Date: Tue, 12 May 2020 16:33:04 +0000 (UTC) From: Ed Maste <emaste@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r360967 - head/sys/netinet/libalias Message-ID: <202005121633.04CGX4Bf051216@repo.freebsd.org>
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Author: emaste Date: Tue May 12 16:33:04 2020 New Revision: 360967 URL: https://svnweb.freebsd.org/changeset/base/360967 Log: libalias: validate packet lengths before accessing headers admbugs: 956 Submitted by: ae Reported by: Lucas Leong (@_wmliang_) of Trend Micro Zero Day Initiative Reported by: Vishnu working with Trend Micro Zero Day Initiative Security: FreeBSD-SA-20:12.libalias Modified: head/sys/netinet/libalias/alias.c Modified: head/sys/netinet/libalias/alias.c ============================================================================== --- head/sys/netinet/libalias/alias.c Tue May 12 16:10:07 2020 (r360966) +++ head/sys/netinet/libalias/alias.c Tue May 12 16:33:04 2020 (r360967) @@ -442,10 +442,15 @@ fragment contained in ICMP data section */ static int IcmpAliasIn(struct libalias *la, struct ip *pip) { - int iresult; struct icmp *ic; + int dlen, iresult; LIBALIAS_LOCK_ASSERT(la); + + dlen = ntohs(pip->ip_len) - (pip->ip_hl << 2); + if (dlen < ICMP_MINLEN) + return (PKT_ALIAS_IGNORED); + /* Return if proxy-only mode is enabled */ if (la->packetAliasMode & PKT_ALIAS_PROXY_ONLY) return (PKT_ALIAS_OK); @@ -464,6 +469,9 @@ IcmpAliasIn(struct libalias *la, struct ip *pip) case ICMP_SOURCEQUENCH: case ICMP_TIMXCEED: case ICMP_PARAMPROB: + if (dlen < ICMP_ADVLENMIN || + dlen < ICMP_ADVLEN(ic)) + return (PKT_ALIAS_IGNORED); iresult = IcmpAliasIn2(la, pip); break; case ICMP_ECHO: @@ -732,10 +740,17 @@ UdpAliasIn(struct libalias *la, struct ip *pip) { struct udphdr *ud; struct alias_link *lnk; + int dlen; LIBALIAS_LOCK_ASSERT(la); + dlen = ntohs(pip->ip_len) - (pip->ip_hl << 2); + if (dlen < sizeof(struct udphdr)) + return (PKT_ALIAS_IGNORED); + ud = (struct udphdr *)ip_next(pip); + if (dlen < ntohs(ud->uh_ulen)) + return (PKT_ALIAS_IGNORED); lnk = FindUdpTcpIn(la, pip->ip_src, pip->ip_dst, ud->uh_sport, ud->uh_dport, @@ -824,12 +839,19 @@ UdpAliasOut(struct libalias *la, struct ip *pip, int m u_short dest_port; u_short proxy_server_port; int proxy_type; - int error; + int dlen, error; LIBALIAS_LOCK_ASSERT(la); /* Return if proxy-only mode is enabled and not proxyrule found.*/ + dlen = ntohs(pip->ip_len) - (pip->ip_hl << 2); + if (dlen < sizeof(struct udphdr)) + return (PKT_ALIAS_IGNORED); + ud = (struct udphdr *)ip_next(pip); + if (dlen < ntohs(ud->uh_ulen)) + return (PKT_ALIAS_IGNORED); + proxy_type = ProxyCheck(la, &proxy_server_address, &proxy_server_port, pip->ip_src, pip->ip_dst, ud->uh_dport, pip->ip_p); @@ -922,8 +944,13 @@ TcpAliasIn(struct libalias *la, struct ip *pip) { struct tcphdr *tc; struct alias_link *lnk; + int dlen; LIBALIAS_LOCK_ASSERT(la); + + dlen = ntohs(pip->ip_len) - (pip->ip_hl << 2); + if (dlen < sizeof(struct tcphdr)) + return (PKT_ALIAS_IGNORED); tc = (struct tcphdr *)ip_next(pip); lnk = FindUdpTcpIn(la, pip->ip_src, pip->ip_dst, @@ -1042,7 +1069,7 @@ TcpAliasIn(struct libalias *la, struct ip *pip) static int TcpAliasOut(struct libalias *la, struct ip *pip, int maxpacketsize, int create) { - int proxy_type, error; + int dlen, proxy_type, error; u_short dest_port; u_short proxy_server_port; struct in_addr dest_address; @@ -1051,6 +1078,10 @@ TcpAliasOut(struct libalias *la, struct ip *pip, int m struct alias_link *lnk; LIBALIAS_LOCK_ASSERT(la); + + dlen = ntohs(pip->ip_len) - (pip->ip_hl << 2); + if (dlen < sizeof(struct tcphdr)) + return (PKT_ALIAS_IGNORED); tc = (struct tcphdr *)ip_next(pip); if (create)
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