linux-kernel - Re: [PATCH] block/bio-integrity: fix a memory leak bug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACVXFVO-gwVhZRajRx41_sYJKDTX2qZUnZVRXCB0NcegVVTGVw@mail.gmail.com>
Date:   Thu, 11 Jul 2019 17:21:54 +0800
From:   Ming Lei <tom.leiming@...il.com>
To:     Wenwen Wang <wang6495@....edu>
Cc:     Wenwen Wang <wenwen@...uga.edu>, Jens Axboe <axboe@...nel.dk>,
        "open list:BLOCK LAYER" <linux-block@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] block/bio-integrity: fix a memory leak bug

On Thu, Jul 11, 2019 at 3:36 PM Wenwen Wang <wang6495@....edu> wrote:
>
> From: Wenwen Wang <wenwen@...uga.edu>
>
> In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
> hold integrity metadata. Later on, the buffer will be attached to the bio
> structure through bio_integrity_add_page(), which returns the number of
> bytes of integrity metadata attached. Due to unexpected situations,
> bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
> needs to be terminated with 'false' returned to indicate this error.
> However, the allocated kernel buffer is not freed on this execution path,
> leading to a memory leak.
>
> To fix this issue, free the allocated buffer before returning from
> bio_integrity_prep().
>
> Signed-off-by: Wenwen Wang <wenwen@...uga.edu>
> ---
>  block/bio-integrity.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index 4db6208..bfae10c 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -276,8 +276,10 @@ bool bio_integrity_prep(struct bio *bio)
>                 ret = bio_integrity_add_page(bio, virt_to_page(buf),
>                                              bytes, offset);
>
> -               if (ret == 0)
> +               if (ret == 0) {
> +                       kfree(buf);
>                         return false;
> +               }

This way may not be enough, and the bio payload needs to be freed.

And you may refer to the error handling for 'IS_ERR(bip)', and bio->bi_status
needs to be set, and bio_endio() needs to be called too.


Thanks,
Ming Lei