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 <maxime.coque...@redhat.com>
---
lib/librte_vhost/vhost_user.c | 87 +++++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index cebc72f78f..a6ab131543 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -75,6 +75,36 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
[VHOST_USER_SEND_RARP] = "VHOST_USER_SEND_RARP",
};
+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],
+ msg->fd_num);
+
+ close_msg_fds(msg);
+
+ return -1;
+}
+
static uint64_t
get_blk_size(int fd)
{
@@ -1104,35 +1134,59 @@ vhost_user_msg_handler(int vid, int fd)
ret = 0;
switch (msg.request) {
case VHOST_USER_GET_FEATURES:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
msg.payload.u64 = vhost_user_get_features();
msg.size = sizeof(msg.payload.u64);
send_vhost_message(fd, &msg);
break;
case VHOST_USER_SET_FEATURES:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_features(dev, msg.payload.u64);
break;
case VHOST_USER_GET_PROTOCOL_FEATURES:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
msg.payload.u64 = VHOST_USER_PROTOCOL_FEATURES;
msg.size = sizeof(msg.payload.u64);
send_vhost_message(fd, &msg);
break;
case VHOST_USER_SET_PROTOCOL_FEATURES:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_protocol_features(dev, msg.payload.u64);
break;
case VHOST_USER_SET_OWNER:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_owner();
break;
case VHOST_USER_RESET_OWNER:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_reset_owner(dev);
break;
case VHOST_USER_SET_MEM_TABLE:
+ if (validate_msg_fds(&msg, msg.payload.memory.nregions) != 0)
+ return -1;
+
vhost_user_set_mem_table(dev, &msg);
break;
case VHOST_USER_SET_LOG_BASE:
+ if (validate_msg_fds(&msg, 1) != 0)
+ return -1;
+
ret = vhost_user_set_log_base(dev, &msg);
if (ret)
break;
@@ -1144,21 +1198,36 @@ vhost_user_msg_handler(int vid, int fd)
send_vhost_message(fd, &msg);
break;
case VHOST_USER_SET_LOG_FD:
+ if (validate_msg_fds(&msg, 1) != 0)
+ return -1;
+
close(msg.fds[0]);
RTE_LOG(INFO, VHOST_CONFIG, "not implemented.\n");
break;
case VHOST_USER_SET_VRING_NUM:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_vring_num(dev, &msg.payload.state);
break;
case VHOST_USER_SET_VRING_ADDR:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_vring_addr(&dev, &msg.payload.addr);
break;
case VHOST_USER_SET_VRING_BASE:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_vring_base(dev, &msg.payload.state);
break;
case VHOST_USER_GET_VRING_BASE:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_get_vring_base(dev, &msg.payload.state);
if (ret)
break;
@@ -1167,28 +1236,46 @@ vhost_user_msg_handler(int vid, int fd)
break;
case VHOST_USER_SET_VRING_KICK:
+ if (validate_msg_fds(&msg, 1) != 0)
+ return -1;
+
ret = vhost_user_set_vring_kick(dev, &msg);
break;
case VHOST_USER_SET_VRING_CALL:
+ if (validate_msg_fds(&msg, 1) != 0)
+ return -1;
+
vhost_user_set_vring_call(dev, &msg);
break;
case VHOST_USER_SET_VRING_ERR:
+ if (validate_msg_fds(&msg, 1) != 0)
+ return -1;
+
if (!(msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK))
close(msg.fds[0]);
RTE_LOG(INFO, VHOST_CONFIG, "not implemented\n");
break;
case VHOST_USER_GET_QUEUE_NUM:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
msg.payload.u64 = VHOST_MAX_QUEUE_PAIRS;
msg.size = sizeof(msg.payload.u64);
send_vhost_message(fd, &msg);
break;
case VHOST_USER_SET_VRING_ENABLE:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_set_vring_enable(dev, &msg.payload.state);
break;
case VHOST_USER_SEND_RARP:
+ if (validate_msg_fds(&msg, 0) != 0)
+ return -1;
+
ret = vhost_user_send_rarp(dev, &msg);
break;
--
2.21.0
