2247677749
http://secunia.com/advisories/31610 LibTIFF LZW Decoder Buffer Underflow Vulnerability Patch extracted from Debian's tiff_3.8.2-7+etch1 "looks fine" ajacoutot@
63 lines
2.0 KiB
Plaintext
63 lines
2.0 KiB
Plaintext
$OpenBSD: patch-libtiff_tif_lzw_c,v 1.1 2008/08/27 18:09:36 jasper Exp $
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Security fix for SA31610
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http://secunia.com/advisories/31610
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LibTIFF LZW Decoder Buffer Underflow Vulnerability
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Patch extracted from Debian's tiff_3.8.2-7+etch1
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--- libtiff/tif_lzw.c.orig Wed Aug 27 15:02:14 2008
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+++ libtiff/tif_lzw.c Wed Aug 27 15:06:01 2008
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@@ -237,6 +237,11 @@ LZWSetupDecode(TIFF* tif)
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sp->dec_codetab[code].length = 1;
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sp->dec_codetab[code].next = NULL;
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} while (code--);
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+ /*
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+ * Zero-out the unused entries
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+ */
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+ _TIFFmemset(&sp->dec_codetab[CODE_CLEAR], 0,
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+ (CODE_FIRST-CODE_CLEAR)*sizeof (code_t));
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}
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return (1);
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}
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@@ -408,12 +413,19 @@ LZWDecode(TIFF* tif, tidata_t op0, tsize_t occ0, tsamp
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break;
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if (code == CODE_CLEAR) {
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free_entp = sp->dec_codetab + CODE_FIRST;
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+ _TIFFmemset(free_entp, 0, (CSIZE-CODE_FIRST)*sizeof (code_t));
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nbits = BITS_MIN;
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nbitsmask = MAXCODE(BITS_MIN);
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maxcodep = sp->dec_codetab + nbitsmask-1;
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NextCode(tif, sp, bp, code, GetNextCode);
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if (code == CODE_EOI)
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break;
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+ if (code == CODE_CLEAR) {
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+ TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
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+ "LZWDecode: Corrupted LZW table at scanline %d",
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+ tif->tif_row);
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+ return (0);
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+ }
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*op++ = (char)code, occ--;
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oldcodep = sp->dec_codetab + code;
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continue;
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@@ -604,12 +616,19 @@ LZWDecodeCompat(TIFF* tif, tidata_t op0, tsize_t occ0,
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break;
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if (code == CODE_CLEAR) {
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free_entp = sp->dec_codetab + CODE_FIRST;
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+ _TIFFmemset(free_entp, 0, (CSIZE-CODE_FIRST)*sizeof (code_t));
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nbits = BITS_MIN;
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nbitsmask = MAXCODE(BITS_MIN);
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maxcodep = sp->dec_codetab + nbitsmask;
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NextCode(tif, sp, bp, code, GetNextCodeCompat);
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if (code == CODE_EOI)
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break;
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+ if (code == CODE_CLEAR) {
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+ TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
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+ "LZWDecode: Corrupted LZW table at scanline %d",
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+ tif->tif_row);
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+ return (0);
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+ }
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*op++ = code, occ--;
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oldcodep = sp->dec_codetab + code;
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continue;
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