From: Matej Mužila <mmuzila@xxxxxxxxxx>
Check if cpmsg->size is in limits of DATA_FRAGMENT
Signed-off-by: Matej Mužila <mmuzila@xxxxxxxxxx>
---
If corrupted data are read from /dev/vmbus/hv_fcopy, pwrite can
read from memory outside of the buffer (defined at line 138).
Added check.
Changes made since v1:
* max value of cmesg->size is now derived from structure
definition in sources/include/uapi/linux/hyperv.h
* Fixed comments
diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
index 6f27e2f..1fc2dc2 100644
--- a/tools/hv/hv_fcopy_daemon.c
+++ b/tools/hv/hv_fcopy_daemon.c
@@ -104,6 +104,10 @@ static int hv_copy_data(struct hv_do_fcopy *cpmsg)
{
ssize_t bytes_written;
+ /* Check if the cpmsg->size is in limits of DATA_FRAGMENT */
+ if (cpmsg->size > sizeof(cpmsg->data))
+ return HV_E_FAIL;
+
bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
cpmsg->offset);
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