[PATCH] test: dm: hash: check digest size before memset

hash_algo_digest_size() returns -EINVAL for an invalid algorithm. The
test success provider passes that result directly to memset(), where it
is converted to a large size_t.

Return the error before touching the output buffer, and exercise the
invalid-algorithm path in the provider-selection test. This addresses
Coverity CIDs 652907 and 652908.

Fixes: 94b349bd902d ("crypto: hash: use DM providers from hash command")
Signed-off-by: James Hilliard <[email protected]>
---
 test/dm/hash.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/test/dm/hash.c b/test/dm/hash.c
index fe949e33de5..6adf916dc77 100644
--- a/test/dm/hash.c
+++ b/test/dm/hash.c
@@ -31,8 +31,14 @@ static int hash_test_success(struct udevice *dev, enum HASH_ALGO algo,
 			     const void *ibuf, const uint32_t ilen,
 			     void *obuf, uint32_t chunk_sz)
 {
+	ssize_t digest_size;
+
 	success_calls++;
-	memset(obuf, 0x5a, hash_algo_digest_size(algo));
+	digest_size = hash_algo_digest_size(algo);
+	if (digest_size < 0)
+		return digest_size;
+
+	memset(obuf, 0x5a, digest_size);
 
 	return 0;
 }
@@ -124,6 +130,14 @@ static int dm_test_hash_provider_selection(struct unit_test_state *uts)
 	for (int i = 0; i < sizeof(digest); i++)
 		ut_asserteq(0x5a, digest[i]);
 
+	memset(digest, 0, sizeof(digest));
+	ret = hash_digest_wd_lookup(HASH_ALGO_INVALID, "test", 4, digest, 4);
+	ut_asserteq(-EINVAL, ret);
+	ut_asserteq(2, unsupported_calls);
+	ut_asserteq(2, success_calls);
+	for (int i = 0; i < sizeof(digest); i++)
+		ut_asserteq(0, digest[i]);
+
 	ut_assertok(hash_test_unbind_all());
 	ut_assertok(hash_test_bind(DM_DRIVER_GET(hash_test_hard_error_drv),
 				   "hash-hard-error"));
-- 
2.53.0