From 3bcddec301bcc3c251b4aab0446427de5fe35c57 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com>
Date: Mon, 8 Jul 2019 15:50:30 +0100
Subject: [PATCH 3/7] slirp: ensure there is enough space in mbuf to
 null-terminate
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RH-Author: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: <20190708155031.7778-4-philmd@redhat.com>
Patchwork-id: 89430
O-Subject: [RHEL-8.0.0 qemu-kvm PATCH 3/4] slirp: ensure there is enough space in mbuf to null-terminate
Bugzilla: 1732324
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Prevents from buffer overflows.
Related to: https://bugzilla.redhat.com/show_bug.cgi?id=1664205

Cc: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

(cherry picked from libslirp commit
306fef58b54d793ba4b259728c21322765bda917)
[ MA - backported with style conflicts fixes ]
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 slirp/tcp_subr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index 393447d..e245e0d 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -646,6 +646,7 @@ tcp_emu(struct socket *so, struct mbuf *m)
 			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
 			so_rcv->sb_wptr += m->m_len;
 			so_rcv->sb_rptr += m->m_len;
+			m_inc(m, m->m_len + 1);
 			m->m_data[m->m_len] = 0; /* NULL terminate */
 			if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
 				if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
@@ -679,6 +680,7 @@ tcp_emu(struct socket *so, struct mbuf *m)
 		}
 
         case EMU_FTP: /* ftp */
+		m_inc(m, m->m_len + 1);
                 *(m->m_data+m->m_len) = 0; /* NUL terminate for strstr */
 		if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
 			/*
@@ -776,6 +778,7 @@ tcp_emu(struct socket *so, struct mbuf *m)
 		/*
 		 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
 		 */
+		m_inc(m, m->m_len + 1);
 		*(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
 		if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
 			 return 1;
-- 
1.8.3.1