File Fix-use-afte-free-in-ip_reass-CVE-2020-1.patch of Package qemu

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File Fix-use-afte-free-in-ip_reass-CVE-2020-1.patch of Package qemu

From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
Date: Sat, 4 Apr 2020 22:42:13 +0200
Subject: Fix use-afte-free in ip_reass() (CVE-2020-1983)
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Git-commit: 2faae0f778f818fadc873308f983289df697eb93
References: bsc#1170940, CVE-2020-1983

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 commit 9bd6c5913271eabcb7768a58197ed3301fe19f2d)
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 src/ip_input.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c
index 8c75d91495dfdb32f00aea66acd3..bdf1f72fce73dc9ad2c2a257618a 100644
--- a/slirp/src/ip_input.c
+++ b/slirp/src/ip_input.c
@@ -325,8 +325,7 @@ 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) {
@@ -350,8 +349,7 @@ 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);
     }

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File Fix-use-afte-free-in-ip_reass-CVE-2020-1.patch of Package qemu

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