Author: melifaro
Date: Thu Nov 5 22:41:54 2020
New Revision: 367402
URL: https://svnweb.freebsd.org/changeset/base/367402
Log:
MFC r367114.
Fix use-after-free in icmp6_notify_error().
Reported by: Maxime Villard <max at m00nbsd.net>
Modified:
stable/12/sys/netinet6/icmp6.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/netinet6/icmp6.c
==============================================================================
--- stable/12/sys/netinet6/icmp6.c Thu Nov 5 22:35:45 2020
(r367401)
+++ stable/12/sys/netinet6/icmp6.c Thu Nov 5 22:41:54 2020
(r367402)
@@ -912,6 +912,7 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp
}
icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
eip6 = (struct ip6_hdr *)(icmp6 + 1);
+ bzero(&icmp6dst, sizeof(icmp6dst));
/* Detect the upper level protocol */
{
@@ -920,7 +921,6 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp
int eoff = off + sizeof(struct icmp6_hdr) +
sizeof(struct ip6_hdr);
struct ip6ctlparam ip6cp;
- struct in6_addr *finaldst = NULL;
int icmp6type = icmp6->icmp6_type;
struct ip6_frag *fh;
struct ip6_rthdr *rth;
@@ -994,10 +994,11 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp
}
rth0 = (struct ip6_rthdr0 *)
(mtod(m, caddr_t) + eoff);
+
/* just ignore a bogus header */
if ((rth0->ip6r0_len % 2) == 0 &&
(hops = rth0->ip6r0_len/2))
- finaldst = (struct in6_addr
*)(rth0 + 1) + (hops - 1);
+ icmp6dst.sin6_addr = *((struct
in6_addr *)(rth0 + 1) + (hops - 1));
}
eoff += rthlen;
nxt = rth->ip6r_nxt;
@@ -1051,13 +1052,10 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp
*/
eip6 = (struct ip6_hdr *)(icmp6 + 1);
- bzero(&icmp6dst, sizeof(icmp6dst));
icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
icmp6dst.sin6_family = AF_INET6;
- if (finaldst == NULL)
+ if (IN6_IS_ADDR_UNSPECIFIED(&icmp6dst.sin6_addr))
icmp6dst.sin6_addr = eip6->ip6_dst;
- else
- icmp6dst.sin6_addr = *finaldst;
if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
goto freeit;
bzero(&icmp6src, sizeof(icmp6src));
@@ -1069,13 +1067,11 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp
icmp6src.sin6_flowinfo =
(eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
- if (finaldst == NULL)
- finaldst = &eip6->ip6_dst;
ip6cp.ip6c_m = m;
ip6cp.ip6c_icmp6 = icmp6;
ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
ip6cp.ip6c_off = eoff;
- ip6cp.ip6c_finaldst = finaldst;
+ ip6cp.ip6c_finaldst = &icmp6dst.sin6_addr;
ip6cp.ip6c_src = &icmp6src;
ip6cp.ip6c_nxt = nxt;
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