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| author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-01-12 14:06:34 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-01-14 12:08:26 -0800 |
| commit | 53d06121542c36ec0f0e5504c8358a768e25cb9a (patch) | |
| tree | 052c22422ad50d2cd9515f706ab9005a10736b96 | |
| parent | fe18bd1cf0827a654fd75079101c551b17e1c639 (diff) | |
| download | lwn-53d06121542c36ec0f0e5504c8358a768e25cb9a.tar.gz lwn-53d06121542c36ec0f0e5504c8358a768e25cb9a.zip | |
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>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -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 5e2d98d10c5d..8e209cecc3b8 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1543,7 +1543,7 @@ 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); @@ -1562,7 +1562,7 @@ 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. |