qemu-kvm/SOURCES/kvm-Drop-bogus-IPv6-messages.patch

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From 89c4300c97739aa3291f0322037bb65068e08d41 Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Tue, 19 Jan 2021 23:34:33 -0500
Subject: [PATCH] Drop bogus IPv6 messages
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Jon Maloy <jmaloy@redhat.com>
Message-id: <20210119233433.1352902-2-jmaloy@redhat.com>
Patchwork-id: 100695
O-Subject: [RHEL-8.4.0 qemu-kvm PATCH 1/1] Drop bogus IPv6 messages
Bugzilla: 1918054
RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
From: Ralf Haferkamp <rhafer@suse.com>
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().
(cherry picked from libslirp commit c7ede54cbd2e2b25385325600958ba0124e31cc0)
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
slirp/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 d9d2b7e9cd4..0f2b17853ad 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);
--
2.27.0