[PATCH] bootstd: android: avoid possible null pointer dereference

[Gary Bisson <bisson.gary@gmail.com>]

- avb_slot_verify_data_free() doesn't check its data parameter
- out_data can be null if avb_slot_verify() fails to allocate memory

Signed-off-by: Gary Bisson <bisson.gary@gmail.com>
---
Another approach would be to fix avb_slot_verify_data_free() to check
its paramter but I believe the goal is not to touch libavb to be closer
to upstream.
---
 boot/bootmeth_android.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/boot/bootmeth_android.c b/boot/bootmeth_android.c
index 3a59a4e3f6..f431b6ae58 100644
--- a/boot/bootmeth_android.c
+++ b/boot/bootmeth_android.c
@@ -481,7 +481,8 @@ static int run_avb_verification(struct bootflow *bflow)
 		if (result != AVB_SLOT_VERIFY_RESULT_OK) {
 			printf("Verification failed, reason: %s\n",
 			       str_avb_slot_error(result));
-			avb_slot_verify_data_free(out_data);
+			if (out_data)
+				avb_slot_verify_data_free(out_data);
 			return log_msg_ret("avb verify", -EIO);
 		}
 		boot_state = AVB_GREEN;
@@ -491,7 +492,8 @@ static int run_avb_verification(struct bootflow *bflow)
 		    result != AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION) {
 			printf("Unlocked verification failed, reason: %s\n",
 			       str_avb_slot_error(result));
-			avb_slot_verify_data_free(out_data);
+			if (out_data)
+				avb_slot_verify_data_free(out_data);
 			return log_msg_ret("avb verify unlocked", -EIO);
 		}
 		boot_state = AVB_ORANGE;
-- 
2.47.2