From: Prasad J Pandit <p...@fedoraproject.org> 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 <864786...@qq.com> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- slirp/tcp_subr.c | 4 ++++ 1 file changed, 4 insertions(+) Update v2: return 1 instead of 0 -> https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg02182.html diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c index fa61349cbb..8b1bd8c8c0 100644 --- a/slirp/tcp_subr.c +++ b/slirp/tcp_subr.c @@ -635,6 +635,10 @@ 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; -- 2.20.1
