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/security/commoncap.c | 65 +++++++++++++++++---------------
1 files changed, 35 insertions(+), 30 deletions(-)
diff --git a/kernel/security/commoncap.c b/kernel/security/commoncap.c
index 876cfe0..09b402c 100644
--- a/kernel/security/commoncap.c
+++ b/kernel/security/commoncap.c
@@ -1,15 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/* Common capabilities, needed by capability.o.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
*/
#include <linux/capability.h>
#include <linux/audit.h>
-#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/lsm_hooks.h>
@@ -58,7 +52,7 @@
* @cred: The credentials to use
* @ns: The user namespace in which we need the capability
* @cap: The capability to check for
- * @audit: Whether to write an audit message or not
+ * @opts: Bitmask of options defined in include/linux/security.h
*
* Determine whether the nominated task has the specified capability amongst
* its effective set, returning 0 if it does, -ve if it does not.
@@ -303,7 +297,8 @@
struct inode *inode = d_backing_inode(dentry);
int error;
- error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
+ error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0,
+ XATTR_NOSECURITY);
return error > 0;
}
@@ -397,8 +392,10 @@
&tmpbuf, size, GFP_NOFS);
dput(dentry);
- if (ret < 0 || !tmpbuf)
- return ret;
+ if (ret < 0 || !tmpbuf) {
+ size = ret;
+ goto out_free;
+ }
fs_ns = inode->i_sb->s_user_ns;
cap = (struct vfs_cap_data *) tmpbuf;
@@ -611,7 +608,8 @@
fs_ns = inode->i_sb->s_user_ns;
size = __vfs_getxattr((struct dentry *)dentry, inode,
- XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
+ XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ,
+ XATTR_NOSECURITY);
if (size == -ENODATA || size == -EOPNOTSUPP)
/* no data, that's ok */
return -ENODATA;
@@ -662,6 +660,8 @@
cpu_caps->permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
cpu_caps->inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+ cpu_caps->rootid = rootkuid;
+
return 0;
}
@@ -670,7 +670,8 @@
* its xattrs and, if present, apply them to the proposed credentials being
* constructed by execve().
*/
-static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_fcap)
+static int get_file_caps(struct linux_binprm *bprm, struct file *file,
+ bool *effective, bool *has_fcap)
{
int rc = 0;
struct cpu_vfs_cap_data vcaps;
@@ -680,7 +681,7 @@
if (!file_caps_enabled)
return 0;
- if (!mnt_may_suid(bprm->file->f_path.mnt))
+ if (!mnt_may_suid(file->f_path.mnt))
return 0;
/*
@@ -688,10 +689,10 @@
* explicit that capability bits are limited to s_user_ns and its
* descendants.
*/
- if (!current_in_userns(bprm->file->f_path.mnt->mnt_sb->s_user_ns))
+ if (!current_in_userns(file->f_path.mnt->mnt_sb->s_user_ns))
return 0;
- rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps);
+ rc = get_vfs_caps_from_disk(file->f_path.dentry, &vcaps);
if (rc < 0) {
if (rc == -EINVAL)
printk(KERN_NOTICE "Invalid argument reading file caps for %s\n",
@@ -702,9 +703,6 @@
}
rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_fcap);
- if (rc == -EINVAL)
- printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
- __func__, rc, bprm->filename);
out:
if (rc)
@@ -823,26 +821,27 @@
}
/**
- * cap_bprm_set_creds - Set up the proposed credentials for execve().
+ * cap_bprm_creds_from_file - Set up the proposed credentials for execve().
* @bprm: The execution parameters, including the proposed creds
+ * @file: The file to pull the credentials from
*
* Set up the proposed credentials for a new execution context being
* constructed by execve(). The proposed creds in @bprm->cred is altered,
* which won't take effect immediately. Returns 0 if successful, -ve on error.
*/
-int cap_bprm_set_creds(struct linux_binprm *bprm)
+int cap_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file)
{
+ /* Process setpcap binaries and capabilities for uid 0 */
const struct cred *old = current_cred();
struct cred *new = bprm->cred;
bool effective = false, has_fcap = false, is_setid;
int ret;
kuid_t root_uid;
- new->cap_ambient = old->cap_ambient;
if (WARN_ON(!cap_ambient_invariant_ok(old)))
return -EPERM;
- ret = get_file_caps(bprm, &effective, &has_fcap);
+ ret = get_file_caps(bprm, file, &effective, &has_fcap);
if (ret < 0)
return ret;
@@ -911,12 +910,11 @@
return -EPERM;
/* Check for privilege-elevated exec. */
- bprm->cap_elevated = 0;
if (is_setid ||
(!__is_real(root_uid, new) &&
(effective ||
__cap_grew(permitted, ambient, new))))
- bprm->cap_elevated = 1;
+ bprm->secureexec = 1;
return 0;
}
@@ -942,7 +940,7 @@
/* Ignore non-security xattrs */
if (strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) != 0)
+ XATTR_SECURITY_PREFIX_LEN) != 0)
return 0;
/*
@@ -974,7 +972,7 @@
/* Ignore non-security xattrs */
if (strncmp(name, XATTR_SECURITY_PREFIX,
- sizeof(XATTR_SECURITY_PREFIX) - 1) != 0)
+ XATTR_SECURITY_PREFIX_LEN) != 0)
return 0;
if (strcmp(name, XATTR_NAME_CAPS) == 0) {
@@ -1366,14 +1364,14 @@
#ifdef CONFIG_SECURITY
-struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
+static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(capable, cap_capable),
LSM_HOOK_INIT(settime, cap_settime),
LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme),
LSM_HOOK_INIT(capget, cap_capget),
LSM_HOOK_INIT(capset, cap_capset),
- LSM_HOOK_INIT(bprm_set_creds, cap_bprm_set_creds),
+ LSM_HOOK_INIT(bprm_creds_from_file, cap_bprm_creds_from_file),
LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv),
LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv),
LSM_HOOK_INIT(inode_getsecurity, cap_inode_getsecurity),
@@ -1387,10 +1385,17 @@
LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory),
};
-void __init capability_add_hooks(void)
+static int __init capability_init(void)
{
security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
"capability");
+ return 0;
}
+DEFINE_LSM(capability) = {
+ .name = "capability",
+ .order = LSM_ORDER_FIRST,
+ .init = capability_init,
+};
+
#endif /* CONFIG_SECURITY */
--
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