af_key: Fix slab-out-of-bounds in pfkey_compile_policy.

commit d90c902449a7561f1b1d58ba5a0d11728ce8b0b2 upstream.

The sadb_x_sec_len is stored in the unit 'byte divided by eight'.
So we have to multiply this value by eight before we can do
size checks. Otherwise we may get a slab-out-of-bounds when
we memcpy the user sec_ctx.

Fixes: df71837d502 ("[LSM-IPSec]: Security association restriction.")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 1b19d6a..cb3c1c4 100644 (file)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3230,7 +3230,7 @@ static struct xfrm_policy *pfkey_compile_policy(struct sock *sk, int opt,
                p += pol->sadb_x_policy_len*8;
                sec_ctx = (struct sadb_x_sec_ctx *)p;
                if (len < pol->sadb_x_policy_len*8 +
-                   sec_ctx->sadb_x_sec_len) {
+                   sec_ctx->sadb_x_sec_len*8) {
                        *dir = -EINVAL;
                        goto out;
                }