thunderbolt: Fix double free of drom buffer

commit 2ffa9a5d76a75abbc1f95c17959fced666095bdd upstream.

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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index 0dde34e3a7c5aa793e8bec8239f297b30ace2d95..545c60c826a1cfe0852f656aa04c86178976a830 100644 (file)
--- 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;
 
 }