[Qemu-devel] [PATCH 1/2] slirp: ensure there is enough space in mbuf to null-terminate

[Marc-André Lureau]

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

Cc: Prasad J Pandit <p...@fedoraproject.org>
Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
 slirp/src/tcp_subr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/slirp/src/tcp_subr.c b/slirp/src/tcp_subr.c
index fde9207b0c..c43598de48 100644
--- a/slirp/src/tcp_subr.c
+++ b/slirp/src/tcp_subr.c
@@ -644,6 +644,7 @@ 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) {
@@ -677,6 +678,7 @@ 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) {
                        /*
@@ -774,6 +776,7 @@ 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;
-- 
2.21.0.313.ge35b8cb8e2