From 1224d9be47e5235f39556d9118c9893ee6e68a4c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= Date: Fri, 4 Sep 2020 15:34:33 +0200 Subject: Return errors rather than mangle documents --- pdf-simple-sign.cpp | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'pdf-simple-sign.cpp') diff --git a/pdf-simple-sign.cpp b/pdf-simple-sign.cpp index 818270e..b724f69 100644 --- a/pdf-simple-sign.cpp +++ b/pdf-simple-sign.cpp @@ -2,7 +2,7 @@ // // pdf-simple-sign: simple PDF signer // -// Copyright (c) 2017, Přemysl Eric Janouch +// Copyright (c) 2017 - 2020, Přemysl Eric Janouch // // Permission to use, copy, modify, and/or distribute this software for any // purpose with or without fee is hereby granted. @@ -869,15 +869,21 @@ static std::string pdf_sign(std::string& document) { if (page.type != pdf_object::DICT) return "invalid or unsupported page tree"; - // XXX assuming this won't be an indirectly referenced array auto& annots = page.dict["Annots"]; - if (annots.type != pdf_object::ARRAY) + if (annots.type != pdf_object::ARRAY) { + // TODO indirectly referenced arrays might not be that hard to support + if (annots.type != pdf_object::END) + return "unexpected Annots"; + annots = {pdf_object::ARRAY}; + } annots.array.emplace_back(pdf_object::REFERENCE, sigfield_n, 0); pdf.update(page.n, [&]{ pdf.document += pdf_serialize(page); }); // 8.6.1 Interactive Form Dictionary - // XXX assuming there are no forms already, overwriting everything + if (root.dict.count("AcroForm")) + return "the document already contains forms, they would be overwritten"; + root.dict["AcroForm"] = {std::map{ {"Fields", {std::vector{ {pdf_object::REFERENCE, sigfield_n, 0} @@ -887,7 +893,7 @@ static std::string pdf_sign(std::string& document) { // Upgrade the document version for SHA-256 etc. // XXX assuming that it's not newer than 1.6 already -- while Cairo can't currently use a newer - // version that 1.5, it's not a bad idea to use cairo_pdf_surface_restrict_to_version() + // version than 1.5, it's not a bad idea to use cairo_pdf_surface_restrict_to_version() root.dict["Version"] = {pdf_object::NAME, "1.6"}; pdf.update(root_ref->second.n, [&]{ pdf.document += pdf_serialize(root); }); pdf.flush_updates(); -- cgit v1.2.3