48 lines
1.5 KiB
Diff
48 lines
1.5 KiB
Diff
From b27192be13da3fb59f51185d9a1f944b3474b2fc Mon Sep 17 00:00:00 2001
|
|
From: Michael Roth <mdroth@linux.vnet.ibm.com>
|
|
Date: Tue, 24 Sep 2019 16:04:04 -0500
|
|
Subject: [PATCH] slirp: ip_reass: Fix use after free
|
|
|
|
Using ip_deq after m_free might read pointers from an allocation reuse.
|
|
|
|
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>
|
|
(from libslirp.git commit c59279437eda91841b9d26079c70b8a540d41204)
|
|
Fixes: CVE-2019-15890
|
|
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
|
|
---
|
|
slirp/src/ip_input.c | 6 ++++--
|
|
1 file changed, 4 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c
|
|
index 68a99de5b5..89ae04e0c1 100644
|
|
--- a/slirp/src/ip_input.c
|
|
+++ b/slirp/src/ip_input.c
|
|
@@ -297,6 +297,7 @@ 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;
|
|
@@ -304,9 +305,10 @@ 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:
|
|
--
|
|
2.19.1
|
|
|