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@xxxxxxxxx>
> Cc: Lukas Wunner <lukas@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
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@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # v3.17+
CC: Lukas Wunner <lukas@xxxxxxxxx>
> ---
> 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
>
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