diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2017-07-19 22:28:55 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-08-26 02:14:48 +0100 |
| commit | 276cb60b67f5c99bf278b5371c6643e4af63f75d (patch) | |
| tree | 5c08b41cdd47e6e30ca4690700bae73ed56f2fe5 | |
| parent | 2cbc76ab0654c9759e390899584c5f788e21dc5a (diff) | |
ipv6: avoid overflow of offset in ip6_find_1stfragopt
commit 6399f1fae4ec29fab5ec76070435555e256ca3a6 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | net/ipv6/output_core.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index 0fcaf38006f9..19f9a4a339b5 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -44,7 +44,7 @@ EXPORT_SYMBOL_GPL(ipv6_proxy_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; @@ -52,6 +52,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) while (offset <= packet_len) { struct ipv6_opt_hdr *exthdr; + unsigned int len; switch (**nexthdr) { @@ -77,7 +78,10 @@ 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; } |