This is a note to let you know that I've just added the patch titled
fs: Check for invalid i_uid in may_follow_link()
to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-check-for-invalid-i_uid-in-may_follow_link.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2d7f9e2ad35e4e7a3086231f19bfab33c6a8a64a Mon Sep 17 00:00:00 2001
From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Date: Tue, 26 Apr 2016 14:36:23 -0500
Subject: fs: Check for invalid i_uid in may_follow_link()
From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
commit 2d7f9e2ad35e4e7a3086231f19bfab33c6a8a64a upstream.
Filesystem uids which don't map into a user namespace may result
in inode->i_uid being INVALID_UID. A symlink and its parent
could have different owners in the filesystem can both get
mapped to INVALID_UID, which may result in following a symlink
when this would not have otherwise been permitted when protected
symlinks are enabled.
Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -901,6 +901,7 @@ static inline int may_follow_link(struct
{
const struct inode *inode;
const struct inode *parent;
+ kuid_t puid;
if (!sysctl_protected_symlinks)
return 0;
@@ -916,7 +917,8 @@ static inline int may_follow_link(struct
return 0;
/* Allowed if parent directory and link owner match. */
- if (uid_eq(parent->i_uid, inode->i_uid))
+ puid = parent->i_uid;
+ if (uid_valid(puid) && uid_eq(puid, inode->i_uid))
return 0;
if (nd->flags & LOOKUP_RCU)
Patches currently in stable-queue which might be from seth.forshee@xxxxxxxxxxxxx are
queue-4.7/cred-reject-inodes-with-invalid-ids-in-set_create_file_as.patch
queue-4.7/fs-check-for-invalid-i_uid-in-may_follow_link.patch
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