diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index ac2eae6670..c53d15b011 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3347,6 +3347,12 @@ psa_status_t psa_asymmetric_sign( psa_key_handle_t handle,
 #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
 
     *signature_length = signature_size;
+    /* Immediately reject a zero-length signature buffer. This guarantees
+     * that signature must be a valid pointer. (On the other hand, the hash
+     * buffer can in principle be empty since it doesn't actually have
+     * to be a hash.) */
+    if( signature_size == 0 )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
 
     status = psa_get_key_from_slot( handle, &slot, PSA_KEY_USAGE_SIGN, alg );
     if( status != PSA_SUCCESS )
@@ -3422,7 +3428,7 @@ exit:
     if( status == PSA_SUCCESS )
         memset( signature + *signature_length, '!',
                 signature_size - *signature_length );
-    else if( signature_size != 0 )
+    else
         memset( signature, '!', signature_size );
     /* If signature_size is 0 then we have nothing to do. We must not call
      * memset because signature may be NULL in this case. */
diff --git a/tests/suites/test_suite_psa_crypto.data b/tests/suites/test_suite_psa_crypto.data
index 16edd382ab..9df4b43be8 100644
--- a/tests/suites/test_suite_psa_crypto.data
+++ b/tests/suites/test_suite_psa_crypto.data
@@ -1561,6 +1561,14 @@ PSA sign: deterministic ECDSA SECP256R1 SHA-256, output buffer too small
 depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_SHA256_C:MBEDTLS_ECDSA_C
 sign_fail:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_CURVE_SECP256R1):"ab45435712649cb30bbddac49197eebf2740ffc7f874d9244c3460f54f322d3a":PSA_ALG_DETERMINISTIC_ECDSA( PSA_ALG_SHA_256 ):"9ac4335b469bbd791439248504dd0d49c71349a295fee5a1c68507f45a9e1c7b":63:PSA_ERROR_BUFFER_TOO_SMALL
 
+PSA sign: RSA PKCS#1 v1.5 SHA-256, empty output buffer
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_SHA256_C
+sign_fail:PSA_KEY_TYPE_RSA_KEY_PAIR:"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":PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_256):"ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad":0:PSA_ERROR_BUFFER_TOO_SMALL
+
+PSA sign: deterministic ECDSA SECP256R1 SHA-256, empty output buffer
+depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_SHA256_C:MBEDTLS_ECDSA_C
+sign_fail:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_CURVE_SECP256R1):"ab45435712649cb30bbddac49197eebf2740ffc7f874d9244c3460f54f322d3a":PSA_ALG_DETERMINISTIC_ECDSA( PSA_ALG_SHA_256 ):"9ac4335b469bbd791439248504dd0d49c71349a295fee5a1c68507f45a9e1c7b":0:PSA_ERROR_BUFFER_TOO_SMALL
+
 PSA sign: deterministic ECDSA SECP256R1, invalid hash algorithm (0)
 depends_on:MBEDTLS_PK_PARSE_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECDSA_DETERMINISTIC
 sign_fail:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_CURVE_SECP256R1):"ab45435712649cb30bbddac49197eebf2740ffc7f874d9244c3460f54f322d3a":PSA_ALG_DETERMINISTIC_ECDSA( 0 ):"9ac4335b469bbd791439248504dd0d49c71349a295fee5a1c68507f45a9e1c7b":72:PSA_ERROR_INVALID_ARGUMENT
diff --git a/tests/suites/test_suite_psa_crypto_se_driver_hal_mocks.function b/tests/suites/test_suite_psa_crypto_se_driver_hal_mocks.function
index e3641789fa..e6b3f7b1fe 100644
--- a/tests/suites/test_suite_psa_crypto_se_driver_hal_mocks.function
+++ b/tests/suites/test_suite_psa_crypto_se_driver_hal_mocks.function
@@ -396,6 +396,7 @@ void mock_generate( int mock_alloc_return_value,
     psa_set_key_lifetime( &attributes, lifetime );
     psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_EXPORT );
     psa_set_key_type( &attributes, PSA_KEY_TYPE_RAW_DATA );
+    psa_set_key_bits( &attributes, 8 );
     TEST_ASSERT( psa_generate_key( &attributes, &handle ) == expected_result );
     TEST_ASSERT( mock_allocate_data.called == 1 );
     TEST_ASSERT( mock_generate_data.called ==
@@ -482,6 +483,8 @@ void mock_sign( int mock_sign_return_value, int expected_result )
     psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
     const uint8_t key_material[3] = {0xfa, 0xca, 0xde};
     psa_algorithm_t algorithm = PSA_ALG_ECDSA(PSA_ALG_SHA_256);
+    const uint8_t hash[1] = {'H'};
+    uint8_t signature[1] = {'S'};
     size_t signature_length;
 
     mock_sign_data.return_value = mock_sign_return_value;
@@ -512,7 +515,9 @@ void mock_sign( int mock_sign_return_value, int expected_result )
                                 key_material, sizeof( key_material ),
                                 &handle ) );
 
-    TEST_ASSERT( psa_asymmetric_sign( handle, algorithm, NULL, 0, NULL, 0,
+    TEST_ASSERT( psa_asymmetric_sign( handle, algorithm,
+                                      hash, sizeof( hash ),
+                                      signature, sizeof( signature ),
                                       &signature_length)
                  == expected_result );
     TEST_ASSERT( mock_sign_data.called == 1 );
@@ -538,6 +543,8 @@ void mock_verify( int mock_verify_return_value, int expected_result )
     psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
     const uint8_t key_material[3] = {0xfa, 0xca, 0xde};
     psa_algorithm_t algorithm = PSA_ALG_ECDSA(PSA_ALG_SHA_256);
+    const uint8_t hash[1] = {'H'};
+    const uint8_t signature[1] = {'S'};
 
     mock_verify_data.return_value = mock_verify_return_value;
     memset( &driver, 0, sizeof( driver ) );
@@ -567,7 +574,9 @@ void mock_verify( int mock_verify_return_value, int expected_result )
                                 key_material, sizeof( key_material ),
                                 &handle ) );
 
-    TEST_ASSERT( psa_asymmetric_verify( handle, algorithm, NULL, 0, NULL, 0)
+    TEST_ASSERT( psa_asymmetric_verify( handle, algorithm,
+                                        hash, sizeof( hash ),
+                                        signature, sizeof( signature ) )
                  == expected_result );
     TEST_ASSERT( mock_verify_data.called == 1 );