ipv6: Check ip6_find_1stfragopt() return value properly.

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 <julia.lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 7dd7eb9513bd02184d45f000ab69d78cb1fa1531)

Orabug: 26175248
CVE-2017-9074

Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>
Reviewed-by: Qing Huang <qing.huang@oracle.com>
Reviewed-by: Jack Vogel <jack.vogel@oracle.com>
 Conflicts:
	net/ipv6/ip6_offload.c

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index f334c5c1a1c9842bcff528b9e8a0fed7b308270d..2d81319e48a407b126a483878a102d1c39a17c78 100644 (file)
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -62,7 +62,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
        const struct net_offload *ops;
        int proto;
        struct frag_hdr *fptr;
-       unsigned int unfrag_ip6hlen;
+       unsigned int payload_len;
        u8 *prevhdr;
        int offset = 0;
        bool encap, udpfrag;
@@ -121,10 +121,10 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
                skb->network_header = (u8 *)ipv6h - skb->head;
 
                if (udpfrag) {
-                       unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
-                       if (unfrag_ip6hlen < 0)
-                               return ERR_PTR(unfrag_ip6hlen);
-                       fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
+                       int err = ip6_find_1stfragopt(skb, &prevhdr);
+                       if (err < 0)
+                               return ERR_PTR(err);
+                       fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
                        fptr->frag_off = htons(offset);
                        if (skb->next)
                                fptr->frag_off |= htons(IP6_MF);

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1e70cb1c5aeb520a6ed9db029eaa42118d4ab1e0..6b96198cc5ebdd72e6801b9466fdb8409d06b0e6 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -641,11 +641,10 @@ int ip6_fragment(struct sock *sk, struct sk_buff *skb,
        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_offload.c b/net/ipv6/udp_offload.c
index 04ed91da6cc94692943486084c9eb3f0cf9b4f03..01582966ffa0b18672d3a7c8ec0ec12f1a73abba 100644 (file)
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -29,6 +29,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
        u8 frag_hdr_sz = sizeof(struct frag_hdr);
        __wsum csum;
        int tnl_hlen;
+       int err;
 
        mss = skb_shinfo(skb)->gso_size;
        if (unlikely(skb->len <= mss))
@@ -97,9 +98,10 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
                /* 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)) +