crypto/x509/x509_vfy.c:1097: error: NULL_DEREFERENCE
  pointer `xs` last assigned on line 1089 could be null and is dereferenced at line 1097, column 8.
Showing all 32 steps of the trace


crypto/x509/x509_vfy.c:1060:1: start of procedure internal_verify()
1058.   	}
1059.   
1060. > static int internal_verify(X509_STORE_CTX *ctx)
1061.   	{
1062.   	int ok=0,n;

crypto/x509/x509_vfy.c:1062:2: 
1060.   static int internal_verify(X509_STORE_CTX *ctx)
1061.   	{
1062. > 	int ok=0,n;
1063.   	X509 *xs,*xi;
1064.   	EVP_PKEY *pkey=NULL;

crypto/x509/x509_vfy.c:1064:2: 
1062.   	int ok=0,n;
1063.   	X509 *xs,*xi;
1064. > 	EVP_PKEY *pkey=NULL;
1065.   	int (*cb)(int xok,X509_STORE_CTX *xctx);
1066.   

crypto/x509/x509_vfy.c:1067:2: 
1065.   	int (*cb)(int xok,X509_STORE_CTX *xctx);
1066.   
1067. > 	cb=ctx->verify_cb;
1068.   
1069.   	n=sk_X509_num(ctx->chain);

crypto/x509/x509_vfy.c:1069:2: 
1067.   	cb=ctx->verify_cb;
1068.   
1069. > 	n=sk_X509_num(ctx->chain);
1070.   	ctx->error_depth=n-1;
1071.   	n--;

crypto/stack/stack.c:301:1: start of procedure sk_num()
  299.   	}
  300.   
  301. > int sk_num(const STACK *st)
  302.   {
  303.   	if(st == NULL) return -1;

crypto/stack/stack.c:303:5: Taking false branch
  301.   int sk_num(const STACK *st)
  302.   {
  303.   	if(st == NULL) return -1;
             ^
  304.   	return st->num;
  305.   }

crypto/stack/stack.c:304:2: 
  302.   {
  303.   	if(st == NULL) return -1;
  304. > 	return st->num;
  305.   }
  306.   

crypto/stack/stack.c:305:1: return from a call to sk_num
  303.   	if(st == NULL) return -1;
  304.   	return st->num;
  305. > }
  306.   
  307.   char *sk_value(const STACK *st, int i)

crypto/x509/x509_vfy.c:1070:2: 
1068.   
1069.   	n=sk_X509_num(ctx->chain);
1070. > 	ctx->error_depth=n-1;
1071.   	n--;
1072.   	xi=sk_X509_value(ctx->chain,n);

crypto/x509/x509_vfy.c:1071:2: 
1069.   	n=sk_X509_num(ctx->chain);
1070.   	ctx->error_depth=n-1;
1071. > 	n--;
1072.   	xi=sk_X509_value(ctx->chain,n);
1073.   

crypto/x509/x509_vfy.c:1072:2: 
1070.   	ctx->error_depth=n-1;
1071.   	n--;
1072. > 	xi=sk_X509_value(ctx->chain,n);
1073.   
1074.   	if (ctx->check_issued(ctx, xi, xi))

crypto/stack/stack.c:307:1: start of procedure sk_value()
  305.   }
  306.   
  307. > char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;

crypto/stack/stack.c:309:6: Taking false branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
              ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:309:13: Taking false branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
                     ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:309:24: Taking false branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
                                ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:310:2: 
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
  310. > 	return st->data[i];
  311.   }
  312.   

crypto/stack/stack.c:311:1: return from a call to sk_value
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
  310.   	return st->data[i];
  311. > }
  312.   
  313.   char *sk_set(STACK *st, int i, char *value)

crypto/x509/x509_vfy.c:1074:6: Taking false branch
1072.   	xi=sk_X509_value(ctx->chain,n);
1073.   
1074.   	if (ctx->check_issued(ctx, xi, xi))
             ^
1075.   		xs=xi;
1076.   	else

crypto/x509/x509_vfy.c:1078:7: Taking false branch
1076.   	else
1077.   		{
1078.   		if (n <= 0)
              ^
1079.   			{
1080.   			ctx->error=X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE;

crypto/x509/x509_vfy.c:1087:4: 
1085.   		else
1086.   			{
1087. > 			n--;
1088.   			ctx->error_depth=n;
1089.   			xs=sk_X509_value(ctx->chain,n);

crypto/x509/x509_vfy.c:1088:4: 
1086.   			{
1087.   			n--;
1088. > 			ctx->error_depth=n;
1089.   			xs=sk_X509_value(ctx->chain,n);
1090.   			}

crypto/x509/x509_vfy.c:1089:4: 
1087.   			n--;
1088.   			ctx->error_depth=n;
1089. > 			xs=sk_X509_value(ctx->chain,n);
1090.   			}
1091.   		}

crypto/stack/stack.c:307:1: start of procedure sk_value()
  305.   }
  306.   
  307. > char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;

crypto/stack/stack.c:309:6: Taking false branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
              ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:309:13: Taking false branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
                     ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:309:24: Taking true branch
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
                                ^
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:309:39: 
  307.   char *sk_value(const STACK *st, int i)
  308.   {
  309. > 	if(!st || (i < 0) || (i >= st->num)) return NULL;
  310.   	return st->data[i];
  311.   }

crypto/stack/stack.c:311:1: return from a call to sk_value
  309.   	if(!st || (i < 0) || (i >= st->num)) return NULL;
  310.   	return st->data[i];
  311. > }
  312.   
  313.   char *sk_set(STACK *st, int i, char *value)

crypto/x509/x509_vfy.c:1094:9: Loop condition is true. Entering loop body
1092.   
1093.   /*	ctx->error=0;  not needed */
1094.   	while (n >= 0)
                ^
1095.   		{
1096.   		ctx->error_depth=n;

crypto/x509/x509_vfy.c:1096:3: 
1094.   	while (n >= 0)
1095.   		{
1096. > 		ctx->error_depth=n;
1097.   		if (!xs->valid)
1098.   			{

crypto/x509/x509_vfy.c:1097:8: Taking false branch
1095.   		{
1096.   		ctx->error_depth=n;
1097.   		if (!xs->valid)
               ^
1098.   			{
1099.   			if ((pkey=X509_get_pubkey(xi)) == NULL)
