Handle context swap + Modify macro name ST_MD5_BLOCK_SIZE

Author: adustm

features/mbedtls/targets/TARGET_STM/md5_alt.c

@@ -17,7 +17,7 @@
  *  limitations under the License.
  *
  */
-
+#if defined(MBEDTLS_MD5_C)
 #include "mbedtls/md5.h"
 
 #if defined(MBEDTLS_MD5_ALT)
@@ -28,6 +28,28 @@ static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }
 
+static void st_md5_restore_hw_context(mbedtls_md5_context *ctx)
+{
+    uint32_t i;
+    /* allow multi-instance of HASH use: save context for HASH HW module CR */
+    HASH->STR = ctx->ctx_save_str;
+    HASH->CR = (ctx->ctx_save_cr | HASH_CR_INIT);
+    for (i=0;i<38;i++) {
+        HASH->CSR[i] = ctx->ctx_save_csr[i];
+    }
+}
+
+static void st_md5_save_hw_context(mbedtls_md5_context *ctx)
+{
+    uint32_t i;
+    /* allow multi-instance of HASH use: restore context for HASH HW module CR */
+    ctx->ctx_save_cr = HASH->CR;
+    ctx->ctx_save_str = HASH->STR;
+    for (i=0;i<38;i++) {
+        ctx->ctx_save_csr[i] = HASH->CSR[i];
+    }
+}
+
 void mbedtls_md5_init( mbedtls_md5_context *ctx )
 {
     mbedtls_zeroize( ctx, sizeof( mbedtls_md5_context ) );
@@ -41,13 +63,6 @@ void mbedtls_md5_free( mbedtls_md5_context *ctx )
 {
     if( ctx == NULL )
         return;
-
-    /* Force the HASH Periheral Clock Reset */
-    __HAL_RCC_HASH_FORCE_RESET();
-
-    /* Release the HASH Periheral Clock Reset */
-    __HAL_RCC_HASH_RELEASE_RESET();
-
     mbedtls_zeroize( ctx, sizeof( mbedtls_md5_context ) );
 }
 
@@ -60,65 +75,84 @@ void mbedtls_md5_clone( mbedtls_md5_context *dst,
 void mbedtls_md5_starts( mbedtls_md5_context *ctx )
 {
     /* HASH IP initialization */
-    HAL_HASH_DeInit(&ctx->hhash_md5);
+    if (HAL_HASH_DeInit(&ctx->hhash_md5) != 0) {
+        // error found to be returned
+        return;
+    }
 
     /* HASH Configuration */
     ctx->hhash_md5.Init.DataType = HASH_DATATYPE_8B;
-    if (HAL_HASH_Init(&ctx->hhash_md5) == HAL_ERROR) {
+    if (HAL_HASH_Init(&ctx->hhash_md5) != 0) {
         // return error code
         return;
     }
+    st_md5_save_hw_context(ctx);
 }
 
-void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[MBEDTLS_MD5_BLOCK_SIZE] )
+void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[ST_MD5_BLOCK_SIZE] )
 {
-    HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, (uint8_t *)data, MBEDTLS_MD5_BLOCK_SIZE);
+    st_md5_restore_hw_context(ctx);
+    if (HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, (uint8_t *)data, ST_MD5_BLOCK_SIZE) != 0) {
+        return; // Return error code here
+    }
+    st_md5_save_hw_context(ctx);
 }
 
 void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen )
 {
     size_t currentlen = ilen;
-    // store mechanism to handle MBEDTLS_MD5_BLOCK_SIZE bytes per MBEDTLS_MD5_BLOCK_SIZE bytes
+    st_md5_restore_hw_context(ctx);
+
+    // store mechanism to accumulate ST_MD5_BLOCK_SIZE bytes (512 bits) in the HW
     if (currentlen == 0){ // only change HW status is size if 0
-        if(ctx->hhash_md5.Phase == HAL_HASH_PHASE_READY)
-        {
+        if(ctx->hhash_md5.Phase == HAL_HASH_PHASE_READY) {
           /* Select the MD5 mode and reset the HASH processor core, so that the HASH will be ready to compute
              the message digest of a new message */
           HASH->CR |= HASH_ALGOSELECTION_MD5 | HASH_CR_INIT;
         }
         ctx->hhash_md5.Phase = HAL_HASH_PHASE_PROCESS;
-    } else if (currentlen < (MBEDTLS_MD5_BLOCK_SIZE-ctx->sbuf_len)) {
+    } else if (currentlen < (ST_MD5_BLOCK_SIZE - ctx->sbuf_len)) {
         // only buffurize
         memcpy(ctx->sbuf+ctx->sbuf_len, input, currentlen);
         ctx->sbuf_len += currentlen;
     } else {
         // fill buffer and process it
-        memcpy(ctx->sbuf + ctx->sbuf_len, input, (MBEDTLS_MD5_BLOCK_SIZE-ctx->sbuf_len));
-        currentlen -= (MBEDTLS_MD5_BLOCK_SIZE-ctx->sbuf_len);
+        memcpy(ctx->sbuf + ctx->sbuf_len, input, (ST_MD5_BLOCK_SIZE - ctx->sbuf_len));
+        currentlen -= (ST_MD5_BLOCK_SIZE - ctx->sbuf_len);
         mbedtls_md5_process(ctx, ctx->sbuf);
-        // now process every input as long as it is %4 bytes
-        size_t iter = currentlen / 4;
-        HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, (uint8_t *)(input+MBEDTLS_MD5_BLOCK_SIZE-ctx->sbuf_len), (iter*4));
-        // sbuf is now fully accumulated, now copy 1 / 2 or 3 remaining bytes
-        ctx->sbuf_len = currentlen % 4;
+        // Process every input as long as it is %64 bytes, ie 512 bits
+        size_t iter = currentlen / ST_MD5_BLOCK_SIZE;
+        if (iter !=0) {
+            if (HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, (uint8_t *)(input + ST_MD5_BLOCK_SIZE - ctx->sbuf_len), (iter * ST_MD5_BLOCK_SIZE)) != 0) {
+                return; // Return error code here
+            }
+        }
+        // sbuf is completely accumulated, now copy up to 63 remaining bytes
+        ctx->sbuf_len = currentlen % ST_MD5_BLOCK_SIZE;
         if (ctx->sbuf_len !=0) {
-            memcpy(ctx->sbuf, input+iter, ctx->sbuf_len);
+            memcpy(ctx->sbuf, input + ilen - ctx->sbuf_len, ctx->sbuf_len);
         }
     }
+    st_md5_save_hw_context(ctx);
 }
 
 void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] )
 {
+    st_md5_restore_hw_context(ctx);
     if (ctx->sbuf_len > 0) {
-        HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, ctx->sbuf, ctx->sbuf_len);
+        if (HAL_HASH_MD5_Accumulate(&ctx->hhash_md5, ctx->sbuf, ctx->sbuf_len) != 0) {
+            return; // Return error code here
+        }
     }
-    mbedtls_zeroize( ctx->sbuf, MBEDTLS_MD5_BLOCK_SIZE);
+    mbedtls_zeroize( ctx->sbuf, ST_MD5_BLOCK_SIZE);
     ctx->sbuf_len = 0;
     __HAL_HASH_START_DIGEST();
 
     if (HAL_HASH_MD5_Finish(&ctx->hhash_md5, output, 10)) {
         // error code to be returned
     }
+    st_md5_save_hw_context(ctx);
 }
 
 #endif /* MBEDTLS_MD5_ALT */
+#endif /* MBEDTLS_MD5_C */

features/mbedtls/targets/TARGET_STM/md5_alt.h

@@ -31,19 +31,22 @@
 extern "C" {
 #endif
 
-#define MBEDTLS_MD5_BLOCK_SIZE (64) // must be a multiple of 4
+#define ST_MD5_BLOCK_SIZE ((size_t)(64)) // HW handles 512 bits, ie 64 bytes
 /**
  * \brief          MD5 context structure
- * \note     HAL_HASH_MD5_Accumulate cannot handle less than 4 bytes, unless it is the last call to the  function
- *           A MBEDTLS_MD5_BLOCK_SIZE bytes buffer is used to save values and handle the processing
- *           MBEDTLS_MD5_BLOCK_SIZE bytes per MBEDTLS_MD5_BLOCK_SIZE bytes
+ * \note     HAL_HASH_MD5_Accumulate will accumulate 512 bits packets, unless it is the last call to the  function
+ *           A ST_MD5_BLOCK_SIZE bytes buffer is used to save values and handle the processing
+ *           ST_MD5_BLOCK_SIZE bytes per ST_MD5_BLOCK_SIZE bytes
  *           If MD5_finish is called and sbuf_len>0, the remaining bytes are accumulated prior to the call to HAL_HASH_MD5_Finish
  */
 typedef struct
 {
-  HASH_HandleTypeDef hhash_md5;/*!< ST HAL HASH struct */
-  unsigned char sbuf[MBEDTLS_MD5_BLOCK_SIZE]; /*!< MBEDTLS_MD5_BLOCK_SIZE buffer to store values so that algorithm is caled once the buffer is filled */
-  unsigned char sbuf_len; /*!< number of bytes to be processed in sbuf */
+    HASH_HandleTypeDef hhash_md5;/*!< ST HAL HASH struct */
+    unsigned char sbuf[ST_MD5_BLOCK_SIZE]; /*!< MBEDTLS_MD5_BLOCK_SIZE buffer to store values so that algorithm is caled once the buffer is filled */
+    unsigned char sbuf_len; /*!< number of bytes to be processed in sbuf */
+    uint32_t ctx_save_cr;
+    uint32_t ctx_save_str;
+    uint32_t ctx_save_csr[38];
 }
 mbedtls_md5_context;
 
@@ -95,7 +98,7 @@ void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, s
 void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] );
 
 /* Internal use */
-void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[64] );
+void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[ST_MD5_BLOCK_SIZE] );
 
 #ifdef __cplusplus
 }