qemu-kvm/SOURCES/kvm-Fix-heap-overflow-in-ip...

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Diff

From 486e74dd9b8515f478698fee494086b339015d51 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com>
Date: Wed, 31 Jul 2019 18:45:29 +0100
Subject: [PATCH 14/14] Fix heap overflow in ip_reass on big packet input
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: <20190731184529.21905-2-philmd@redhat.com>
Patchwork-id: 89820
O-Subject: [RHEL-8.1.0 qemu-kvm PATCH 1/1] Fix heap overflow in ip_reass on big packet input
Bugzilla: 1734751
RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
When the first fragment does not fit in the preallocated buffer, q will
already be pointing to the ext buffer, so we mustn't try to update it.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(cherry picked from libslirp commit 126c04acbabd7ad32c2b018fe10dfac2a3bc1210)
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
slirp/ip_input.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/slirp/ip_input.c b/slirp/ip_input.c
index 348e1dc..07d8808 100644
--- a/slirp/ip_input.c
+++ b/slirp/ip_input.c
@@ -334,6 +334,8 @@ insert:
q = fp->frag_link.next;
m = dtom(slirp, q);
+ int was_ext = m->m_flags & M_EXT;
+
q = (struct ipasfrag *) q->ipf_next;
while (q != (struct ipasfrag*)&fp->frag_link) {
struct mbuf *t = dtom(slirp, q);
@@ -356,7 +358,7 @@ insert:
* the old buffer (in the mbuf), so we must point ip
* into the new buffer.
*/
- if (m->m_flags & M_EXT) {
+ if (!was_ext && m->m_flags & M_EXT) {
int delta = (char *)q - m->m_dat;
q = (struct ipasfrag *)(m->m_ext + delta);
}
--
1.8.3.1