diff options
| author | Teddy Engel <engel.teddy@gmail.com> | 2026-05-19 21:36:33 +0000 |
|---|---|---|
| committer | Cy Schubert <cy@FreeBSD.org> | 2026-05-20 15:33:43 +0000 |
| commit | c028080749c09e68c555155df0e9f681ba63c6ae (patch) | |
| tree | 03efa9d6a7b6c0f3a94081fae8eaa6cf169ad28d | |
| parent | cdc40489a7a617b742e295cf9005b3569b45e823 (diff) | |
ipfilter: Fix NULL dereferences in ipf_checkicmp6matchingstate()
Add NULL checks for ic6 (the ICMPv6 header pointer from fin->fin_dp)
and oic (the inner ICMPv6 header from ofin.fin_dp after ipf_makefrip).
These pointers can be NULL when processing malformed ICMPv6 error
packets with extension headers.
Also fix the length validation: the original check (fin->fin_plen <
sizeof(ip6_t)) could never trigger because an earlier check already
ensures fin->fin_plen >= ICMP6ERR_MINPKTLEN (48). Replace with a proper
check that fin->fin_dlen contains at least ICMPERR_ICMPHLEN +
sizeof(ip6_t) bytes to ensure sufficient data exists for both the
ICMPv6 error header and the embedded IPv6 header.
PR: 288333
MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/2214
Signed-off-by: Teddy Engel <engel.teddy@gmail.com>
| -rw-r--r-- | sys/netpfil/ipfilter/netinet/ip_state.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/sys/netpfil/ipfilter/netinet/ip_state.c b/sys/netpfil/ipfilter/netinet/ip_state.c index c8d6e4e0feb3..d5a04e326321 100644 --- a/sys/netpfil/ipfilter/netinet/ip_state.c +++ b/sys/netpfil/ipfilter/netinet/ip_state.c @@ -4364,9 +4364,13 @@ ipf_checkicmp6matchingstate(fr_info_t *fin) } ic6 = fin->fin_dp; + if (ic6 == NULL) { + SBUMPD(ipf_state_stats, iss_icmp6_miss); + return (NULL); + } oip6 = (ip6_t *)((char *)ic6 + ICMPERR_ICMPHLEN); - if (fin->fin_plen < sizeof(*oip6)) { + if (fin->fin_dlen < ICMPERR_ICMPHLEN + sizeof(*oip6)) { SBUMPD(ipf_state_stats, iss_icmp_short); return (NULL); } @@ -4408,6 +4412,10 @@ ipf_checkicmp6matchingstate(fr_info_t *fin) if (oip6->ip6_nxt == IPPROTO_ICMPV6) { oic = ofin.fin_dp; + if (oic == NULL) { + SBUMPD(ipf_state_stats, iss_icmp6_miss); + return (NULL); + } /* * an ICMP error can only be generated as a result of an * ICMP query, not as the response on an ICMP error |