From 935bb933e4a74de7326a4373340fd50655712334 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20=C5=A0tetiar?= <ynezz@true.cz>
Date: Tue, 14 Jan 2020 08:57:05 +0100
Subject: blobmsg: blobmsg_vprintf: prefer vsnprintf
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Better safe than sorry and while at it add handling of possible
*printf() failures.

Reviewed-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
---
 blobmsg.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/blobmsg.c
+++ b/blobmsg.c
@@ -296,10 +296,17 @@ blobmsg_vprintf(struct blob_buf *buf, co
 	len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 	va_end(arg2);
 
+	if (len < 0)
+		return -1;
+
 	sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 	if (!sbuf)
 		return -1;
-	ret = vsprintf(sbuf, format, arg);
+
+	ret = vsnprintf(sbuf, len + 1, format, arg);
+	if (ret < 0)
+		return -1;
+
 	blobmsg_add_string_buffer(buf);
 
 	return ret;