From: Ben Hutchings Date: Thu, 28 Jan 2016 00:49:22 +0000 (+0000) Subject: Fix possible stack buffer overflow in s46_to_env when copying IPv6 prefixes X-Git-Tag: debian/1.1+git20160131-1~8^2~5 X-Git-Url: https://git.decadent.org.uk/gitweb/?p=odhcp6c.git;a=commitdiff_plain;h=fe22a82fa0bd187a39d130d593c4d56d4749a174;hp=62968599557ac81b0f811481f6b06886ddcf0cdb Fix possible stack buffer overflow in s46_to_env when copying IPv6 prefixes An 8-bit prefix-length field can be as large as 255, but values larger than 128 will result in a buffer overflow when copying to in6. Signed-off-by: Ben Hutchings --- diff --git a/src/script.c b/src/script.c index 89cb0d6..3579331 100644 --- a/src/script.c +++ b/src/script.c @@ -282,7 +282,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len size_t prefix6len = rule->prefix6_len; prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1; - if (olen < sizeof(struct dhcpv6_s46_rule) + prefix6len) + if (prefix6len > sizeof(in6) || + olen < sizeof(struct dhcpv6_s46_rule) + prefix6len) continue; memcpy(&in6, rule->ipv6_prefix, prefix6len); @@ -311,7 +312,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len size_t prefix6len = dmr->dmr_prefix6_len; prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1; - if (olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len) + if (prefix6len > sizeof(in6) || + olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len) continue; memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len); @@ -330,7 +332,8 @@ static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len size_t prefix6len = bind->bindprefix6_len; prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1; - if (olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len) + if (prefix6len > sizeof(in6) || + olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len) continue; memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);