diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-01-15 23:39:01 +0200 |
|---|---|---|
| committer | Adrian Bunk <bunk@kernel.org> | 2008-01-16 01:48:15 +0200 |
| commit | fb7a7420ea718a6504e5c620ada0e42b23446b27 (patch) | |
| tree | 72a6690d9bbf86ab95f5ef5c72d0954ed2bcd8bc | |
| parent | 0c0b10ef376c7b320197160f21d6c626ab0a6f4d (diff) | |
Use access mode instead of open flags to determine needed permissions (CVE-2008-0001)
patch 974a9f0b47da74e28f68b9c8645c3786aa5ace1a in mainline
Way back when (in commit 834f2a4a1554dc5b2598038b3fe8703defcbe467, aka
"VFS: Allow the filesystem to return a full file pointer on open intent"
to be exact), Trond changed the open logic to keep track of the original
flags to a file open, in order to pass down the the intent of a dentry
lookup to the low-level filesystem.
However, when doing that reorganization, it changed the meaning of
namei_flags, and thus inadvertently changed the test of access mode for
directories (and RO filesystem) to use the wrong flag. So fix those
test back to use access mode ("acc_mode") rather than the open flag
("flag").
Issue noticed by Bill Roman at Datalight.
Reported-and-tested-by: Bill Roman <bill.roman@datalight.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
| -rw-r--r-- | fs/namei.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c index 3ece3a93dd9..0d2d26823f7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1489,7 +1489,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) if (S_ISLNK(inode->i_mode)) return -ELOOP; - if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE)) + if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE)) return -EISDIR; error = vfs_permission(nd, acc_mode); @@ -1508,7 +1508,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) return -EACCES; flag &= ~O_TRUNC; - } else if (IS_RDONLY(inode) && (flag & FMODE_WRITE)) + } else if (IS_RDONLY(inode) && (acc_mode & MAY_WRITE)) return -EROFS; /* * An append-only file must be opened in append mode for writing. |