| From 4fc0d23e8f6d795c679623d2ed2cbe6a7a17b9c7 Mon Sep 17 00:00:00 2001 |
| From: Li Zhou <li.zhou@windriver.com> |
| Date: Tue, 10 Sep 2019 20:02:15 -0700 |
| Subject: [PATCH] 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> |
| |
| Upstream-Status: Backport |
| CVE: CVE-2019-15890 |
| Signed-off-by: Li Zhou <li.zhou@windriver.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 8c75d914..c07d7d40 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 +300,10 @@ 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: |
| -- |
| 2.23.0 |
| |