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[2/6] vhost: fix vring index check

Message ID 20200518131704.715877-3-ferruh.yigit@intel.com (mailing list archive)
State Accepted, archived
Delegated to: David Marchand
Headers show
Series Fix vhost security issues | expand


Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Ferruh Yigit May 18, 2020, 1:17 p.m. UTC
From: Maxime Coquelin <maxime.coquelin@redhat.com>

vhost_user_check_and_alloc_queue_pair() is used to extract
a vring index from a payload. This function validates the
index and is called early on in when performing message
handling. Most message handlers depend on it correctly
validating the vring index.

Depending on the message type the vring index is in
different parts of the payload. The function contains a
switch/case for each type and copies the index. This is
stored in a uint16. This index is then validated. Depending
on the message, the source index is an unsigned int. If
integer truncation occurs (uint->uint16) the top 16 bits
of the index are never validated.

When they are used later on  (e.g. in
vhost_user_set_vring_num() or vhost_user_set_vring_addr())
it can lead to out of bound indexing. The out of bound
indexed data gets written to, and hence this can cause
memory corruption.

This patch fixes this vulnerability by declaring vring
index as an unsigned int in

Fixes: 160cbc815b41 ("vhost: remove a hack on queue allocation")
Cc: stable@dpdk.org

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Xiaolong Ye <xiaolong.ye@intel.com>
Reviewed-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
 lib/librte_vhost/vhost_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 1eea371fc8..e51a8a6b77 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2526,7 +2526,7 @@  static int
 vhost_user_check_and_alloc_queue_pair(struct virtio_net *dev,
 			struct VhostUserMsg *msg)
-	uint16_t vring_idx;
+	uint32_t vring_idx;
 	switch (msg->request.master) {