From 95cf6abd88bedca0533ababfdb6480c3174f3b81 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Fri, 17 Jan 2020 12:00:37 +0100 Subject: [PATCH 3/3] slirp: use correct size while emulating commands MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Philippe Mathieu-Daudé Message-id: <20200117120037.12800-4-philmd@redhat.com> Patchwork-id: 93397 O-Subject: [RHEL-7.7.z qemu-kvm + RHEL-7.8 qemu-kvm + RHEL-7.9 qemu-kvm PATCH v2 3/3] slirp: use correct size while emulating commands Bugzilla: 1791560 RH-Acked-by: Stefano Garzarella RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Thomas Huth From: Prasad J Pandit While emulating services in tcp_emu(), it uses 'mbuf' size 'm->m_size' to write commands via snprintf(3). Use M_FREEROOM(m) size to avoid possible OOB access. Signed-off-by: Prasad J Pandit Signed-off-by: Samuel Thibault Message-Id: <20200109094228.79764-3-ppandit@redhat.com> (cherry picked from libslirp commit 82ebe9c370a0e2970fb5695aa19aa5214a6a1c80) Signed-off-by: Philippe Mathieu-Daudé Signed-off-by: Miroslav Rezanina --- slirp/tcp_subr.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c index 321c2a4..19e2245 100644 --- a/slirp/tcp_subr.c +++ b/slirp/tcp_subr.c @@ -648,7 +648,7 @@ tcp_emu(struct socket *so, struct mbuf *m) n4 = (laddr & 0xff); m->m_len = bptr - m->m_data; /* Adjust length */ - m->m_len += snprintf(bptr, m->m_size - m->m_len, + m->m_len += snprintf(bptr, M_FREEROOM(m), "ORT %d,%d,%d,%d,%d,%d\r\n%s", n1, n2, n3, n4, n5, n6, x==7?buff:""); return 1; @@ -681,7 +681,7 @@ tcp_emu(struct socket *so, struct mbuf *m) n4 = (laddr & 0xff); m->m_len = bptr - m->m_data; /* Adjust length */ - m->m_len += snprintf(bptr, m->m_size - m->m_len, + m->m_len += snprintf(bptr, M_FREEROOM(m), "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s", n1, n2, n3, n4, n5, n6, x==7?buff:""); @@ -707,8 +707,8 @@ tcp_emu(struct socket *so, struct mbuf *m) if (m->m_data[m->m_len-1] == '\0' && lport != 0 && (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr, htons(lport), SS_FACCEPTONCE)) != NULL) - m->m_len = snprintf(m->m_data, m->m_size, "%d", - ntohs(so->so_fport)) + 1; + m->m_len = snprintf(m->m_data, M_ROOM(m), + "%d", ntohs(so->so_fport)) + 1; return 1; case EMU_IRC: -- 1.8.3.1