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authorH.J. Lu <hjl.tools@gmail.com>2019-01-21 11:35:18 -0800
committerH.J. Lu <hjl.tools@gmail.com>2019-01-21 11:35:34 -0800
commitc7c54f65b080affb87a1513dee449c8ad6143c8b (patch)
tree7843555220fda4dbbe023b2035a8de081810128a
parentee915088a0231cd421054dbd8abab7aadf331153 (diff)
x86-64 strncpy: 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 strncpy 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/strcpy-avx2.S: Use RDX_LP for length. * sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S: Likewise. * sysdeps/x86_64/multiarch/strcpy-ssse3.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-strncpy. * sysdeps/x86_64/x32/tst-size_t-strncpy.c: New file.
-rw-r--r--ChangeLog10
-rw-r--r--sysdeps/x86_64/multiarch/strcpy-avx2.S4
-rw-r--r--sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S4
-rw-r--r--sysdeps/x86_64/multiarch/strcpy-ssse3.S6
-rw-r--r--sysdeps/x86_64/x32/Makefile2
-rw-r--r--sysdeps/x86_64/x32/tst-size_t-strncpy.c58
6 files changed, 76 insertions, 8 deletions
diff --git a/ChangeLog b/ChangeLog
index 7be0a2e81e..a0412f7a3e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,16 @@
[BZ# 24097]
CVE-2019-6488
+ * sysdeps/x86_64/multiarch/strcpy-avx2.S: Use RDX_LP for length.
+ * sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S: Likewise.
+ * sysdeps/x86_64/multiarch/strcpy-ssse3.S: Likewise.
+ * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-strncpy.
+ * sysdeps/x86_64/x32/tst-size_t-strncpy.c: New file.
+
+2019-01-21 H.J. Lu <hongjiu.lu@intel.com>
+
+ [BZ# 24097]
+ CVE-2019-6488
* sysdeps/x86_64/multiarch/strcmp-avx2.S: Use RDX_LP for length.
* sysdeps/x86_64/multiarch/strcmp-sse42.S: Likewise.
* sysdeps/x86_64/strcmp.S: Likewise.
diff --git a/sysdeps/x86_64/multiarch/strcpy-avx2.S b/sysdeps/x86_64/multiarch/strcpy-avx2.S
index 81677f9060..e72a0cad7d 100644
--- a/sysdeps/x86_64/multiarch/strcpy-avx2.S
+++ b/sysdeps/x86_64/multiarch/strcpy-avx2.S
@@ -49,8 +49,8 @@
.section .text.avx,"ax",@progbits
ENTRY (STRCPY)
# ifdef USE_AS_STRNCPY
- mov %rdx, %r8
- test %r8, %r8
+ mov %RDX_LP, %R8_LP
+ test %R8_LP, %R8_LP
jz L(ExitZero)
# endif
mov %rsi, %rcx
diff --git a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
index b7c79976ea..0d6914e113 100644
--- a/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
+++ b/sysdeps/x86_64/multiarch/strcpy-sse2-unaligned.S
@@ -40,8 +40,8 @@
.text
ENTRY (STRCPY)
# ifdef USE_AS_STRNCPY
- mov %rdx, %r8
- test %r8, %r8
+ mov %RDX_LP, %R8_LP
+ test %R8_LP, %R8_LP
jz L(ExitZero)
# endif
mov %rsi, %rcx
diff --git a/sysdeps/x86_64/multiarch/strcpy-ssse3.S b/sysdeps/x86_64/multiarch/strcpy-ssse3.S
index ec53f2a632..39e6ad762c 100644
--- a/sysdeps/x86_64/multiarch/strcpy-ssse3.S
+++ b/sysdeps/x86_64/multiarch/strcpy-ssse3.S
@@ -31,13 +31,13 @@ ENTRY (STRCPY)
mov %rsi, %rcx
# ifdef USE_AS_STRNCPY
- mov %rdx, %r8
+ mov %RDX_LP, %R8_LP
# endif
mov %rdi, %rdx
# ifdef USE_AS_STRNCPY
- test %r8, %r8
+ test %R8_LP, %R8_LP
jz L(Exit0)
- cmp $8, %r8
+ cmp $8, %R8_LP
jbe L(StrncpyExit8Bytes)
# endif
cmpb $0, (%rcx)
diff --git a/sysdeps/x86_64/x32/Makefile b/sysdeps/x86_64/x32/Makefile
index db30283977..2a9e20a90b 100644
--- a/sysdeps/x86_64/x32/Makefile
+++ b/sysdeps/x86_64/x32/Makefile
@@ -8,7 +8,7 @@ endif
ifeq ($(subdir),string)
tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \
tst-size_t-memrchr tst-size_t-memset tst-size_t-strncasecmp \
- tst-size_t-strncmp
+ tst-size_t-strncmp tst-size_t-strncpy
endif
ifeq ($(subdir),wcsmbs)
diff --git a/sysdeps/x86_64/x32/tst-size_t-strncpy.c b/sysdeps/x86_64/x32/tst-size_t-strncpy.c
new file mode 100644
index 0000000000..4dec71e6b3
--- /dev/null
+++ b/sysdeps/x86_64/x32/tst-size_t-strncpy.c
@@ -0,0 +1,58 @@
+/* Test strncpy 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 "strncpy"
+#include "test-size_t.h"
+
+IMPL (strncpy, 1)
+
+typedef char *(*proto_t) (char *, const char*, size_t);
+
+static void *
+__attribute__ ((noinline, noclone))
+do_strncpy (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_strncpy (dest, src);
+ int res = strncmp (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>