linux-kernel - Re: [Linux-kernel-mentees] [PATCH v2] block/floppy: Prevent kernel-infoleak in raw_cmd

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: <20200729134214.GA5493@kadam>
Date:   Wed, 29 Jul 2020 16:42:14 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Denis Efremov <efremov@...ux.com>
Cc:     Peilin Ye <yepeilin.cs@...il.com>, Jens Axboe <axboe@...nel.dk>,
        Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [Linux-kernel-mentees] [PATCH v2] block/floppy: Prevent
 kernel-infoleak in raw_cmd_copyout()

On Wed, Jul 29, 2020 at 04:22:41PM +0300, Denis Efremov wrote:
> 
> On 7/29/20 3:58 PM, Dan Carpenter wrote:
> > Argh...  This isn't right still.  The "ptr" comes from raw_cmd_copyin()
> > 
> > ptr = kmalloc(sizeof(struct floppy_raw_cmd), GFP_KERNEL);
> > 
> 
> copy_from_user overwrites the padding bytes:
> 	ptr = kmalloc(sizeof(struct floppy_raw_cmd), GFP_KERNEL);
> 	if (!ptr)
> 		return -ENOMEM;
> 	*rcmd = ptr;
> 	ret = copy_from_user(ptr, param, sizeof(*ptr));
> 
> I think memcpy should be safe in this patch.

Oh yeah.  You're right.  My bad.  I just saw the:

	ptr->next = NULL;
	ptr->buffer_length = 0;
	ptr->kernel_data = NULL;

Assignments and I missed the copy_from_user.

regards,
dan carpenter