From: Maxime Coquelin <[email protected]>
vhost_user_set_log_base() is a message handler that is
called to handle the VHOST_USER_SET_LOG_BASE message.
Its payload contains a 64 bit size and offset. Both are
added up and used as a size when calling mmap().
There is no integer overflow check. If an integer overflow
occurs a smaller memory map would be created than
requested. Since the returned mapping is mapped as writable
and used for logging, a memory corruption could occur.
CVE-2020-10722
Fixes: fbc4d248b198 ("vhost: fix offset while mmaping log base address")
Cc: [email protected]
Reported-by: Ilja Van Sprundel <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
Reviewed-by: Xiaolong Ye <[email protected]>
Reviewed-by: Ilja Van Sprundel <[email protected]>
---
lib/librte_vhost/vhost_user.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index bd1be01040..1eea371fc8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2059,10 +2059,10 @@ vhost_user_set_log_base(struct virtio_net **pdev,
struct VhostUserMsg *msg,
size = msg->payload.log.mmap_size;
off = msg->payload.log.mmap_offset;
- /* Don't allow mmap_offset to point outside the mmap region */
- if (off > size) {
+ /* Check for mmap size and offset overflow. */
+ if (off >= -size) {
VHOST_LOG_CONFIG(ERR,
- "log offset %#"PRIx64" exceeds log size %#"PRIx64"\n",
+ "log offset %#"PRIx64" and log size %#"PRIx64"
overflow\n",
off, size);
return RTE_VHOST_MSG_RESULT_ERR;
}
--
2.25.2
