From f7c2d2d7ebf9a110cafbe53199457c318f61a192 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 17 May 2017 22:54:11 -0400 Subject: ipv6: Check ip6_find_1stfragopt() return value properly. commit 7dd7eb9513bd02184d45f000ab69d78cb1fa1531 upstream. Do not use unsigned variables to see if it returns a negative error or not. Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options") Reported-by: Julia Lawall Signed-off-by: David S. Miller [bwh: Backported to 3.2: adjust filenames, context] Signed-off-by: Ben Hutchings --- net/ipv6/af_inet6.c | 9 ++++----- net/ipv6/ip6_output.c | 7 +++---- net/ipv6/udp.c | 8 +++++--- 3 files changed, 12 insertions(+), 12 deletions(-) diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 914c7d5..b0e4fb8 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -785,7 +785,6 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, u32 features) const struct inet6_protocol *ops; int proto; struct frag_hdr *fptr; - unsigned int unfrag_ip6hlen; u8 *prevhdr; int offset = 0; @@ -824,11 +823,11 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, u32 features) ipv6h->payload_len = htons(skb->len - skb->mac_len - sizeof(*ipv6h)); if (proto == IPPROTO_UDP) { - unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); - if (unfrag_ip6hlen < 0) - return ERR_PTR(unfrag_ip6hlen); + int err = ip6_find_1stfragopt(skb, &prevhdr); + if (err < 0) + return ERR_PTR(err); fptr = (struct frag_hdr *)(skb_network_header(skb) + - unfrag_ip6hlen); + err); fptr->frag_off = htons(offset); if (skb->next != NULL) fptr->frag_off |= htons(IP6_MF); diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index dd31060..81a7803 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -631,11 +631,10 @@ int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) u8 *prevhdr, nexthdr = 0; struct net *net = dev_net(skb_dst(skb)->dev); - hlen = ip6_find_1stfragopt(skb, &prevhdr); - if (hlen < 0) { - err = hlen; + err = ip6_find_1stfragopt(skb, &prevhdr); + if (err < 0) goto fail; - } + hlen = err; nexthdr = *prevhdr; mtu = ip6_skb_dst_mtu(skb); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 8157ae0..5f0d519 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1316,6 +1316,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, u32 features) u8 frag_hdr_sz = sizeof(struct frag_hdr); int offset; __wsum csum; + int err; mss = skb_shinfo(skb)->gso_size; if (unlikely(skb->len <= mss)) @@ -1352,9 +1353,10 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, u32 features) /* Find the unfragmentable header and shift it left by frag_hdr_sz * bytes to insert fragment header. */ - unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); - if (unfrag_ip6hlen < 0) - return ERR_PTR(unfrag_ip6hlen); + err = ip6_find_1stfragopt(skb, &prevhdr); + if (err < 0) + return ERR_PTR(err); + unfrag_ip6hlen = err; nexthdr = *prevhdr; *prevhdr = NEXTHDR_FRAGMENT; unfrag_len = skb_network_header(skb) - skb_mac_header(skb) + -- cgit v1.1