[PATCH v2] firmware: arm_ffa: Fix NULL dereference in ffa_partition_info_get()

[Unnathi Chalicheemala <unnathi.chalicheemala@oss.qualcomm.com>]

ffa_partition_info_get() passes uuid_str directly to uuid_parse()
without a NULL check. When a caller passes NULL, uuid_parse() ->
__uuid_parse() -> uuid_is_valid() dereferences the pointer, causing
a kernel panic:

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000040
pc : uuid_parse+0x40/0xac
lr : ffa_partition_info_get+0x1c/0x94 [arm_ffa]

Add a NULL guard before uuid_parse() so a NULL argument returns
-ENODEV instead of crashing. Callers are expected to always supply
a valid partition UUID, so NULL is not a supported input.

Fixes: d0c0bce83122 ("firmware: arm_ffa: Setup in-kernel users of FFA partitions")
Signed-off-by: Unnathi Chalicheemala <unnathi.chalicheemala@oss.qualcomm.com>
---
Changes in v2:
- Drop special-casing of NULL/empty string to uuid_null; treat NULL as
  an error instead - as pointed out by Sudeep in v1.
- Simplify to a single NULL guard before uuid_parse() rather than a
  separate branch
- Link to v1: https://patch.msgid.link/20260611-ffa_partition_nullptr_fix-v1-1-ec2b7ef7e130@oss.qualcomm.com
---
 drivers/firmware/arm_ffa/driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index b9f17fda7243..4090be782329 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -1129,7 +1129,7 @@ static int ffa_partition_info_get(const char *uuid_str,
 	uuid_t uuid;
 	struct ffa_partition_info *pbuf;
 
-	if (uuid_parse(uuid_str, &uuid)) {
+	if (!uuid_str || uuid_parse(uuid_str, &uuid)) {
 		pr_err("invalid uuid (%s)\n", uuid_str);
 		return -ENODEV;
 	}

---
base-commit: ba3e43a9e601636f5edb54e259a74f96ca3b8fd8
change-id: 20260604-ffa_partition_nullptr_fix-66f37bb2630b

Best regards,
--  
Unnathi Chalicheemala <unnathi.chalicheemala@oss.qualcomm.com>