[PATCH 6.0 0172/1073] platform/chrome: cros_ec_typec: zero out stale pointers

Greg Kroah-Hartman
2022-12-28T15:15:37Z

From: Victor Ding <victording@chromium.org>

[ Upstream commit 9a8aadcf0b459c1257b9477fd6402e1d5952ae07 ]

`cros_typec_get_switch_handles` allocates four pointers when obtaining
type-c switch handles. These pointers are all freed if failing to obtain
any of them; therefore, pointers in `port` become stale. The stale
pointers eventually cause use-after-free or double free in later code
paths. Zeroing out all pointer fields after freeing to eliminate these
stale pointers.

Fixes: f28adb41dab4 ("platform/chrome: cros_ec_typec: Register Type C switches")
Fixes: 1a8912caba02 ("platform/chrome: cros_ec_typec: Get retimer handle")
Signed-off-by: Victor Ding <victording@chromium.org>
Acked-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20221207093924.v2.1.I1864b6a7ee98824118b93677868d22d3750f439b@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/chrome/cros_ec_typec.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 00208ffbe2e7..a54bf964521f 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -168,10 +168,13 @@ static int cros_typec_get_switch_handles(struct cros_typec_port *port,

role_sw_err:
typec_switch_put(port->ori_sw);
+ port->ori_sw = NULL;
ori_sw_err:
typec_retimer_put(port->retimer);
+ port->retimer = NULL;
retimer_sw_err:
typec_mux_put(port->mux);
+ port->mux = NULL;
mux_err:
return -ENODEV;
}
--
2.35.1