| From a33ea192428d9c9307f1140f3e25631a6ef7657c Mon Sep 17 00:00:00 2001 |
| From: Jon Maloy <jmaloy@redhat.com> |
| Date: Sat, 20 Jun 2020 15:02:59 -0400 |
| Subject: [PATCH 12/12] Fix use-afte-free in ip_reass() (CVE-2020-1983) |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| RH-Author: Jon Maloy <jmaloy@redhat.com> |
| Message-id: <20200620150259.3352467-2-jmaloy@redhat.com> |
| Patchwork-id: 97678 |
| O-Subject: [RHEL-8.3.0 qemu-kvm PATCH 1/1] Fix use-afte-free in ip_reass() (CVE-2020-1983) |
| Bugzilla: 1838070 |
| RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> |
| |
| From: Marc-André Lureau <marcandre.lureau@redhat.com> |
| |
| The q pointer is updated when the mbuf data is moved from m_dat to |
| m_ext. |
| |
| m_ext buffer may also be realloc()'ed and moved during m_cat(): |
| q should also be updated in this case. |
| |
| Reported-by: Aviv Sasson <asasson@paloaltonetworks.com> |
| Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> |
| Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> |
| |
| (cherry picked from libslirp commit 9bd6c5913271eabcb7768a58197ed3301fe19f2d) |
| Signed-off-by: Jon Maloy <jmaloy@redhat.com> |
| Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com> |
| |
| slirp/src/ip_input.c | 5 ++--- |
| 1 file changed, 2 insertions(+), 3 deletions(-) |
| |
| diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c |
| index df1c846ade..0f5d522ec1 100644 |
| |
| |
| @@ -329,7 +329,7 @@ insert: |
| q = fp->frag_link.next; |
| m = dtom(slirp, q); |
| |
| - int was_ext = m->m_flags & M_EXT; |
| + int delta = (char *)q - (m->m_flags & M_EXT ? m->m_ext : m->m_dat); |
| |
| q = (struct ipasfrag *)q->ipf_next; |
| while (q != (struct ipasfrag *)&fp->frag_link) { |
| @@ -353,8 +353,7 @@ insert: |
| * the old buffer (in the mbuf), so we must point ip |
| * into the new buffer. |
| */ |
| - if (!was_ext && m->m_flags & M_EXT) { |
| - int delta = (char *)q - m->m_dat; |
| + if (m->m_flags & M_EXT) { |
| q = (struct ipasfrag *)(m->m_ext + delta); |
| } |
| |
| -- |
| 2.27.0 |
| |