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| author | Al Viro <viro@zeniv.linux.org.uk> | 2011-06-03 18:24:58 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-06-03 18:24:58 -0400 |
| commit | 9e1f1de02c2275d7172e18dc4e7c2065777611bf (patch) | |
| tree | 15e9d202e64275cdbff6ed1d54804da5966d7d8d /include | |
| parent | 1fa7b6a29c61358cc2ca6f64cef4aa0e1a7ca74c (diff) | |
| download | linux-0-day-9e1f1de02c2275d7172e18dc4e7c2065777611bf.tar.gz linux-0-day-9e1f1de02c2275d7172e18dc4e7c2065777611bf.tar.xz | |
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.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index c55d6b7cd5d68..646a1836152a9 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; } |