@@ -24,7 +24,13 @@ Changes to build and runtime requirements:
Security related changes:
- [Add security related changes here]
+ CVE-2019-7309: x86-64 memcmp used signed Jcc instructions to check
+ size. For x86-64, memcmp on an object size larger than SSIZE_MAX
+ has undefined behavior. On x32, the size_t argument may be passed
+ in the lower 32 bits of the 64-bit RDX register with non-zero upper
+ 32 bits. When it happened with the sign bit of RDX register set,
+ memcmp gave the wrong result since it treated the size argument as
+ zero. Reported by H.J. Lu.
The following bugs are resolved with this release:
@@ -21,14 +21,18 @@
.text
ENTRY (memcmp)
- test %rdx, %rdx
+#ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+#endif
+ test %RDX_LP, %RDX_LP
jz L(finz)
cmpq $1, %rdx
- jle L(finr1b)
+ jbe L(finr1b)
subq %rdi, %rsi
movq %rdx, %r10
cmpq $32, %r10
- jge L(gt32)
+ jae L(gt32)
/* Handle small chunks and last block of less than 32 bytes. */
L(small):
testq $1, %r10
@@ -156,7 +160,7 @@ L(A32):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
- jge L(mt16)
+ jae L(mt16)
/* Pre-unroll to be ready for unrolled 64B loop. */
testq $32, %rdi
jz L(A64)
@@ -178,7 +182,7 @@ L(A64):
movq %r11, %r10
andq $-64, %r10
cmpq %r10, %rdi
- jge L(mt32)
+ jae L(mt32)
L(A64main):
movdqu (%rdi,%rsi), %xmm0
@@ -216,7 +220,7 @@ L(mt32):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
- jge L(mt16)
+ jae L(mt16)
L(A32main):
movdqu (%rdi,%rsi), %xmm0
@@ -254,7 +258,7 @@ L(ATR):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
- jge L(mt16)
+ jae L(mt16)
testq $16, %rdi
jz L(ATR32)
@@ -325,7 +329,7 @@ L(ATR64main):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
- jge L(mt16)
+ jae L(mt16)
L(ATR32res):
movdqa (%rdi,%rsi), %xmm0
@@ -8,7 +8,8 @@ endif
ifeq ($(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-strncpy tst-size_t-strnlen
+ tst-size_t-strncmp tst-size_t-strncpy tst-size_t-strnlen \
+ tst-size_t-memcmp-2
endif
ifeq ($(subdir),wcsmbs)
new file mode 100644
@@ -0,0 +1,79 @@
+/* Test memcmp 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_MAIN
+#ifdef WIDE
+# define TEST_NAME "wmemcmp"
+#else
+# define TEST_NAME "memcmp"
+#endif
+
+#include "test-size_t.h"
+
+#ifdef WIDE
+# include <inttypes.h>
+# include <wchar.h>
+
+# define MEMCMP wmemcmp
+# define CHAR wchar_t
+#else
+# define MEMCMP memcmp
+# define CHAR char
+#endif
+
+IMPL (MEMCMP, 1)
+
+typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);
+
+static int
+__attribute__ ((noinline, noclone))
+do_memcmp (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 / sizeof (CHAR) }, buf1 };
+ parameter_t src = { { 0 }, buf2 };
+
+ memcpy (buf1, buf2, page_size);
+
+ CHAR *p = (CHAR *) buf1;
+ p[page_size / sizeof (CHAR) - 1] = (CHAR) 1;
+
+ int ret = 0;
+ FOR_EACH_IMPL (impl, 0)
+ {
+ src.fn = impl->fn;
+ int res = do_memcmp (dest, src);
+ if (res >= 0)
+ {
+ 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>