File 0115-slirp-check-data-length-while-emula.patch of Package qemu.20395

From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Sun, 13 Jan 2019 23:29:48 +0530
Subject: slirp: check data length while emulating ident function

While emulating identification protocol, tcp_emu() does not check
available space in the 'sc_rcv->sb_data' buffer. It could lead to
heap buffer overflow issue. Add check to avoid it.

Reported-by: Kira <864786842@qq.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(cherry picked from commit a7104eda7dab99d0cdbd3595c211864cba415905)
[BR: BSC#1123156 CVE-2019-6778,  modify patch to use spaces instead of tabs]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 slirp/tcp_subr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index da0d53743f55d2b9f90365a416e4..1c5aeb2c2b445470f147473333f7 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -638,6 +638,10 @@ tcp_emu(struct socket *so, struct mbuf *m)
 			socklen_t addrlen = sizeof(struct sockaddr_in);
 			struct sbuf *so_rcv = &so->so_rcv;
 
+    if (m->m_len > so_rcv->sb_datalen - (so_rcv->sb_wptr - so_rcv->sb_data)) {
+        return 1;
+    }
+
 			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;