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authorSabrina Dubroca <sd@queasysnail.net>2017-07-19 22:28:55 +0200
committerDavid S. Miller <davem@davemloft.net>2017-07-19 22:50:14 -0700
commit6399f1fae4ec29fab5ec76070435555e256ca3a6 (patch)
tree3bf30f18bbd1c9eb4b37786cba7fe73e70ea014b /net/ipv6/output_core.c
parent1e6c22aef28364dcc5f03c04a05ec463bc2b3431 (diff)
downloadlinux-stericsson-6399f1fae4ec29fab5ec76070435555e256ca3a6.tar.gz
ipv6: avoid overflow of offset in ip6_find_1stfragopt
In some cases, offset can overflow and can cause an infinite loop in ip6_find_1stfragopt(). Make it unsigned int to prevent the overflow, and cap it at IPV6_MAXPLEN, since packets larger than that should be invalid. This problem has been here since before the beginning of git history. Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/output_core.c')
-rw-r--r--net/ipv6/output_core.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index e9065b8d3af8..abb2c307fbe8 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -78,7 +78,7 @@ EXPORT_SYMBOL(ipv6_select_ident);
int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
- u16 offset = sizeof(struct ipv6hdr);
+ unsigned int offset = sizeof(struct ipv6hdr);
unsigned int packet_len = skb_tail_pointer(skb) -
skb_network_header(skb);
int found_rhdr = 0;
@@ -86,6 +86,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
while (offset <= packet_len) {
struct ipv6_opt_hdr *exthdr;
+ unsigned int len;
switch (**nexthdr) {
@@ -111,7 +112,10 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
offset);
- offset += ipv6_optlen(exthdr);
+ len = ipv6_optlen(exthdr);
+ if (len + offset >= IPV6_MAXPLEN)
+ return -EINVAL;
+ offset += len;
*nexthdr = &exthdr->nexthdr;
}