From: Steffen Klassert <steffen.klassert@secunet.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: net/key: slab-out-of-bounds in pfkey_compile_policy
Date: Fri, 5 May 2017 11:11:05 +0200 [thread overview]
Message-ID: <20170505091105.GA9813@secunet.com> (raw)
In-Reply-To: <CAAeHK+xqxvEWMXS9sDNi2seUqFzJkijKJhivB8JDehpCJvBAaw@mail.gmail.com>
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.
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 <andreyknvl@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@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
next prev parent reply other threads:[~2017-05-05 9:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-02 16:45 net/key: slab-out-of-bounds in pfkey_compile_policy Andrey Konovalov
2017-05-02 16:46 ` Andrey Konovalov
2017-05-02 16:47 ` Andrey Konovalov
2017-05-05 9:11 ` Steffen Klassert [this message]
2017-05-05 12:18 ` Andrey Konovalov
2017-05-08 11:49 ` Steffen Klassert
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