| From 90b1929638fb5fed4e5fc65f95b7a76e339e0640 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com> |
| Date: Mon, 9 Sep 2019 09:13:33 +0200 |
| Subject: [PATCH 01/12] 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: <20190909091333.18511-2-philmd@redhat.com> |
| Patchwork-id: 90336 |
| O-Subject: [RHEL-7.8 qemu-kvm PATCH 1/1] Using ip_deq after m_free might read pointers from an allocation reuse. |
| Bugzilla: 1749735 |
| RH-Acked-by: John Snow <jsnow@redhat.com> |
| RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com> |
| RH-Acked-by: Thomas Huth <thuth@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: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| slirp/ip_input.c | 6 ++++-- |
| 1 file changed, 4 insertions(+), 2 deletions(-) |
| |
| diff --git a/slirp/ip_input.c b/slirp/ip_input.c |
| index 5226224..9e95b40 100644 |
| |
| |
| @@ -296,6 +296,7 @@ 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; |
| @@ -303,9 +304,10 @@ 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: |
| -- |
| 1.8.3.1 |
| |