From c78d94189dced04def987a17f16097fcb197a186 Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Mon, 18 May 2020 14:17:00 +0100 Subject: [PATCH] vhost: fix vring index check 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 vhost_user_check_and_alloc_queue_pair(). CVE-2020-10723 Fixes: 160cbc815b41 ("vhost: remove a hack on queue allocation") Cc: stable@dpdk.org Reported-by: Ilja Van Sprundel Signed-off-by: Maxime Coquelin Reviewed-by: Xiaolong Ye Reviewed-by: Ilja Van Sprundel --- lib/librte_vhost/vhost_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c index ff5b13169f..6dbba04760 100644 --- a/lib/librte_vhost/vhost_user.c +++ b/lib/librte_vhost/vhost_user.c @@ -2534,7 +2534,7 @@ 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) { case VHOST_USER_SET_VRING_KICK: -- 2.20.1