[PATCH] protect ext2 ioctl modifying append_only immutable etc with i_mutex
Port commit a090d9132c1e53e3517111123680c15afb25c0a4 into ext2:
All modifications of ->i_flags in inodes that might be visible to somebody
else must be under ->i_mutex. That patch fixes ext2 ioctl() setting S_APPEND.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index 1dfba77..e3cf8c8 100644
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -44,6 +44,7 @@
if (!S_ISDIR(inode->i_mode))
flags &= ~EXT2_DIRSYNC_FL;
+ mutex_lock(&inode->i_mutex);
oldflags = ei->i_flags;
/*
@@ -53,13 +54,16 @@
* This test looks nicer. Thanks to Pauline Middelink
*/
if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
- if (!capable(CAP_LINUX_IMMUTABLE))
+ if (!capable(CAP_LINUX_IMMUTABLE)) {
+ mutex_unlock(&inode->i_mutex);
return -EPERM;
+ }
}
flags = flags & EXT2_FL_USER_MODIFIABLE;
flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
ei->i_flags = flags;
+ mutex_unlock(&inode->i_mutex);
ext2_set_inode_flags(inode);
inode->i_ctime = CURRENT_TIME_SEC;