From: Peilin Ye <yepeilin.cs@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>,
Sumit Saxena <sumit.saxena@broadcom.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Shivasharan S <shivasharan.srikanteshwara@broadcom.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-kernel-mentees@lists.linuxfoundation.org,
megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH] scsi/megaraid: Prevent kernel-infoleak in kioc_to_mimd()
Date: Tue, 28 Jul 2020 06:57:04 -0400 [thread overview]
Message-ID: <20200728105704.GA407553@PWN> (raw)
In-Reply-To: <20200728084137.GC2571@kadam>
On Tue, Jul 28, 2020 at 11:41:37AM +0300, Dan Carpenter wrote:
> On Mon, Jul 27, 2020 at 05:02:35PM -0400, Peilin Ye wrote:
> > hinfo_to_cinfo() does no operation on `cinfo` when `hinfo` is NULL,
> > causing kioc_to_mimd() to copy uninitialized stack memory to userspace.
> > Fix it by initializing `cinfo` with memset().
>
> But "hinfo" can't be NULL so this patch isn't required. It's a bit
> hard for Smatch to follow the code.
>
> We know that "opcode" is 82 so the buffer is allocated by mimd_to_kioc()
> -> mraid_mm_attach_buf().
You are right. mraid_mm_ioctl() returns -ENOMEM and never reaches
kioc_to_mimd() if mraid_mm_attach_buf() failed to get a buffer, so
`hinfo` can never be NULL for kioc_to_mimd().
Next time I will trace the data flow more carefully. Thank you for
pointing this out!
Peilin Ye
> Generally, don't silence static checker warnings unless it makes the
> code more readable. It's the checker writer's job to fix their own code.
> In this case, that's me, but parsing the code is quite complicated and I
> don't have a plan for how to fix it.
>
> regards,
> dan carpenter
>
prev parent reply other threads:[~2020-07-28 10:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 21:02 [Linux-kernel-mentees] [PATCH] scsi/megaraid: Prevent kernel-infoleak in kioc_to_mimd() Peilin Ye
2020-07-28 8:41 ` Dan Carpenter
2020-07-28 8:57 ` Dan Carpenter
2020-07-28 10:57 ` Peilin Ye [this message]
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