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 <julia.lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 914c7d5..b0e4fb8 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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) +