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From:   harshad shirwadkar <harshadshirwadkar@gmail.com>
Date:   Thu, 25 Feb 2021 07:51:09 -0800
Message-ID: <CAD+ocbwkQ4rMYhiOm4msnBH65vh6Pm25ZkPsC2pD0sFy68bPgA@mail.gmail.com>
Subject: Re: [PATCH] debugfs: fix memory leak problem in read_list()
To:     Zhiqiang Liu <liuzhiqiang26@huawei.com>
Cc:     Ext4 Developers List <linux-ext4@vger.kernel.org>,
        "Theodore Y. Ts'o" <tytso@mit.edu>,
        linfeilong <linfeilong@huawei.com>,
        lihaotian <lihaotian9@huawei.com>,
        "lijinlin (A)" <lijinlin3@huawei.com>
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On Sat, Feb 20, 2021 at 12:41 AM Zhiqiang Liu <liuzhiqiang26@huawei.com> wrote:
>
>
> In read_list func, if strtoull() fails in while loop,
> we will return the error code directly. Then, memory of
> variable lst will be leaked without setting to *list.
>
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> Signed-off-by: linfeilong <linfeilong@huawei.com>
> ---
>  debugfs/util.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/debugfs/util.c b/debugfs/util.c
> index be6b550e..9e880548 100644
> --- a/debugfs/util.c
> +++ b/debugfs/util.c
> @@ -530,12 +530,16 @@ errcode_t read_list(char *str, blk64_t **list, size_t *len)
>
>                 errno = 0;
>                 y = x = strtoull(tok, &e, 0);
> -               if (errno)
> -                       return errno;
> +               if (errno) {
> +                       retval = errno;
> +                       break;
> +               }
Shouldn't we have `goto err;` here instead of break? strtoull failure
here indicates that no valid value was found, so instead of returning
the allocated memory, we should just free the memory and return error.

- Harshad
>                 if (*e == '-') {
>                         y = strtoull(e + 1, NULL, 0);
> -                       if (errno)
> -                               return errno;
> +                       if (errno) {
> +                               retval = errno;
> +                               break;
> +                       }
>                 } else if (*e != 0) {
>                         retval = EINVAL;
>                         break;
> --
> 2.19.1
>
>