pdfsig: Sign form signature fields with an appearance

utils/CMakeLists.txt

+include(FindGettext)
 
 set(common_srcs
   parseargs.cc
@@ -92,6 +93,17 @@ target_link_libraries(pdfinfo ${common_libs})
 install(TARGETS pdfinfo DESTINATION bin)
 install(FILES pdfinfo.1 DESTINATION ${CMAKE_INSTALL_MANDIR}/man1)
 
+if (GETTEXT_FOUND AND ENABLE_NSS3)
+  add_definitions(-DHAVE_GETTEXT)
+  add_definitions(-DCMAKE_INSTALL_LOCALEDIR="${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LOCALEDIR}")
+  file(GLOB _dirs "${CMAKE_CURRENT_SOURCE_DIR}/po/*")
+  foreach (_dir ${_dirs})
+    if (IS_DIRECTORY "${_dir}")
+      add_subdirectory("${_dir}")
+    endif ()
+  endforeach()
+endif ()
+
 if (ENABLE_NSS3)
   # pdfsig
   set(pdfsig_SOURCES ${common_srcs}

utils/pdfsig.1

@@ -46,6 +46,9 @@ Do not validate the certificate.
 .B \-no-ocsp
 Do not perform online OCSP certificate revocation check (local Certificate Revocation Lists (CRL) are still used).
 .TP
+.B \-no-appearance
+Do not add appearance information when signing existing fields (signer name and date).
+.TP
 .B \-aia
 Enable the use of Authority Information Access (AIA) extension to fetch missing certificates to build the certificate chain.
 .TP

utils/pdfsig.cc

@@ -38,6 +38,7 @@
 #include "Page.h"
 #include "PDFDoc.h"
 #include "PDFDocFactory.h"
+#include "DateInfo.h"
 #include "Error.h"
 #include "GlobalParams.h"
 #include "SignatureHandler.h"
@@ -49,6 +50,14 @@
 #    include <libgen.h>
 #endif
 
+#ifdef HAVE_GETTEXT
+#    include <libintl.h>
+#    include <clocale>
+#    define _(STRING) gettext(STRING)
+#else
+#    define _(STRING) STRING
+#endif
+
 static const char *getReadableSigState(SignatureValidationStatus sig_vs)
 {
     switch (sig_vs) {
@@ -135,6 +144,7 @@ static bool printVersion = false;
 static bool printHelp = false;
 static bool dontVerifyCert = false;
 static bool noOCSPRevocationCheck = false;
+static bool noAppearance = false;
 static bool dumpSignatures = false;
 static bool etsiCAdESdetached = false;
 static char signatureName[256] = "";
@@ -151,6 +161,7 @@ static const ArgDesc argDesc[] = { { "-nssdir", argGooString, &nssDir, 0, "path
                                    { "-nss-pwd", argGooString, &nssPassword, 0, "password to access the NSS database (if any)" },
                                    { "-nocert", argFlag, &dontVerifyCert, 0, "don't perform certificate validation" },
                                    { "-no-ocsp", argFlag, &noOCSPRevocationCheck, 0, "don't perform online OCSP certificate revocation check" },
+                                   { "-no-appearance", argFlag, &noAppearance, 0, "don't add appearance information when signing existing fields" },
                                    { "-aia", argFlag, &useAIACertFetch, 0, "use Authority Information Access (AIA) extension for certificate fetching" },
                                    { "-dump", argFlag, &dumpSignatures, 0, "dump all signatures into current directory" },
                                    { "-add-signature", argFlag, &addNewSignature, 0, "adds a new signature to the document" },
@@ -236,6 +247,30 @@ static std::string TextStringToUTF8(const std::string &str)
     return convertedStr;
 }
 
+static __attribute__((format(printf, 1, 2))) std::string FmtStr(const char *fmt, ...)
+{
+    va_list ap;
+    int size;
+
+    if (noAppearance) {
+        return "";
+    }
+
+    va_start(ap, fmt);
+    size = std::vsnprintf(nullptr, 0, fmt, ap);
+    va_end(ap);
+    if (size < 0) {
+        return "";
+    }
+
+    std::vector<char> buffer(size + 1);
+    va_start(ap, fmt);
+    std::vsnprintf(&buffer[0], buffer.size(), fmt, ap);
+    va_end(ap);
+
+    return std::string(buffer.begin(), buffer.end() - 1);
+}
+
 int main(int argc, char *argv[])
 {
     char *time_str = nullptr;
@@ -439,8 +474,22 @@ int main(int argc, char *argv[])
             printf("Unexpected number of widgets for the signature: %d\n", ffs->getNumWidgets());
             return 2;
         }
+#ifdef HAVE_GETTEXT
+        if (!noAppearance) {
+            setlocale(LC_ALL, "");
+            bindtextdomain("pdfsig", CMAKE_INSTALL_LOCALEDIR);
+            textdomain("pdfsig");
+        }
+#endif
         FormWidgetSignature *fws = static_cast<FormWidgetSignature *>(ffs->getWidget(0));
-        const bool success = fws->signDocument(argv[2], certNickname, digestName, pw, rs.get());
+        SignatureHandler sigHandler(certNickname, SEC_OID_SHA256);
+        const std::string timestamp = timeToStringWithFormat(nullptr, "%Y.%m.%d %H:%M:%S ");
+        const std::string signerName = sigHandler.getSignerName();
+        const AnnotColor blackColor(0, 0, 0);
+        const std::string signatureText(FmtStr(_("Digitally signed by %s"), signerName.c_str()) + "\n" + FmtStr(_("Date: %s"), timestamp.c_str()));
+        const auto gSignatureText = (signatureText.empty() || noAppearance) ? std::make_unique<GooString>("") : utf8ToUtf16WithBom(signatureText);
+        const auto gSignatureLeftText = (signerName.empty() || noAppearance) ? std::make_unique<GooString>("") : utf8ToUtf16WithBom(signerName);
+        const bool success = fws->signDocumentWithAppearance(argv[2], certNickname, digestName, pw, rs.get(), nullptr, {}, {}, *gSignatureText, *gSignatureLeftText, 0, 0, std::make_unique<AnnotColor>(blackColor));
         return success ? 0 : 3;
     }
 

utils/po/en/CMakeLists.txt

+get_filename_component(_lang ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+gettext_process_po_files(${_lang} ALL INSTALL_DESTINATION ${CMAKE_INSTALL_LOCALEDIR} PO_FILES
+  pdfsig.po
+)

utils/po/en/pdfsig.po

+# English translations for pdfsig package.
+# Copyright (C) 2022 Erich E. Hoover
+# This file is distributed under the same license as the pdfsig package.
+# Erich E. Hoover <erich.e.hoover@gmail.com>, 2022.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: pdfsig VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2022-10-25 13:46-0600\n"
+"PO-Revision-Date: 2022-10-25 13:56-0600\n"
+"Last-Translator: Erich Hoover <erich.e.hoover@gmail.com>\n"
+"Language-Team: English\n"
+"Language: en\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=ASCII\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+#: utils/pdfsig.cc:481
+#, c-format
+msgid "Date: %s"
+msgstr "Date: %s"
+
+#: utils/pdfsig.cc:480
+#, c-format
+msgid "Digitally signed by %s"
+msgstr "Digitally signed by %s"

utils/po/pdfsig.pot

+# Translations for pdfsig PDF signing tool.
+# Copyright (C) 2022 Erich E. Hoover
+# This file is distributed under the same license as the pdfsig package.
+# Erich E. Hoover <erich.e.hoover@gmail.com>, 2022.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: pdfsig VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2022-10-25 13:46-0600\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: Erich E. Hoover <erich.e.hoover@gmail.com>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=CHARSET\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: utils/pdfsig.cc:481
+#, c-format
+msgid "Date: %s"
+msgstr ""
+
+#: utils/pdfsig.cc:480
+#, c-format
+msgid "Digitally signed by %s"
+msgstr ""