[PATCH] efi_loader: Extra checks while opening an OPTEE session

[Ilias Apalodimas]

When opening an OP-TEE session we need to check the internal return
value of OP-TEE call arguments as well the return code of the
function itself.
The code was also ignoring to close the OP-TEE session in case the
shared memory registration failed.

Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 lib/efi_loader/efi_variable_tee.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index be6f3dfad469..717d0b45e7cd 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -45,10 +45,11 @@ static int get_connection(struct mm_connection *conn)
 	memset(&arg, 0, sizeof(arg));
 	tee_optee_ta_uuid_to_octets(arg.uuid, &uuid);
 	rc = tee_open_session(tee, &arg, 0, NULL);
-	if (!rc) {
-		conn->tee = tee;
-		conn->session = arg.session;
-	}
+	if (rc || arg.ret != TEE_SUCCESS)
+		return rc == 0 ? -EIO : rc;
+
+	conn->tee = tee;
+	conn->session = arg.session;
 
 	return rc;
 }
@@ -88,6 +89,7 @@ static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
 
 	if (tee_shm_register(conn.tee, comm_buf, buf_size, 0, &shm)) {
 		log_err("Unable to register shared memory\n");
+		tee_close_session(conn.tee, conn.session);
 		return EFI_UNSUPPORTED;
 	}
 
-- 
2.30.0.rc1