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From 473851d211cf8805a161820337ca74cc9615d6ef Mon Sep 17 00:00:00 2001
From: Nathan Baker <nathanb@lenovo-chrome.com>
Date: Tue, 6 Feb 2018 10:13:57 -0500
Subject: [PATCH] Fix for bug 2772
It is possible to craft a TIFF document where the IFD list is circular,
leading to an infinite loop while traversing the chain. The libtiff
directory reader has a failsafe that will break out of this loop after
reading 65535 directory entries, but it will continue processing,
consuming time and resources to process what is essentially a bogus TIFF
document.
This change fixes the above behavior by breaking out of processing when
a TIFF document has >= 65535 directories and terminating with an error.
---
contrib/addtiffo/tif_overview.c | 14 +++++++++++++-
tools/tiff2pdf.c | 10 ++++++++++
tools/tiffcrop.c | 13 +++++++++++--
3 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/contrib/addtiffo/tif_overview.c b/contrib/addtiffo/tif_overview.c
index c61ffbb..03b3573 100644
--- a/contrib/addtiffo/tif_overview.c
+++ b/contrib/addtiffo/tif_overview.c
@@ -65,6 +65,8 @@
# define MAX(a,b) ((a>b) ? a : b)
#endif
+#define TIFF_DIR_MAX 65534
+
void TIFFBuildOverviews( TIFF *, int, int *, int, const char *,
int (*)(double,void*), void * );
@@ -91,6 +93,7 @@ uint32 TIFF_WriteOverview( TIFF *hTIFF, uint32 nXSize, uint32 nYSize,
{
toff_t nBaseDirOffset;
toff_t nOffset;
+ tdir_t iNumDir;
(void) bUseSubIFDs;
@@ -147,7 +150,16 @@ uint32 TIFF_WriteOverview( TIFF *hTIFF, uint32 nXSize, uint32 nYSize,
return 0;
TIFFWriteDirectory( hTIFF );
- TIFFSetDirectory( hTIFF, (tdir_t) (TIFFNumberOfDirectories(hTIFF)-1) );
+ iNumDir = TIFFNumberOfDirectories(hTIFF);
+ if( iNumDir > TIFF_DIR_MAX )
+ {
+ TIFFErrorExt( TIFFClientdata(hTIFF),
+ "TIFF_WriteOverview",
+ "File `%s' has too many directories.\n",
+ TIFFFileName(hTIFF) );
+ exit(-1);
+ }
+ TIFFSetDirectory( hTIFF, (tdir_t) (iNumDir - 1) );
nOffset = TIFFCurrentDirOffset( hTIFF );
diff --git a/tools/tiff2pdf.c b/tools/tiff2pdf.c
index 984ef65..832a247 100644
--- a/tools/tiff2pdf.c
+++ b/tools/tiff2pdf.c
@@ -68,6 +68,8 @@ extern int getopt(int, char**, char*);
#define PS_UNIT_SIZE 72.0F
+#define TIFF_DIR_MAX 65534
+
/* This type is of PDF color spaces. */
typedef enum {
T2P_CS_BILEVEL = 0x01, /* Bilevel, black and white */
@@ -1049,6 +1053,14 @@ void t2p_read_tiff_init(T2P* t2p, TIFF* input){
uint16* tiff_transferfunction[3];
directorycount=TIFFNumberOfDirectories(input);
+ if(directorycount > TIFF_DIR_MAX) {
+ TIFFError(
+ TIFF2PDF_MODULE,
+ "TIFF contains too many directories, %s",
+ TIFFFileName(input));
+ t2p->t2p_error = T2P_ERR_ERROR;
+ return;
+ }
t2p->tiff_pages = (T2P_PAGE*) _TIFFmalloc(TIFFSafeMultiply(tmsize_t,directorycount,sizeof(T2P_PAGE)));
if(t2p->tiff_pages==NULL){
TIFFError(
diff --git a/tools/tiffcrop.c b/tools/tiffcrop.c
index 91a38f6..e466dae 100644
--- a/tools/tiffcrop.c
+++ b/tools/tiffcrop.c
@@ -217,6 +215,8 @@ extern int getopt(int argc, char * const argv[], const char *optstring);
#define DUMP_TEXT 1
#define DUMP_RAW 2
+#define TIFF_DIR_MAX 65534
+
/* Offsets into buffer for margins and fixed width and length segments */
struct offset {
uint32 tmargin;
@@ -2233,7 +2234,7 @@ main(int argc, char* argv[])
pageNum = -1;
else
total_images = 0;
- /* read multiple input files and write to output file(s) */
+ /* Read multiple input files and write to output file(s) */
while (optind < argc - 1)
{
in = TIFFOpen (argv[optind], "r");
@@ -2241,7 +2242,14 @@ main(int argc, char* argv[])
return (-3);
/* If only one input file is specified, we can use directory count */
- total_images = TIFFNumberOfDirectories(in);
+ total_images = TIFFNumberOfDirectories(in);
+ if (total_images > TIFF_DIR_MAX)
+ {
+ TIFFError (TIFFFileName(in), "File contains too many directories");
+ if (out != NULL)
+ (void) TIFFClose(out);
+ return (1);
+ }
if (image_count == 0)
{
dirnum = 0;
--
libgit2 0.26.0
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