Included changes from the TI PR project-chip#9479

src/crypto/CHIPCryptoPAL.h

@@ -74,18 +74,20 @@ constexpr size_t kEmitDerIntegerWithoutTagOverhead = 1; // 1 sign stuffer
 constexpr size_t kEmitDerIntegerOverhead           = 3; // Tag + Length byte + 1 sign stuffer
 
 /*
- * Worst case is OpenSSL, so let's use its worst case and let static assert tell us if
- * we are wrong, since `typedef SHA_LONG unsigned int` is default.
+ * Size of a static intance of the SHA256 context.
+ *
+ * This must account for the worst case size for all platforms. Currently the
+ * worst case size is the TI hardware accelerated version of mbedtls. This is
+ * 76 words long for the driver context. The previous worst case was OpenSSL
+ * with the following sturuct sizing.
  *   SHA_LONG h[8];
  *   SHA_LONG Nl, Nh;
  *   SHA_LONG data[SHA_LBLOCK]; // SHA_LBLOCK is 16 for SHA256
  *   unsigned int num, md_len;
  *
- * We also have to account for possibly some custom extensions on some targets,
- * especially for mbedTLS, so an extra sizeof(uint64_t) is added to account.
+ * Let the static assert tell us if we are wrong.
  */
-constexpr size_t kMAX_Hash_SHA256_Context_Size =
-    ((sizeof(unsigned int) * (8 + 2 + 16 + 2)) + sizeof(uint64_t) + (24 * sizeof(uint64_t)));
+constexpr size_t kMAX_Hash_SHA256_Context_Size = (sizeof(unsigned int) * 76);
 
 /*
  * Overhead to encode a raw ECDSA signature in X9.62 format in ASN.1 DER

src/platform/cc13x2_26x2/crypto/aes_alt.c

@@ -40,23 +40,28 @@ void mbedtls_aes_init(mbedtls_aes_context * ctx)
 {
     AESECB_Params AESECBParams;
 
-    if (ref_num++ == 0)
+    if (ref_num == 0)
     {
         AESECB_Params_init(&AESECBParams);
         AESECBParams.returnBehavior = AESECB_RETURN_BEHAVIOR_POLLING;
         AESECB_handle               = AESECB_open(CONFIG_AESECB_1, &AESECBParams);
 
         // handle will be NULL if open failed, subsequent calls will fail with a generic HW error
     }
+    ref_num++;
 }
 
 void mbedtls_aes_free(mbedtls_aes_context * ctx)
 {
-    if (--ref_num == 0)
+    if (ref_num > 0)
     {
-        AESECB_close(AESECB_handle);
+        ref_num--;
+        if (ref_num == 0)
+        {
+            AESECB_close(AESECB_handle);
 
-        AESECB_handle = NULL;
+            AESECB_handle = NULL;
+        }
     }
 
     memset((void *) ctx, 0x00, sizeof(ctx));