Commit 82ebe9c3 authored by Prasad J Pandit's avatar Prasad J Pandit Committed by Samuel Thibault

slirp: use correct size while emulating commands

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: default avatarPrasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Samuel Thibault's avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Message-Id: <20200109094228.79764-3-ppandit@redhat.com>
parent ce131029
Pipeline #96305 passed with stage
in 2 minutes and 37 seconds
......@@ -681,7 +681,7 @@ int 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;
......@@ -716,8 +716,7 @@ int 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 : "");
......@@ -743,8 +742,8 @@ int 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:
......
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