From 1c2008fa37e13e270b2b3f05c53b8bb24cae6b91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?=
 <manuel.pegourie-gonnard@arm.com>
Date: Thu, 16 Mar 2023 10:20:29 +0100
Subject: [PATCH] PEM: always use MD light
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Note: PEM_PARSE already auto-enables MD_LIGHT in build_info.h

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
---
 include/mbedtls/mbedtls_config.h     |  4 ++
 library/pem.c                        | 93 ----------------------------
 tests/suites/test_suite_pem.function |  3 +
 3 files changed, 7 insertions(+), 93 deletions(-)

diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 87181a697d..f460e0d44f 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -2775,6 +2775,10 @@
  *          library/x509_csr.c
  *
  * Requires: MBEDTLS_BASE64_C
+ *           optionally MBEDTLS_MD5_C, or PSA Crypto with MD5 (see below)
+ *
+ * \warning When parsing password-protected files, if MD5 is provided only by
+ * a PSA driver, you must call psa_crypto_init() before the first file.
  *
  * This modules adds support for decoding / parsing PEM files.
  */
diff --git a/library/pem.c b/library/pem.c
index 84bbb3df10..264c2e4776 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -39,13 +39,6 @@
 #include "psa/crypto.h"
 #endif
 
-#if !defined(MBEDTLS_MD5_C)
-#include "mbedtls/psa_util.h"
-#define PSA_TO_MBEDTLS_ERR(status) PSA_TO_MBEDTLS_ERR_LIST(status,          \
-                                                           psa_to_md_errors,                     \
-                                                           psa_generic_status_to_mbedtls)
-#endif
-
 #include "mbedtls/legacy_or_psa.h"
 
 #if defined(MBEDTLS_HAS_ALG_MD5_VIA_MD_OR_PSA_BASED_ON_USE_PSA) &&  \
@@ -94,7 +87,6 @@ static int pem_get_iv(const unsigned char *s, unsigned char *iv,
     return 0;
 }
 
-#if defined(MBEDTLS_MD5_C)
 static int pem_pbkdf1(unsigned char *key, size_t keylen,
                       unsigned char *iv,
                       const unsigned char *pwd, size_t pwdlen)
@@ -168,91 +160,6 @@ exit:
 
     return ret;
 }
-#else
-static int pem_pbkdf1(unsigned char *key, size_t keylen,
-                      unsigned char *iv,
-                      const unsigned char *pwd, size_t pwdlen)
-{
-    unsigned char md5sum[16];
-    psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT;
-    size_t output_length = 0;
-    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
-
-
-    if ((status = psa_hash_setup(&operation, PSA_ALG_MD5)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_update(&operation, pwd, pwdlen)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_update(&operation, iv, 8)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_finish(&operation, md5sum,
-                                  PSA_HASH_LENGTH(PSA_ALG_MD5),
-                                  &output_length)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_abort(&operation)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    /*
-     * key[ 0..15] = MD5(pwd || IV)
-     */
-    if (keylen <= 16) {
-        memcpy(key, md5sum, keylen);
-        goto exit;
-    }
-
-    memcpy(key, md5sum, 16);
-
-    /*
-     * key[16..23] = MD5(key[ 0..15] || pwd || IV])
-     */
-    if ((status = psa_hash_setup(&operation, PSA_ALG_MD5)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_update(&operation, md5sum, 16)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_update(&operation, pwd, pwdlen)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_update(&operation, iv, 8)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_finish(&operation, md5sum,
-                                  PSA_HASH_LENGTH(PSA_ALG_MD5),
-                                  &output_length)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    if ((status = psa_hash_abort(&operation)) != PSA_SUCCESS) {
-        goto exit;
-    }
-
-    size_t use_len = 16;
-    if (keylen < 32) {
-        use_len = keylen - 16;
-    }
-
-    memcpy(key + 16, md5sum, use_len);
-
-exit:
-    mbedtls_platform_zeroize(md5sum, 16);
-
-    return PSA_TO_MBEDTLS_ERR(status);
-}
-#endif /* MBEDTLS_MD5_C */
 
 #if defined(MBEDTLS_DES_C)
 /*
diff --git a/tests/suites/test_suite_pem.function b/tests/suites/test_suite_pem.function
index 25b66f8b65..9546614125 100644
--- a/tests/suites/test_suite_pem.function
+++ b/tests/suites/test_suite_pem.function
@@ -44,6 +44,8 @@ void mbedtls_pem_read_buffer(char *header, char *footer, char *data,
     size_t pwd_len = strlen(pwd);
     const unsigned char *buf;
 
+    MD_PSA_INIT();
+
     mbedtls_pem_init(&ctx);
 
     ret = mbedtls_pem_read_buffer(&ctx, header, footer, (unsigned char *) data,
@@ -60,5 +62,6 @@ void mbedtls_pem_read_buffer(char *header, char *footer, char *data,
 
 exit:
     mbedtls_pem_free(&ctx);
+    MD_PSA_DONE();
 }
 /* END_CASE */