File Drop-bogus-IPv6-messages.patch of Package qemu.30221
From: Ralf Haferkamp <rhafer@suse.com>
Date: Fri, 3 Jul 2020 14:51:16 +0200
Subject: Drop bogus IPv6 messages
Git-commit: c7ede54cbd2e2b25385325600958ba0124e31cc0
References: bsc#1172380 CVE-2020-10756
Drop IPv6 message shorter than what's mentioned in the payload
length header (+ the size of the IPv6 header). They're invalid an could
lead to data leakage in icmp6_send_echoreply().
Signed-off-by: Jose R Ziviani <jose.ziviani@suse.com>
---
src/ip6_input.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/slirp/src/ip6_input.c b/slirp/src/ip6_input.c
index dfcbfd6a78a8f78e45f89427f5a5..d88d1ab92355eda0f83970ba7f3b 100644
--- a/slirp/src/ip6_input.c
+++ b/slirp/src/ip6_input.c
@@ -49,6 +49,13 @@ void ip6_input(struct mbuf *m)
goto bad;
}
+ // Check if the message size is big enough to hold what's
+ // set in the payload length header. If not this is an invalid
+ // packet
+ if (m->m_len < ntohs(ip6->ip_pl) + sizeof(struct ip6)) {
+ goto bad;
+ }
+
/* check ip_ttl for a correct ICMP reply */
if (ip6->ip_hl == 0) {
icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);