Fix missing error handling in bhyve(8) device models.

Approved by:	so
Security:	SA-21:13.bhyve
Security:	CVE-2021-29631

4 files changed, 16 insertions, 10 deletions

diff --git a/usr.sbin/bhyve/pci_virtio_9p.c b/usr.sbin/bhyve/pci_virtio_9p.c
index 7e8542a46e05..7e11fba649b7 100644
--- a/usr.sbin/bhyve/pci_virtio_9p.c
+++ b/usr.sbin/bhyve/pci_virtio_9p.c
@@ -195,13 +195,15 @@ pci_vt9p_notify(void *vsc, struct vqueue_info *vq)
 	struct iovec iov[VT9P_MAX_IOV];
 	struct pci_vt9p_softc *sc;
 	struct pci_vt9p_request *preq;
-	uint16_t idx, n, i;
+	int n;
+	uint16_t idx, i;
 	uint16_t flags[VT9P_MAX_IOV];
 
 	sc = vsc;
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, &idx, iov, VT9P_MAX_IOV, flags);
+		assert(n >= 1 && n <= VT9P_MAX_IOV);
 		preq = calloc(1, sizeof(struct pci_vt9p_request));
 		preq->vsr_sc = sc;
 		preq->vsr_idx = idx;
diff --git a/usr.sbin/bhyve/pci_virtio_console.c b/usr.sbin/bhyve/pci_virtio_console.c
index 133902ccb129..2f87220a0e4f 100644
--- a/usr.sbin/bhyve/pci_virtio_console.c
+++ b/usr.sbin/bhyve/pci_virtio_console.c
@@ -421,6 +421,7 @@ pci_vtcon_sock_rx(int fd __unused, enum ev_type t __unused, void *arg)
 
 	do {
 		n = vq_getchain(vq, &idx, &iov, 1, NULL);
+		assert(n == 1);
 		len = readv(sock->vss_conn_fd, &iov, n);
 
 		if (len == 0 || (len < 0 && errno == EWOULDBLOCK)) {
@@ -561,7 +562,6 @@ pci_vtcon_control_send(struct pci_vtcon_softc *sc,
 		return;
 
 	n = vq_getchain(vq, &idx, &iov, 1, NULL);
-
 	assert(n == 1);
 
 	memcpy(iov.iov_base, ctrl, sizeof(struct pci_vtcon_control));
@@ -580,7 +580,8 @@ pci_vtcon_notify_tx(void *vsc, struct vqueue_info *vq)
 	struct pci_vtcon_softc *sc;
 	struct pci_vtcon_port *port;
 	struct iovec iov[1];
-	uint16_t idx, n;
+	int n;
+	uint16_t idx;
 	uint16_t flags[8];
 
 	sc = vsc;
@@ -588,7 +589,7 @@ pci_vtcon_notify_tx(void *vsc, struct vqueue_info *vq)
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, &idx, iov, 1, flags);
-		assert(n >= 1);
+		assert(n == 1);
 		if (port != NULL)
 			port->vsp_cb(port, port->vsp_arg, iov, 1);
 
diff --git a/usr.sbin/bhyve/pci_virtio_rnd.c b/usr.sbin/bhyve/pci_virtio_rnd.c
index 10ba9ddfbfaf..46267c6e4c84 100644
--- a/usr.sbin/bhyve/pci_virtio_rnd.c
+++ b/usr.sbin/bhyve/pci_virtio_rnd.c
@@ -113,7 +113,7 @@ pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
 {
 	struct iovec iov;
 	struct pci_vtrnd_softc *sc;
-	int len;
+	int len, n;
 	uint16_t idx;
 
 	sc = vsc;
@@ -124,7 +124,8 @@ pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
 	}
 
 	while (vq_has_descs(vq)) {
-		vq_getchain(vq, &idx, &iov, 1, NULL);
+		n = vq_getchain(vq, &idx, &iov, 1, NULL);
+		assert(n == 1);
 
 		len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
 
diff --git a/usr.sbin/bhyve/pci_virtio_scsi.c b/usr.sbin/bhyve/pci_virtio_scsi.c
index 92a3311b6924..a2b83b77148e 100644
--- a/usr.sbin/bhyve/pci_virtio_scsi.c
+++ b/usr.sbin/bhyve/pci_virtio_scsi.c
@@ -557,15 +557,16 @@ pci_vtscsi_controlq_notify(void *vsc, struct vqueue_info *vq)
 {
 	struct pci_vtscsi_softc *sc;
 	struct iovec iov[VTSCSI_MAXSEG];
-	uint16_t idx, n;
+	uint16_t idx;
 	void *buf = NULL;
 	size_t bufsize;
-	int iolen;
+	int iolen, n;
 
 	sc = vsc;
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, &idx, iov, VTSCSI_MAXSEG, NULL);
+		assert(n >= 1 && n <= VTSCSI_MAXSEG);
 		bufsize = iov_to_buf(iov, n, &buf);
 		iolen = pci_vtscsi_control_handle(sc, buf, bufsize);
 		buf_to_iov(buf + bufsize - iolen, iolen, iov, n,
@@ -595,8 +596,8 @@ pci_vtscsi_requestq_notify(void *vsc, struct vqueue_info *vq)
 	struct pci_vtscsi_request *req;
 	struct iovec iov[VTSCSI_MAXSEG];
 	uint16_t flags[VTSCSI_MAXSEG];
-	uint16_t idx, n, i;
-	int readable;
+	uint16_t idx, i;
+	int readable, n;
 
 	sc = vsc;
 	q = &sc->vss_queues[vq->vq_num - 2];
@@ -604,6 +605,7 @@ pci_vtscsi_requestq_notify(void *vsc, struct vqueue_info *vq)
 	while (vq_has_descs(vq)) {
 		readable = 0;
 		n = vq_getchain(vq, &idx, iov, VTSCSI_MAXSEG, flags);
+		assert(n >= 1 && n <= VTSCSI_MAXSEG);
 
 		/* Count readable descriptors */
 		for (i = 0; i < n; i++) {