qemu-kvm/0021-Using-ip_deq-after-m_free-might-read-pointers-from-a.patch
Danilo C. L. de Paula 1261d6ce5b Rebase to qemu 4.2
- Rebase to qemu-4.2
- Resolves: bz#1783250
  (rebase qemu-kvm to 4.2)
2019-12-13 13:10:42 +00:00

62 lines
2.1 KiB
Diff

From ab9ebc29bb9bb142e73a160750a451d40bfe9746 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com>
Date: Mon, 16 Sep 2019 17:07:00 +0100
Subject: Using ip_deq after m_free might read pointers from an allocation
reuse.
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: <20190916170700.647-2-philmd@redhat.com>
Patchwork-id: 90470
O-Subject: [RHEL-AV-8.1.0 qemu-kvm PATCH 1/1] Using ip_deq after m_free might read pointers from an allocation reuse.
Bugzilla: 1749737
RH-Acked-by: Danilo de Paula <ddepaula@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
This would be difficult to exploit, but that is still related with
CVE-2019-14378 which generates fragmented IP packets that would trigger this
issue and at least produce a DoS.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(cherry picked from libslirp commit c59279437eda91841b9d26079c70b8a540d41204)
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
slirp/src/ip_input.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c
index 8c75d91495..df1c846ade 100644
--- a/slirp/src/ip_input.c
+++ b/slirp/src/ip_input.c
@@ -292,6 +292,7 @@ static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
*/
while (q != (struct ipasfrag *)&fp->frag_link &&
ip->ip_off + ip->ip_len > q->ipf_off) {
+ struct ipasfrag *prev;
i = (ip->ip_off + ip->ip_len) - q->ipf_off;
if (i < q->ipf_len) {
q->ipf_len -= i;
@@ -299,9 +300,11 @@ static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
m_adj(dtom(slirp, q), i);
break;
}
+ prev = q;
q = q->ipf_next;
- m_free(dtom(slirp, q->ipf_prev));
- ip_deq(q->ipf_prev);
+ ip_deq(prev);
+ m_free(dtom(slirp, prev));
+
}
insert:
--
2.21.0