net: qrtr: fix 32-bit integer overflow in qrtr_endpoint_post()

commit 2005486 upstream.

qrtr_endpoint_post() validates an incoming packet with

	if (!size || len != ALIGN(size, 4) + hdrlen)
		goto err;

where size comes from the wire. On 32-bit, size_t is 32 bits and
ALIGN(size, 4) wraps to 0 for size >= 0xfffffffd, so the check
passes and skb_put_data(skb, data + hdrlen, size) writes past the
hdrlen-sized skb and oopses the kernel. 64-bit is unaffected.

This is the 32-bit residual of ad9d24c ("net: qrtr: fix OOB
Read in qrtr_endpoint_post"), which fixed only the 64-bit case.

Reject any size that cannot fit the buffer before the ALIGN.

Fixes: ad9d24c ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260611125455.2352279-1-michael.bommarito@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: mjbommar

net/qrtr/af_qrtr.c

@@ -491,7 +491,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 		goto err;
 	}
 
-	if (!size || len != ALIGN(size, 4) + hdrlen)
+	if (!size || size > len || len != ALIGN(size, 4) + hdrlen)
 		goto err;
 
 	if ((cb->type == QRTR_TYPE_NEW_SERVER ||