crypto: fix assert() on malformed hex input

Use the StringBytes::IsValidString() function introduced in commit
dce26cc to ensure that the input string meets the expectations of the
other StringBytes functions before processing it further.

Fixes the following assertion:

    Assertion failed: (str->Length() % 2 == 0 && "invalid hex string
    length"), function StorageSize, file ../../src/string_bytes.cc,
    line 301.

Fixes #5725.

src/node_crypto.cc

@@ -2265,10 +2265,13 @@ class Cipher : public ObjectWrap {
     unsigned char* out = 0;
     int out_len = 0, r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = cipher->CipherUpdate(buf, written, &out, &out_len);
       delete[] buf;
     } else {
@@ -2574,10 +2577,13 @@ class Decipher : public ObjectWrap {
     unsigned char* out = 0;
     int out_len = 0, r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = cipher->DecipherUpdate(buf, written, &out, &out_len);
       delete[] buf;
     } else {
@@ -2763,10 +2769,13 @@ class Hmac : public ObjectWrap {
     // Only copy the data if we have to, because it's a string
     int r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = hmac->HmacUpdate(buf, written);
       delete[] buf;
     } else {
@@ -2892,10 +2901,13 @@ class Hash : public ObjectWrap {
     // Only copy the data if we have to, because it's a string
     int r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = hash->HashUpdate(buf, written);
       delete[] buf;
     } else {
@@ -3055,10 +3067,13 @@ class Sign : public ObjectWrap {
     // Only copy the data if we have to, because it's a string
     int r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = sign->SignUpdate(buf, written);
       delete[] buf;
     } else {
@@ -3280,10 +3295,13 @@ class Verify : public ObjectWrap {
     // Only copy the data if we have to, because it's a string
     int r;
     if (args[0]->IsString()) {
+      Local<String> string = args[0].As<String>();
       enum encoding encoding = ParseEncoding(args[1], BINARY);
-      size_t buflen = StringBytes::StorageSize(args[0], encoding);
+      if (!StringBytes::IsValidString(string, encoding))
+        return ThrowTypeError("Bad input string");
+      size_t buflen = StringBytes::StorageSize(string, encoding);
       char* buf = new char[buflen];
-      size_t written = StringBytes::Write(buf, buflen, args[0], encoding);
+      size_t written = StringBytes::Write(buf, buflen, string, encoding);
       r = verify->VerifyUpdate(buf, written);
       delete[] buf;
     } else {

test/simple/test-crypto.js

@@ -915,3 +915,25 @@ assert.throws(function() {
   c.update('update', 'utf-8');
   c.final('utf8');  // Should not throw.
 })();
+
+// Regression tests for #5725: hex input that's not a power of two should
+// throw, not assert in C++ land.
+assert.throws(function() {
+  crypto.createCipher('aes192', 'test').update('0', 'hex');
+}, /Bad input string/);
+
+assert.throws(function() {
+  crypto.createDecipher('aes192', 'test').update('0', 'hex');
+}, /Bad input string/);
+
+assert.throws(function() {
+  crypto.createHash('sha1').update('0', 'hex');
+}, /Bad input string/);
+
+assert.throws(function() {
+  crypto.createSign('RSA-SHA1').update('0', 'hex');
+}, /Bad input string/);
+
+assert.throws(function() {
+  crypto.createVerify('RSA-SHA1').update('0', 'hex');
+}, /Bad input string/);