* [PATCH] samples/landlock: fix path_list memory leak
@ 2021-04-27 18:37 trix
2021-04-27 19:13 ` Nick Desaulniers
0 siblings, 1 reply; 5+ messages in thread
From: trix @ 2021-04-27 18:37 UTC (permalink / raw)
To: mic, nathan, ndesaulniers
Cc: linux-security-module, linux-kernel, clang-built-linux, Tom Rix
From: Tom Rix <trix@redhat.com>
Clang static analysis reports this error
sandboxer.c:134:8: warning: Potential leak of memory
pointed to by 'path_list'
ret = 0;
^
path_list is allocated in parse_path() but never freed.
Signed-off-by: Tom Rix <trix@redhat.com>
---
samples/landlock/sandboxer.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 7a15910d2171..4629d011ed61 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -134,6 +134,8 @@ static int populate_ruleset(
ret = 0;
out_free_name:
+ if (path_list)
+ free(path_list);
free(env_path_name);
return ret;
}
--
2.26.3
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] samples/landlock: fix path_list memory leak
2021-04-27 18:37 [PATCH] samples/landlock: fix path_list memory leak trix
@ 2021-04-27 19:13 ` Nick Desaulniers
2021-04-28 9:58 ` Mickaël Salaün
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2021-04-27 19:13 UTC (permalink / raw)
To: Tom Rix
Cc: mic, Nathan Chancellor, linux-security-module, LKML, clang-built-linux
On Tue, Apr 27, 2021 at 11:38 AM <trix@redhat.com> wrote:
>
> From: Tom Rix <trix@redhat.com>
>
> Clang static analysis reports this error
>
> sandboxer.c:134:8: warning: Potential leak of memory
> pointed to by 'path_list'
> ret = 0;
> ^
> path_list is allocated in parse_path() but never freed.
>
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> samples/landlock/sandboxer.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
> index 7a15910d2171..4629d011ed61 100644
> --- a/samples/landlock/sandboxer.c
> +++ b/samples/landlock/sandboxer.c
> @@ -134,6 +134,8 @@ static int populate_ruleset(
> ret = 0;
>
> out_free_name:
> + if (path_list)
> + free(path_list);
I don't think the conditional is even necessary? By our first `goto
out_free_name;`, `parse_path` has already been called/memory for
`path_list` has already been allocated. `parse_path` doesn't check
whether `malloc` has failed.
> free(env_path_name);
> return ret;
> }
> --
> 2.26.3
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] samples/landlock: fix path_list memory leak
2021-04-27 19:13 ` Nick Desaulniers
@ 2021-04-28 9:58 ` Mickaël Salaün
2021-04-28 15:36 ` Tom Rix
0 siblings, 1 reply; 5+ messages in thread
From: Mickaël Salaün @ 2021-04-28 9:58 UTC (permalink / raw)
To: Nick Desaulniers, Tom Rix
Cc: Nathan Chancellor, linux-security-module, LKML,
clang-built-linux, James Morris, Linus Torvalds
On 27/04/2021 21:13, Nick Desaulniers wrote:
> On Tue, Apr 27, 2021 at 11:38 AM <trix@redhat.com> wrote:
>>
>> From: Tom Rix <trix@redhat.com>
>>
>> Clang static analysis reports this error
>>
>> sandboxer.c:134:8: warning: Potential leak of memory
>> pointed to by 'path_list'
>> ret = 0;
>> ^
>> path_list is allocated in parse_path() but never freed.
>>
>> Signed-off-by: Tom Rix <trix@redhat.com>
>> ---
>> samples/landlock/sandboxer.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
>> index 7a15910d2171..4629d011ed61 100644
>> --- a/samples/landlock/sandboxer.c
>> +++ b/samples/landlock/sandboxer.c
>> @@ -134,6 +134,8 @@ static int populate_ruleset(
>> ret = 0;
>>
>> out_free_name:
>> + if (path_list)
>> + free(path_list);
>
> I don't think the conditional is even necessary? By our first `goto
> out_free_name;`, `parse_path` has already been called/memory for
> `path_list` has already been allocated. `parse_path` doesn't check
> whether `malloc` has failed.
Indeed, no need for the path_list check. In practice, this memory leak
doesn't stay long because of the execve, but I missed this free anyway.
Thanks!
Reviewed-by: Mickaël Salaün <mic@linux.microsoft.com>
>
>> free(env_path_name);
>> return ret;
>> }
>> --
>> 2.26.3
>>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] samples/landlock: fix path_list memory leak
2021-04-28 9:58 ` Mickaël Salaün
@ 2021-04-28 15:36 ` Tom Rix
2021-04-28 18:04 ` Mickaël Salaün
0 siblings, 1 reply; 5+ messages in thread
From: Tom Rix @ 2021-04-28 15:36 UTC (permalink / raw)
To: Mickaël Salaün, Nick Desaulniers
Cc: Nathan Chancellor, linux-security-module, LKML,
clang-built-linux, James Morris, Linus Torvalds
On 4/28/21 2:58 AM, Mickaël Salaün wrote:
> On 27/04/2021 21:13, Nick Desaulniers wrote:
>> On Tue, Apr 27, 2021 at 11:38 AM <trix@redhat.com> wrote:
>>> From: Tom Rix <trix@redhat.com>
>>>
>>> Clang static analysis reports this error
>>>
>>> sandboxer.c:134:8: warning: Potential leak of memory
>>> pointed to by 'path_list'
>>> ret = 0;
>>> ^
>>> path_list is allocated in parse_path() but never freed.
>>>
>>> Signed-off-by: Tom Rix <trix@redhat.com>
>>> ---
>>> samples/landlock/sandboxer.c | 2 ++
>>> 1 file changed, 2 insertions(+)
>>>
>>> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
>>> index 7a15910d2171..4629d011ed61 100644
>>> --- a/samples/landlock/sandboxer.c
>>> +++ b/samples/landlock/sandboxer.c
>>> @@ -134,6 +134,8 @@ static int populate_ruleset(
>>> ret = 0;
>>>
>>> out_free_name:
>>> + if (path_list)
>>> + free(path_list);
>> I don't think the conditional is even necessary? By our first `goto
>> out_free_name;`, `parse_path` has already been called/memory for
>> `path_list` has already been allocated. `parse_path` doesn't check
>> whether `malloc` has failed.
> Indeed, no need for the path_list check. In practice, this memory leak
> doesn't stay long because of the execve, but I missed this free anyway.
> Thanks!
Ok, the general problem of not checking if malloc and friends succeeds
is a different problem.
So remove the check and keep the free ?
Tom
> Reviewed-by: Mickaël Salaün <mic@linux.microsoft.com>
>
>>> free(env_path_name);
>>> return ret;
>>> }
>>> --
>>> 2.26.3
>>>
>>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] samples/landlock: fix path_list memory leak
2021-04-28 15:36 ` Tom Rix
@ 2021-04-28 18:04 ` Mickaël Salaün
0 siblings, 0 replies; 5+ messages in thread
From: Mickaël Salaün @ 2021-04-28 18:04 UTC (permalink / raw)
To: Tom Rix, Nick Desaulniers
Cc: Nathan Chancellor, linux-security-module, LKML,
clang-built-linux, James Morris, Linus Torvalds
On 28/04/2021 17:36, Tom Rix wrote:
>
> On 4/28/21 2:58 AM, Mickaël Salaün wrote:
>> On 27/04/2021 21:13, Nick Desaulniers wrote:
>>> On Tue, Apr 27, 2021 at 11:38 AM <trix@redhat.com> wrote:
>>>> From: Tom Rix <trix@redhat.com>
>>>>
>>>> Clang static analysis reports this error
>>>>
>>>> sandboxer.c:134:8: warning: Potential leak of memory
>>>> pointed to by 'path_list'
>>>> ret = 0;
>>>> ^
>>>> path_list is allocated in parse_path() but never freed.
>>>>
>>>> Signed-off-by: Tom Rix <trix@redhat.com>
>>>> ---
>>>> samples/landlock/sandboxer.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/samples/landlock/sandboxer.c
>>>> b/samples/landlock/sandboxer.c
>>>> index 7a15910d2171..4629d011ed61 100644
>>>> --- a/samples/landlock/sandboxer.c
>>>> +++ b/samples/landlock/sandboxer.c
>>>> @@ -134,6 +134,8 @@ static int populate_ruleset(
>>>> ret = 0;
>>>>
>>>> out_free_name:
>>>> + if (path_list)
>>>> + free(path_list);
>>> I don't think the conditional is even necessary? By our first `goto
>>> out_free_name;`, `parse_path` has already been called/memory for
>>> `path_list` has already been allocated. `parse_path` doesn't check
>>> whether `malloc` has failed.
>> Indeed, no need for the path_list check. In practice, this memory leak
>> doesn't stay long because of the execve, but I missed this free anyway.
>> Thanks!
>
> Ok, the general problem of not checking if malloc and friends succeeds
> is a different problem.
>
> So remove the check and keep the free ?
Yes please.
>
> Tom
>
>> Reviewed-by: Mickaël Salaün <mic@linux.microsoft.com>
>>
>>>> free(env_path_name);
>>>> return ret;
>>>> }
>>>> --
>>>> 2.26.3
>>>>
>>>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-04-27 18:37 [PATCH] samples/landlock: fix path_list memory leak trix
2021-04-27 19:13 ` Nick Desaulniers
2021-04-28 9:58 ` Mickaël Salaün
2021-04-28 15:36 ` Tom Rix
2021-04-28 18:04 ` Mickaël Salaün
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