Fix potential memory leak in SHA Copy and zero-initialize temp GetHash contexts; zero HMAC dst hash before copy to prevent shared pointers

Author: night1rider

wolfcrypt/src/hmac.c

@@ -331,6 +331,11 @@ int wc_HmacCopy(Hmac* src, Hmac* dst) {
 
     XMEMCPY(dst, src, sizeof(*dst));
 
+    /* Zero hash context after shallow copy to prevent shared sub-pointers
+     * (e.g., msg, W buffers) with src. The hash Copy function will perform
+     * the proper deep copy. */
+    XMEMSET(&dst->hash, 0, sizeof(wc_HmacHash));
+
     ret = HmacKeyCopyHash(src->macType, &src->hash, &dst->hash);
 
     if (ret != 0)

wolfcrypt/src/sha.c

@@ -1172,6 +1172,10 @@ int wc_ShaCopy(wc_Sha* src, wc_Sha* dst)
     ret = 0; /* Reset ret to 0 to avoid returning the callback error code */
 #endif /* WOLF_CRYPTO_CB && WOLF_CRYPTO_CB_COPY */
 
+    /* Free dst resources before copy to prevent memory leaks (e.g., msg
+     * buffer, W cache, hardware contexts). XMEMCPY overwrites dst. */
+    wc_ShaFree(dst);
+
     XMEMCPY(dst, src, sizeof(wc_Sha));
 
 #if defined(WOLFSSL_SILABS_SE_ACCEL) && defined(WOLFSSL_SILABS_SE_ACCEL_3)

wolfcrypt/src/sha256.c

@@ -2582,14 +2582,9 @@ int wc_Sha224_Grow(wc_Sha224* sha224, const byte* in, int inSz)
         ret = 0; /* Reset ret to 0 to avoid returning the callback error code */
 #endif /* WOLF_CRYPTO_CB && WOLF_CRYPTO_CB_COPY */
 
-        /* Free dst's msg buffer before copy to prevent potential memory leak
-         * when XMEMCPY overwrites dst with src's pointers. */
-    #if defined(WOLFSSL_HASH_KEEP)
-        if (dst->msg != NULL) {
-            XFREE(dst->msg, dst->heap, DYNAMIC_TYPE_TMP_BUFFER);
-            dst->msg = NULL;
-        }
-    #endif
+        /* Free dst resources before copy to prevent memory leaks (e.g., msg
+         * buffer, W cache, hardware contexts). XMEMCPY overwrites dst. */
+        wc_Sha224Free(dst);
 
         XMEMCPY(dst, src, sizeof(wc_Sha224));
 
@@ -2737,14 +2732,9 @@ int wc_Sha256Copy(wc_Sha256* src, wc_Sha256* dst)
     ret = 0; /* Reset ret to 0 to avoid returning the callback error code */
 #endif /* WOLF_CRYPTO_CB && WOLF_CRYPTO_CB_COPY */
 
-    /* Free dst's msg buffer before copy to prevent potential memory leak
-     * when XMEMCPY overwrites dst with src's pointers. */
-#if defined(WOLFSSL_HASH_KEEP)
-    if (dst->msg != NULL) {
-        XFREE(dst->msg, dst->heap, DYNAMIC_TYPE_TMP_BUFFER);
-        dst->msg = NULL;
-    }
-#endif
+    /* Free dst resources before copy to prevent memory leaks (e.g., msg
+     * buffer, W cache, hardware contexts). XMEMCPY overwrites dst. */
+    wc_Sha256Free(dst);
 
     XMEMCPY(dst, src, sizeof(wc_Sha256));
 

wolfcrypt/src/sha512.c

@@ -2249,14 +2249,9 @@ int wc_Sha512Copy(wc_Sha512* src, wc_Sha512* dst)
     ret = 0; /* Reset ret to 0 to avoid returning the callback error code */
 #endif /* WOLF_CRYPTO_CB && WOLF_CRYPTO_CB_COPY */
 
-    /* Free dst's msg buffer before copy to prevent potential memory leak
-     * when XMEMCPY overwrites dst with src's pointers. */
-#if defined(WOLFSSL_HASH_KEEP)
-    if (dst->msg != NULL) {
-        XFREE(dst->msg, dst->heap, DYNAMIC_TYPE_TMP_BUFFER);
-        dst->msg = NULL;
-    }
-#endif
+    /* Free dst resources before copy to prevent memory leaks (e.g., msg
+     * buffer, W cache, hardware contexts). XMEMCPY overwrites dst. */
+    wc_Sha512Free(dst);
 
     XMEMCPY(dst, src, sizeof(wc_Sha512));
 #ifdef WOLFSSL_SMALL_STACK_CACHE
@@ -2696,14 +2691,9 @@ int wc_Sha384Copy(wc_Sha384* src, wc_Sha384* dst)
     ret = 0; /* Reset ret to 0 to avoid returning the callback error code */
 #endif /* WOLF_CRYPTO_CB && WOLF_CRYPTO_CB_COPY */
 
-    /* Free dst's msg buffer before copy to prevent potential memory leak
-     * when XMEMCPY overwrites dst with src's pointers. */
-#if defined(WOLFSSL_HASH_KEEP)
-    if (dst->msg != NULL) {
-        XFREE(dst->msg, dst->heap, DYNAMIC_TYPE_TMP_BUFFER);
-        dst->msg = NULL;
-    }
-#endif
+    /* Free dst resources before copy to prevent memory leaks (e.g., msg
+     * buffer, W cache, hardware contexts). XMEMCPY overwrites dst. */
+    wc_Sha384Free(dst);
 
     XMEMCPY(dst, src, sizeof(wc_Sha384));