From f00484b9519df933723deb38fff943dc291a793d Mon Sep 17 00:00:00 2001
From: Su_Laus <[EMAIL REDACTED]>
Date: Tue, 30 Aug 2022 16:56:48 +0200
Subject: [PATCH] Revised handling of TIFFTAG_INKNAMES and related
TIFFTAG_NUMBEROFINKS value
In order to solve the buffer overflow issues related to TIFFTAG_INKNAMES and related TIFFTAG_NUMBEROFINKS value, a revised handling of those tags within LibTiff is proposed:
Behaviour for writing:
`NumberOfInks` MUST fit to the number of inks in the `InkNames` string.
`NumberOfInks` is automatically set when `InkNames` is set.
If `NumberOfInks` is different to the number of inks within `InkNames` string, that will be corrected and a warning is issued.
If `NumberOfInks` is not equal to samplesperpixel only a warning will be issued.
Behaviour for reading:
When reading `InkNames` from a TIFF file, the `NumberOfInks` will be set automatically to the number of inks in `InkNames` string.
If `NumberOfInks` is different to the number of inks within `InkNames` string, that will be corrected and a warning is issued.
If `NumberOfInks` is not equal to samplesperpixel only a warning will be issued.
This allows the safe use of the NumberOfInks value to read out the InkNames without buffer overflow
This MR will close the following issues: #149, #150, #152, #168 (to be checked), #250, #269, #398 and #456.
It also fixes the old bug at http://bugzilla.maptools.org/show_bug.cgi?id=2599, for which the limitation of `NumberOfInks = SPP` was introduced, which is in my opinion not necessary and does not solve the general issue.
---
libtiff/tif_dir.c | 119 ++++++++++++++++++++++++-----------------
libtiff/tif_dir.h | 2 +
libtiff/tif_dirinfo.c | 2 +-
libtiff/tif_dirwrite.c | 5 ++
libtiff/tif_print.c | 4 ++
5 files changed, 82 insertions(+), 50 deletions(-)
diff --git a/libtiff/tif_dir.c b/libtiff/tif_dir.c
index 793e8a79..816f7756 100644
--- a/libtiff/tif_dir.c
+++ b/libtiff/tif_dir.c
@@ -136,32 +136,30 @@ setExtraSamples(TIFF* tif, va_list ap, uint32_t* v)
}
/*
- * Confirm we have "samplesperpixel" ink names separated by \0. Returns
+ * Count ink names separated by \0. Returns
* zero if the ink names are not as expected.
*/
-static uint32_t
-checkInkNamesString(TIFF* tif, uint32_t slen, const char* s)
+static uint16_t
+countInkNamesString(TIFF *tif, uint32_t slen, const char *s)
{
- TIFFDirectory* td = &tif->tif_dir;
- uint16_t i = td->td_samplesperpixel;
+ uint16_t i = 0;
+ const char *ep = s + slen;
+ const char *cp = s;
if (slen > 0) {
- const char* ep = s+slen;
- const char* cp = s;
- for (; i > 0; i--) {
+ do {
for (; cp < ep && *cp != '\0'; cp++) {}
if (cp >= ep)
goto bad;
cp++; /* skip \0 */
- }
- return ((uint32_t)(cp - s));
+ i++;
+ } while (cp < ep);
+ return (i);
}
bad:
TIFFErrorExt(tif->tif_clientdata, "TIFFSetField",
- "%s: Invalid InkNames value; expecting %"PRIu16" names, found %"PRIu16,
- tif->tif_name,
- td->td_samplesperpixel,
- (uint16_t)(td->td_samplesperpixel-i));
+ "%s: Invalid InkNames value; no NUL at given buffer end location %"PRIu32", after %"PRIu16" ink",
+ tif->tif_name, slen, i);
return (0);
}
@@ -478,13 +476,61 @@ _TIFFVSetField(TIFF* tif, uint32_t tag, va_list ap)
_TIFFsetFloatArray(&td->td_refblackwhite, va_arg(ap, float*), 6);
break;
case TIFFTAG_INKNAMES:
- v = (uint16_t) va_arg(ap, uint16_vap);
- s = va_arg(ap, char*);
- v = checkInkNamesString(tif, v, s);
- status = v > 0;
- if( v > 0 ) {
- _TIFFsetNString(&td->td_inknames, s, v);
- td->td_inknameslen = v;
+ {
+ v = (uint16_t) va_arg(ap, uint16_vap);
+ s = va_arg(ap, char*);
+ uint16_t ninksinstring;
+ ninksinstring = countInkNamesString(tif, v, s);
+ status = ninksinstring > 0;
+ if(ninksinstring > 0 ) {
+ _TIFFsetNString(&td->td_inknames, s, v);
+ td->td_inknameslen = v;
+ /* Set NumberOfInks to the value ninksinstring */
+ if (TIFFFieldSet(tif, FIELD_NUMBEROFINKS))
+ {
+ if (td->td_numberofinks != ninksinstring) {
+ TIFFErrorExt(tif->tif_clientdata, module,
+ "Warning %s; Tag %s:\n Value %"PRIu16" of NumberOfInks is different from the number of inks %"PRIu16".\n -> NumberOfInks value adapted to %"PRIu16"",
+ tif->tif_name, fip->field_name, td->td_numberofinks, ninksinstring, ninksinstring);
+ td->td_numberofinks = ninksinstring;
+ }
+ } else {
+ td->td_numberofinks = ninksinstring;
+ TIFFSetFieldBit(tif, FIELD_NUMBEROFINKS);
+ }
+ if (TIFFFieldSet(tif, FIELD_SAMPLESPERPIXEL))
+ {
+ if (td->td_numberofinks != td->td_samplesperpixel) {
+ TIFFErrorExt(tif->tif_clientdata, module,
+ "Warning %s; Tag %s:\n Value %"PRIu16" of NumberOfInks is different from the SamplesPerPixel value %"PRIu16"",
+ tif->tif_name, fip->field_name, td->td_numberofinks, td->td_samplesperpixel);
+ }
+ }
+ }
+ }
+ break;
+ case TIFFTAG_NUMBEROFINKS:
+ v = (uint16_t)va_arg(ap, uint16_vap);
+ /* If InkNames already set also NumberOfInks is set accordingly and should be equal */
+ if (TIFFFieldSet(tif, FIELD_INKNAMES))
+ {
+ if (v != td->td_numberofinks) {
+ TIFFErrorExt(tif->tif_clientdata, module,
+ "Error %s; Tag %s:\n It is not possible to set the value %"PRIu32" for NumberOfInks\n which is different from the number of inks in the InkNames tag (%"PRIu16")",
+ tif->tif_name, fip->field_name, v, td->td_numberofinks);
+ /* Do not set / overwrite number of inks already set by InkNames case accordingly. */
+ status = 0;
+ }
+ } else {
+ td->td_numberofinks = (uint16_t)v;
+ if (TIFFFieldSet(tif, FIELD_SAMPLESPERPIXEL))
+ {
+ if (td->td_numberofinks != td->td_samplesperpixel) {
+ TIFFErrorExt(tif->tif_clientdata, module,
+ "Warning %s; Tag %s:\n Value %"PRIu32" of NumberOfInks is different from the SamplesPerPixel value %"PRIu16"",
+ tif->tif_name, fip->field_name, v, td->td_samplesperpixel);
+ }
+ }
}
break;
case TIFFTAG_PERSAMPLE:
@@ -986,34 +1032,6 @@ _TIFFVGetField(TIFF* tif, uint32_t tag, va_list ap)
if (fip->field_bit == FIELD_CUSTOM) {
standard_tag = 0;
}
-
- if( standard_tag == TIFFTAG_NUMBEROFINKS )
- {
- int i;
- for (i = 0; i < td->td_customValueCount; i++) {
- uint16_t val;
- TIFFTagValue *tv = td->td_customValues + i;
- if (tv->info->field_tag != standard_tag)
- continue;
- if( tv->value == NULL )
- return 0;
- val = *(uint16_t *)tv->value;
- /* Truncate to SamplesPerPixel, since the */
- /* setting code for INKNAMES assume that there are SamplesPerPixel */
- /* inknames. */
- /* Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2599 */
- if( val > td->td_samplesperpixel )
- {
- TIFFWarningExt(tif->tif_clientdata,"_TIFFVGetField",
- "Truncating NumberOfInks from %u to %"PRIu16,
- val, td->td_samplesperpixel);
- val = td->td_samplesperpixel;
- }
- *va_arg(ap, uint16_t*) = val;
- return 1;
- }
- return 0;
- }
switch (standard_tag) {
case TIFFTAG_SUBFILETYPE:
@@ -1195,6 +1213,9 @@ _TIFFVGetField(TIFF* tif, uint32_t tag, va_list ap)
case TIFFTAG_INKNAMES:
*va_arg(ap, const char**) = td->td_inknames;
break;
+ case TIFFTAG_NUMBEROFINKS:
+ *va_arg(ap, uint16_t *) = td->td_numberofinks;
+ break;
default:
{
int i;
diff --git a/libtiff/tif_dir.h b/libtiff/tif_dir.h
index 09065648..0c251c9e 100644
--- a/libtiff/tif_dir.h
+++ b/libtiff/tif_dir.h
@@ -117,6 +117,7 @@ typedef struct {
/* CMYK parameters */
int td_inknameslen;
char* td_inknames;
+ uint16_t td_numberofinks; /* number of inks in InkNames string */
int td_customValueCount;
TIFFTagValue *td_customValues;
@@ -174,6 +175,7 @@ typedef struct {
#define FIELD_TRANSFERFUNCTION 44
#define FIELD_INKNAMES 46
#define FIELD_SUBIFD 49
+#define FIELD_NUMBEROFINKS 50
/* FIELD_CUSTOM (see tiffio.h) 65 */
/* end of support for well-known tags; codec-private tags follow */
#define FIELD_CODEC 66 /* base of codec-private tags */
diff --git a/libtiff/tif_dirinfo.c b/libtiff/tif_dirinfo.c
index 3371cb5c..3b4bcd33 100644
--- a/libtiff/tif_dirinfo.c
+++ b/libtiff/tif_dirinfo.c
@@ -114,7 +114,7 @@ tiffFields[] = {
{ TIFFTAG_SUBIFD, -1, -1, TIFF_IFD8, 0, TIFF_SETGET_C16_IFD8, TIFF_SETGET_UNDEFINED, FIELD_SUBIFD, 1, 1, "SubIFD", (TIFFFieldArray*) &tiffFieldArray },
{ TIFFTAG_INKSET, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 0, 0, "InkSet", NULL },
{ TIFFTAG_INKNAMES, -1, -1, TIFF_ASCII, 0, TIFF_SETGET_C16_ASCII, TIFF_SETGET_UNDEFINED, FIELD_INKNAMES, 1, 1, "InkNames", NULL },
- { TIFFTAG_NUMBEROFINKS, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 0, "NumberOfInks", NULL },
+ { TIFFTAG_NUMBEROFINKS, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UNDEFINED, FIELD_NUMBEROFINKS, 1, 0, "NumberOfInks", NULL },
{ TIFFTAG_DOTRANGE, 2, 2, TIFF_SHORT, 0, TIFF_SETGET_UINT16_PAIR, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 0, 0, "DotRange", NULL },
{ TIFFTAG_TARGETPRINTER, -1, -1, TIFF_ASCII, 0, TIFF_SETGET_ASCII, TIFF_SETGET_UNDEFINED, FIELD_CUSTOM, 1, 0, "TargetPrinter", NULL },
{ TIFFTAG_EXTRASAMPLES, -1, -1, TIFF_SHORT, 0, TIFF_SETGET_C16_UINT16, TIFF_SETGET_UNDEFINED, FIELD_EXTRASAMPLES, 0, 1, "ExtraSamples", NULL },
diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c
index 6c86fdca..062e4610 100644
--- a/libtiff/tif_dirwrite.c
+++ b/libtiff/tif_dirwrite.c
@@ -626,6 +626,11 @@ TIFFWriteDirectorySec(TIFF* tif, int isimage, int imagedone, uint64_t* pdiroff)
if (!TIFFWriteDirectoryTagAscii(tif,&ndir,dir,TIFFTAG_INKNAMES,tif->tif_dir.td_inknameslen,tif->tif_dir.td_inknames))
goto bad;
}
+ if (TIFFFieldSet(tif, FIELD_NUMBEROFINKS))
+ {
+ if (!TIFFWriteDirectoryTagShort(tif, &ndir, dir, TIFFTAG_NUMBEROFINKS, tif->tif_dir.td_numberofinks))
+ goto bad;
+ }
if (TIFFFieldSet(tif,FIELD_SUBIFD))
{
if (!TIFFWriteDirectoryTagSubifd(tif,&ndir,dir))
diff --git a/libtiff/tif_print.c b/libtiff/tif_print.c
index 16ce5780..a91b9e7b 100644
--- a/libtiff/tif_print.c
+++ b/libtiff/tif_print.c
@@ -397,6 +397,10 @@ TIFFPrintDirectory(TIFF* tif, FILE* fd, long flags)
}
fputs("\n", fd);
}
+ if (TIFFFieldSet(tif, FIELD_NUMBEROFINKS)) {
+ fprintf(fd, " NumberOfInks: %d\n",
+ td->td_numberofinks);
+ }
if (TIFFFieldSet(tif,FIELD_THRESHHOLDING)) {
fprintf(fd, " Thresholding: ");
switch (td->td_threshholding) {