From a0b2e40bae795bfcf58492e0081665a29a2cc9e2 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com>

Date: Fri, 17 Jan 2020 11:49:40 +0100

Subject: [PATCH 5/7] tcp_emu: Fix oob access

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RH-Author: Philippe Mathieu-Daudé <philmd@redhat.com>

Message-id: <20200117114942.12236-2-philmd@redhat.com>

Patchwork-id: 93393

O-Subject: [RHEL-7.7.z qemu-kvm-rhev + RHEL-7.8 qemu-kvm-rhev + RHEL-7.9 qemu-kvm-rhev + RHEL-8.1.0 qemu-kvm + RHEL-8.2.0 qemu-kvm + RHEL-7.7.z qemu-kvm-ma + RHEL-7.8 qemu-kvm-ma + RHEL-7.9 qemu-kvm-ma PATCH 1/3] tcp_emu: Fix oob access

Bugzilla: 1791566

RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Thomas Huth <thuth@redhat.com>

From: Samuel Thibault <samuel.thibault@ens-lyon.org>

The main loop only checks for one available byte, while we sometimes

need two bytes.

(cherry picked from libslirp commit 2655fffed7a9e765bcb4701dd876e9dab975f289)

[PMD: backported with style conflicts,

      CHANGELOG.md absent in downstream]

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 slirp/tcp_subr.c | 7 +++++++

 1 file changed, 7 insertions(+)

diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c

index 0152f72..decfd9b 100644

--- a/slirp/tcp_subr.c

+++ b/slirp/tcp_subr.c

@@ -892,6 +892,9 @@ tcp_emu(struct socket *so, struct mbuf *m)

 				break;

 			 case 5:

+				if (bptr == m->m_data + m->m_len - 1)

+					return 1; /* We need two bytes */

+

 				/*

 				 * The difference between versions 1.0 and

 				 * 2.0 is here. For future versions of

@@ -907,6 +910,10 @@ tcp_emu(struct socket *so, struct mbuf *m)

 				/* This is the field containing the port

 				 * number that RA-player is listening to.

 				 */

+

+				if (bptr == m->m_data + m->m_len - 1)

+					return 1; /* We need two bytes */

+

 				lport = (((u_char*)bptr)[0] << 8)

 				+ ((u_char *)bptr)[1];

 				if (lport < 6970)

-- 

1.8.3.1