8 +4079,7 @@
return -EINVAL;
if (flag & AT_REMOVEDIR)
- return do_rmdir(dfd, pathname);
-
+ return do_rmdir(dfd, getname(pathname));
return do_unlinkat(dfd, getname(pathname));
}
@@ -4254,9 +4088,9 @@
return do_unlinkat(AT_FDCWD, getname(pathname));
}
-int vfs_symlink2(struct vfsmount *mnt, struct inode *dir, struct dentry *dentry, const char *oldname)
+int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
{
- int error = may_create(mnt, dir, dentry);
+ int error = may_create(dir, dentry);
if (error)
return error;
@@ -4273,15 +4107,9 @@
fsnotify_create(dir, dentry);
return error;
}
-EXPORT_SYMBOL(vfs_symlink2);
-
-int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
-{
- return vfs_symlink2(NULL, dir, dentry, oldname);
-}
EXPORT_SYMBOL(vfs_symlink);
-long do_symlinkat(const char __user *oldname, int newdfd,
+static long do_symlinkat(const char __user *oldname, int newdfd,
const char __user *newname)
{
int error;
@@ -4301,7 +4129,7 @@
error = security_path_symlink(&path, dentry, from->name);
if (!error)
- error = vfs_symlink2(path.mnt, path.dentry->d_inode, dentry, from->name);
+ error = vfs_symlink(path.dentry->d_inode, dentry, from->name);
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
@@ -4342,7 +4170,7 @@
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
*/
-int vfs_link2(struct vfsmount *mnt, struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode)
+int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode)
{
struct inode *inode = old_dentry->d_inode;
unsigned max_links = dir->i_sb->s_max_links;
@@ -4351,7 +4179,7 @@
if (!inode)
return -ENOENT;
- error = may_create(mnt, dir, new_dentry);
+ error = may_create(dir, new_dentry);
if (error)
return error;
@@ -4401,13 +4229,7 @@
fsnotify_link(dir, inode, new_dentry);
return error;
}
-EXPORT_SYMBOL(vfs_link2);
-
-int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode)
-{
- return vfs_link2(NULL, old_dentry, dir, new_dentry, delegated_inode);
-}
-EXPORT_SYMBOL(vfs_link);
+EXPORT_SYMBOL_NS(vfs_link, ANDROID_GKI_VFS_EXPORT_ONLY);
/*
* Hardlinks are often used in delicate situations. We avoid
@@ -4418,7 +4240,7 @@
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+static int do_linkat(int olddfd, const char __user *oldname, int newdfd,
const char __user *newname, int flags)
{
struct dentry *new_dentry;
@@ -4462,7 +4284,7 @@
error = security_path_link(old_path.dentry, &new_path, new_dentry);
if (error)
goto out_dput;
- error = vfs_link2(old_path.mnt, old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode);
+ error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode);
out_dput:
done_path_create(&new_path, new_dentry);
if (delegated_inode) {
@@ -4526,7 +4348,7 @@
* sb->s_vfs_rename_mutex. We might be more accurate, but that's another
* story.
* c) we have to lock _four_ objects - parents and victim (if it exists),
- * and source (if it is not a directory).
+ * and source.
* And that - after we got ->i_mutex on parents (until then we don't know
* whether the target exists). Solution: try to be smart with locking
* order for inodes. We rely on the fact that tree topology may change
@@ -4544,8 +4366,7 @@
* ->i_mutex on parents, which works but leads to some truly excessive
* locking].
*/
-int vfs_rename2(struct vfsmount *mnt,
- struct inode *old_dir, struct dentry *old_dentry,
+int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
struct inode **delegated_inode, unsigned int flags)
{
@@ -4560,19 +4381,19 @@
if (source == target)
return 0;
- error = may_delete(mnt, old_dir, old_dentry, is_dir);
+ error = may_delete(old_dir, old_dentry, is_dir);
if (error)
return error;
if (!target) {
- error = may_create(mnt, new_dir, new_dentry);
+ error = may_create(new_dir, new_dentry);
} else {
new_is_dir = d_is_dir(new_dentry);
if (!(flags & RENAME_EXCHANGE))
- error = may_delete(mnt, new_dir, new_dentry, is_dir);
+ error = may_delete(new_dir, new_dentry, is_dir);
else
- error = may_delete(mnt, new_dir, new_dentry, new_is_dir);
+ error = may_delete(new_dir, new_dentry, new_is_dir);
}
if (error)
return error;
@@ -4586,12 +4407,12 @@
*/
if (new_dir != old_dir) {
if (is_dir) {
- error = inode_permission2(mnt, source, MAY_WRITE);
+ error = inode_permission(source, MAY_WRITE);
if (error)
return error;
}
if ((flags & RENAME_EXCHANGE) && new_is_dir) {
- error = inode_permission2(mnt, target, MAY_WRITE);
+ error = inode_permission(target, MAY_WRITE);
if (error)
return error;
}
@@ -4604,10 +4425,16 @@
take_dentry_name_snapshot(&old_name, old_dentry);
dget(new_dentry);
- if (!is_dir || (flags & RENAME_EXCHANGE))
- lock_two_nondirectories(source, target);
- else if (target)
- inode_lock(target);
+ /*
+ * Lock all moved children. Moved directories may need to change parent
+ * pointer so they need the lock to prevent against concurrent
+ * directory changes moving parent pointer. For regular files we've
+ * historically always done this. The lockdep locking subclasses are
+ * somewhat arbitrary but RENAME_EXCHANGE in particular can swap
+ * regular files and directories so it's difficult to tell which
+ * subclasses to use.
+ */
+ lock_two_inodes(source, target, I_MUTEX_NORMAL, I_MUTEX_NONDIR2);
error = -EBUSY;
if (is_local_mountpoint(old_dentry) || is_local_mountpoint(new_dentry))
@@ -4651,16 +4478,15 @@
d_exchange(old_dentry, new_dentry);
}
out:
- if (!is_dir || (flags & RENAME_EXCHANGE))
- unlock_two_nondirectories(source, target);
- else if (target)
+ inode_unlock(source);
+ if (target)
inode_unlock(target);
dput(new_dentry);
if (!error) {
- fsnotify_move(old_dir, new_dir, old_name.name, is_dir,
+ fsnotify_move(old_dir, new_dir, &old_name.name, is_dir,
!(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
if (flags & RENAME_EXCHANGE) {
- fsnotify_move(new_dir, old_dir, old_dentry->d_name.name,
+ fsnotify_move(new_dir, old_dir, &old_dentry->d_name,
new_is_dir, NULL, new_dentry);
}
}
@@ -4668,18 +4494,10 @@
return error;
}
-EXPORT_SYMBOL(vfs_rename2);
+EXPORT_SYMBOL_NS(vfs_rename, ANDROID_GKI_VFS_EXPORT_ONLY);
-int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry,
- struct inode **delegated_inode, unsigned int flags)
-{
- return vfs_rename2(NULL, old_dir, old_dentry, new_dir, new_dentry, delegated_inode, flags);
-}
-EXPORT_SYMBOL(vfs_rename);
-
-static int do_renameat2(int olddfd, const char __user *oldname, int newdfd,
- const char __user *newname, unsigned int flags)
+int do_renameat2(int olddfd, struct filename *from, int newdfd,
+ struct filename *to, unsigned int flags)
{
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
@@ -4687,35 +4505,30 @@
struct qstr old_last, new_last;
int old_type, new_type;
struct inode *delegated_inode = NULL;
- struct filename *from;
- struct filename *to;
unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;
bool should_retry = false;
- int error;
+ int error = -EINVAL;
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
- return -EINVAL;
+ goto put_both;
if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
(flags & RENAME_EXCHANGE))
- return -EINVAL;
-
- if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))
- return -EPERM;
+ goto put_both;
if (flags & RENAME_EXCHANGE)
target_flags = 0;
retry:
- from = filename_parentat(olddfd, getname(oldname), lookup_flags,
- &old_path, &old_last, &old_type);
+ from = filename_parentat(olddfd, from, lookup_flags, &old_path,
+ &old_last, &old_type);
if (IS_ERR(from)) {
error = PTR_ERR(from);
- goto exit;
+ goto put_new;
}
- to = filename_parentat(newdfd, getname(newname), lookup_flags,
- &new_path, &new_last, &new_type);
+ to = filename_parentat(newdfd, to, lookup_flags, &new_path, &new_last,
+ &new_type);
if (IS_ERR(to)) {
error = PTR_ERR(to);
goto exit1;
@@ -4789,7 +4602,7 @@
&new_path, new_dentry, flags);
if (error)
goto exit5;
- error = vfs_rename2(old_path.mnt, old_path.dentry->d_inode, old_dentry,
+ error = vfs_rename(old_path.dentry->d_inode, old_dentry,
new_path.dentry->d_inode, new_dentry,
&delegated_inode, flags);
exit5:
@@ -4808,49 +4621,41 @@
if (retry_estale(error, lookup_flags))
should_retry = true;
path_put(&new_path);
- putname(to);
exit1:
path_put(&old_path);
- putname(from);
if (should_retry) {
should_retry = false;
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-exit:
+put_both:
+ if (!IS_ERR(from))
+ putname(from);
+put_new:
+ if (!IS_ERR(to))
+ putname(to);
return error;
}
SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, unsigned int, flags)
{
- return do_renameat2(olddfd, oldname, newdfd, newname, flags);
+ return do_renameat2(olddfd, getname(oldname), newdfd, getname(newname),
+ flags);
}
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
- return do_renameat2(olddfd, oldname, newdfd, newname, 0);
+ return do_renameat2(olddfd, getname(oldname), newdfd, getname(newname),
+ 0);
}
SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
- return do_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_renameat2(AT_FDCWD, getname(oldname), AT_FDCWD,
+ getname(newname), 0);
}
-
-int vfs_whiteout(struct inode *dir, struct dentry *dentry)
-{
- int error = may_create(NULL, dir, dentry);
- if (error)
- return error;
-
- if (!dir->i_op->mknod)
- return -EPERM;
-
- return dir->i_op->mknod(dir, dentry,
- S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
-}
-EXPORT_SYMBOL(vfs_whiteout);
int readlink_copy(char __user *buffer, int buflen, const char *link)
{
@@ -4987,7 +4792,7 @@
{
struct address_space *mapping = inode->i_mapping;
struct page *page;
- void *fsdata;
+ void *fsdata = NULL;
int err;
unsigned int flags = 0;
if (nofs)
--
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