| commit | 56ad3e54dad6cdcee8668d170df161d89581846f | |
| author | Greg Kurz <groug@kaod.org> | |
| Sun, 26 Feb 2017 22:42:26 +0000 (26 23:42 +0100) | ||
| committer | Greg Kurz <groug@kaod.org> | |
| Tue, 28 Feb 2017 10:21:15 +0000 (28 11:21 +0100) | ||
| tree | 1408dc37298a3c74d867820793ecfc8fd0dfa317 | treesnapshot (tar.gz zip) |
| parent | 996a0d76d7e756e4023ef79bc37bfe629b9eaca7 | commitdiff |
9pfs: local: lgetxattr: don't follow symlinks
The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().
local_lgetxattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().
local_lgetxattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>