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From: "Mickaël Salaün" <mic@digikod.net>
To: Nick Desaulniers <ndesaulniers@google.com>, Tom Rix <trix@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>,
	linux-security-module@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	James Morris <jmorris@namei.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] samples/landlock: fix path_list memory leak
Date: Wed, 28 Apr 2021 11:58:59 +0200	[thread overview]
Message-ID: <6108e69b-0470-cd71-e477-ba64641cbf58@digikod.net> (raw)
In-Reply-To: <CAKwvOdmj5YvWZZWwcq1G7JgRALwPbqwiROiedMeEbBst2sGeiQ@mail.gmail.com>


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
>>
> 
> 

  reply	other threads:[~2021-04-28  9:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
2021-04-28 15:36     ` Tom Rix
2021-04-28 18:04       ` Mickaël Salaün

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