[Devel] [PATCH RH7] ms/xfrm: check id proto in validate_tmpl()

[Vasily Averin]

From: Cong Wang <xiyou.wangcong at gmail.com>

syzbot reported a kernel warning in xfrm_state_fini(), which
indicates that we have entries left in the list
net->xfrm.state_all whose proto is zero. And
xfrm_id_proto_match() doesn't consider them as a match with
IPSEC_PROTO_ANY in this case.

Proto with value 0 is probably not a valid value, at least
verify_newsa_info() doesn't consider it valid either.

This patch fixes it by checking the proto value in
validate_tmpl() and rejecting invalid ones, like what iproute2
does in xfrm_xfrmproto_getbyname().

Reported-by: syzbot <syzkaller at googlegroups.com>
Cc: Steffen Klassert <steffen.klassert at secunet.com>
Cc: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Cong Wang <xiyou.wangcong at gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert at secunet.com>

(cherry-picked from commit 6a53b7593233ab9e4f96873ebacc0f653a55c3e1)
https://jira.sw.ru/browse/PSBM-123084
Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
---
 net/xfrm/xfrm_user.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 472e1e2..e2dd99f 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1391,6 +1391,21 @@ static int validate_tmpl(int nr, struct xfrm_user_tmpl *ut, u16 family)
 		default:
 			return -EINVAL;
 		}
+
+		switch (ut[i].id.proto) {
+		case IPPROTO_AH:
+		case IPPROTO_ESP:
+		case IPPROTO_COMP:
+#if IS_ENABLED(CONFIG_IPV6)
+		case IPPROTO_ROUTING:
+		case IPPROTO_DSTOPTS:
+#endif
+		case IPSEC_PROTO_ANY:
+			break;
+		default:
+			return -EINVAL;
+		}
+
 	}
 
 	return 0;
-- 
1.8.3.1