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ipv6: Check ip6_find_1stfragopt() return value properly.

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

Fixes: 2423496af3 ("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>
This commit is contained in:
David S. Miller 2017-05-17 22:54:11 -04:00
parent 579f1d926c
commit 7dd7eb9513
3 changed files with 12 additions and 12 deletions
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9
net/ipv6/ip6_offload.c
View File

@ -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);

7
net/ipv6/ip6_output.c
View File

@ -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);

8
net/ipv6/udp_offload.c
View File

@ -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)) +