From 30f509686d8abc2ffd7fe34401d00cf7a86d8ea9 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Sun, 9 Dec 2018 14:22:17 +0100
Subject: [PATCH] block: validate amount of arguments for the "autofs" command
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Using argv[3] without checking argc value could result in undefined
behavior. It could result in a crash or accessing a NULL that separates
argv from envp on UNIX.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: John Crispin <john@phrozen.org>
---
 block.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block.c b/block.c
index 46050b4..a0bbf47 100644
--- a/block.c
+++ b/block.c
@@ -1157,6 +1157,10 @@ static int main_autofs(int argc, char **argv)
 		}
 		return 0;
 	}
+
+	if (argc < 4)
+		return -EINVAL;
+
 	return mount_action(argv[2], argv[3], TYPE_AUTOFS);
 }
 
-- 
2.25.1