* [PATCH] thunderbolt: Fix double free of drom buffer
@ 2016-04-10 10:48 Andreas Noever
2016-05-02 17:30 ` Bjorn Helgaas
0 siblings, 1 reply; 3+ messages in thread
From: Andreas Noever @ 2016-04-10 10:48 UTC (permalink / raw)
To: helgaas, linux-pci; +Cc: linux-kernel, Andreas Noever, Lukas Wunner, stable
If tb_drom_read fails sw->drom is freed but not set to NULL. sw->drom
is then freed again in the error path of sw_switch_alloc.
The bug can be triggered by unplugging a thunderbolt device shortly
after it is detected by the thunderbolt driver.
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
---
drivers/thunderbolt/eeprom.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index 0dde34e..545c60c 100644
--- a/drivers/thunderbolt/eeprom.c
+++ b/drivers/thunderbolt/eeprom.c
@@ -444,6 +444,7 @@ int tb_drom_read(struct tb_switch *sw)
return tb_drom_parse_entries(sw);
err:
kfree(sw->drom);
+ sw->drom = NULL;
return -EIO;
}
--
2.8.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] thunderbolt: Fix double free of drom buffer
2016-04-10 10:48 [PATCH] thunderbolt: Fix double free of drom buffer Andreas Noever
@ 2016-05-02 17:30 ` Bjorn Helgaas
2016-05-02 23:18 ` Andreas Noever
0 siblings, 1 reply; 3+ messages in thread
From: Bjorn Helgaas @ 2016-05-02 17:30 UTC (permalink / raw)
To: Andreas Noever; +Cc: linux-pci, linux-kernel, Lukas Wunner, stable
On Sun, Apr 10, 2016 at 12:48:27PM +0200, Andreas Noever wrote:
> If tb_drom_read fails sw->drom is freed but not set to NULL. sw->drom
> is then freed again in the error path of sw_switch_alloc.
s/sw_switch_alloc/tb_switch_alloc/ ?
> The bug can be triggered by unplugging a thunderbolt device shortly
> after it is detected by the thunderbolt driver.
>
> Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
> Cc: Lukas Wunner <lukas@wunner.de>
> Cc: stable@vger.kernel.org
How far back would this need to be applied? What is the commit where
the but was introduced?
I applied this to pci/thunderbolt for v4.7 with the following
changelog. If I did it wrong, I'll gladly update it, especially if
you have specific symptoms of a bug or oops that would help people
find this fix.
thunderbolt: Fix double free of drom buffer
If tb_drom_read() fails, sw->drom is freed but not set to NULL. sw->drom
is then freed again in the error path of tb_switch_alloc().
The bug can be triggered by unplugging a thunderbolt device shortly after
it is detected by the thunderbolt driver.
Clear sw->drom if tb_drom_read() fails.
[bhelgaas: add Fixes:, stable versions of interest]
Fixes: 343fcb8c70d7 ("thunderbolt: Fix nontrivial endpoint devices.")
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v3.17+
CC: Lukas Wunner <lukas@wunner.de>
> ---
> drivers/thunderbolt/eeprom.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
> index 0dde34e..545c60c 100644
> --- a/drivers/thunderbolt/eeprom.c
> +++ b/drivers/thunderbolt/eeprom.c
> @@ -444,6 +444,7 @@ int tb_drom_read(struct tb_switch *sw)
> return tb_drom_parse_entries(sw);
> err:
> kfree(sw->drom);
> + sw->drom = NULL;
> return -EIO;
>
> }
> --
> 2.8.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] thunderbolt: Fix double free of drom buffer
2016-05-02 17:30 ` Bjorn Helgaas
@ 2016-05-02 23:18 ` Andreas Noever
0 siblings, 0 replies; 3+ messages in thread
From: Andreas Noever @ 2016-05-02 23:18 UTC (permalink / raw)
To: Bjorn Helgaas; +Cc: linux-pci, linux-kernel, Lukas Wunner, stable
On Mon, May 2, 2016 at 7:30 PM, Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Sun, Apr 10, 2016 at 12:48:27PM +0200, Andreas Noever wrote:
>> If tb_drom_read fails sw->drom is freed but not set to NULL. sw->drom
>> is then freed again in the error path of sw_switch_alloc.
>
> s/sw_switch_alloc/tb_switch_alloc/ ?
>
>> The bug can be triggered by unplugging a thunderbolt device shortly
>> after it is detected by the thunderbolt driver.
>>
>> Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
>> Cc: Lukas Wunner <lukas@wunner.de>
>> Cc: stable@vger.kernel.org
>
> How far back would this need to be applied? What is the commit where
> the but was introduced?
>
> I applied this to pci/thunderbolt for v4.7 with the following
> changelog. If I did it wrong, I'll gladly update it, especially if
> you have specific symptoms of a bug or oops that would help people
> find this fix.
>
> thunderbolt: Fix double free of drom buffer
>
> If tb_drom_read() fails, sw->drom is freed but not set to NULL. sw->drom
> is then freed again in the error path of tb_switch_alloc().
>
> The bug can be triggered by unplugging a thunderbolt device shortly after
> it is detected by the thunderbolt driver.
>
> Clear sw->drom if tb_drom_read() fails.
The changelog is correct. The bug can be triggered starting from
343fcb8c ("thunderbolt: Fix nontrivial endpoint devices.") which is in
3.17-rc1. I observed crashes during subsequent hotplug operations (pci
core, sometimes in pciehp). But by nature of a double free bug these
were not very reliable (used kasan to track it down).
Thanks
Andreas
> [bhelgaas: add Fixes:, stable versions of interest]
> Fixes: 343fcb8c70d7 ("thunderbolt: Fix nontrivial endpoint devices.")
> Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> CC: stable@vger.kernel.org # v3.17+
> CC: Lukas Wunner <lukas@wunner.de>
>
>> ---
>> drivers/thunderbolt/eeprom.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
>> index 0dde34e..545c60c 100644
>> --- a/drivers/thunderbolt/eeprom.c
>> +++ b/drivers/thunderbolt/eeprom.c
>> @@ -444,6 +444,7 @@ int tb_drom_read(struct tb_switch *sw)
>> return tb_drom_parse_entries(sw);
>> err:
>> kfree(sw->drom);
>> + sw->drom = NULL;
>> return -EIO;
>>
>> }
>> --
>> 2.8.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-04-10 10:48 [PATCH] thunderbolt: Fix double free of drom buffer Andreas Noever
2016-05-02 17:30 ` Bjorn Helgaas
2016-05-02 23:18 ` Andreas Noever
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