[ 06/48] fix autofs/afs/etc. magic mountpoint breakage

From: Willy Tarreau
Date: Sun Nov 16 2014 - 17:06:00 EST

2.6.32-longterm review patch. If anyone has any objections, please let me know.


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

We end up trying to kfree() nd.last.name on open("/mnt/tmp", O_CREAT)
if /mnt/tmp is an autofs direct mount. The reason is that nd.last_type
is bogus here; we want LAST_BIND for everything of that kind and we
get LAST_NORM left over from finding parent directory.

So make sure that it *is* set properly; set to LAST_BIND before
doing ->follow_link() - for normal symlinks it will be changed
by __vfs_follow_link() and everything else needs it set that way.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
(cherry picked from commit 86acdca1b63e6890540fa19495cfc708beff3d8b)
[wt: fixes CVE-2014-0203]
Signed-off-by: Willy Tarreau <w@xxxxxx>
fs/namei.c | 1 +
fs/proc/base.c | 1 -
2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index b0afbd4..0d766d2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -635,6 +635,7 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata
+ nd->last_type = LAST_BIND;
cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
error = PTR_ERR(cookie);
if (!IS_ERR(cookie)) {
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 67f7dc0..c75c5cd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1381,7 +1381,6 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
goto out;

error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
- nd->last_type = LAST_BIND;
return ERR_PTR(error);

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