2017-08-02 17:51:07

by Vladis Dronov

Subject: [PATCH] xfrm: policy: check policy direction value

The 'dir' parameter in xfrm_migrate() is a user-controlled byte which is used
as an array index. This can lead to an out-of-bound access, kernel lockup and
DoS. Add a check for the 'dir' value.

This fixes CVE-2017-11600.

References: https://bugzilla.redhat.com/show_bug.cgi?id=1474928
Fixes: 80c9abaabf42 ("[XFRM]: Extension for dynamic update of endpoint address(es)")
Cc: <[email protected]> # v2.6.21-rc1
Reported-by: "bo Zhang" <[email protected]>
Signed-off-by: Vladis Dronov <[email protected]>
---
net/xfrm/xfrm_policy.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index ff61d85..6f5a0dad 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3308,9 +3308,15 @@ int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
struct xfrm_state *x_new[XFRM_MAX_DEPTH];
struct xfrm_migrate *mp;

+ /* Stage 0 - sanity checks */
if ((err = xfrm_migrate_check(m, num_migrate)) < 0)
goto out;

+ if (dir >= XFRM_POLICY_MAX) {
+ err = -EINVAL;
+ goto out;
+ }
+
/* Stage 1 - find policy */
if ((pol = xfrm_migrate_policy_find(sel, dir, type, net)) == NULL) {
err = -ENOENT;
--
2.9.4

2017-08-03 11:05:52

by Steffen Klassert

Subject: Re: [PATCH] xfrm: policy: check policy direction value

On Wed, Aug 02, 2017 at 07:50:14PM +0200, Vladis Dronov wrote:
> The 'dir' parameter in xfrm_migrate() is a user-controlled byte which is used
> as an array index. This can lead to an out-of-bound access, kernel lockup and
> DoS. Add a check for the 'dir' value.
>
> This fixes CVE-2017-11600.
>
> References: https://bugzilla.redhat.com/show_bug.cgi?id=1474928
> Fixes: 80c9abaabf42 ("[XFRM]: Extension for dynamic update of endpoint address(es)")
> Cc: <[email protected]> # v2.6.21-rc1
> Reported-by: "bo Zhang" <[email protected]>
> Signed-off-by: Vladis Dronov <[email protected]>

Applied to the ipsec tree, thanks!