[PATCH AUTOSEL for 4.9 36/50] IPsec: do not ignore crypto err in ah4 input

From: Levin, Alexander (Sasha Levin)
Date: Tue Oct 24 2017 - 22:14:35 EST


From: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>

[ Upstream commit ebd89a2d0675f1325c2be5b7576fd8cb7e8defd0 ]

ah4 input processing uses the asynchronous hash crypto API which
supplies an error code as part of the operation completion but
the error code was being ignored.

Treat a crypto API error indication as a verification failure.

While a crypto API reported error would almost certainly result
in a memcpy of the digest failing anyway and thus the security
risk seems minor, performing a memory compare on what might be
uninitialized memory is wrong.

Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
net/ipv4/ah4.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index f2a71025a770..22377c8ff14b 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -270,6 +270,9 @@ static void ah_input_done(struct crypto_async_request *base, int err)
int ihl = ip_hdrlen(skb);
int ah_hlen = (ah->hdrlen + 2) << 2;

+ if (err)
+ goto out;
+
work_iph = AH_SKB_CB(skb)->tmp;
auth_data = ah_tmp_auth(work_iph, ihl);
icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
--
2.11.0