1From 49723b0eb683cca80142b01a48ba1475fed5188a Mon Sep 17 00:00:00 2001
2From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
3Date: Fri, 23 Mar 2018 15:35:39 +0100
4Subject: [PATCH] Fix for bug 2772
5
6It is possible to craft a TIFF document where the IFD list is circular,
7leading to an infinite loop while traversing the chain. The libtiff
8directory reader has a failsafe that will break out of this loop after
9reading 65535 directory entries, but it will continue processing,
10consuming time and resources to process what is essentially a bogus TIFF
11document.
12
13This change fixes the above behavior by breaking out of processing when
14a TIFF document has >= 65535 directories and terminating with an error.
15---
16 contrib/addtiffo/tif_overview.c | 14 +++++++++++++-
17 tools/tiff2pdf.c                | 10 ++++++++++
18 tools/tiffcrop.c                | 13 +++++++++++--
19 3 files changed, 34 insertions(+), 3 deletions(-)
20
21diff --git a/contrib/addtiffo/tif_overview.c b/contrib/addtiffo/tif_overview.c
22index c61ffbb..03b3573 100644
23--- a/contrib/addtiffo/tif_overview.c
24+++ b/contrib/addtiffo/tif_overview.c
25@@ -65,6 +65,8 @@
26 #  define MAX(a,b)      ((a>b) ? a : b)
27 #endif
28
29+#define TIFF_DIR_MAX  65534
30+
31 void TIFFBuildOverviews( TIFF *, int, int *, int, const char *,
32                          int (*)(double,void*), void * );
33
34@@ -91,6 +93,7 @@ uint32 TIFF_WriteOverview( TIFF *hTIFF, uint32 nXSize, uint32 nYSize,
35 {
36     toff_t	nBaseDirOffset;
37     toff_t	nOffset;
38+    tdir_t	iNumDir;
39
40     (void) bUseSubIFDs;
41
42@@ -147,7 +150,16 @@ uint32 TIFF_WriteOverview( TIFF *hTIFF, uint32 nXSize, uint32 nYSize,
43         return 0;
44
45     TIFFWriteDirectory( hTIFF );
46-    TIFFSetDirectory( hTIFF, (tdir_t) (TIFFNumberOfDirectories(hTIFF)-1) );
47+    iNumDir = TIFFNumberOfDirectories(hTIFF);
48+    if( iNumDir > TIFF_DIR_MAX )
49+    {
50+        TIFFErrorExt( TIFFClientdata(hTIFF),
51+                      "TIFF_WriteOverview",
52+                      "File `%s' has too many directories.\n",
53+                      TIFFFileName(hTIFF) );
54+        exit(-1);
55+    }
56+    TIFFSetDirectory( hTIFF, (tdir_t) (iNumDir - 1) );
57
58     nOffset = TIFFCurrentDirOffset( hTIFF );
59
60diff --git a/tools/tiff2pdf.c b/tools/tiff2pdf.c
61index 454befb..bdb9126 100644
62--- a/tools/tiff2pdf.c
63+++ b/tools/tiff2pdf.c
64@@ -68,6 +68,8 @@ extern int getopt(int, char**, char*);
65
66 #define PS_UNIT_SIZE	72.0F
67
68+#define TIFF_DIR_MAX    65534
69+
70 /* This type is of PDF color spaces. */
71 typedef enum {
72 	T2P_CS_BILEVEL = 0x01,	/* Bilevel, black and white */
73@@ -1049,6 +1051,14 @@ void t2p_read_tiff_init(T2P* t2p, TIFF* input){
74 	uint16 xuint16=0;
75
76 	directorycount=TIFFNumberOfDirectories(input);
77+	if(directorycount > TIFF_DIR_MAX) {
78+		TIFFError(
79+			TIFF2PDF_MODULE,
80+			"TIFF contains too many directories, %s",
81+			TIFFFileName(input));
82+		t2p->t2p_error = T2P_ERR_ERROR;
83+		return;
84+	}
85 	t2p->tiff_pages = (T2P_PAGE*) _TIFFmalloc(TIFFSafeMultiply(tmsize_t,directorycount,sizeof(T2P_PAGE)));
86 	if(t2p->tiff_pages==NULL){
87 		TIFFError(
88diff --git a/tools/tiffcrop.c b/tools/tiffcrop.c
89index c69177e..c60cb38 100644
90--- a/tools/tiffcrop.c
91+++ b/tools/tiffcrop.c
92@@ -217,6 +217,8 @@ extern int getopt(int argc, char * const argv[], const char *optstring);
93 #define DUMP_TEXT   1
94 #define DUMP_RAW    2
95
96+#define TIFF_DIR_MAX  65534
97+
98 /* Offsets into buffer for margins and fixed width and length segments */
99 struct offset {
100   uint32  tmargin;
101@@ -2233,7 +2235,7 @@ main(int argc, char* argv[])
102     pageNum = -1;
103   else
104     total_images = 0;
105-  /* read multiple input files and write to output file(s) */
106+  /* Read multiple input files and write to output file(s) */
107   while (optind < argc - 1)
108     {
109     in = TIFFOpen (argv[optind], "r");
110@@ -2241,7 +2243,14 @@ main(int argc, char* argv[])
111       return (-3);
112
113     /* If only one input file is specified, we can use directory count */
114-    total_images = TIFFNumberOfDirectories(in);
115+    total_images = TIFFNumberOfDirectories(in);
116+    if (total_images > TIFF_DIR_MAX)
117+      {
118+      TIFFError (TIFFFileName(in), "File contains too many directories");
119+      if (out != NULL)
120+        (void) TIFFClose(out);
121+      return (1);
122+      }
123     if (image_count == 0)
124       {
125       dirnum = 0;
126--
1272.13.6
128
129