From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:51885) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gik5F-0007VL-12 for qemu-devel@nongnu.org; Sun, 13 Jan 2019 13:02:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gik5D-0004ln-RX for qemu-devel@nongnu.org; Sun, 13 Jan 2019 13:02:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48816) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gik5D-0004h6-LU for qemu-devel@nongnu.org; Sun, 13 Jan 2019 13:02:03 -0500 From: P J P Date: Sun, 13 Jan 2019 23:29:48 +0530 Message-Id: <20190113175948.21076-1-ppandit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v2] slirp: check data length while emulating ident function List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: QEMU Developers Cc: Samuel Thibault , Jason Wang , Kira <864786842@qq.com>, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Jan Kiszka , Prasad J Pandit From: Prasad J Pandit 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 --- 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 =3D sizeof(struct sockaddr_in); struct sbuf *so_rcv =3D &so->so_rcv; =20 + 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 +=3D m->m_len; so_rcv->sb_rptr +=3D m->m_len; --=20 2.20.1