From: Andrew Scull <ascull@google.com>
Date: Mon, 30 May 2022 10:00:01 +0000 (+0000)
Subject: serial: sandbox: Fix buffer underflow in puts
X-Git-Url: http://git.dujemihanovic.xyz/img/static/git-favicon.png?a=commitdiff_plain;h=337b26e4688720560662246eb7703860b68bd6e2;p=u-boot.git

serial: sandbox: Fix buffer underflow in puts

Fix the buffer underflow that would occur if puts is called with length
of zero.

Fixes: efa51f2bd64 ("serial: sandbox: Implement puts")
Cc: Sean Anderson <sean.anderson@seco.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
---

diff --git a/drivers/serial/sandbox.c b/drivers/serial/sandbox.c
index e726e19c46..13b54921c4 100644
--- a/drivers/serial/sandbox.c
+++ b/drivers/serial/sandbox.c
@@ -114,7 +114,7 @@ static ssize_t sandbox_serial_puts(struct udevice *dev, const char *s,
 	struct sandbox_serial_priv *priv = dev_get_priv(dev);
 	ssize_t ret;
 
-	if (s[len - 1] == '\n')
+	if (len && s[len - 1] == '\n')
 		priv->start_of_line = true;
 
 	if (sandbox_serial_enabled) {