Merge #17753: util: Don't allow Base32/64-decoding or ParseMoney(…) on strings with embedded NUL characters. Add tests.

137c80d579502e329964d7d1028a9507d4667774 tests: Add tests for decoding/parsing of base32, base64 and money strings containing NUL characters (practicalswift)
a6fc26da55dea3b76bd89fbbca24ded170238674 util: Don't allow DecodeBase32(...) of strings with embedded NUL characters (practicalswift)
93cc18b0f6fa5fa8144079a4f51904d8b3087e94 util: Don't allow DecodeBase64(...) of strings with embedded NUL characters (practicalswift)
ccc53e43c5464058171d6291da861a88184b230e util: Don't allow ParseMoney(...) of strings with embedded NUL characters (practicalswift)

Pull request description:

  Don't allow Base32/64-decoding or `ParseMoney(…)` on strings with embedded `NUL` characters. Add tests.

  Added tests before:

  ```
  $ src/test/test_bitcoin
  Running 385 test cases...
  test/base32_tests.cpp(31): error: in "base32_tests/base32_testvectors":
      check failure == true has failed [false != true]
  test/base64_tests.cpp(31): error: in "base64_tests/base64_testvectors":
      check failure == true has failed [false != true]
  test/util_tests.cpp(1074): error: in "util_tests/util_ParseMoney":
      check !ParseMoney(std::string("\0-1", 3), ret) has failed
  test/util_tests.cpp(1076): error: in "util_tests/util_ParseMoney":
      check !ParseMoney(std::string("1\0", 2), ret) has failed

  *** 4 failures are detected in the test module "Bitcoin Core Test Suite"
  ```

  Added tests after:

  ```
  $ src/test/test_bitcoin
  Running 385 test cases...

  *** No errors detected
  ```

ACKs for top commit:
  laanwj:
    Code review ACK 137c80d579502e329964d7d1028a9507d4667774

Tree-SHA512: 9486a0d32b4cf686bf5a47a0778338ac571fa39c66ad6d6d6cede58ec798e87bb50a2f9b7fd79ecd1fef1ba284e4073c1b430110967073ff87bdbbde7cada447

src/test/base32_tests.cpp

@@ -23,6 +23,17 @@ BOOST_AUTO_TEST_CASE(base32_testvectors)
         std::string strDec = DecodeBase32(vstrOut[i]);
         BOOST_CHECK_EQUAL(strDec, vstrIn[i]);
     }
+
+    // Decoding strings with embedded NUL characters should fail
+    bool failure;
+    (void)DecodeBase32(std::string("invalid", 7), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
+    (void)DecodeBase32(std::string("AWSX3VPP", 8), &failure);
+    BOOST_CHECK_EQUAL(failure, false);
+    (void)DecodeBase32(std::string("AWSX3VPP\0invalid", 16), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
+    (void)DecodeBase32(std::string("AWSX3VPPinvalid", 15), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/test/base64_tests.cpp

@@ -20,6 +20,17 @@ BOOST_AUTO_TEST_CASE(base64_testvectors)
         std::string strDec = DecodeBase64(strEnc);
         BOOST_CHECK_EQUAL(strDec, vstrIn[i]);
     }
+
+    // Decoding strings with embedded NUL characters should fail
+    bool failure;
+    (void)DecodeBase64(std::string("invalid", 7), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
+    (void)DecodeBase64(std::string("nQB/pZw=", 8), &failure);
+    BOOST_CHECK_EQUAL(failure, false);
+    (void)DecodeBase64(std::string("nQB/pZw=\0invalid", 16), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
+    (void)DecodeBase64(std::string("nQB/pZw=invalid", 15), &failure);
+    BOOST_CHECK_EQUAL(failure, true);
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/test/util_tests.cpp

@@ -640,6 +640,11 @@ BOOST_AUTO_TEST_CASE(util_ParseMoney)
 
     // Parsing negative amounts must fail
     BOOST_CHECK(!ParseMoney("-1", ret));
+
+    // Parsing strings with embedded NUL characters should fail
+    BOOST_CHECK(!ParseMoney(std::string("\0-1", 3), ret));
+    BOOST_CHECK(!ParseMoney(std::string("\01", 2), ret));
+    BOOST_CHECK(!ParseMoney(std::string("1\0", 2), ret));
 }
 
 BOOST_AUTO_TEST_CASE(util_IsHex)

src/util/moneystr.cpp

@@ -8,6 +8,7 @@
 #include <primitives/transaction.h>
 #include <tinyformat.h>
 #include <util/strencodings.h>
+#include <util/string.h>
 
 std::string FormatMoney(const CAmount& n)
 {
@@ -33,6 +34,9 @@ std::string FormatMoney(const CAmount& n)
 
 bool ParseMoney(const std::string& str, CAmount& nRet)
 {
+    if (!ValidAsCString(str)) {
+        return false;
+    }
     return ParseMoney(str.c_str(), nRet);
 }
 

src/util/strencodings.cpp

@@ -191,6 +191,12 @@ std::vector<unsigned char> DecodeBase64(const char* p, bool* pf_invalid)
 
 std::string DecodeBase64(const std::string& str, bool* pf_invalid)
 {
+    if (!ValidAsCString(str)) {
+        if (pf_invalid) {
+            *pf_invalid = true;
+        }
+        return {};
+    }
     std::vector<unsigned char> vchRet = DecodeBase64(str.c_str(), pf_invalid);
     return std::string((const char*)vchRet.data(), vchRet.size());
 }
@@ -264,6 +270,12 @@ std::vector<unsigned char> DecodeBase32(const char* p, bool* pf_invalid)
 
 std::string DecodeBase32(const std::string& str, bool* pf_invalid)
 {
+    if (!ValidAsCString(str)) {
+        if (pf_invalid) {
+            *pf_invalid = true;
+        }
+        return {};
+    }
     std::vector<unsigned char> vchRet = DecodeBase32(str.c_str(), pf_invalid);
     return std::string((const char*)vchRet.data(), vchRet.size());
 }