Revisions 5-6 of the standard security handler key the file on the
password processed with SASLprep (ISO 32000-2 7.6.4.3.3, Algorithm 2.A
step a). pdfcraft-crypt writes and reads it so, but the vendored
hayro-syntax skipped the step ("TODO: Do the above.") and used the UTF-8
bytes as typed. A password that SASLprep changes (a decomposed "cafe" +
U+0301, a no-break space, fullwidth letters typed by an IME in full-width
mode) was wrong for the renderer: Protect with such an open password was
rolled back ("the password is incorrect"), and an AES-256 file with such a
password did not open in a session with it, although pdfcraft-cos
accepted it.
- hayro-syntax (vendored patch 16) tries an R5/R6 password in its SASLprep
form (as pdfcraft-crypt computes it: as given if SASLprep refuses it,
UTF-8, at most 127 bytes), then, when that differs, as given.
stringprep, already in the tree through pdfcraft-crypt, is an optional
dependency enabled by the std feature; without std nothing changes.
- Tests: hayro-syntax crypto::pdfcraft_password_tests (candidate list and
R5/R6 dictionaries built from prepared passwords) and two engine tests
(Protect and reopen, and pdfcraft-cos-encrypted files) for the three
cases, with precomposed "caf\u{E9}" as the control. The dictionary test
and both engine tests fail without the fix.
Fixes#1296.
Joel Tony