From: Maxime Coquelin Date: Tue, 3 Sep 2019 15:34:22 +0000 (+0200) Subject: vhost: fix possible denial of service by leaking FDs X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=bf472259dde6;p=dpdk.git vhost: fix possible denial of service by leaking FDs A malicious Vhost-user master could send in loop hand-crafted vhost-user messages containing more file descriptors the vhost-user slave expects. Doing so causes the application using the vhost-user library to run out of FDs. This issue has been assigned CVE-2019-14818 Fixes: 8f972312b8f4 ("vhost: support vhost-user") Signed-off-by: Maxime Coquelin --- diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c index d4c9cd3f29..90ecee1977 100644 --- a/lib/librte_vhost/vhost_user.c +++ b/lib/librte_vhost/vhost_user.c @@ -92,6 +92,36 @@ static const char *vhost_message_str[VHOST_USER_MAX] = { static int send_vhost_reply(int sockfd, struct VhostUserMsg *msg); static int read_vhost_message(int sockfd, struct VhostUserMsg *msg); +static void +close_msg_fds(struct VhostUserMsg *msg) +{ + int i; + + for (i = 0; i < msg->fd_num; i++) + close(msg->fds[i]); +} + +/* + * Ensure the expected number of FDs is received, + * close all FDs and return an error if this is not the case. + */ +static int +validate_msg_fds(struct VhostUserMsg *msg, int expected_fds) +{ + if (msg->fd_num == expected_fds) + return 0; + + RTE_LOG(ERR, VHOST_CONFIG, + " Expect %d FDs for request %s, received %d\n", + expected_fds, + vhost_message_str[msg->request.master], + msg->fd_num); + + close_msg_fds(msg); + + return -1; +} + static uint64_t get_blk_size(int fd) { @@ -204,18 +234,25 @@ vhost_backend_cleanup(struct virtio_net *dev) */ static int vhost_user_set_owner(struct virtio_net **pdev __rte_unused, - struct VhostUserMsg *msg __rte_unused, + struct VhostUserMsg *msg, int main_fd __rte_unused) { + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + return RTE_VHOST_MSG_RESULT_OK; } static int vhost_user_reset_owner(struct virtio_net **pdev, - struct VhostUserMsg *msg __rte_unused, + struct VhostUserMsg *msg, int main_fd __rte_unused) { struct virtio_net *dev = *pdev; + + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + vhost_destroy_device_notify(dev); cleanup_device(dev, 0); @@ -233,6 +270,9 @@ vhost_user_get_features(struct virtio_net **pdev, struct VhostUserMsg *msg, struct virtio_net *dev = *pdev; uint64_t features = 0; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + rte_vhost_driver_get_features(dev->ifname, &features); msg->payload.u64 = features; @@ -252,6 +292,9 @@ vhost_user_get_queue_num(struct virtio_net **pdev, struct VhostUserMsg *msg, struct virtio_net *dev = *pdev; uint32_t queue_num = 0; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + rte_vhost_driver_get_queue_num(dev->ifname, &queue_num); msg->payload.u64 = (uint64_t)queue_num; @@ -274,6 +317,9 @@ vhost_user_set_features(struct virtio_net **pdev, struct VhostUserMsg *msg, struct rte_vdpa_device *vdpa_dev; int did = -1; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + rte_vhost_driver_get_features(dev->ifname, &vhost_features); if (features & ~vhost_features) { RTE_LOG(ERR, VHOST_CONFIG, @@ -357,6 +403,9 @@ vhost_user_set_vring_num(struct virtio_net **pdev, struct virtio_net *dev = *pdev; struct vhost_virtqueue *vq = dev->virtqueue[msg->payload.state.index]; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + vq->size = msg->payload.state.num; /* VIRTIO 1.0, 2.4 Virtqueues says: @@ -798,6 +847,9 @@ vhost_user_set_vring_addr(struct virtio_net **pdev, struct VhostUserMsg *msg, struct vhost_vring_addr *addr = &msg->payload.addr; bool access_ok; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (dev->mem == NULL) return RTE_VHOST_MSG_RESULT_ERR; @@ -839,6 +891,9 @@ vhost_user_set_vring_base(struct virtio_net **pdev, struct vhost_virtqueue *vq = dev->virtqueue[msg->payload.state.index]; uint64_t val = msg->payload.state.num; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (vq_is_packed(dev)) { /* * Bit[0:14]: avail index @@ -1000,6 +1055,9 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg, int populate; int fd; + if (validate_msg_fds(msg, memory->nregions) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (memory->nregions > VHOST_MEMORY_MAX_NREGIONS) { RTE_LOG(ERR, VHOST_CONFIG, "too many memory regions (%u)\n", memory->nregions); @@ -1010,8 +1068,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg, RTE_LOG(INFO, VHOST_CONFIG, "(%d) memory regions not changed\n", dev->vid); - for (i = 0; i < memory->nregions; i++) - close(msg->fds[i]); + close_msg_fds(msg); return RTE_VHOST_MSG_RESULT_OK; } @@ -1154,6 +1211,10 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg, "Failed to read qemu ack on postcopy set-mem-table\n"); goto err_mmap; } + + if (validate_msg_fds(&ack_msg, 0) != 0) + goto err_mmap; + if (ack_msg.request.master != VHOST_USER_SET_MEM_TABLE) { RTE_LOG(ERR, VHOST_CONFIG, "Bad qemu ack on postcopy set-mem-table (%d)\n", @@ -1503,6 +1564,9 @@ vhost_user_set_vring_call(struct virtio_net **pdev, struct VhostUserMsg *msg, struct vhost_vring_file file; struct vhost_virtqueue *vq; + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + file.index = msg->payload.u64 & VHOST_USER_VRING_IDX_MASK; if (msg->payload.u64 & VHOST_USER_VRING_NOFD_MASK) file.fd = VIRTIO_INVALID_EVENTFD; @@ -1524,6 +1588,9 @@ static int vhost_user_set_vring_err(struct virtio_net **pdev __rte_unused, struct VhostUserMsg *msg, int main_fd __rte_unused) { + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (!(msg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) close(msg->fds[0]); RTE_LOG(INFO, VHOST_CONFIG, "not implemented\n"); @@ -1724,6 +1791,9 @@ vhost_user_set_vring_kick(struct virtio_net **pdev, struct VhostUserMsg *msg, struct vhost_vring_file file; struct vhost_virtqueue *vq; + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + file.index = msg->payload.u64 & VHOST_USER_VRING_IDX_MASK; if (msg->payload.u64 & VHOST_USER_VRING_NOFD_MASK) file.fd = VIRTIO_INVALID_EVENTFD; @@ -1794,6 +1864,9 @@ vhost_user_get_vring_base(struct virtio_net **pdev, struct vhost_virtqueue *vq = dev->virtqueue[msg->payload.state.index]; uint64_t val; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + /* We have to stop the queue (virtio) if it is running. */ vhost_destroy_device_notify(dev); @@ -1869,6 +1942,9 @@ vhost_user_set_vring_enable(struct virtio_net **pdev, struct rte_vdpa_device *vdpa_dev; int did = -1; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + RTE_LOG(INFO, VHOST_CONFIG, "set queue enable: %d to qp idx: %d\n", enable, index); @@ -1899,6 +1975,9 @@ vhost_user_get_protocol_features(struct virtio_net **pdev, struct virtio_net *dev = *pdev; uint64_t features, protocol_features; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + rte_vhost_driver_get_features(dev->ifname, &features); rte_vhost_driver_get_protocol_features(dev->ifname, &protocol_features); @@ -1927,6 +2006,9 @@ vhost_user_set_protocol_features(struct virtio_net **pdev, uint64_t protocol_features = msg->payload.u64; uint64_t slave_protocol_features = 0; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + rte_vhost_driver_get_protocol_features(dev->ifname, &slave_protocol_features); if (protocol_features & ~slave_protocol_features) { @@ -1953,6 +2035,9 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg, uint64_t size, off; void *addr; + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (fd < 0) { RTE_LOG(ERR, VHOST_CONFIG, "invalid log fd: %d\n", fd); return RTE_VHOST_MSG_RESULT_ERR; @@ -2016,6 +2101,9 @@ static int vhost_user_set_log_fd(struct virtio_net **pdev __rte_unused, struct VhostUserMsg *msg, int main_fd __rte_unused) { + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + close(msg->fds[0]); RTE_LOG(INFO, VHOST_CONFIG, "not implemented.\n"); @@ -2039,6 +2127,9 @@ vhost_user_send_rarp(struct virtio_net **pdev, struct VhostUserMsg *msg, struct rte_vdpa_device *vdpa_dev; int did = -1; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + RTE_LOG(DEBUG, VHOST_CONFIG, ":: mac: %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); @@ -2066,6 +2157,10 @@ vhost_user_net_set_mtu(struct virtio_net **pdev, struct VhostUserMsg *msg, int main_fd __rte_unused) { struct virtio_net *dev = *pdev; + + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (msg->payload.u64 < VIRTIO_MIN_MTU || msg->payload.u64 > VIRTIO_MAX_MTU) { RTE_LOG(ERR, VHOST_CONFIG, "Invalid MTU size (%"PRIu64")\n", @@ -2086,6 +2181,9 @@ vhost_user_set_req_fd(struct virtio_net **pdev, struct VhostUserMsg *msg, struct virtio_net *dev = *pdev; int fd = msg->fds[0]; + if (validate_msg_fds(msg, 1) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (fd < 0) { RTE_LOG(ERR, VHOST_CONFIG, "Invalid file descriptor for slave channel (%d)\n", @@ -2171,6 +2269,9 @@ vhost_user_iotlb_msg(struct virtio_net **pdev, struct VhostUserMsg *msg, uint16_t i; uint64_t vva, len; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + switch (imsg->type) { case VHOST_IOTLB_UPDATE: len = imsg->size; @@ -2217,6 +2318,9 @@ vhost_user_set_postcopy_advise(struct virtio_net **pdev, #ifdef RTE_LIBRTE_VHOST_POSTCOPY struct uffdio_api api_struct; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK); if (dev->postcopy_ufd == -1) { @@ -2252,6 +2356,9 @@ vhost_user_set_postcopy_listen(struct virtio_net **pdev, { struct virtio_net *dev = *pdev; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + if (dev->mem && dev->mem->nregions) { RTE_LOG(ERR, VHOST_CONFIG, "Regions already registered at postcopy-listen\n"); @@ -2268,6 +2375,9 @@ vhost_user_postcopy_end(struct virtio_net **pdev, struct VhostUserMsg *msg, { struct virtio_net *dev = *pdev; + if (validate_msg_fds(msg, 0) != 0) + return RTE_VHOST_MSG_RESULT_ERR; + dev->postcopy_listening = 0; if (dev->postcopy_ufd >= 0) { close(dev->postcopy_ufd); @@ -2621,6 +2731,7 @@ skip_to_post_handle: if (!handled) { RTE_LOG(ERR, VHOST_CONFIG, "vhost message (req: %d) was not handled.\n", request); + close_msg_fds(&msg); ret = RTE_VHOST_MSG_RESULT_ERR; }