[PATCH] bcache-tools: check whether allocating memory fails in tree()

[PATCH] bcache-tools: check whether allocating memory fails in tree()

[Zhiqiang Liu]

In tree(), we do not check whether malloc() returns NULL,
it may cause potential Null pointer dereference problem.
In addition, when we fail to list devices, we should free(out)
before return.

Signed-off-by: ZhiqiangLiu <lzhq28@mail.ustc.edu.cn>
---
 bcache.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/bcache.c b/bcache.c
index 044d401..1c4cef9 100644
--- a/bcache.c
+++ b/bcache.c
@@ -174,7 +174,7 @@ void replace_line(char **dest, const char *from, const char *to)

 int tree(void)
 {
-	char *out = (char *)malloc(4096);
+	char *out;
 	const char *begin = ".\n";
 	const char *middle = "├─";
 	const char *tail = "└─";
@@ -184,8 +184,15 @@ int tree(void)
 	INIT_LIST_HEAD(&head);
 	int ret;

+	out = (char *)malloc(4096);
+	if (out == NULL) {
+		fprintf(stderr, "Error: fail to allocate memory buffer\n");
+		return 1;
+	}
+
 	ret = list_bdevs(&head);
 	if (ret != 0) {
+		free(out);
 		fprintf(stderr, "Failed to list devices\n");
 		return ret;
 	}
-- 
2.30.0

Re: [PATCH] bcache-tools: check whether allocating memory fails in tree()

[Coly Li]

On 2/27/21 10:35 AM, Zhiqiang Liu wrote:
> 
> In tree(), we do not check whether malloc() returns NULL,
> it may cause potential Null pointer dereference problem.
> In addition, when we fail to list devices, we should free(out)
> before return.
> 
> Signed-off-by: ZhiqiangLiu <lzhq28@mail.ustc.edu.cn>

Applied. BTW, I change your above name string from ZhiqiangLiu to
Zhiqiang Liu, because of the checkpatch.pl warning.


Thanks.

Coly Li


> ---
>  bcache.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/bcache.c b/bcache.c
> index 044d401..1c4cef9 100644
> --- a/bcache.c
> +++ b/bcache.c
> @@ -174,7 +174,7 @@ void replace_line(char **dest, const char *from, const char *to)
> 
>  int tree(void)
>  {
> -	char *out = (char *)malloc(4096);
> +	char *out;
>  	const char *begin = ".\n";
>  	const char *middle = "├─";
>  	const char *tail = "└─";
> @@ -184,8 +184,15 @@ int tree(void)
>  	INIT_LIST_HEAD(&head);
>  	int ret;
> 
> +	out = (char *)malloc(4096);
> +	if (out == NULL) {
> +		fprintf(stderr, "Error: fail to allocate memory buffer\n");
> +		return 1;
> +	}
> +
>  	ret = list_bdevs(&head);
>  	if (ret != 0) {
> +		free(out);
>  		fprintf(stderr, "Failed to list devices\n");
>  		return ret;
>  	}
> 

Re: [PATCH] bcache-tools: check whether allocating memory fails in tree()

[Zhiqiang Liu]

Thank you for doing that.

Zhiqiang Liu

On 2021/3/2 21:33, Coly Li wrote:
> On 2/27/21 10:35 AM, Zhiqiang Liu wrote:
>>
>> In tree(), we do not check whether malloc() returns NULL,
>> it may cause potential Null pointer dereference problem.
>> In addition, when we fail to list devices, we should free(out)
>> before return.
>>
>> Signed-off-by: ZhiqiangLiu <lzhq28@mail.ustc.edu.cn>
> 
> Applied. BTW, I change your above name string from ZhiqiangLiu to
> Zhiqiang Liu, because of the checkpatch.pl warning.
> 
> 
> Thanks.
> 
> Coly Li
> 
> 
>> ---
>>  bcache.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/bcache.c b/bcache.c
>> index 044d401..1c4cef9 100644
>> --- a/bcache.c
>> +++ b/bcache.c
>> @@ -174,7 +174,7 @@ void replace_line(char **dest, const char *from, const char *to)
>>
>>  int tree(void)
>>  {
>> -	char *out = (char *)malloc(4096);
>> +	char *out;
>>  	const char *begin = ".\n";
>>  	const char *middle = "├─";
>>  	const char *tail = "└─";
>> @@ -184,8 +184,15 @@ int tree(void)
>>  	INIT_LIST_HEAD(&head);
>>  	int ret;
>>
>> +	out = (char *)malloc(4096);
>> +	if (out == NULL) {
>> +		fprintf(stderr, "Error: fail to allocate memory buffer\n");
>> +		return 1;
>> +	}
>> +
>>  	ret = list_bdevs(&head);
>>  	if (ret != 0) {
>> +		free(out);
>>  		fprintf(stderr, "Failed to list devices\n");
>>  		return ret;
>>  	}
>>
> 
> 
> .
>