ipv6: Check ip6_find_1stfragopt() return value properly.

Do not use unsigned variables to see if it returns a negative
error or not.

Fixes: f131fb620cdb ("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>

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index eab36abc9f22910e9814df1f9470d53224132a22..280268f1dd7b0972d7fadbcc9e28b043ceae423d 100644 (file)
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -63,7 +63,6 @@ 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;
@@ -116,10 +115,10 @@ 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 01deecda2f8432346ab68811f57699618bcea520..d4a31becbd25dda895d7391e1e65c2de237bf2a3 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -597,11 +597,10 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
        int ptr, offset = 0, err = 0;
        u8 *prevhdr, nexthdr = 0;
 
-       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 b348cff4739510b0d55bb601d29a7adf27b24f6d..a2267f80febbb6f31459097f27bd89d51d0f2b11 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))
@@ -90,9 +91,10 @@ 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)) +