[PATCH 5.10] staging: vchiq_arm: Avoid NULL ptr deref in vchiq_dump_platform_instances

[Roman Demidov]

From: Stefan Wahren <stefan.wahren at i2se.com>

commit aa899e686d442c63d50f4d369cc02dbbf0941cb0 upstream.

vchiq_get_state() can return a NULL pointer. So handle this cases and
avoid a NULL pointer derefence in vchiq_dump_platform_instances.

Reviewed-by: Nicolas Saenz Julienne <nsaenz at kernel.org>
Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
Link: https://lore.kernel.org/r/1642968143-19281-17-git-send-email-stefan.wahren@i2se.com
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
Signed-off-by: Roman Demidov <roman.demidov.nn at gmail.com>
---
Backport fix for CVE-2022-49106

 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 178cf90fb3e5..adde80b56073 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -2063,6 +2063,9 @@ int vchiq_dump_platform_instances(void *dump_context)
 	int len;
 	int i;
 
+	if (!state)
+		return -ENOTCONN;
+
 	/* There is no list of instances, so instead scan all services,
 		marking those that have been dumped. */
 
-- 
2.53.0