[gs-commits] mupdf 1.16.1.80 Set signature content end marker to /Type

commit 3d1edf46d4ae4fd483141c1eae1977b22695c001
Author: Pete McLaughlin <[email protected]>
Date:   Thu Oct 3 09:39:10 2019 +0100

    Set signature content end marker to /Type /Sig.
    
    In commit a56db95ef we added the optional '/Type /Sig' entry to the
    signature dictionary, but the code in pdf-write.c:complete_signatures()
    was still using the '/Filter' entry as the marker for the end of the
    digest content. This resulted in the calculations for the byte range
    being out by 8 as we were including the recently added /Type /Sig entry,
    and resulted in verify errors when we parsed the digest in
    pdf-form.c:validate_certificate_data().
    
    This commit modifies pdf-form.c:pdf_signature_set_value() to add the
    /Type entry after the other entries so that the mandatory /Filter entry
    is still directly after the contents.

diff --git a/source/pdf/pdf-form.c b/source/pdf/pdf-form.c
index 2729f2e..9b5d044 100644
--- a/source/pdf/pdf-form.c
+++ b/source/pdf/pdf-form.c
@@ -1322,7 +1322,6 @@ void pdf_signature_set_value(fz_context *ctx, pdf_document *doc, pdf_obj *field,
 	pdf_obj *v = NULL;
 	pdf_obj *indv;
 	int vnum;
-	pdf_obj *contents;
 	int max_digest_size;
 	char *buf = NULL;
 
@@ -1341,11 +1340,15 @@ void pdf_signature_set_value(fz_context *ctx, pdf_document *doc, pdf_obj *field,
 
 		buf = fz_calloc(ctx, max_digest_size, 1);
 
+		/* Ensure that the /Filter entry is the first entry in the
+		   dictionary after the digest contents since we look for
+		   this tag when completing signatures in pdf-write.c in order
+		   to generate the correct byte range. */
 		pdf_dict_put_array(ctx, v, PDF_NAME(ByteRange), 4);
 		pdf_dict_put_string(ctx, v, PDF_NAME(Contents), buf, max_digest_size);
-		pdf_dict_put(ctx, v, PDF_NAME(Type), PDF_NAME(Sig));
 		pdf_dict_put(ctx, v, PDF_NAME(Filter), PDF_NAME(Adobe_PPKLite));
 		pdf_dict_put(ctx, v, PDF_NAME(SubFilter), PDF_NAME(adbe_pkcs7_detached));
+		pdf_dict_put(ctx, v, PDF_NAME(Type), PDF_NAME(Sig));
 
 		/* Record details within the document structure so that contents
 		* and byte_range can be updated with their correct values at

http://git.ghostscript.com/?p=mupdf.git;a=commit;h=3d1edf46d4ae4fd483141c1eae1977b22695c001

--
MuPDF library
Artifex Software, Inc.