Correctly report high-S violations

[sipa]

Reported in #6862 (comment)

[laanwj]

utACK sipa@9d95187

[paveljanik]

utACK sipa@9d95187
... passively waiting for some High S tx to compare log output ;-)

[laanwj]

@paveljanik wrong commit hash :)

[paveljanik]

Yes, testing two PRs at one time 8)

[paveljanik]

ACK

Thx for random volunteer who sends a lot of High S now...

Before the change:

2016-02-10 17:28:54 ERROR: AcceptToMemoryPoolWorker: CheckInputs: 9f8604786542fc4decdd8c5e739eb2c57ba9a7bd67b2c21ecdb99abffb8f643c, non-mandatory-script-verify-flag (unknown error) (code 64)

after:

2016-02-10 19:06:42 ERROR: AcceptToMemoryPoolWorker: CheckInputs: 896a30d13dfd36612e7a77de8e085653d904dea9ecf8af0451f0ed6a78f8dd83, non-mandatory-script-verify-flag (Non-canonical signature: S value is unnecessarily high) (code 64)

[laanwj]

Tested ACK 9d95187
Without patch:

["0x48 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef001","0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG","LOW_S","P2PK with high S"] 
-> unknown error

With patch:

["0x48 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef001","0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG","LOW_S","P2PK with high S"] 
-> Non-canonical signature: S value is unnecessarily high

BTW: would it be useful to add a field for the expected script_error to the invalid tx tests, so that this is verified are part of the unit tests? (not in this pull)

[laanwj]

Cherry-picked to 0.12 as 889e5b3

[dcousens]

utACK