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authorAl Viro <viro@zeniv.linux.org.uk>2011-06-03 18:24:58 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2011-06-03 18:24:58 -0400
commit9e1f1de02c2275d7172e18dc4e7c2065777611bf (patch)
tree15e9d202e64275cdbff6ed1d54804da5966d7d8d /include
parent1fa7b6a29c61358cc2ca6f64cef4aa0e1a7ca74c (diff)
more conservative S_NOSEC handling
Caching "we have already removed suid/caps" was overenthusiastic as merged. On network filesystems we might have had suid/caps set on another client, silently picked by this client on revalidate, all of that *without* clearing the S_NOSEC flag. AFAICS, the only reasonably sane way to deal with that is * new superblock flag; unless set, S_NOSEC is not going to be set. * local block filesystems set it in their ->mount() (more accurately, mount_bdev() does, so does btrfs ->mount(), users of mount_bdev() other than local block ones clear it) * if any network filesystem (or a cluster one) wants to use S_NOSEC, it'll need to set MS_NOSEC in sb->s_flags *AND* take care to clear S_NOSEC when inode attribute changes are picked from other clients. It's not an earth-shattering hole (anybody that can set suid on another client will almost certainly be able to write to the file before doing that anyway), but it's a bug that needs fixing. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
-rw-r--r--include/linux/fs.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c55d6b7cd5d6..646a1836152a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -208,6 +208,7 @@ struct inodes_stat_t {
#define MS_KERNMOUNT (1<<22) /* this is a kern_mount call */
#define MS_I_VERSION (1<<23) /* Update inode I_version field */
#define MS_STRICTATIME (1<<24) /* Always perform atime updates */
+#define MS_NOSEC (1<<28)
#define MS_BORN (1<<29)
#define MS_ACTIVE (1<<30)
#define MS_NOUSER (1<<31)
@@ -2591,7 +2592,7 @@ static inline int is_sxid(mode_t mode)
static inline void inode_has_no_xattr(struct inode *inode)
{
- if (!is_sxid(inode->i_mode))
+ if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))
inode->i_flags |= S_NOSEC;
}