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authorgordon <gordon@FreeBSD.org>2018-11-27 19:43:16 +0000
committergordon <gordon@FreeBSD.org>2018-11-27 19:43:16 +0000
commitbf767d041f0f530ffe95ee4870830193d344771b (patch)
treefb30b9f821fde3d05f4286e35e03cb993c40d3a2
parente0e60f4844598ff1cb636aa9b15cfe442a411e3e (diff)
downloadFreeBSD-src-bf767d041f0f530ffe95ee4870830193d344771b.zip
FreeBSD-src-bf767d041f0f530ffe95ee4870830193d344771b.tar.gz
Fix ICMP buffer underwrite. [EN-18:13.icmp]
Approved by: so Security: FreeBSD-EN-18:13.icmp Security: CVE-2018-17156
-rw-r--r--sys/netinet/ip_icmp.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c
index 56578f3..47725c7 100644
--- a/sys/netinet/ip_icmp.c
+++ b/sys/netinet/ip_icmp.c
@@ -310,7 +310,8 @@ stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) -
#endif
icmplen = min(icmplen, M_TRAILINGSPACE(m) -
sizeof(struct ip) - ICMP_MINLEN);
- m_align(m, ICMP_MINLEN + icmplen);
+ m_align(m, sizeof(struct ip) + ICMP_MINLEN + icmplen);
+ m->m_data += sizeof(struct ip);
m->m_len = ICMP_MINLEN + icmplen;
/* XXX MRT make the outgoing packet use the same FIB
@@ -352,6 +353,8 @@ stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) -
* reply should bypass as well.
*/
m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
+ KASSERT(M_LEADINGSPACE(m) >= sizeof(struct ip),
+ ("insufficient space for ip header"));
m->m_data -= sizeof(struct ip);
m->m_len += sizeof(struct ip);
m->m_pkthdr.len = m->m_len;
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