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x86-64 memset/wmemset: 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 memset/wmemset 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/memset-avx512-no-vzeroupper.S: Use
	RDX_LP for length.  Clear the upper 32 bits of RDX register.
	* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S: Likewise.
	* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-wmemset.
	* sysdeps/x86_64/x32/tst-size_t-memset.c: New file.
	* sysdeps/x86_64/x32/tst-size_t-wmemset.c: Likewise.
This commit is contained in:
H.J. Lu 2019-01-21 11:32:24 -08:00
parent ecd8b842cf
commit 82d0b4a4d7
6 changed files with 132 additions and 16 deletions
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11
ChangeLog
View File

@ -1,3 +1,14 @@
2019-01-21 H.J. Lu <hongjiu.lu@intel.com>
[BZ# 24097]
CVE-2019-6488
* sysdeps/x86_64/multiarch/memset-avx512-no-vzeroupper.S: Use
RDX_LP for length. Clear the upper 32 bits of RDX register.
* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S: Likewise.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-wmemset.
* sysdeps/x86_64/x32/tst-size_t-memset.c: New file.
* sysdeps/x86_64/x32/tst-size_t-wmemset.c: Likewise.
2019-01-21 H.J. Lu <hongjiu.lu@intel.com>
[BZ# 24097]

6
sysdeps/x86_64/multiarch/memset-avx512-no-vzeroupper.S
View File

@ -29,12 +29,16 @@
.section .text.avx512,"ax",@progbits
#if defined PIC
ENTRY (MEMSET_CHK)
cmpq %rdx, %rcx
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END (MEMSET_CHK)
#endif
ENTRY (MEMSET)
# ifdef __ILP32__
/* Clear the upper 32 bits. */
mov %edx, %edx
# endif
vpxor %xmm0, %xmm0, %xmm0
vmovd %esi, %xmm1
lea (%rdi, %rdx), %rsi

34
sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
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@ -75,8 +75,8 @@
.section SECTION(.text),"ax",@progbits
#if VEC_SIZE == 16 && IS_IN (libc)
ENTRY (__bzero)
movq %rdi, %rax /* Set return value. */
movq %rsi, %rdx /* Set n. */
mov %RDI_LP, %RAX_LP /* Set return value. */
mov %RSI_LP, %RDX_LP /* Set n. */
pxor %xmm0, %xmm0
jmp L(entry_from_bzero)
END (__bzero)
@ -86,13 +86,13 @@ weak_alias (__bzero, bzero)
#if IS_IN (libc)
# if defined SHARED
ENTRY_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
cmpq %rdx, %rcx
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
# endif
ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
shlq $2, %rdx
shl $2, %RDX_LP
WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
jmp L(entry_from_bzero)
END (WMEMSET_SYMBOL (__wmemset, unaligned))
@ -100,13 +100,17 @@ END (WMEMSET_SYMBOL (__wmemset, unaligned))
#if defined SHARED && IS_IN (libc)
ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
cmpq %rdx, %rcx
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
#endif
ENTRY (MEMSET_SYMBOL (__memset, unaligned))
MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
# ifdef __ILP32__
/* Clear the upper 32 bits. */
mov %edx, %edx
# endif
L(entry_from_bzero):
cmpq $VEC_SIZE, %rdx
jb L(less_vec)
@ -122,14 +126,14 @@ END (MEMSET_SYMBOL (__memset, unaligned))
# if VEC_SIZE == 16
ENTRY (__memset_chk_erms)
cmpq %rdx, %rcx
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END (__memset_chk_erms)
/* Only used to measure performance of REP STOSB. */
ENTRY (__memset_erms)
/* Skip zero length. */
testq %rdx, %rdx
test %RDX_LP, %RDX_LP
jnz L(stosb)
movq %rdi, %rax
ret
@ -141,11 +145,11 @@ ENTRY (MEMSET_SYMBOL (__memset, erms))
L(stosb):
/* Issue vzeroupper before rep stosb. */
VZEROUPPER
movq %rdx, %rcx
mov %RDX_LP, %RCX_LP
movzbl %sil, %eax
movq %rdi, %rdx
mov %RDI_LP, %RDX_LP
rep stosb
movq %rdx, %rax
mov %RDX_LP, %RAX_LP
ret
# if VEC_SIZE == 16
END (__memset_erms)
@ -155,16 +159,20 @@ END (MEMSET_SYMBOL (__memset, erms))
# if defined SHARED && IS_IN (libc)
ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
cmpq %rdx, %rcx
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
# endif
ENTRY (MEMSET_SYMBOL (__memset, unaligned_erms))
MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
cmpq $VEC_SIZE, %rdx
# ifdef __ILP32__
/* Clear the upper 32 bits. */
mov %edx, %edx
# endif
cmp $VEC_SIZE, %RDX_LP
jb L(less_vec)
cmpq $(VEC_SIZE * 2), %rdx
cmp $(VEC_SIZE * 2), %RDX_LP
ja L(stosb_more_2x_vec)
/* From VEC and to 2 * VEC. No branch when size == VEC_SIZE. */
VMOVU %VEC(0), -VEC_SIZE(%rdi,%rdx)

4
sysdeps/x86_64/x32/Makefile
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@ -7,9 +7,9 @@ endif
ifeq ($(subdir),string)
tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \
tst-size_t-memrchr
tst-size_t-memrchr tst-size_t-memset
endif
ifeq ($(subdir),wcsmbs)
tests += tst-size_t-wmemchr tst-size_t-wmemcmp
tests += tst-size_t-wmemchr tst-size_t-wmemcmp tst-size_t-wmemset
endif

73
sysdeps/x86_64/x32/tst-size_t-memset.c Normal file
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@ -0,0 +1,73 @@
/* Test memset 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/>. */
#ifdef WIDE
# define TEST_NAME "wmemset"
#else
# define TEST_NAME "memset"
#endif /* WIDE */
#include "test-size_t.h"
#ifdef WIDE
# include <wchar.h>
# define MEMSET wmemset
# define CHAR wchar_t
#else
# define MEMSET memset
# define CHAR char
#endif /* WIDE */
IMPL (MEMSET, 1)
typedef CHAR *(*proto_t) (CHAR *, int, size_t);
static void *
__attribute__ ((noinline, noclone))
do_memset (parameter_t a, parameter_t b)
{
return CALL (&b, a.p, (uintptr_t) b.p, a.len);
}
static int
test_main (void)
{
test_init ();
CHAR ch = 0x23;
parameter_t src = { { page_size / sizeof (CHAR) }, buf2 };
parameter_t c = { { 0 }, (void *) (uintptr_t) ch };
int ret = 0;
FOR_EACH_IMPL (impl, 0)
{
c.fn = impl->fn;
CHAR *p = (CHAR *) do_memset (src, c);
size_t i;
for (i = 0; i < src.len; i++)
if (p[i] != ch)
{
error (0, 0, "Wrong result in function %s", impl->name);
ret = 1;
}
}
return ret ? EXIT_FAILURE : EXIT_SUCCESS;
}
#include <support/test-driver.c>

20
sysdeps/x86_64/x32/tst-size_t-wmemset.c Normal file
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@ -0,0 +1,20 @@
/* Test wmemset 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-memset.c"