Merge pull request #1175 from davidhorstmann-arm/cipher-multipart-test-fix-backport

[Backport 2.28] Fix a multipart test that overwrites the same buffer twice
diff --git a/tests/suites/test_suite_psa_crypto.data b/tests/suites/test_suite_psa_crypto.data
index 03cc2ff..c5211f9 100644
--- a/tests/suites/test_suite_psa_crypto.data
+++ b/tests/suites/test_suite_psa_crypto.data
@@ -1971,6 +1971,11 @@
 depends_on:PSA_WANT_ALG_CBC_NO_PADDING:PSA_WANT_KEY_TYPE_AES
 cipher_verify_output_multipart:PSA_ALG_CBC_NO_PADDING:PSA_KEY_TYPE_AES:"2b7e151628aed2a6abf7158809cf4f3c":"6bc1bee22e409f96e93d7e117393172a":16
 
+# Encrypt 48 bytes total, initially 16. This forces both calls to update() to output data.
+PSA symmetric encrypt/decrypt multipart: AES-CBC-nopad, 48 bytes, good
+depends_on:PSA_WANT_ALG_CBC_NO_PADDING:PSA_WANT_KEY_TYPE_AES
+cipher_verify_output_multipart:PSA_ALG_CBC_NO_PADDING:PSA_KEY_TYPE_AES:"2b7e151628aed2a6abf7158809cf4f3c":"6bc1bee22e409f96e93d7e117393172a6bc1bee22e409f96e93d7e117393172a6bc1bee22e409f96e93d7e117393172a":16
+
 PSA symmetric encrypt/decrypt multipart: AES-CBC-PKCS#7, 16 bytes
 depends_on:PSA_WANT_ALG_CBC_PKCS7:PSA_WANT_KEY_TYPE_AES
 cipher_verify_output_multipart:PSA_ALG_CBC_PKCS7:PSA_KEY_TYPE_AES:"2b7e151628aed2a6abf7158809cf4f3c":"6bc1bee22e409f96e93d7e117393172a":16
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 796a62a..26f7350 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -3291,7 +3291,8 @@
     PSA_ASSERT(psa_cipher_update(&operation1,
                                  input->x + first_part_size,
                                  input->len - first_part_size,
-                                 output1, output1_buffer_size,
+                                 output1 + output1_length,
+                                 output1_buffer_size - output1_length,
                                  &function_output_length));
     TEST_LE_U(function_output_length,
               PSA_CIPHER_UPDATE_OUTPUT_SIZE(key_type,
@@ -3337,7 +3338,8 @@
     PSA_ASSERT(psa_cipher_update(&operation2,
                                  output1 + first_part_size,
                                  output1_length - first_part_size,
-                                 output2, output2_buffer_size,
+                                 output2 + output2_length,
+                                 output2_buffer_size - output2_length,
                                  &function_output_length));
     TEST_LE_U(function_output_length,
               PSA_CIPHER_UPDATE_OUTPUT_SIZE(key_type,