linux-kernel - Re: [PATCH v2] zram: fix possible use after free in zcomp

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: <20150907235922.GB6896@swordfish>
Date:	Tue, 8 Sep 2015 08:59:22 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:	Luis Henriques <luis.henriques@...onical.com>
Cc:	Minchan Kim <minchan@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH v2] zram: fix possible use after free in zcomp_create()

On (09/07/15 15:13), Luis Henriques wrote:
> zcomp_create() verifies the success of zcomp_strm_{multi,siggle}_create()
> through comp->stream, which can potentially be pointing to memory that was
> freed if these functions returned an error.
> 
> Fixes: beca3ec71fe5 ("zram: add multi stream functionality")
> Cc: stable@...r.kernel.org
> Signed-off-by: Luis Henriques <luis.henriques@...onical.com>

Cc Andrew


Acked-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>

	-ss

> ---
> Changes since v1:
>  * Check zcomp_strm_{multi,siggle}_create() return code instead
>    comp->stream (suggested by Sergey)
> 
> drivers/block/zram/zcomp.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
> index 965d1afb0eaa..8d2cdfd307db 100644
> --- a/drivers/block/zram/zcomp.c
> +++ b/drivers/block/zram/zcomp.c
> @@ -336,6 +336,7 @@ struct zcomp *zcomp_create(const char *compress, int max_strm)
>  {
>  	struct zcomp *comp;
>  	struct zcomp_backend *backend;
> +	int ret;
>  
>  	backend = find_backend(compress);
>  	if (!backend)
> @@ -347,10 +348,10 @@ struct zcomp *zcomp_create(const char *compress, int max_strm)
>  
>  	comp->backend = backend;
>  	if (max_strm > 1)
> -		zcomp_strm_multi_create(comp, max_strm);
> +		ret = zcomp_strm_multi_create(comp, max_strm);
>  	else
> -		zcomp_strm_single_create(comp);
> -	if (!comp->stream) {
> +		ret = zcomp_strm_single_create(comp);
> +	if (ret) {
>  		kfree(comp);
>  		return ERR_PTR(-ENOMEM);
>  	}
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/