42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
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Copied from Debian.
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From: mancha <mancha1 AT zoho DOT com>
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Date: Mon, 3 Nov 2014
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Subject: Info-ZIP UnZip buffer overflow
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Bug-Debian: http://bugs.debian.org/776589
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By carefully crafting a corrupt ZIP archive with "extra fields" that
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purport to have compressed blocks larger than the corresponding
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uncompressed blocks in STORED no-compression mode, an attacker can
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trigger a heap overflow that can result in application crash or
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possibly have other unspecified impact.
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This patch ensures that when extra fields use STORED mode, the
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"compressed" and uncompressed block sizes match.
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--- a/extract.c
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+++ b/extract.c
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@@ -2228,6 +2228,7 @@
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ulg eb_ucsize;
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uch *eb_ucptr;
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int r;
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+ ush eb_compr_method;
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if (compr_offset < 4) /* field is not compressed: */
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return PK_OK; /* do nothing and signal OK */
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@@ -2244,6 +2245,14 @@
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((eb_ucsize > 0L) && (eb_size <= (compr_offset + EB_CMPRHEADLEN))))
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return IZ_EF_TRUNC; /* no/bad compressed data! */
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+ /* 2014-11-03 Michal Zalewski, SMS.
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+ * For STORE method, compressed and uncompressed sizes must agree.
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+ * http://www.info-zip.org/phpBB3/viewtopic.php?f=7&t=450
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+ */
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+ eb_compr_method = makeword( eb + (EB_HEADSIZE + compr_offset));
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+ if ((eb_compr_method == STORED) && (eb_size - compr_offset != eb_ucsize))
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+ return PK_ERR;
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+
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if (
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#ifdef INT_16BIT
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(((ulg)(extent)eb_ucsize) != eb_ucsize) ||
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