[PATCH] net/ipv6: Fix CALIPSO causing GPF with datagram support
From: Richard Haines <hidden>
Date: 2017-06-05 15:44:40
Also in:
linux-security-module, selinux
Subsystem:
networking [general], networking [labeled] (netlabel, labeled ipsec, secmark), the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Paul Moore, Linus Torvalds
When using CALIPSO with IPPROTO_UDP it is possible to trigger a GPF as the IP header may have moved. Also update the payload length after adding the CALIPSO option. Signed-off-by: Richard Haines <redacted> --- net/ipv6/calipso.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c
index 37ac9de..8d772fe 100644
--- a/net/ipv6/calipso.c
+++ b/net/ipv6/calipso.c@@ -1319,7 +1319,7 @@ static int calipso_skbuff_setattr(struct sk_buff *skb, struct ipv6hdr *ip6_hdr; struct ipv6_opt_hdr *hop; unsigned char buf[CALIPSO_MAX_BUFFER]; - int len_delta, new_end, pad; + int len_delta, new_end, pad, payload; unsigned int start, end; ip6_hdr = ipv6_hdr(skb);
@@ -1346,6 +1346,8 @@ static int calipso_skbuff_setattr(struct sk_buff *skb, if (ret_val < 0) return ret_val; + ip6_hdr = ipv6_hdr(skb); /* Reset as skb_cow() may have moved it */ + if (len_delta) { if (len_delta > 0) skb_push(skb, len_delta);
@@ -1355,6 +1357,8 @@ static int calipso_skbuff_setattr(struct sk_buff *skb, sizeof(*ip6_hdr) + start); skb_reset_network_header(skb); ip6_hdr = ipv6_hdr(skb); + payload = ntohs(ip6_hdr->payload_len); + ip6_hdr->payload_len = htons(payload + len_delta); } hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
--
2.9.4