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X-Received-From: 2607:f8b0:4864:20::535 Subject: [Qemu-devel] [PATCH v3] slirp: check for ioctlsocket error and 0-length udp payload. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vic Lee , Jan Kiszka , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Samuel Thibault Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Sometimes sorecvfrom() is called from slirp.c because revents =3D=3D G_IO_I= N, but there is 0 bytes available and recvfrom could be blocking indefinitely. This is likely due to 0-length udp payload. This also adds an error checking for ioctlsocket. Signed-off-by: Vic Lee --- slirp/socket.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/slirp/socket.c b/slirp/socket.c index 4876ea3f31..af732f78fb 100644 --- a/slirp/socket.c +++ b/slirp/socket.c @@ -529,6 +529,15 @@ sorecvfrom(struct socket *so) int n; #endif =20 + if (ioctlsocket(so->s, FIONREAD, &n) !=3D 0) { + DEBUG_MISC((dfd, " ioctlsocket errno =3D %d-%s\n", + errno, strerror(errno))); + return; + } + if (n =3D=3D 0) { + return; + } + m =3D m_get(so->slirp); if (!m) { return; @@ -552,7 +561,6 @@ sorecvfrom(struct socket *so) */ len =3D M_FREEROOM(m); /* if (so->so_fport !=3D htons(53)) { */ - ioctlsocket(so->s, FIONREAD, &n); =20 if (n > len) { n =3D (m->m_data - m->m_dat) + m->m_len + n + 1; --=20 2.20.1