On Fri, May 5, 2017 at 11:11 AM, Steffen Klassert
<steffen.klass...@secunet.com> wrote:
> On Tue, May 02, 2017 at 06:45:03PM +0200, Andrey Konovalov wrote:
>> Hi,
>>
>> I've got the following error report while fuzzing the kernel with syzkaller.
>>
>> On commit d3b5d35290d729a2518af00feca867385a1b08fa (4.11).
>>
>> A reproducer and .config are attached.
>>
>> ==================================================================
>> BUG: KASAN: slab-out-of-bounds in pfkey_compile_policy+0x8e6/0xd40 at
>> addr ffff88006701f798
>> Read of size 1280 by task a.out/4181
>
>
> This bug was introduced twelve years ago...
>
> This patch is based just on code review, I don't have an option to
> function test this. But I see that we now exit with -EINVAL before the
> memcpy that causes the slab-out-of-bounds when using your reproducer,
> so it should at least fix the bug.
Hi Steffen,
This patch fixes the issue for me.
Thanks!
Tested-by: Andrey Konovalov <andreyk...@google.com>
>
> Subject: [PATCH RFC] af_key: Fix slab-out-of-bounds in pfkey_compile_policy.
>
> 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 <andreyk...@google.com>
> Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com>
> ---
> net/key/af_key.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/key/af_key.c b/net/key/af_key.c
> index c1950bb..512dc43 100644
> --- a/net/key/af_key.c
> +++ b/net/key/af_key.c
> @@ -3285,7 +3285,7 @@ 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;
> }
> --
> 2.7.4
>
>
