Date:   Mon, 3 Jan 2022 18:01:55 +0530
From:   riteshh <riteshh@linux.ibm.com>
To:     zhanchengbin <zhanchengbin1@huawei.com>
Cc:     "Theodore Ts'o" <tytso@mit.edu>, linux-ext4@vger.kernel.org,
        liuzhiqiang26@huawei.com, linfeilong@huawei.com
Subject: Re: [PATCH] setup_tdb : fix memory leak
Message-ID: <20220103122202.tz6wv5tyf4xmeb2t@riteshh-domain>
References: <3a0cbb4e-6ea3-356a-433d-3a7a6466b018@huawei.com>
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In-Reply-To: <3a0cbb4e-6ea3-356a-433d-3a7a6466b018@huawei.com>
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On 21/11/30 02:40PM, zhanchengbin wrote:
> In setup_tdb(), need free tdb_dir before return,
> otherwise it will cause memory leak.
>
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> Signed-off-by: zhanchengbin <zhanchengbin1@huawei.com>
> ---
>  e2fsck/dirinfo.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/e2fsck/dirinfo.c b/e2fsck/dirinfo.c
> index 49d624c5..a2b36d8e 100644
> --- a/e2fsck/dirinfo.c
> +++ b/e2fsck/dirinfo.c
> @@ -49,7 +49,7 @@ static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
>  	ext2_ino_t		threshold;
>  	errcode_t		retval;
>  	mode_t			save_umask;
> -	char			*tdb_dir, uuid[40];
> +	char			*tdb_dir = NULL, uuid[40];
>  	int			fd, enable;
>
>  	profile_get_string(ctx->profile, "scratch_files", "directory", 0, 0,
> @@ -61,11 +61,11 @@ static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
>
>  	if (!enable || !tdb_dir || access(tdb_dir, W_OK) ||
>  	    (threshold && num_dirs <= threshold))
> -		return;
> +		goto error;
>
>  	retval = ext2fs_get_mem(strlen(tdb_dir) + 64, &db->tdb_fn);

I think freeing of db->tdb_fn should also be handled in case of an error.

>  	if (retval)
> -		return;
> +		goto error;
>
>  	uuid_unparse(ctx->fs->super->s_uuid, uuid);
>  	sprintf(db->tdb_fn, "%s/%s-dirinfo-XXXXXX", tdb_dir, uuid);
> @@ -74,7 +74,7 @@ static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
>  	umask(save_umask);
>  	if (fd < 0) {
>  		db->tdb = NULL;
> -		return;
> +		goto error;

So in case of an error we should call ext2fs_free_mem(&db->tdb_fn), right?

Rest looks good to me.

-ritesh


>  	}
>
>  	if (num_dirs < 99991)
> @@ -83,6 +83,11 @@ static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
>  	db->tdb = tdb_open(db->tdb_fn, num_dirs, TDB_NOLOCK | TDB_NOSYNC,
>  			   O_RDWR | O_CREAT | O_TRUNC, 0600);
>  	close(fd);
> +
> +error:
> +	if(tdb_dir) {
> +		free(tdb_dir);
> +	}
>  }
>  #endif
>
> --
> 2.23.0
>
>