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Fix for bug 2772

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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.
This commit is contained in:
Nathan Baker 2018-02-06 10:13:57 -05:00
parent eafc7e3052
commit 473851d211
3 changed files with 34 additions and 3 deletions
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14
contrib/addtiffo/tif_overview.c
View File

@ -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 );

10
tools/tiff2pdf.c
View File

@ -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 */
@ -1051,6 +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(

13
tools/tiffcrop.c
View File

@ -215,6 +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;
@ -2232,7 +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");
@ -2240,7 +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;