x86-64 memcpy: 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 memcpy 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/memcpy-ssse3-back.S: Use RDX_LP for
	length.  Clear the upper 32 bits of RDX register.
	* sysdeps/x86_64/multiarch/memcpy-ssse3.S: Likewise.
	* sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S:
	Likewise.
	* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
	Likewise.
	* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memcpy.
	tst-size_t-wmemchr.
	* sysdeps/x86_64/x32/tst-size_t-memcpy.c: New file.

(cherry picked from commit 231c56760c)

ChangeLog

@@ -1,3 +1,18 @@
+2019-02-01  H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #24097]
+	CVE-2019-6488
+	* sysdeps/x86_64/multiarch/memcpy-ssse3-back.S: Use RDX_LP for
+	length.  Clear the upper 32 bits of RDX register.
+	* sysdeps/x86_64/multiarch/memcpy-ssse3.S: Likewise.
+	* sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S:
+	Likewise.
+	* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
+	Likewise.
+	* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memcpy.
+	tst-size_t-wmemchr.
+	* sysdeps/x86_64/x32/tst-size_t-memcpy.c: New file.
+
 2019-02-01  H.J. Lu  <hongjiu.lu@intel.com>
 
 	[BZ #24097]

sysdeps/x86_64/multiarch/memcpy-ssse3-back.S

@@ -45,28 +45,33 @@
 	.section .text.ssse3,"ax",@progbits
 #if !defined USE_AS_MEMPCPY && !defined USE_AS_MEMMOVE
 ENTRY (MEMPCPY_CHK)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMPCPY_CHK)
 
 ENTRY (MEMPCPY)
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start)
 END (MEMPCPY)
 #endif
 
 #if !defined USE_AS_BCOPY
 ENTRY (MEMCPY_CHK)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMCPY_CHK)
 #endif
 
 ENTRY (MEMCPY)
-	mov	%rdi, %rax
+	mov	%RDI_LP, %RAX_LP
 #ifdef USE_AS_MEMPCPY
-	add	%rdx, %rax
+	add	%RDX_LP, %RAX_LP
+#endif
+
+#ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	mov	%edx, %edx
 #endif
 
 #ifdef USE_AS_MEMMOVE

sysdeps/x86_64/multiarch/memcpy-ssse3.S

@@ -45,28 +45,33 @@
 	.section .text.ssse3,"ax",@progbits
 #if !defined USE_AS_MEMPCPY && !defined USE_AS_MEMMOVE
 ENTRY (MEMPCPY_CHK)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMPCPY_CHK)
 
 ENTRY (MEMPCPY)
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start)
 END (MEMPCPY)
 #endif
 
 #if !defined USE_AS_BCOPY
 ENTRY (MEMCPY_CHK)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMCPY_CHK)
 #endif
 
 ENTRY (MEMCPY)
-	mov	%rdi, %rax
+	mov	%RDI_LP, %RAX_LP
 #ifdef USE_AS_MEMPCPY
-	add	%rdx, %rax
+	add	%RDX_LP, %RAX_LP
+#endif
+
+#ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	mov	%edx, %edx
 #endif
 
 #ifdef USE_AS_MEMMOVE

sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S

@@ -24,27 +24,31 @@
 
 	.section .text.avx512,"ax",@progbits
 ENTRY (__mempcpy_chk_avx512_no_vzeroupper)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (__mempcpy_chk_avx512_no_vzeroupper)
 
 ENTRY (__mempcpy_avx512_no_vzeroupper)
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start)
 END (__mempcpy_avx512_no_vzeroupper)
 
 ENTRY (__memmove_chk_avx512_no_vzeroupper)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (__memmove_chk_avx512_no_vzeroupper)
 
 ENTRY (__memmove_avx512_no_vzeroupper)
-	mov	%rdi, %rax
+	mov	%RDI_LP, %RAX_LP
 # ifdef USE_AS_MEMPCPY
-	add	%rdx, %rax
+	add	%RDX_LP, %RAX_LP
 # endif
 L(start):
+# ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	mov	%edx, %edx
+# endif
 	lea	(%rsi, %rdx), %rcx
 	lea	(%rdi, %rdx), %r9
 	cmp	$512, %rdx

sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S

@@ -107,20 +107,20 @@
 	.section SECTION(.text),"ax",@progbits
 #if defined SHARED && IS_IN (libc)
 ENTRY (MEMMOVE_CHK_SYMBOL (__mempcpy_chk, unaligned))
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMMOVE_CHK_SYMBOL (__mempcpy_chk, unaligned))
 #endif
 
 ENTRY (MEMPCPY_SYMBOL (__mempcpy, unaligned))
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start)
 END (MEMPCPY_SYMBOL (__mempcpy, unaligned))
 
 #if defined SHARED && IS_IN (libc)
 ENTRY (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned))
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned))
 #endif
@@ -128,9 +128,13 @@ END (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned))
 ENTRY (MEMMOVE_SYMBOL (__memmove, unaligned))
 	movq	%rdi, %rax
 L(start):
-	cmpq	$VEC_SIZE, %rdx
+# ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	movl	%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(more_2x_vec)
 #if !defined USE_MULTIARCH || !IS_IN (libc)
 L(last_2x_vec):
@@ -150,32 +154,32 @@ END (MEMMOVE_SYMBOL (__memmove, unaligned))
 
 # if VEC_SIZE == 16
 ENTRY (__mempcpy_chk_erms)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (__mempcpy_chk_erms)
 
 /* Only used to measure performance of REP MOVSB.  */
 ENTRY (__mempcpy_erms)
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start_movsb)
 END (__mempcpy_erms)
 
 ENTRY (__memmove_chk_erms)
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (__memmove_chk_erms)
 
 ENTRY (__memmove_erms)
 	movq	%rdi, %rax
 L(start_movsb):
-	movq	%rdx, %rcx
-	cmpq	%rsi, %rdi
+	mov	%RDX_LP, %RCX_LP
+	cmp	%RSI_LP, %RDI_LP
 	jb	1f
 	/* Source == destination is less common.  */
 	je	2f
-	leaq	(%rsi,%rcx), %rdx
-	cmpq	%rdx, %rdi
+	lea	(%rsi,%rcx), %RDX_LP
+	cmp	%RDX_LP, %RDI_LP
 	jb	L(movsb_backward)
 1:
 	rep movsb
@@ -195,20 +199,20 @@ strong_alias (__memmove_chk_erms, __memcpy_chk_erms)
 
 # ifdef SHARED
 ENTRY (MEMMOVE_CHK_SYMBOL (__mempcpy_chk, unaligned_erms))
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMMOVE_CHK_SYMBOL (__mempcpy_chk, unaligned_erms))
 # endif
 
 ENTRY (MEMMOVE_SYMBOL (__mempcpy, unaligned_erms))
-	movq	%rdi, %rax
-	addq	%rdx, %rax
+	mov	%RDI_LP, %RAX_LP
+	add	%RDX_LP, %RAX_LP
 	jmp	L(start_erms)
 END (MEMMOVE_SYMBOL (__mempcpy, unaligned_erms))
 
 # ifdef SHARED
 ENTRY (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned_erms))
-	cmpq	%rdx, %rcx
+	cmp	%RDX_LP, %RCX_LP
 	jb	HIDDEN_JUMPTARGET (__chk_fail)
 END (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned_erms))
 # endif
@@ -216,9 +220,13 @@ END (MEMMOVE_CHK_SYMBOL (__memmove_chk, unaligned_erms))
 ENTRY (MEMMOVE_SYMBOL (__memmove, unaligned_erms))
 	movq	%rdi, %rax
 L(start_erms):
-	cmpq	$VEC_SIZE, %rdx
+# ifdef __ILP32__
+	/* Clear the upper 32 bits.  */
+	movl	%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(movsb_more_2x_vec)
 L(last_2x_vec):
 	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE. */
@@ -245,7 +253,7 @@ L(movsb):
 # endif
 	jb	L(more_8x_vec_backward)
 1:
-	movq	%rdx, %rcx
+	mov	%RDX_LP, %RCX_LP
 	rep movsb
 L(nop):
 	ret

sysdeps/x86_64/x32/Makefile

@@ -6,7 +6,7 @@ CFLAGS-s_llround.c += -fno-builtin-lround
 endif
 
 ifeq ($(subdir),string)
-tests += tst-size_t-memchr tst-size_t-memcmp
+tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy
 endif
 
 ifeq ($(subdir),wcsmbs)

sysdeps/x86_64/x32/tst-size_t-memcpy.c

@@ -0,0 +1,58 @@
+/* Test memcpy 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 TEST_NAME "memcpy"
+#include "test-size_t.h"
+
+IMPL (memcpy, 1)
+
+typedef void *(*proto_t) (void *, const void *, size_t);
+
+static void *
+__attribute__ ((noinline, noclone))
+do_memcpy (parameter_t a, parameter_t b)
+{
+  return CALL (&b, a.p, b.p, a.len);
+}
+
+static int
+test_main (void)
+{
+  test_init ();
+
+  parameter_t dest = { { page_size }, buf1 };
+  parameter_t src = { { 0 }, buf2 };
+
+  int ret = 0;
+  FOR_EACH_IMPL (impl, 0)
+    {
+      src.fn = impl->fn;
+      do_memcpy (dest, src);
+      int res = memcmp (dest.p, src.p, dest.len);
+      if (res)
+	{
+	  error (0, 0, "Wrong result in function %s: %i != 0",
+		 impl->name, res);
+	  ret = 1;
+	}
+    }
+
+  return ret ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>