103 lines
3.7 KiB
Diff
103 lines
3.7 KiB
Diff
From 55c3f68d638ac1263a386e0aaa004bb6e8bde731 Mon Sep 17 00:00:00 2001
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Message-Id: <55c3f68d638ac1263a386e0aaa004bb6e8bde731.1516782952.git.mjg@fedoraproject.org>
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From: Sebastian Rasmussen <sebras@gmail.com>
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Date: Mon, 11 Dec 2017 14:09:15 +0100
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Subject: [PATCH] Bugs 698804/698810/698811: Keep PDF object numbers below
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limit.
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This ensures that:
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* xref tables with objects pointers do not grow out of bounds.
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* other readers, e.g. Adobe Acrobat can parse PDFs written by mupdf.
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---
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include/mupdf/pdf/object.h | 3 +++
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source/pdf/pdf-repair.c | 5 +----
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source/pdf/pdf-xref.c | 21 ++++++++++++---------
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3 files changed, 16 insertions(+), 13 deletions(-)
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diff --git a/include/mupdf/pdf/object.h b/include/mupdf/pdf/object.h
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index 21ed8595..4177112b 100644
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--- a/include/mupdf/pdf/object.h
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+++ b/include/mupdf/pdf/object.h
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@@ -3,6 +3,9 @@
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typedef struct pdf_document_s pdf_document;
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+/* Defined in PDF 1.7 according to Acrobat limit. */
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+#define PDF_MAX_OBJECT_NUMBER 8388607
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+
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/*
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* Dynamic objects.
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* The same type of objects as found in PDF and PostScript.
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diff --git a/source/pdf/pdf-repair.c b/source/pdf/pdf-repair.c
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index ca149bd3..0c29758e 100644
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--- a/source/pdf/pdf-repair.c
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+++ b/source/pdf/pdf-repair.c
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@@ -6,9 +6,6 @@
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/* Scan file for objects and reconstruct xref table */
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-/* Define in PDF 1.7 to be 8388607, but mupdf is more lenient. */
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-#define MAX_OBJECT_NUMBER (10 << 20)
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-
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struct entry
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{
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int num;
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@@ -436,7 +433,7 @@ pdf_repair_xref(fz_context *ctx, pdf_document *doc)
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break;
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}
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- if (num <= 0 || num > MAX_OBJECT_NUMBER)
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+ if (num <= 0 || num > PDF_MAX_OBJECT_NUMBER)
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{
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fz_warn(ctx, "ignoring object with invalid object number (%d %d R)", num, gen);
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goto have_next_token;
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diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
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index 00586dbd..6284e70b 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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@@ -868,11 +868,12 @@ pdf_read_old_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
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fz_seek(ctx, file, -(2 + (int)strlen(s)), SEEK_CUR);
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}
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- if (ofs < 0)
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- fz_throw(ctx, FZ_ERROR_GENERIC, "out of range object num in xref: %d", (int)ofs);
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- if (ofs > INT64_MAX - len)
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- fz_throw(ctx, FZ_ERROR_GENERIC, "xref section object numbers too big");
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-
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+ if (ofs < 0 || ofs > PDF_MAX_OBJECT_NUMBER
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+ || len < 0 || len > PDF_MAX_OBJECT_NUMBER
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+ || ofs + len - 1 > PDF_MAX_OBJECT_NUMBER)
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+ {
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+ fz_throw(ctx, FZ_ERROR_GENERIC, "xref subsection object numbers are out of range");
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+ }
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/* broken pdfs where size in trailer undershoots entries in xref sections */
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if (ofs + len > xref_len)
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{
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@@ -933,10 +934,8 @@ pdf_read_new_xref_section(fz_context *ctx, pdf_document *doc, fz_stream *stm, in
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pdf_xref_entry *table;
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int i, n;
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- if (i0 < 0 || i1 < 0 || i0 > INT_MAX - i1)
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- fz_throw(ctx, FZ_ERROR_GENERIC, "negative xref stream entry index");
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- //if (i0 + i1 > pdf_xref_len(ctx, doc))
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- // fz_throw(ctx, FZ_ERROR_GENERIC, "xref stream has too many entries");
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+ if (i0 < 0 || i0 > PDF_MAX_OBJECT_NUMBER || i1 < 0 || i1 > PDF_MAX_OBJECT_NUMBER || i0 + i1 - 1 > PDF_MAX_OBJECT_NUMBER)
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+ fz_throw(ctx, FZ_ERROR_GENERIC, "xref subsection object numbers are out of range");
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table = pdf_xref_find_subsection(ctx, doc, i0, i1);
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for (i = i0; i < i0 + i1; i++)
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@@ -2086,6 +2085,10 @@ pdf_create_object(fz_context *ctx, pdf_document *doc)
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/* TODO: reuse free object slots by properly linking free object chains in the ofs field */
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pdf_xref_entry *entry;
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int num = pdf_xref_len(ctx, doc);
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+
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+ if (num > PDF_MAX_OBJECT_NUMBER)
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+ fz_throw(ctx, FZ_ERROR_GENERIC, "too many objects stored in pdf");
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+
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entry = pdf_get_incremental_xref_entry(ctx, doc, num);
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entry->type = 'f';
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entry->ofs = -1;
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--
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2.16.1.338.gd8f744ddde
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