git: 20f96f215562 - stable/13 - bhyve: Fix vq_getchain() error handling bugs in various device models

[Mark Johnston]

The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=20f96f215562c7533053e01b186066ad935d11d0

commit 20f96f215562c7533053e01b186066ad935d11d0
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-08-24 18:10:08 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-08-24 18:29:48 +0000

    bhyve: Fix vq_getchain() error handling bugs in various device models
    
    Reviewed by:    grehan, khng
    Approved by:    so
    Security:       CVE-2021-29631
    Security:       FreeBSD-SA-21:13.bhyve
    
    (cherry picked from commit 71fbc6faed62e8eb5864f7c40839740f5e9f5558)
---
 usr.sbin/bhyve/pci_virtio_9p.c      | 3 ++-
 usr.sbin/bhyve/pci_virtio_console.c | 6 +++---
 usr.sbin/bhyve/pci_virtio_rnd.c     | 5 +++--
 usr.sbin/bhyve/pci_virtio_scsi.c    | 8 +++++---
 4 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/usr.sbin/bhyve/pci_virtio_9p.c b/usr.sbin/bhyve/pci_virtio_9p.c
index f96d53858225..70f3eba4bc34 100644
--- a/usr.sbin/bhyve/pci_virtio_9p.c
+++ b/usr.sbin/bhyve/pci_virtio_9p.c
@@ -198,12 +198,13 @@ pci_vt9p_notify(void *vsc, struct vqueue_info *vq)
 	struct pci_vt9p_softc *sc;
 	struct pci_vt9p_request *preq;
 	struct vi_req req;
-	uint16_t n;
+	int n;
 
 	sc = vsc;
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, iov, VT9P_MAX_IOV, &req);
+		assert(n >= 1 && n <= VT9P_MAX_IOV);
 		preq = calloc(1, sizeof(struct pci_vt9p_request));
 		preq->vsr_sc = sc;
 		preq->vsr_idx = req.idx;
diff --git a/usr.sbin/bhyve/pci_virtio_console.c b/usr.sbin/bhyve/pci_virtio_console.c
index 6832a3f92774..71c3375a57ac 100644
--- a/usr.sbin/bhyve/pci_virtio_console.c
+++ b/usr.sbin/bhyve/pci_virtio_console.c
@@ -442,6 +442,7 @@ pci_vtcon_sock_rx(int fd __unused, enum ev_type t __unused, void *arg)
 
 	do {
 		n = vq_getchain(vq, &iov, 1, &req);
+		assert(n == 1);
 		len = readv(sock->vss_conn_fd, &iov, n);
 
 		if (len == 0 || (len < 0 && errno == EWOULDBLOCK)) {
@@ -582,7 +583,6 @@ pci_vtcon_control_send(struct pci_vtcon_softc *sc,
 		return;
 
 	n = vq_getchain(vq, &iov, 1, &req);
-
 	assert(n == 1);
 
 	memcpy(iov.iov_base, ctrl, sizeof(struct pci_vtcon_control));
@@ -602,14 +602,14 @@ pci_vtcon_notify_tx(void *vsc, struct vqueue_info *vq)
 	struct pci_vtcon_port *port;
 	struct iovec iov[1];
 	struct vi_req req;
-	uint16_t n;
+	int n;
 
 	sc = vsc;
 	port = pci_vtcon_vq_to_port(sc, vq);
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, iov, 1, &req);
-		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 1d2d6144f949..7274d0b05912 100644
--- a/usr.sbin/bhyve/pci_virtio_rnd.c
+++ b/usr.sbin/bhyve/pci_virtio_rnd.c
@@ -114,7 +114,7 @@ pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
 	struct iovec iov;
 	struct pci_vtrnd_softc *sc;
 	struct vi_req req;
-	int len;
+	int len, n;
 
 	sc = vsc;
 
@@ -124,7 +124,8 @@ pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
 	}
 
 	while (vq_has_descs(vq)) {
-		vq_getchain(vq, &iov, 1, &req);
+		n = vq_getchain(vq, &iov, 1, &req);
+		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 e8124b9b3441..37eba90fa2bc 100644
--- a/usr.sbin/bhyve/pci_virtio_scsi.c
+++ b/usr.sbin/bhyve/pci_virtio_scsi.c
@@ -559,15 +559,16 @@ pci_vtscsi_controlq_notify(void *vsc, struct vqueue_info *vq)
 	struct pci_vtscsi_softc *sc;
 	struct iovec iov[VTSCSI_MAXSEG];
 	struct vi_req req;
-	uint16_t n;
 	void *buf = NULL;
 	size_t bufsize;
-	int iolen;
+	int iolen, n;
 
 	sc = vsc;
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, iov, VTSCSI_MAXSEG, &req);
+		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,
@@ -597,13 +598,14 @@ pci_vtscsi_requestq_notify(void *vsc, struct vqueue_info *vq)
 	struct pci_vtscsi_request *req;
 	struct iovec iov[VTSCSI_MAXSEG];
 	struct vi_req vireq;
-	uint16_t n;
+	int n;
 
 	sc = vsc;
 	q = &sc->vss_queues[vq->vq_num - 2];
 
 	while (vq_has_descs(vq)) {
 		n = vq_getchain(vq, iov, VTSCSI_MAXSEG, &vireq);
+		assert(n >= 1 && n <= VTSCSI_MAXSEG);
 
 		req = calloc(1, sizeof(struct pci_vtscsi_request));
 		req->vsr_idx = vireq.idx;