vmci_transport_dgram_enqueue() does not check the return value
of memcpy_from_msg().  If memcpy_from_msg() fails, it is possible that
uninitialized memory contents are sent unintentionally instead of user's
message in the datagram to the destination.  Return with an error if
memcpy_from_msg() fails.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 0f7db23a07af ("vmci_transport: switch ->enqeue_dgram, ->enqueue_stream and ->dequeue_stream to msghdr")
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Vishnu Dasa <vdasa@vmware.com>
---
V1->V2 Fix memory leaking and updates for description
V2->V3 Return the value of memcpy_from_msg()
V3->V4 Updates for description

 net/vmw_vsock/vmci_transport.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 842c94286d31..36eb16a40745 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1711,7 +1711,11 @@ static int vmci_transport_dgram_enqueue(
 	if (!dg)
 		return -ENOMEM;
 
-	memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
+	err = memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
+	if (err) {
+		kfree(dg);
+		return err;
+	}
 
 	dg->dst = vmci_make_handle(remote_addr->svm_cid,
 				   remote_addr->svm_port);
-- 
2.30.3

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Tue,  6 Dec 2022 09:58:34 +0300 you wrote:
> vmci_transport_dgram_enqueue() does not check the return value
> of memcpy_from_msg().  If memcpy_from_msg() fails, it is possible that
> uninitialized memory contents are sent unintentionally instead of user's
> message in the datagram to the destination.  Return with an error if
> memcpy_from_msg() fails.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> [...]

Here is the summary with links:
  - [v4] net: vmw_vsock: vmci: Check memcpy_from_msg()
    https://git.kernel.org/netdev/net/c/44aa5a6dba82

You are awesome, thank you!
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