| Message ID | 9597319ba96a966ee580bd04f36584b52dfa2c48.1503059705.git.sbrivio@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Stefano Brivio <sbrivio@redhat.com> Date: Fri, 18 Aug 2017 14:40:53 +0200 > A packet length of exactly IPV6_MAXPLEN is allowed, we should > refuse parsing options only if the size is 64KiB or more. > > While at it, remove one extra variable and one assignment which > were also introduced by the commit that introduced the size > check. Checking the sum 'offset + len' and only later adding > 'len' to 'offset' doesn't provide any advantage over directly > summing to 'offset' and checking it. > > Fixes: 6399f1fae4ec ("ipv6: avoid overflow of offset in ip6_find_1stfragopt") > Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Applied, thanks.
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index abb2c307fbe8..a338bbc33cf3 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -86,7 +86,6 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) while (offset <= packet_len) { struct ipv6_opt_hdr *exthdr; - unsigned int len; switch (**nexthdr) { @@ -112,10 +111,9 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + offset); - len = ipv6_optlen(exthdr); - if (len + offset >= IPV6_MAXPLEN) + offset += ipv6_optlen(exthdr); + if (offset > IPV6_MAXPLEN) return -EINVAL; - offset += len; *nexthdr = &exthdr->nexthdr; }
A packet length of exactly IPV6_MAXPLEN is allowed, we should refuse parsing options only if the size is 64KiB or more. While at it, remove one extra variable and one assignment which were also introduced by the commit that introduced the size check. Checking the sum 'offset + len' and only later adding 'len' to 'offset' doesn't provide any advantage over directly summing to 'offset' and checking it. Fixes: 6399f1fae4ec ("ipv6: avoid overflow of offset in ip6_find_1stfragopt") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> --- net/ipv6/output_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)