From 4c0939a29e2c1739f0141c87ecd7940825734a22 Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Fri, 29 Sep 2017 13:41:05 +0200 Subject: [PATCH] ip xfrm: use correct key length for netlink message When SA is added manually using "ip xfrm state add", xfrm_state_modify() uses alg_key_len field of struct xfrm_algo for the length of key passed to kernel in the netlink message. However alg_key_len is bit length of the key while we need byte length here. This is usually harmless as kernel ignores the excess data but when the bit length of the key exceeds 512 (XFRM_ALGO_KEY_BUF_SIZE), it can result in buffer overflow. We can simply divide by 8 here as the only place setting alg_key_len is in xfrm_algo_parse() where it is always set to a multiple of 8 (and there are already multiple places using "algo->alg_key_len / 8"). Signed-off-by: Michal Kubecek --- ip/xfrm_state.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ip/xfrm_state.c b/ip/xfrm_state.c index 4483fb8f7..99fdec232 100644 --- a/ip/xfrm_state.c +++ b/ip/xfrm_state.c @@ -539,7 +539,7 @@ static int xfrm_state_modify(int cmd, unsigned int flags, int argc, char **argv) xfrm_algo_parse((void *)&alg, type, name, key, buf, sizeof(alg.buf)); - len += alg.u.alg.alg_key_len; + len += alg.u.alg.alg_key_len / 8; addattr_l(&req.n, sizeof(req.buf), type, (void *)&alg, len); -- 2.47.2