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hc
2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/fs/namei.c
....@@ -2724,7 +2724,7 @@
27242724 	dput(path->dentry);
27252725 	path->dentry = parent;
27262726 	child = d_hash_and_lookup(parent, &this);
2727
-	if (!child)
2727
+	if (IS_ERR_OR_NULL(child))
27282728 		return -ENOENT;
27292729 
27302730 	path->dentry = child;
....@@ -2866,8 +2866,8 @@
28662866 		return p;
28672867 	}
28682868 
2869
-	inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
2870
-	inode_lock_nested(p2->d_inode, I_MUTEX_PARENT2);
2869
+	lock_two_inodes(p1->d_inode, p2->d_inode,
2870
+			I_MUTEX_PARENT, I_MUTEX_PARENT2);
28712871 	return NULL;
28722872 }
28732873 EXPORT_SYMBOL(lock_rename);
....@@ -2882,6 +2882,63 @@
28822882 }
28832883 EXPORT_SYMBOL(unlock_rename);
28842884 
2885
+/**
2886
+ * mode_strip_umask - handle vfs umask stripping
2887
+ * @dir:	parent directory of the new inode
2888
+ * @mode:	mode of the new inode to be created in @dir
2889
+ *
2890
+ * Umask stripping depends on whether or not the filesystem supports POSIX
2891
+ * ACLs. If the filesystem doesn't support it umask stripping is done directly
2892
+ * in here. If the filesystem does support POSIX ACLs umask stripping is
2893
+ * deferred until the filesystem calls posix_acl_create().
2894
+ *
2895
+ * Returns: mode
2896
+ */
2897
+static inline umode_t mode_strip_umask(const struct inode *dir, umode_t mode)
2898
+{
2899
+	if (!IS_POSIXACL(dir))
2900
+		mode &= ~current_umask();
2901
+	return mode;
2902
+}
2903
+
2904
+/**
2905
+ * vfs_prepare_mode - prepare the mode to be used for a new inode
2906
+ * @dir:	parent directory of the new inode
2907
+ * @mode:	mode of the new inode
2908
+ * @mask_perms:	allowed permission by the vfs
2909
+ * @type:	type of file to be created
2910
+ *
2911
+ * This helper consolidates and enforces vfs restrictions on the @mode of a new
2912
+ * object to be created.
2913
+ *
2914
+ * Umask stripping depends on whether the filesystem supports POSIX ACLs (see
2915
+ * the kernel documentation for mode_strip_umask()). Moving umask stripping
2916
+ * after setgid stripping allows the same ordering for both non-POSIX ACL and
2917
+ * POSIX ACL supporting filesystems.
2918
+ *
2919
+ * Note that it's currently valid for @type to be 0 if a directory is created.
2920
+ * Filesystems raise that flag individually and we need to check whether each
2921
+ * filesystem can deal with receiving S_IFDIR from the vfs before we enforce a
2922
+ * non-zero type.
2923
+ *
2924
+ * Returns: mode to be passed to the filesystem
2925
+ */
2926
+static inline umode_t vfs_prepare_mode(const struct inode *dir, umode_t mode,
2927
+				       umode_t mask_perms, umode_t type)
2928
+{
2929
+	mode = mode_strip_sgid(dir, mode);
2930
+	mode = mode_strip_umask(dir, mode);
2931
+
2932
+	/*
2933
+	 * Apply the vfs mandated allowed permission mask and set the type of
2934
+	 * file to be created before we call into the filesystem.
2935
+	 */
2936
+	mode &= (mask_perms & ~S_IFMT);
2937
+	mode |= (type & S_IFMT);
2938
+
2939
+	return mode;
2940
+}
2941
+
28852942 int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
28862943 		bool want_excl)
28872944 {
....@@ -2891,8 +2948,8 @@
28912948 
28922949 	if (!dir->i_op->create)
28932950 		return -EACCES;	/* shouldn't it be ENOSYS? */
2894
-	mode &= S_IALLUGO;
2895
-	mode |= S_IFREG;
2951
+
2952
+	mode = vfs_prepare_mode(dir, mode, S_IALLUGO, S_IFREG);
28962953 	error = security_inode_create(dir, dentry, mode);
28972954 	if (error)
28982955 		return error;
....@@ -3156,8 +3213,7 @@
31563213 	if (open_flag & O_CREAT) {
31573214 		if (open_flag & O_EXCL)
31583215 			open_flag &= ~O_TRUNC;
3159
-		if (!IS_POSIXACL(dir->d_inode))
3160
-			mode &= ~current_umask();
3216
+		mode = vfs_prepare_mode(dir->d_inode, mode, mode, mode);
31613217 		if (likely(got_write))
31623218 			create_error = may_o_create(&nd->path, dentry, mode);
31633219 		else
....@@ -3370,8 +3426,7 @@
33703426 	child = d_alloc(dentry, &slash_name);
33713427 	if (unlikely(!child))
33723428 		goto out_err;
3373
-	if (!IS_POSIXACL(dir))
3374
-		mode &= ~current_umask();
3429
+	mode = vfs_prepare_mode(dir, mode, mode, mode);
33753430 	error = dir->i_op->tmpfile(dir, child, mode);
33763431 	if (error)
33773432 		goto out_err;
....@@ -3632,6 +3687,7 @@
36323687 	if (!dir->i_op->mknod)
36333688 		return -EPERM;
36343689 
3690
+	mode = vfs_prepare_mode(dir, mode, mode, mode);
36353691 	error = devcgroup_inode_mknod(mode, dev);
36363692 	if (error)
36373693 		return error;
....@@ -3680,9 +3736,8 @@
36803736 	if (IS_ERR(dentry))
36813737 		return PTR_ERR(dentry);
36823738 
3683
-	if (!IS_POSIXACL(path.dentry->d_inode))
3684
-		mode &= ~current_umask();
3685
-	error = security_path_mknod(&path, dentry, mode, dev);
3739
+	error = security_path_mknod(&path, dentry,
3740
+			mode_strip_umask(path.dentry->d_inode, mode), dev);
36863741 	if (error)
36873742 		goto out;
36883743 	switch (mode & S_IFMT) {
....@@ -3730,7 +3785,7 @@
37303785 	if (!dir->i_op->mkdir)
37313786 		return -EPERM;
37323787 
3733
-	mode &= (S_IRWXUGO|S_ISVTX);
3788
+	mode = vfs_prepare_mode(dir, mode, S_IRWXUGO | S_ISVTX, 0);
37343789 	error = security_inode_mkdir(dir, dentry, mode);
37353790 	if (error)
37363791 		return error;
....@@ -3757,9 +3812,8 @@
37573812 	if (IS_ERR(dentry))
37583813 		return PTR_ERR(dentry);
37593814 
3760
-	if (!IS_POSIXACL(path.dentry->d_inode))
3761
-		mode &= ~current_umask();
3762
-	error = security_path_mkdir(&path, dentry, mode);
3815
+	error = security_path_mkdir(&path, dentry,
3816
+			mode_strip_umask(path.dentry->d_inode, mode));
37633817 	if (!error)
37643818 		error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
37653819 	done_path_create(&path, dentry);
....@@ -4294,7 +4348,7 @@
42944348  *	   sb->s_vfs_rename_mutex. We might be more accurate, but that's another
42954349  *	   story.
42964350  *	c) we have to lock _four_ objects - parents and victim (if it exists),
4297
- *	   and source (if it is not a directory).
4351
+ *	   and source.
42984352  *	   And that - after we got ->i_mutex on parents (until then we don't know
42994353  *	   whether the target exists).  Solution: try to be smart with locking
43004354  *	   order for inodes.  We rely on the fact that tree topology may change
....@@ -4371,10 +4425,16 @@
43714425 
43724426 	take_dentry_name_snapshot(&old_name, old_dentry);
43734427 	dget(new_dentry);
4374
-	if (!is_dir || (flags & RENAME_EXCHANGE))
4375
-		lock_two_nondirectories(source, target);
4376
-	else if (target)
4377
-		inode_lock(target);
4428
+	/*
4429
+	 * Lock all moved children. Moved directories may need to change parent
4430
+	 * pointer so they need the lock to prevent against concurrent
4431
+	 * directory changes moving parent pointer. For regular files we've
4432
+	 * historically always done this. The lockdep locking subclasses are
4433
+	 * somewhat arbitrary but RENAME_EXCHANGE in particular can swap
4434
+	 * regular files and directories so it's difficult to tell which
4435
+	 * subclasses to use.
4436
+	 */
4437
+	lock_two_inodes(source, target, I_MUTEX_NORMAL, I_MUTEX_NONDIR2);
43784438 
43794439 	error = -EBUSY;
43804440 	if (is_local_mountpoint(old_dentry) || is_local_mountpoint(new_dentry))
....@@ -4418,9 +4478,8 @@
44184478 			d_exchange(old_dentry, new_dentry);
44194479 	}
44204480 out:
4421
-	if (!is_dir || (flags & RENAME_EXCHANGE))
4422
-		unlock_two_nondirectories(source, target);
4423
-	else if (target)
4481
+	inode_unlock(source);
4482
+	if (target)
44244483 		inode_unlock(target);
44254484 	dput(new_dentry);
44264485 	if (!error) {