From 41b471d235b87c7d3bd1e7e91063b3b8fc6dd52e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Date: Wed, 22 Apr 2015 19:07:19 +0000
Subject: [PATCH] nvram: refuse to open NVRAM for writing if it's too big to be
 handled
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Otherwise writing anything will result in loosing data.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45565 3c298f89-4303-0410-b956-a3cf2f4a3e73
---
 package/utils/nvram/src/nvram.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package/utils/nvram/src/nvram.c b/package/utils/nvram/src/nvram.c
index f2c79ff7ba..0e1c726837 100644
--- a/package/utils/nvram/src/nvram.c
+++ b/package/utils/nvram/src/nvram.c
@@ -389,8 +389,8 @@ nvram_handle_t * nvram_open(const char *file, int rdonly)
 
 				header = nvram_header(h);
 
-				if( header->magic == NVRAM_MAGIC )
-				{
+				if (header->magic == NVRAM_MAGIC &&
+				    (rdonly || header->len < NVRAM_SPACE)) {
 					_nvram_rehash(h);
 					free(mtd);
 					return h;