From b6c0fa3b435375918714e107b22de2ef13a41c26 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Sun, 13 Jan 2019 23:29:48 +0530 Subject: [PATCH] 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 Signed-off-by: Samuel Thibault CVE: CVE-2019-6778 Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=a7104eda7dab99d0cdbd3595c211864cba415905] Signed-off-by: Dan Tran --- slirp/tcp_subr.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c index 8d0f94b75f..7277aadfdf 100644 --- a/slirp/tcp_subr.c +++ b/slirp/tcp_subr.c @@ -640,6 +640,11 @@ 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; -- 2.22.0.vfs.1.1.57.gbaf16c8