55 lines
1.9 KiB
Diff
55 lines
1.9 KiB
Diff
From b03def134988da8c800adac1a38a41a1f09a1d89 Mon Sep 17 00:00:00 2001
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Message-Id: <b03def134988da8c800adac1a38a41a1f09a1d89.1518616030.git.mjg@fedoraproject.org>
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From: Sebastian Rasmussen <sebras@gmail.com>
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Date: Thu, 1 Feb 2018 16:36:14 +0100
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Subject: [PATCH] Bug 698830: Avoid recursion when loading object streams
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objects.
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If there were indirect references in the object stream dictionary and
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one of those indirect references referred to an object inside the object
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stream itself, mupdf would previously enter recursion only bounded by the
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exception stack. After this commit the object stream is checked if it is
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marked immediately after being loaded. If it is marked then we terminate
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the recursion at this point, if it is not marked then mark it and
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attempt to load the desired object within. We also take care to unmark
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the stream object when done or upon exception.
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---
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source/pdf/pdf-xref.c | 14 ++++++++++++++
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1 file changed, 14 insertions(+)
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diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
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index 723b543c..ed09094c 100644
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--- a/source/pdf/pdf-xref.c
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+++ b/source/pdf/pdf-xref.c
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@@ -1576,6 +1576,19 @@ pdf_load_obj_stm(fz_context *ctx, pdf_document *doc, int num, pdf_lexbuf *buf, i
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{
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objstm = pdf_load_object(ctx, doc, num);
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+ if (pdf_obj_marked(ctx, objstm))
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+ fz_throw(ctx, FZ_ERROR_GENERIC, "recursive object stream lookup");
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+ }
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+ fz_catch(ctx)
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+ {
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+ pdf_drop_obj(ctx, objstm);
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+ fz_rethrow(ctx);
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+ }
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+
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+ fz_try(ctx)
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+ {
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+ pdf_mark_obj(ctx, objstm);
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+
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count = pdf_to_int(ctx, pdf_dict_get(ctx, objstm, PDF_NAME_N));
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first = pdf_to_int(ctx, pdf_dict_get(ctx, objstm, PDF_NAME_First));
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@@ -1655,6 +1668,7 @@ pdf_load_obj_stm(fz_context *ctx, pdf_document *doc, int num, pdf_lexbuf *buf, i
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fz_drop_stream(ctx, stm);
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fz_free(ctx, ofsbuf);
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fz_free(ctx, numbuf);
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+ pdf_unmark_obj(ctx, objstm);
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pdf_drop_obj(ctx, objstm);
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}
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fz_catch(ctx)
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--
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2.16.1.312.g365a692731
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