| commit | 3e36aba757f76673007a80b3cd56a4062c2e3462 | |
| author | Greg Kurz <groug@kaod.org> | |
| Sun, 26 Feb 2017 22:42:43 +0000 (26 23:42 +0100) | ||
| committer | Greg Kurz <groug@kaod.org> | |
| Tue, 28 Feb 2017 10:21:15 +0000 (28 11:21 +0100) | ||
| tree | fde3ba123eb07da546df251adc8fc3c710949735 | treesnapshot (tar.gz zip) |
| parent | 5507904e362df252f6065cb27d1ff98372db6abc | commitdiff |
9pfs: local: lsetxattr: don't follow symlinks
The local_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().
local_lsetxattr() 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_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().
local_lsetxattr() 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>