From: Kees Cook <keescook@chromium.org>
To: Pavel Machek <pavel@ucw.cz>
Cc: pali.rohar@gmail.com, sre@kernel.org,
"kernel list" <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-omap@vger.kernel.org, "Tony Lindgren" <tony@atomide.com>,
"Kevin Hilman" <khilman@kernel.org>,
"Aaro Koskinen" <aaro.koskinen@iki.fi>,
ivo.g.dimitrov.75@gmail.com, patrikbachan@gmail.com,
"Serge E. Hallyn" <serge@hallyn.com>,
abcloriens@gmail.com, "Clayton Craft" <clayton@craftyguy.net>,
martijn@brixit.nl, "Sakari Ailus" <sakari.ailus@linux.intel.com>,
"Filip Matijević" <filip.matijevic.pz@gmail.com>,
"Mark Brown" <broonie@kernel.org>,
peter.ujfalusi@ti.com,
"moderated for non-subscribers" <alsa-devel@alsa-project.org>,
security@kernel.org
Subject: Re: linux-next on n900: oops in codec_reg_show() when grepping sysfs
Date: Thu, 8 Mar 2018 11:47:50 -0800 [thread overview]
Message-ID: <CAGXu5jK1cvTOCT_OZVwk20LCNt6QLEM5CoLBXpT9JaHpwEKeJg@mail.gmail.com> (raw)
In-Reply-To: <20180308151421.GA13160@amd>
On Thu, Mar 8, 2018 at 7:14 AM, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> pavel@n900:/sys$ uname -a
> Linux n900 4.16.0-rc4-next-20180308 #71 Thu Mar 8 15:27:49 CET 2018
> armv7l GNU/Linux
> pavel@n900:/sys$ grep -ri fasdfasdf .
>
> leads to an oops:
>
> [ 2278.331878] DSS: context saved
> [ 2278.820343] Unable to handle kernel NULL pointer dereference at
> virtual address 00000004
> [ 2278.828948] pgd = c36040a2
> [ 2278.831787] [00000004] *pgd=876c4831, *pte=00000000, *ppte=00000000
> [ 2278.838439] Internal error: Oops: 17 [#1] ARM
> [ 2278.843017] Modules linked in:
> [ 2278.846221] CPU: 0 PID: 16337 Comm: grep Tainted: G W
> 4.16.0-rc4-next-20180308 #71
> [ 2278.855529] Hardware name: Nokia RX-51 board
> [ 2278.860015] PC is at soc_codec_reg_show+0x8/0x19c
> [ 2278.864959] LR is at codec_reg_show+0x28/0x30
Looks like a NULL codec (driver has offsetof of 0x4).
static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf,
size_t count, loff_t pos)
{
...
loff_t p = 0;
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
...
This would paper over it. I have no idea that the lifetime expectation
are for codec and driver...
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 96c44f6576c9..78ad165ad424 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -137,6 +137,9 @@ static ssize_t soc_codec_reg_show(struct
snd_soc_codec *codec, char *buf,
size_t total = 0;
loff_t p = 0;
+ if (!codec || !codec->driver)
+ return 0;
+
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
-Kees
--
Kees Cook
Pixel Security
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: Pavel Machek <pavel@ucw.cz>
Cc: peter.ujfalusi@ti.com,
"moderated for non-subscribers" <alsa-devel@alsa-project.org>,
ivo.g.dimitrov.75@gmail.com, "Kevin Hilman" <khilman@kernel.org>,
"Tony Lindgren" <tony@atomide.com>,
security@kernel.org, "Aaro Koskinen" <aaro.koskinen@iki.fi>,
"kernel list" <linux-kernel@vger.kernel.org>,
sre@kernel.org, martijn@brixit.nl,
"Filip Matijević" <filip.matijevic.pz@gmail.com>,
"Mark Brown" <broonie@kernel.org>,
abcloriens@gmail.com,
"Sakari Ailus" <sakari.ailus@linux.intel.com>,
pali.rohar@gmail.com, "Clayton Craft" <clayton@craftyguy.net>,
linux-omap@vger.kernel.org, patrikbachan@gmail.com,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
"Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: linux-next on n900: oops in codec_reg_show() when grepping sysfs
Date: Thu, 8 Mar 2018 11:47:50 -0800 [thread overview]
Message-ID: <CAGXu5jK1cvTOCT_OZVwk20LCNt6QLEM5CoLBXpT9JaHpwEKeJg@mail.gmail.com> (raw)
In-Reply-To: <20180308151421.GA13160@amd>
On Thu, Mar 8, 2018 at 7:14 AM, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> pavel@n900:/sys$ uname -a
> Linux n900 4.16.0-rc4-next-20180308 #71 Thu Mar 8 15:27:49 CET 2018
> armv7l GNU/Linux
> pavel@n900:/sys$ grep -ri fasdfasdf .
>
> leads to an oops:
>
> [ 2278.331878] DSS: context saved
> [ 2278.820343] Unable to handle kernel NULL pointer dereference at
> virtual address 00000004
> [ 2278.828948] pgd = c36040a2
> [ 2278.831787] [00000004] *pgd=876c4831, *pte=00000000, *ppte=00000000
> [ 2278.838439] Internal error: Oops: 17 [#1] ARM
> [ 2278.843017] Modules linked in:
> [ 2278.846221] CPU: 0 PID: 16337 Comm: grep Tainted: G W
> 4.16.0-rc4-next-20180308 #71
> [ 2278.855529] Hardware name: Nokia RX-51 board
> [ 2278.860015] PC is at soc_codec_reg_show+0x8/0x19c
> [ 2278.864959] LR is at codec_reg_show+0x28/0x30
Looks like a NULL codec (driver has offsetof of 0x4).
static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf,
size_t count, loff_t pos)
{
...
loff_t p = 0;
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
...
This would paper over it. I have no idea that the lifetime expectation
are for codec and driver...
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 96c44f6576c9..78ad165ad424 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -137,6 +137,9 @@ static ssize_t soc_codec_reg_show(struct
snd_soc_codec *codec, char *buf,
size_t total = 0;
loff_t p = 0;
+ if (!codec || !codec->driver)
+ return 0;
+
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
-Kees
--
Kees Cook
Pixel Security
WARNING: multiple messages have this Message-ID (diff)
From: keescook@chromium.org (Kees Cook)
To: linux-arm-kernel@lists.infradead.org
Subject: linux-next on n900: oops in codec_reg_show() when grepping sysfs
Date: Thu, 8 Mar 2018 11:47:50 -0800 [thread overview]
Message-ID: <CAGXu5jK1cvTOCT_OZVwk20LCNt6QLEM5CoLBXpT9JaHpwEKeJg@mail.gmail.com> (raw)
In-Reply-To: <20180308151421.GA13160@amd>
On Thu, Mar 8, 2018 at 7:14 AM, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> pavel at n900:/sys$ uname -a
> Linux n900 4.16.0-rc4-next-20180308 #71 Thu Mar 8 15:27:49 CET 2018
> armv7l GNU/Linux
> pavel at n900:/sys$ grep -ri fasdfasdf .
>
> leads to an oops:
>
> [ 2278.331878] DSS: context saved
> [ 2278.820343] Unable to handle kernel NULL pointer dereference at
> virtual address 00000004
> [ 2278.828948] pgd = c36040a2
> [ 2278.831787] [00000004] *pgd=876c4831, *pte=00000000, *ppte=00000000
> [ 2278.838439] Internal error: Oops: 17 [#1] ARM
> [ 2278.843017] Modules linked in:
> [ 2278.846221] CPU: 0 PID: 16337 Comm: grep Tainted: G W
> 4.16.0-rc4-next-20180308 #71
> [ 2278.855529] Hardware name: Nokia RX-51 board
> [ 2278.860015] PC is at soc_codec_reg_show+0x8/0x19c
> [ 2278.864959] LR is at codec_reg_show+0x28/0x30
Looks like a NULL codec (driver has offsetof of 0x4).
static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf,
size_t count, loff_t pos)
{
...
loff_t p = 0;
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
...
This would paper over it. I have no idea that the lifetime expectation
are for codec and driver...
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 96c44f6576c9..78ad165ad424 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -137,6 +137,9 @@ static ssize_t soc_codec_reg_show(struct
snd_soc_codec *codec, char *buf,
size_t total = 0;
loff_t p = 0;
+ if (!codec || !codec->driver)
+ return 0;
+
wordsize = min_bytes_needed(codec->driver->reg_cache_size) * 2;
regsize = codec->driver->reg_word_size * 2;
-Kees
--
Kees Cook
Pixel Security
next prev parent reply other threads:[~2018-03-08 19:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-08 15:14 linux-next on n900: oops in codec_reg_show() when grepping sysfs Pavel Machek
2018-03-08 15:14 ` Pavel Machek
2018-03-08 19:47 ` Kees Cook [this message]
2018-03-08 19:47 ` Kees Cook
2018-03-08 19:47 ` Kees Cook
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