commit 86cc2a8811c0ecaa347a5e512ea99e1bd18bda67
from: Sven M. Hallberg <pesco@khjk.org>
date: Fri Jun 19 18:40:13 2020 UTC

ignore but log leading junk bytes

commit - f3f182b7c7d2bc96123e895c4e58e1bdceab98ca
commit + 86cc2a8811c0ecaa347a5e512ea99e1bd18bda67
blob - 6050dc39de88d9fa711e55f184f61421d9ab5ff7
blob + 129e1591f556a77f2c976bb3b91c4a17977f5dcb
--- pdf.c
+++ pdf.c
@@ -1120,6 +1120,8 @@ init_parser(struct Env *aux)
 
 	H_RULE(xr_td,	SEQ(xrefs, KW("trailer"), ws, dict));
 
+	H_RULE(start_junk,  VIOL(h_many1(h_butnot(h_ch_range(0, 255), header)),
+	                        "Junk bytes before %PDF header (severity=1)"));
 	H_RULE(hdr_junk,    CHX(comment,
 	    VIOL(h_many1(h_butnot(h_ch_range(0, 255), SEQ(npair, wel, KW("obj")))),
 	    "Uncommented junk after header (severity=1)")));
@@ -1131,10 +1133,10 @@ init_parser(struct Env *aux)
 				   VIOL(h_many1(h_butnot(h_ch_range(0, 255), LIT("%%EOF"))),
 					"Data after final %%EOF (severity=7)"),
 				   end));
-	H_RULE(pdf,	SEQ(header, OPT(hdr_junk), h_many1(tail), final_eof_junk));
+	H_RULE(pdf,	SEQ(OPT(start_junk), header, OPT(hdr_junk), h_many1(tail), final_eof_junk));
 
 	/* debug parser to consume as much as possible */
-	H_RULE(pdfdbg,	SEQ(header, OPT(hdr_junk), h_many(tail), body, OPT(xr_td), OPT(SEQ(startxr, final_eof_junk))));
+	H_RULE(pdfdbg,	SEQ(OPT(start_junk), header, OPT(hdr_junk), h_many(tail), body, OPT(xr_td), OPT(SEQ(startxr, final_eof_junk))));
 
 	/*
 	 * filters