main/tiff: fix CVE-2018-7456

2 files changed, 176 insertions, 2 deletions

diff --git a/main/tiff/APKBUILD b/main/tiff/APKBUILD
index 1985f53210..fb55851083 100644
--- a/main/tiff/APKBUILD
+++ b/main/tiff/APKBUILD
@@ -3,7 +3,7 @@
 # Maintainer: Michael Mason <ms13sp@gmail.com>
 pkgname=tiff
 pkgver=4.0.9
-pkgrel=2
+pkgrel=3
 pkgdesc="Provides support for the Tag Image File Format or TIFF"
 url="http://www.libtiff.org/"
 arch="all"
@@ -15,9 +15,12 @@ subpackages="$pkgname-doc $pkgname-dev $pkgname-tools"
 source="http://download.osgeo.org/libtiff/$pkgname-$pkgver.tar.gz
 	CVE-2017-18013.patch
 	CVE-2018-5784.patch
+	CVE-2018-7456.patch
 	"
 
 # secfixes:
+#   4.0.9-r3:
+#     - CVE-2018-7456
 #   4.0.9-r2:
 #     - CVE-2018-5784
 #   4.0.9-r1:
@@ -107,4 +110,5 @@ sha256sums="6e7bdeec2c310734e734d19aae3a71ebe37a4d842e0e23dbb1b8921c0026cfcd  ti
 560808f75587b03bcb0f98f123abb7fd642443edc4e5ea31e14510e2f79068a3  CVE-2017-18013.patch"
 sha512sums="04f3d5eefccf9c1a0393659fe27f3dddd31108c401ba0dc587bca152a1c1f6bc844ba41622ff5572da8cc278593eff8c402b44e7af0a0090e91d326c2d79f6cd  tiff-4.0.9.tar.gz
 3a31e4315ecc5c5bf709e2ca0fefb5bc7ff50c79f911b8b8366be38d007d3f79e89982700a620b2d82739313fbd79041428dbf3ecf0a790c9ec3bc2e211d6fce  CVE-2017-18013.patch
-c9cb1f712241c5bbd01910d4f4becf50ba8498bb04393f45451af4ace948b6a41b3d887adc9fbce1a53edeb0aeba03868f4d31428f3c5813ed14bb4b6f4c0f96  CVE-2018-5784.patch"
+c9cb1f712241c5bbd01910d4f4becf50ba8498bb04393f45451af4ace948b6a41b3d887adc9fbce1a53edeb0aeba03868f4d31428f3c5813ed14bb4b6f4c0f96  CVE-2018-5784.patch
+8f3ad4065f6ef349c4bd0fe9161cbe19744fbbc89f17c52eb4e43548ca4816f09c7f7e270cb77ced820a95ca009b5f7ad65ee79e7b23ffe1d31c137e3b2bef47  CVE-2018-7456.patch"
diff --git a/main/tiff/CVE-2018-7456.patch b/main/tiff/CVE-2018-7456.patch
new file mode 100644
index 0000000000..b2d081a5d7
--- /dev/null
+++ b/main/tiff/CVE-2018-7456.patch
@@ -0,0 +1,170 @@
+From be4c85b16e8801a16eec25e80eb9f3dd6a96731b Mon Sep 17 00:00:00 2001
+From: Hugo Lefeuvre <hle@debian.org>
+Date: Sun, 8 Apr 2018 14:07:08 -0400
+Subject: [PATCH] Fix NULL pointer dereference in TIFFPrintDirectory
+
+The TIFFPrintDirectory function relies on the following assumptions,
+supposed to be guaranteed by the specification:
+
+(a) A Transfer Function field is only present if the TIFF file has
+    photometric type < 3.
+
+(b) If SamplesPerPixel > Color Channels, then the ExtraSamples field
+    has count SamplesPerPixel - (Color Channels) and contains
+    information about supplementary channels.
+
+While respect of (a) and (b) are essential for the well functioning of
+TIFFPrintDirectory, no checks are realized neither by the callee nor
+by TIFFPrintDirectory itself. Hence, following scenarios might happen
+and trigger the NULL pointer dereference:
+
+(1) TIFF File of photometric type 4 or more has illegal Transfer
+    Function field.
+
+(2) TIFF File has photometric type 3 or less and defines a
+    SamplesPerPixel field such that SamplesPerPixel > Color Channels
+    without defining all extra samples in the ExtraSamples fields.
+
+In this patch, we address both issues with respect of the following
+principles:
+
+(A) In the case of (1), the defined transfer table should be printed
+    safely even if it isn't 'legal'. This allows us to avoid expensive
+    checks in TIFFPrintDirectory. Also, it is quite possible that
+    an alternative photometric type would be developed (not part of the
+    standard) and would allow definition of Transfer Table. We want
+    libtiff to be able to handle this scenario out of the box.
+
+(B) In the case of (2), the transfer table should be printed at its
+    right size, that is if TIFF file has photometric type Palette
+    then the transfer table should have one row and not three, even
+    if two extra samples are declared.
+
+In order to fulfill (A) we simply add a new 'i < 3' end condition to
+the broken TIFFPrintDirectory loop. This makes sure that in any case
+where (b) would be respected but not (a), everything stays fine.
+
+(B) is fulfilled by the loop condition
+'i < td->td_samplesperpixel - td->td_extrasamples'. This is enough as
+long as (b) is respected.
+
+Naturally, we also make sure (b) is respected. This is done in the
+TIFFReadDirectory function by making sure any non-color channel is
+counted in ExtraSamples.
+
+This commit addresses CVE-2018-7456.
+---
+ libtiff/tif_dirread.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ libtiff/tif_print.c   |  2 +-
+ 2 files changed, 63 insertions(+), 1 deletion(-)
+
+diff --git a/libtiff/tif_dirread.c b/libtiff/tif_dirread.c
+index 6baa7b3..af5b84a 100644
+--- a/libtiff/tif_dirread.c
++++ b/libtiff/tif_dirread.c
+@@ -165,6 +165,7 @@ static int TIFFFetchStripThing(TIFF* tif, TIFFDirEntry* dir, uint32 nstrips, uin
+ static int TIFFFetchSubjectDistance(TIFF*, TIFFDirEntry*);
+ static void ChopUpSingleUncompressedStrip(TIFF*);
+ static uint64 TIFFReadUInt64(const uint8 *value);
++static int _TIFFGetMaxColorChannels(uint16 photometric);
+ 
+ static int _TIFFFillStrilesInternal( TIFF *tif, int loadStripByteCount );
+ 
+@@ -3505,6 +3506,35 @@ static void TIFFReadDirEntryOutputErr(TIFF* tif, enum TIFFReadDirEntryErr err, c
+ }
+ 
+ /*
++ * Return the maximum number of color channels specified for a given photometric
++ * type. 0 is returned if photometric type isn't supported or no default value
++ * is defined by the specification.
++ */
++static int _TIFFGetMaxColorChannels( uint16 photometric )
++{
++    switch (photometric) {
++	case PHOTOMETRIC_PALETTE:
++	case PHOTOMETRIC_MINISWHITE:
++	case PHOTOMETRIC_MINISBLACK:
++            return 1;
++	case PHOTOMETRIC_YCBCR:
++	case PHOTOMETRIC_RGB:
++	case PHOTOMETRIC_CIELAB:
++            return 3;
++	case PHOTOMETRIC_SEPARATED:
++	case PHOTOMETRIC_MASK:
++            return 4;
++	case PHOTOMETRIC_LOGL:
++	case PHOTOMETRIC_LOGLUV:
++	case PHOTOMETRIC_CFA:
++	case PHOTOMETRIC_ITULAB:
++	case PHOTOMETRIC_ICCLAB:
++	default:
++            return 0;
++    }
++}
++
++/*
+  * Read the next TIFF directory from a file and convert it to the internal
+  * format. We read directories sequentially.
+  */
+@@ -3520,6 +3550,7 @@ TIFFReadDirectory(TIFF* tif)
+ 	uint32 fii=FAILED_FII;
+         toff_t nextdiroff;
+     int bitspersample_read = FALSE;
++        int color_channels;
+ 
+ 	tif->tif_diroff=tif->tif_nextdiroff;
+ 	if (!TIFFCheckDirOffset(tif,tif->tif_nextdiroff))
+@@ -4024,6 +4055,37 @@ TIFFReadDirectory(TIFF* tif)
+ 			}
+ 		}
+ 	}
++
++	/*
++	 * Make sure all non-color channels are extrasamples.
++	 * If it's not the case, define them as such.
++	 */
++        color_channels = _TIFFGetMaxColorChannels(tif->tif_dir.td_photometric);
++        if (color_channels && tif->tif_dir.td_samplesperpixel - tif->tif_dir.td_extrasamples > color_channels) {
++                uint16 old_extrasamples;
++                uint16 *new_sampleinfo;
++
++                TIFFWarningExt(tif->tif_clientdata,module, "Sum of Photometric type-related "
++                    "color channels and ExtraSamples doesn't match SamplesPerPixel. "
++                    "Defining non-color channels as ExtraSamples.");
++
++                old_extrasamples = tif->tif_dir.td_extrasamples;
++                tif->tif_dir.td_extrasamples = (tif->tif_dir.td_samplesperpixel - color_channels);
++
++                // sampleinfo should contain information relative to these new extra samples
++                new_sampleinfo = (uint16*) _TIFFcalloc(tif->tif_dir.td_extrasamples, sizeof(uint16));
++                if (!new_sampleinfo) {
++                    TIFFErrorExt(tif->tif_clientdata, module, "Failed to allocate memory for "
++                                "temporary new sampleinfo array (%d 16 bit elements)",
++                                tif->tif_dir.td_extrasamples);
++                    goto bad;
++                }
++
++                memcpy(new_sampleinfo, tif->tif_dir.td_sampleinfo, old_extrasamples * sizeof(uint16));
++                _TIFFsetShortArray(&tif->tif_dir.td_sampleinfo, new_sampleinfo, tif->tif_dir.td_extrasamples);
++                _TIFFfree(new_sampleinfo);
++        }
++
+ 	/*
+ 	 * Verify Palette image has a Colormap.
+ 	 */
+diff --git a/libtiff/tif_print.c b/libtiff/tif_print.c
+index 8deceb2..1d86adb 100644
+--- a/libtiff/tif_print.c
++++ b/libtiff/tif_print.c
+@@ -544,7 +544,7 @@ TIFFPrintDirectory(TIFF* tif, FILE* fd, long flags)
+ 				uint16 i;
+ 				fprintf(fd, "    %2ld: %5u",
+ 				    l, td->td_transferfunction[0][l]);
+-				for (i = 1; i < td->td_samplesperpixel; i++)
++				for (i = 1; i < td->td_samplesperpixel - td->td_extrasamples && i < 3; i++)
+ 					fprintf(fd, " %5u",
+ 					    td->td_transferfunction[i][l]);
+ 				fputc('\n', fd);
+--
+libgit2 0.27.0
+