misc: fastrpc: fix memory corruption on probe

Add the missing sanity check on the probed-session count to avoid corrupting memory beyond the fixed-size slab-allocated session array when there are more than FASTRPC_MAX_SESSIONS sessions defined in the devicetree. Fixes: f6f9279 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model") Cc: [email protected] # 5.1 Signed-off-by: Johan Hovold <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
kawasaki · Sep 1, 2022 · 9baa141 · 9baa141
1 parent 5ef251b
commit 9baa141
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
@@ -1943,6 +1943,11 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
 	of_property_read_u32(dev->of_node, "qcom,nsessions", &sessions);
 
 	spin_lock_irqsave(&cctx->lock, flags);
+	if (cctx->sesscount >= FASTRPC_MAX_SESSIONS) {
+		dev_err(&pdev->dev, "too many sessions\n");
+		spin_unlock_irqrestore(&cctx->lock, flags);
+		return -ENOSPC;
+	}
 	sess = &cctx->session[cctx->sesscount];
 	sess->used = false;
 	sess->valid = true;