From 817e48d8a2998b19dc36a77f8363b5f74bc3fa9e Mon Sep 17 00:00:00 2001
From: Lukasz Majewski <l.majewski@majess.pl>
Date: Mon, 14 Sep 2015 00:57:03 +0200
Subject: [PATCH] env: import: hashtable: Prevent buffer overrun when importing
environment from file
Lets consider following scenario:
- One uses echo -n "key=value" to define environment variable in a file (single variable)
- The file content is "key=value" without any terminating byte (e.g. 0x0a or
0x0d).
- The file is loaded to u-boot non zero'ed RAM buffer (with load command).
- Then "env import -t -r $loadaddr $filesize" is executed.
- Due to lack of proper termination byte we have classical example of buffer
overrun.
This patch prevents from this by allocating one extra byte than size and
explicitly null terminate it.
There should be no change for normal env import operation after applying
this patch.
Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
---
lib/hashtable.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/hashtable.c b/lib/hashtable.c
index 18ed5901ec2..7df424ad87a 100644
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -789,12 +789,13 @@ int himport_r(struct hsearch_data *htab,
}
/* we allocate new space to make sure we can write to the array */
- if ((data = malloc(size)) == NULL) {
- debug("himport_r: can't malloc %zu bytes\n", size);
+ if ((data = malloc(size + 1)) == NULL) {
+ debug("himport_r: can't malloc %zu bytes\n", size + 1);
__set_errno(ENOMEM);
return 0;
}
memcpy(data, env, size);
+ data[size] = '\0';
dp = data;
/* make a local copy of the list of variables */
--
GitLab