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authorH.J. Lu <hjl.tools@gmail.com>2019-01-21 11:25:56 -0800
committerH.J. Lu <hjl.tools@gmail.com>2019-01-21 11:26:07 -0800
commitb304fc201d2f6baf52ea790df8643e99772243cd (patch)
tree502227813e790ba46c8f6e4ee826cb3f36ffb9bb /sysdeps/x86_64/x32/tst-size_t-wmemcmp.c
parent97700a34f36721b11a754cf37a1cc40695ece1fd (diff)
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x86-64 memcmp/wmemcmp: Properly handle the length parameter [BZ# 24097]
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits.  The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.

This pach fixes memcmp/wmemcmp for x32.  Tested on x86-64 and x32.  On
x86-64, libc.so is the same with and withou the fix.

	[BZ# 24097]
	CVE-2019-6488
	* sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S: Use RDX_LP for
	length.  Clear the upper 32 bits of RDX register.
	* sysdeps/x86_64/multiarch/memcmp-sse4.S: Likewise.
	* sysdeps/x86_64/multiarch/memcmp-ssse3.S: Likewise.
	* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memcmp and
	tst-size_t-wmemcmp.
	* sysdeps/x86_64/x32/tst-size_t-memcmp.c: New file.
	* sysdeps/x86_64/x32/tst-size_t-wmemcmp.c: Likewise.
Diffstat (limited to 'sysdeps/x86_64/x32/tst-size_t-wmemcmp.c')
-rw-r--r--sysdeps/x86_64/x32/tst-size_t-wmemcmp.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c b/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c
new file mode 100644
index 0000000000..e8b5ffd0d5
--- /dev/null
+++ b/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c
@@ -0,0 +1,20 @@
+/* Test wmemcmp with size_t in the lower 32 bits of 64-bit register.
+   Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define WIDE 1
+#include "tst-size_t-memcmp.c"