173 lines
7.4 KiB
Diff
173 lines
7.4 KiB
Diff
From 284ae90ae567de4ca53a3f32b472096f0da573a5 Mon Sep 17 00:00:00 2001
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From: Su Laus <sulau@freenet.de>
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Date: Sun, 5 Nov 2023 03:50:21 +0800
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Subject: [PATCH 1/2] Prevent some out-of-memory attacks
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Some small fuzzer files fake large amounts of data and provoke out-of-memory situations. For non-compressed data content / tags, out-of-memory can be prevented by comparing with the file size.
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At image reading, data size of some tags / data structures (StripByteCounts, StripOffsets, StripArray, TIFF directory) is compared with file size to prevent provoked out-of-memory attacks.
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See issue https://gitlab.com/libtiff/libtiff/-/issues/614#note_1602683857
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---
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libtiff/tif_dirread.c | 94 +++++++++++++++++++++++++++++++++++++++++--
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1 file changed, 90 insertions(+), 4 deletions(-)
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diff --git a/libtiff/tif_dirread.c b/libtiff/tif_dirread.c
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index a762c67..2428257 100644
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--- a/libtiff/tif_dirread.c
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+++ b/libtiff/tif_dirread.c
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@@ -866,8 +866,23 @@ static enum TIFFReadDirEntryErr TIFFReadDirEntryArrayWithLimit(
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datasize=(*count)*typesize;
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assert((tmsize_t)datasize>0);
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- if( isMapped(tif) && datasize > (uint64_t)tif->tif_size )
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- return TIFFReadDirEntryErrIo;
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+ /* Before allocating a huge amount of memory for corrupted files, check if
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+ * size of requested memory is not greater than file size.
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+ */
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ if (datasize > filesize)
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+ {
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+ TIFFWarningExt(tif->tif_clientdata, "ReadDirEntryArray",
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+ "Requested memory size for tag %d (0x%x) %" PRIu32
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated, tag not read",
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+ direntry->tdir_tag, direntry->tdir_tag, datasize,
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+ filesize);
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+ return (TIFFReadDirEntryErrAlloc);
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+ }
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+
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+ if (isMapped(tif) && datasize > (uint64_t)tif->tif_size)
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+ return TIFFReadDirEntryErrIo;
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if( !isMapped(tif) &&
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(((tif->tif_flags&TIFF_BIGTIFF) && datasize > 8) ||
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@@ -4592,6 +4607,19 @@ EstimateStripByteCounts(TIFF* tif, TIFFDirEntry* dir, uint16_t dircount)
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if( !_TIFFFillStrilesInternal( tif, 0 ) )
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return -1;
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+ /* Before allocating a huge amount of memory for corrupted files, check if
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+ * size of requested memory is not greater than file size. */
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ uint64_t allocsize = (uint64_t)td->td_nstrips * sizeof(uint64_t);
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+ if (allocsize > filesize)
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+ {
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+ TIFFWarningExt(tif->tif_clientdata, module,
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+ "Requested memory size for StripByteCounts of %" PRIu64
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated",
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+ allocsize, filesize);
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+ return -1;
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+ }
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if (td->td_stripbytecount_p)
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_TIFFfree(td->td_stripbytecount_p);
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td->td_stripbytecount_p = (uint64_t*)
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@@ -4602,9 +4630,7 @@ EstimateStripByteCounts(TIFF* tif, TIFFDirEntry* dir, uint16_t dircount)
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if (td->td_compression != COMPRESSION_NONE) {
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uint64_t space;
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- uint64_t filesize;
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uint16_t n;
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- filesize = TIFFGetFileSize(tif);
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if (!(tif->tif_flags&TIFF_BIGTIFF))
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space=sizeof(TIFFHeaderClassic)+2+dircount*12+4;
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else
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@@ -4912,6 +4938,20 @@ TIFFFetchDirectory(TIFF* tif, uint64_t diroff, TIFFDirEntry** pdir,
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dircount16 = (uint16_t)dircount64;
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dirsize = 20;
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}
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+ /* Before allocating a huge amount of memory for corrupted files, check
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+ * if size of requested memory is not greater than file size. */
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ uint64_t allocsize = (uint64_t)dircount16 * dirsize;
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+ if (allocsize > filesize)
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+ {
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+ TIFFWarningExt(
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+ tif->tif_clientdata, module,
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+ "Requested memory size for TIFF directory of %" PRIu64
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated, TIFF directory not read",
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+ allocsize, filesize);
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+ return 0;
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+ }
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origdir = _TIFFCheckMalloc(tif, dircount16,
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dirsize, "to read TIFF directory");
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if (origdir == NULL)
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@@ -5015,6 +5055,20 @@ TIFFFetchDirectory(TIFF* tif, uint64_t diroff, TIFFDirEntry** pdir,
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"Sanity check on directory count failed, zero tag directories not supported");
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return 0;
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}
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+ /* Before allocating a huge amount of memory for corrupted files, check
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+ * if size of requested memory is not greater than file size. */
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ uint64_t allocsize = (uint64_t)dircount16 * dirsize;
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+ if (allocsize > filesize)
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+ {
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+ TIFFWarningExt(
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+ tif->tif_clientdata, module,
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+ "Requested memory size for TIFF directory of %" PRIu64
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated, TIFF directory not read",
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+ allocsize, filesize);
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+ return 0;
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+ }
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origdir = _TIFFCheckMalloc(tif, dircount16,
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dirsize,
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"to read TIFF directory");
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@@ -5058,6 +5112,8 @@ TIFFFetchDirectory(TIFF* tif, uint64_t diroff, TIFFDirEntry** pdir,
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}
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}
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}
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+ /* No check against filesize needed here because "dir" should have same size
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+ * than "origdir" checked above. */
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dir = (TIFFDirEntry*)_TIFFCheckMalloc(tif, dircount16,
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sizeof(TIFFDirEntry),
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"to read TIFF directory");
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@@ -5852,6 +5908,20 @@ TIFFFetchStripThing(TIFF* tif, TIFFDirEntry* dir, uint32_t nstrips, uint64_t** l
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return(0);
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}
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+ /* Before allocating a huge amount of memory for corrupted files, check
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+ * if size of requested memory is not greater than file size. */
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ uint64_t allocsize = (uint64_t)nstrips * sizeof(uint64_t);
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+ if (allocsize > filesize)
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+ {
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+ TIFFWarningExt(tif->tif_clientdata, module,
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+ "Requested memory size for StripArray of %" PRIu64
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated",
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+ allocsize, filesize);
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+ _TIFFfree(data);
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+ return (0);
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+ }
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resizeddata=(uint64_t*)_TIFFCheckMalloc(tif, nstrips, sizeof(uint64_t), "for strip array");
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if (resizeddata==0) {
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_TIFFfree(data);
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@@ -5947,6 +6017,22 @@ static void allocChoppedUpStripArrays(TIFF* tif, uint32_t nstrips,
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}
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bytecount = last_offset + last_bytecount - offset;
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+ /* Before allocating a huge amount of memory for corrupted files, check if
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+ * size of StripByteCount and StripOffset tags is not greater than
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+ * file size.
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+ */
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+ uint64_t allocsize = (uint64_t)nstrips * sizeof(uint64_t) * 2;
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+ uint64_t filesize = TIFFGetFileSize(tif);
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+ if (allocsize > filesize)
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+ {
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+ TIFFWarningExt(tif->tif_clientdata, "allocChoppedUpStripArrays",
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+ "Requested memory size for StripByteCount and "
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+ "StripOffsets %" PRIu64
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+ " is greather than filesize %" PRIu64
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+ ". Memory not allocated",
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+ allocsize, filesize);
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+ return;
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+ }
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newcounts = (uint64_t*) _TIFFCheckMalloc(tif, nstrips, sizeof (uint64_t),
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"for chopped \"StripByteCounts\" array");
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newoffsets = (uint64_t*) _TIFFCheckMalloc(tif, nstrips, sizeof (uint64_t),
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--
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2.33.0
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