commit f6a0d57e4d08806723d63fd108805f6e34bcdf7d
author Kusumit Ghoderao <Kusumit.Ghoderao@silabs.com> Mon Jun 05 14:55:56 2023 +0530
committer Kusumit Ghoderao <Kusumit.Ghoderao@silabs.com> Tue Jun 06 15:05:41 2023 +0530
tree 6d256ad391ca478477c876d940f0affb9edcd00d
parent a4346cdc502d9bd26266e79311221eed17d7f122

Add pbkdf2 function to key_derivation_output_bytes

Signed-off-by: Kusumit Ghoderao <Kusumit.Ghoderao@silabs.com>

library/psa_crypto.c

diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index f438c87..38ceb46 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -5529,6 +5529,66 @@
     mbedtls_free(input);
     return status;
 }
+
+static psa_status_t psa_key_derivation_pbkdf2_read(
+    psa_pbkdf2_key_derivation_t *pbkdf2,
+    psa_algorithm_t kdf_alg,
+    uint8_t *output,
+    size_t output_length)
+{
+    psa_status_t status;
+    psa_algorithm_t prf_alg;
+    uint8_t prf_output_length;
+    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+    psa_set_key_bits(&attributes, PSA_BYTES_TO_BITS(pbkdf2->password_length));
+    psa_set_key_usage_flags(&attributes, PSA_KEY_USAGE_SIGN_MESSAGE);
+
+    if (PSA_ALG_IS_PBKDF2_HMAC(kdf_alg)) {
+        prf_alg = PSA_ALG_HMAC(PSA_ALG_PBKDF2_HMAC_GET_HASH(kdf_alg));
+        prf_output_length = PSA_HASH_LENGTH(prf_alg);
+        psa_set_key_type(&attributes, PSA_KEY_TYPE_HMAC);
+    }
+
+    switch (pbkdf2->state) {
+        case PSA_PBKDF2_STATE_PASSWORD_SET:
+            /* Initially we need a new block so bytes_used is equal to block size*/
+            pbkdf2->bytes_used = prf_output_length;
+            pbkdf2->state = PSA_PBKDF2_STATE_OUTPUT;
+            break;
+        case PSA_PBKDF2_STATE_OUTPUT:
+            break;
+        default:
+            return PSA_ERROR_BAD_STATE;
+    }
+
+    while (output_length != 0) {
+        uint8_t n = prf_output_length - pbkdf2->bytes_used;
+        if (n > output_length) {
+            n = (uint8_t) output_length;
+        }
+        memcpy(output, pbkdf2->output_block + pbkdf2->bytes_used, n);
+        output += n;
+        output_length -= n;
+        pbkdf2->bytes_used += n;
+
+        if (output_length == 0) {
+            break;
+        }
+
+        /* We need a new block */
+        pbkdf2->bytes_used = 0;
+        pbkdf2->block_number++;
+
+        status = psa_key_derivation_pbkdf2_generate_block(pbkdf2, prf_alg,
+                                                          prf_output_length,
+                                                          &attributes);
+        if (status != PSA_SUCCESS) {
+            return status;
+        }
+    }
+
+    return PSA_SUCCESS;
+}
 #endif /* MBEDTLS_PSA_BUILTIN_ALG_PBKDF2_HMAC */
 
 psa_status_t psa_key_derivation_output_bytes(
@@ -5586,11 +5646,8 @@
 #endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_ECJPAKE_TO_PMS */
 #if defined(MBEDTLS_PSA_BUILTIN_ALG_PBKDF2_HMAC)
     if (PSA_ALG_IS_PBKDF2_HMAC(kdf_alg)) {
-        /* As output functionality is not added yet return
-         * PSA_ERROR_NOT_SUPPORTED for now if inputs are passed correctly.
-         * If input validation fails operation is aborted and output_bytes
-         * will return PSA_ERROR_BAD_STATE */
-        status = PSA_ERROR_NOT_SUPPORTED;
+        status = psa_key_derivation_pbkdf2_read(&operation->ctx.pbkdf2, kdf_alg,
+                                                output, output_length);
     } else
 #endif /* MBEDTLS_PSA_BUILTIN_ALG_PBKDF2_HMAC */