@@ -93,6 +93,7 @@ int XzCheck_Final(CXzCheck *p, Byte *digest)

           return 0;

       cl_finish_hash(p->sha, digest);

+      p->sha = NULL;

       break;

     default:

       return 0;

@@ -614,7 +614,11 @@ SRes XzUnpacker_Create(CXzUnpacker *p, ISzAlloc *alloc)

 void XzUnpacker_Free(CXzUnpacker *p)

 {

+  if (!p)

+    return;

   MixCoder_Free(&p->decoder);

+  cl_hash_destroy(p->sha);

+  p->sha = NULL;

 }

 SRes XzUnpacker_Code(CXzUnpacker *p, Byte *dest, SizeT *destLen,

@@ -816,8 +820,10 @@ SRes XzUnpacker_Code(CXzUnpacker *p, Byte *dest, SizeT *destLen,

             p->state = XZ_STATE_STREAM_INDEX_CRC;

             p->indexSize += 4;

             p->pos = 0;

-            if ((p->sha))

+            if ((p->sha)) {

                 cl_finish_hash(p->sha, digest);

+                p->sha = NULL;

+            }

             if (memcmp(digest, p->shaDigest, SHA256_DIGEST_SIZE) != 0)

               return SZ_ERROR_CRC;

@@ -57,6 +57,8 @@ int cli_XzInit(struct CLI_XZ *XZ) {

 }

 void cli_XzShutdown(struct CLI_XZ *XZ) {

+    if (!XZ)

+        return;

     XzUnpacker_Free(&XZ->state);

 }