netfilter: ip6t_eui: fix read outside array bounds
Use memcmp() instead of open coded comparison that reads one byte past
the intended end.
Based on patch from Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv6/netfilter/ip6t_eui64.c b/net/ipv6/netfilter/ip6t_eui64.c
index db610ba..ca287f6 100644
--- a/net/ipv6/netfilter/ip6t_eui64.c
+++ b/net/ipv6/netfilter/ip6t_eui64.c
@@ -23,7 +23,6 @@
eui64_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
{
unsigned char eui64[8];
- int i = 0;
if (!(skb_mac_header(skb) >= skb->head &&
skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
@@ -42,12 +41,8 @@
eui64[4] = 0xfe;
eui64[0] ^= 0x02;
- i = 0;
- while (ipv6_hdr(skb)->saddr.s6_addr[8 + i] == eui64[i]
- && i < 8)
- i++;
-
- if (i == 8)
+ if (!memcmp(ipv6_hdr(skb)->saddr.s6_addr + 8, eui64,
+ sizeof(eui64)))
return true;
}
}