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From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: Pavel Skripkin <paskripkin@gmail.com>
Cc: gustavoars@kernel.org, sam@ravnborg.org, tomi.valkeinen@ti.com,
	linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF
Date: Sun, 27 Jun 2021 02:14:23 +0300	[thread overview]
Message-ID: <20210626231423.GA38365@macbook.musicnaut.iki.fi> (raw)
In-Reply-To: <20210625223323.13930-1-paskripkin@gmail.com>

Hi,

On Sat, Jun 26, 2021 at 01:33:23AM +0300, Pavel Skripkin wrote:
> In case of allocation failures, all code paths was jumping
> to this code:
> 
> err:
> 	kfree(fbi);
> 	kfree(var);
> 	kfree(fbops);
> 
> 	return r;
> 
> Since all 3 pointers placed on stack and don't initialized, they
> will be filled with some random values, which leads to
> deferencing random pointers in kfree(). Fix it by rewriting
> error handling path.

They are initialized before the first goto:

[...]
	fbi = NULL;
	var = NULL;
	fbops = NULL;

	fbi = kzalloc(sizeof(*fbi), GFP_KERNEL);
	if (fbi == NULL) {
		r = -ENOMEM;
		goto err;
	}
[...]

A.

WARNING: multiple messages have this Message-ID (diff)
From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: Pavel Skripkin <paskripkin@gmail.com>
Cc: linux-fbdev@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	gustavoars@kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, tomi.valkeinen@ti.com,
	linux-omap@vger.kernel.org, sam@ravnborg.org
Subject: Re: [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF
Date: Sun, 27 Jun 2021 02:14:23 +0300	[thread overview]
Message-ID: <20210626231423.GA38365@macbook.musicnaut.iki.fi> (raw)
In-Reply-To: <20210625223323.13930-1-paskripkin@gmail.com>

Hi,

On Sat, Jun 26, 2021 at 01:33:23AM +0300, Pavel Skripkin wrote:
> In case of allocation failures, all code paths was jumping
> to this code:
> 
> err:
> 	kfree(fbi);
> 	kfree(var);
> 	kfree(fbops);
> 
> 	return r;
> 
> Since all 3 pointers placed on stack and don't initialized, they
> will be filled with some random values, which leads to
> deferencing random pointers in kfree(). Fix it by rewriting
> error handling path.

They are initialized before the first goto:

[...]
	fbi = NULL;
	var = NULL;
	fbops = NULL;

	fbi = kzalloc(sizeof(*fbi), GFP_KERNEL);
	if (fbi == NULL) {
		r = -ENOMEM;
		goto err;
	}
[...]

A.
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: Pavel Skripkin <paskripkin@gmail.com>
Cc: linux-fbdev@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	gustavoars@kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, tomi.valkeinen@ti.com,
	linux-omap@vger.kernel.org, sam@ravnborg.org
Subject: Re: [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF
Date: Sun, 27 Jun 2021 02:14:23 +0300	[thread overview]
Message-ID: <20210626231423.GA38365@macbook.musicnaut.iki.fi> (raw)
In-Reply-To: <20210625223323.13930-1-paskripkin@gmail.com>

Hi,

On Sat, Jun 26, 2021 at 01:33:23AM +0300, Pavel Skripkin wrote:
> In case of allocation failures, all code paths was jumping
> to this code:
> 
> err:
> 	kfree(fbi);
> 	kfree(var);
> 	kfree(fbops);
> 
> 	return r;
> 
> Since all 3 pointers placed on stack and don't initialized, they
> will be filled with some random values, which leads to
> deferencing random pointers in kfree(). Fix it by rewriting
> error handling path.

They are initialized before the first goto:

[...]
	fbi = NULL;
	var = NULL;
	fbops = NULL;

	fbi = kzalloc(sizeof(*fbi), GFP_KERNEL);
	if (fbi == NULL) {
		r = -ENOMEM;
		goto err;
	}
[...]

A.

  reply	other threads:[~2021-06-26 23:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 22:33 [PATCH] OMAP: DSS2: OMAPFB: fix potential GPF Pavel Skripkin
2021-06-25 22:33 ` Pavel Skripkin
2021-06-25 22:33 ` Pavel Skripkin
2021-06-26 23:14 ` Aaro Koskinen [this message]
2021-06-26 23:14   ` Aaro Koskinen
2021-06-26 23:14   ` Aaro Koskinen
2021-06-27  8:48   ` Pavel Skripkin
2021-06-27  8:48     ` Pavel Skripkin
2021-06-27  8:48     ` Pavel Skripkin

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