consensus: Incorrect conversion from boolean to byte array

[dergoegge]

Libbitcoin models the script execution stack as a stack of variants (each element is either a int64_t, bool or chunk_xptr). For some operations, the various types need to be converted so that e.g. the elements can be compared.

The conversion of a boolean to a byte array (data_chunk) is currently implemented incorrectly. false is encoded as {0} and true is encoded as {1}:

libbitcoin-system/include/bitcoin/system/impl/machine/number.ipp

Lines 115 to 118 in 2d57336

	inline data_chunk chunk::from_bool(bool vary) NOEXCEPT
	{
	return { bc::to_int<uint8_t>(vary) };
	}

According to the reference implementation, false is encoded as {} (empty byte array).

This difference can be demonstrated by the following test case:

libbitcoin test case

diff --git a/test/chain/script.hpp b/test/chain/script.hpp
index 3a8c506f7..c985f8e57 100644
--- a/test/chain/script.hpp
+++ b/test/chain/script.hpp
@@ -521,7 +521,8 @@ const script_test_list valid_context_free_scripts
     { "nop", "nop10 1", "" },
     { "[42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242]", "[2.42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242] equal", "basic push signedness check" },
     { "[1.42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242]", "[2.42424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242424242] equal", "basic pushdata1 signedness check" },
-    { "0x00", "size 0 equal", "basic op_0 execution" }
+    { "0x00", "size 0 equal", "basic op_0 execution" },
+    { "", "0 1 equal size 0 equal", "boolean encoding" }
 }};

 // These are always invalid.

Bitcoin Core test case

diff --git a/src/test/data/tx_valid.json b/src/test/data/tx_valid.json
index 70df0d0f69..0aeaaeec45 100644
--- a/src/test/data/tx_valid.json
+++ b/src/test/data/tx_valid.json
@@ -5,6 +5,9 @@
 ["serializedTransaction, excluded verifyFlags]"],
 ["Objects that are only a single string (like this one) are ignored"],

+["Boolean encoding"],
+[[["0000000000000000000000000000000000000000000000000000000000000000", 0, "0 1 EQUAL SIZE 0 EQUAL"]], "020000000100000000000000000000000000000000000000000000000000000000000000000000000000ffffffff0100000000000000000000000000", "STRICTENC,LOW_S,SIGPUSHONLY,MINIMALDATA,DISCOURAGE_UPGRADABLE_NOPS,CLEANSTACK,MINIMALIF,NULLFAIL,DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM,WITNESS_PUBKEYTYPE,CONST_SCRIPTCODE,TAPROOT,DISCOURAGE_UPGRADABLE_PUBKEYTYPE,DISCOURAGE_OP_SUCCESS,DISCOURAGE_UPGRADABLE_TAPROOT_VERSION"],
+
 ["The following is 23b397edccd3740a74adb603c9756370fafcde9bcc4483eb271ecad09a94dd63"],
 ["It is of particular interest because it contains an invalidly-encoded signature which OpenSSL accepts"],
 ["See http://r6.ca/blog/20111119T211504Z.html"],

[evoskuil]

Thanks Niklas!

[evoskuil]

#1525

[evoskuil]

Resolved.