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Index: head/include/string.h
===================================================================
--- head/include/string.h
+++ head/include/string.h
@@ -134,6 +134,8 @@
void swab(const void * __restrict, void * __restrict, ssize_t);
#endif /* _SWAB_DECLARED */
+int timingsafe_bcmp(const void *, const void *, size_t);
+int timingsafe_memcmp(const void *, const void *, size_t);
#endif /* __BSD_VISIBLE */
#if __POSIX_VISIBLE >= 200809 || defined(_XLOCALE_H_)
Index: head/lib/libc/string/Makefile.inc
===================================================================
--- head/lib/libc/string/Makefile.inc
+++ head/lib/libc/string/Makefile.inc
@@ -16,7 +16,10 @@
strcspn.c strdup.c strerror.c strlcat.c strlcpy.c strlen.c strmode.c \
strncat.c strncmp.c strncpy.c strndup.c strnlen.c strnstr.c \
strpbrk.c strrchr.c strsep.c strsignal.c strspn.c strstr.c strtok.c \
- strxfrm.c swab.c wcpcpy.c wcpncpy.c wcscasecmp.c wcscat.c \
+ strxfrm.c swab.c \
+ timingsafe_bcmp.c \
+ timingsafe_memcmp.c \
+ wcpcpy.c wcpncpy.c wcscasecmp.c wcscat.c \
wcschr.c wcscmp.c wcscoll.c wcscpy.c wcscspn.c wcsdup.c \
wcslcat.c wcslcpy.c wcslen.c wcsncasecmp.c wcsncat.c wcsncmp.c \
wcsncpy.c wcsnlen.c wcspbrk.c \
@@ -34,7 +37,9 @@
memcmp.3 memcpy.3 memmem.3 memmove.3 memset.3 strcasecmp.3 strcat.3 \
strchr.3 strcmp.3 strcoll.3 strcpy.3 strdup.3 strerror.3 \
string.3 strlcpy.3 strlen.3 strmode.3 strpbrk.3 strsep.3 \
- strspn.3 strstr.3 strtok.3 strxfrm.3 swab.3 wcscoll.3 wcstok.3 \
+ strspn.3 strstr.3 strtok.3 strxfrm.3 swab.3 \
+ timingsafe_bcmp.3 \
+ wcscoll.3 wcstok.3 \
wcswidth.3 wcsxfrm.3 wmemchr.3
MLINKS+=bzero.3 explicit_bzero.3
@@ -69,6 +74,7 @@
strstr.3 strcasestr_l.3
MLINKS+=strtok.3 strtok_r.3
MLINKS+=strxfrm.3 strxfrm_l.3
+MLINKS+=timingsafe_bcmp.3 timingsafe_memcmp.3
MLINKS+=wmemchr.3 wcpcpy.3 \
wmemchr.3 wcpncpy.3 \
wmemchr.3 wcscasecmp.3 \
Index: head/lib/libc/string/Symbol.map
===================================================================
--- head/lib/libc/string/Symbol.map
+++ head/lib/libc/string/Symbol.map
@@ -104,6 +104,11 @@
explicit_bzero;
};
+FBSD_1.5 {
+ timingsafe_bcmp;
+ timingsafe_memcmp;
+};
+
FBSDprivate_1.0 {
__strtok_r;
};
Index: head/lib/libc/string/bcmp.3
===================================================================
--- head/lib/libc/string/bcmp.3
+++ head/lib/libc/string/bcmp.3
@@ -30,7 +30,7 @@
.\" @(#)bcmp.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
-.Dd June 4, 1993
+.Dd August 15, 2016
.Dt BCMP 3
.Os
.Sh NAME
@@ -62,7 +62,8 @@
.Xr strcasecmp 3 ,
.Xr strcmp 3 ,
.Xr strcoll 3 ,
-.Xr strxfrm 3
+.Xr strxfrm 3 ,
+.Xr timingsafe_bcmp 3
.Sh HISTORY
A
.Fn bcmp
Index: head/lib/libc/string/memcmp.3
===================================================================
--- head/lib/libc/string/memcmp.3
+++ head/lib/libc/string/memcmp.3
@@ -32,7 +32,7 @@
.\" @(#)memcmp.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
-.Dd June 4, 1993
+.Dd August 15, 2016
.Dt MEMCMP 3
.Os
.Sh NAME
@@ -75,6 +75,7 @@
.Xr strcmp 3 ,
.Xr strcoll 3 ,
.Xr strxfrm 3 ,
+.Xr timingsafe_memcmp 3 ,
.Xr wmemcmp 3
.Sh STANDARDS
The
Index: head/lib/libc/string/timingsafe_bcmp.3
===================================================================
--- head/lib/libc/string/timingsafe_bcmp.3
+++ head/lib/libc/string/timingsafe_bcmp.3
@@ -0,0 +1,92 @@
+.\" $OpenBSD: timingsafe_bcmp.3,v 1.2 2014/06/21 20:22:15 tedu Exp $
+.\"
+.\" Copyright (c) 2014 Google Inc.
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.\" $FreeBSD$
+.Dd August 15, 2016
+.Dt TIMINGSAFE_BCMP 3
+.Os
+.Sh NAME
+.Nm timingsafe_bcmp ,
+.Nm timingsafe_memcmp
+.Nd timing-safe byte sequence comparisons
+.Sh SYNOPSIS
+.In string.h
+.Ft int
+.Fn timingsafe_bcmp "const void *b1" "const void *b2" "size_t len"
+.Ft int
+.Fn timingsafe_memcmp "const void *b1" "const void *b2" "size_t len"
+.Sh DESCRIPTION
+The
+.Fn timingsafe_bcmp
+and
+.Fn timingsafe_memcmp
+functions lexicographically compare the first
+.Fa len
+bytes (each interpreted as an
+.Vt unsigned char )
+pointed to by
+.Fa b1
+and
+.Fa b2 .
+.Pp
+Additionally, their running times are independent of the byte sequences compared,
+making them safe to use for comparing secret values such as cryptographic MACs.
+In contrast,
+.Xr bcmp 3
+and
+.Xr memcmp 3
+may short-circuit after finding the first differing byte.
+.Sh RETURN VALUES
+The
+.Fn timingsafe_bcmp
+function returns 0 or not zero if the byte sequence pointed to by
+.Fa b1
+compares equal to or not equal to (respectively)
+the byte sequence pointed to by
+.Fa b2 .
+.Pp
+The
+.Fn timingsafe_memcmp
+function returns a negative value, 0, or positive value if the byte sequence
+pointed to by
+.Fa b1
+compares less than, equal to, or greater than (respectively)
+the byte sequence pointed to by
+.Fa b2 .
+.Sh SEE ALSO
+.Xr bcmp 3 ,
+.Xr memcmp 3
+.Sh STANDARDS
+The
+.Fn timingsafe_bcmp
+and
+.Fn timingsafe_memcmp
+functions are
+.Fx
+extensions.
+.Sh HISTORY
+The
+.Fn timingsafe_bcmp
+function first appeared in
+.Ox 4.9 .
+.Pp
+The
+.Fn timingsafe_memcmp
+function first appeared in
+.Ox 5.6 .
+.Pp
+Both functions first appeared in
+.Fx 12.0 .
Index: head/lib/libc/string/timingsafe_bcmp.c
===================================================================
--- head/lib/libc/string/timingsafe_bcmp.c
+++ head/lib/libc/string/timingsafe_bcmp.c
@@ -0,0 +1,36 @@
+/* $OpenBSD: timingsafe_bcmp.c,v 1.3 2015/08/31 02:53:57 guenther Exp $ */
+/*
+ * Copyright (c) 2010 Damien Miller. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <string.h>
+
+int __timingsafe_bcmp(const void *, const void *, size_t);
+
+int
+__timingsafe_bcmp(const void *b1, const void *b2, size_t n)
+{
+ const unsigned char *p1 = b1, *p2 = b2;
+ int ret = 0;
+
+ for (; n > 0; n--)
+ ret |= *p1++ ^ *p2++;
+ return (ret != 0);
+}
+
+__weak_reference(__timingsafe_bcmp, timingsafe_bcmp);
Index: head/lib/libc/string/timingsafe_memcmp.c
===================================================================
--- head/lib/libc/string/timingsafe_memcmp.c
+++ head/lib/libc/string/timingsafe_memcmp.c
@@ -0,0 +1,53 @@
+/* $OpenBSD: timingsafe_memcmp.c,v 1.2 2015/08/31 02:53:57 guenther Exp $ */
+/*
+ * Copyright (c) 2014 Google Inc.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <limits.h>
+#include <string.h>
+
+int __timingsafe_memcmp(const void *, const void *, size_t);
+
+int
+__timingsafe_memcmp(const void *b1, const void *b2, size_t len)
+{
+ const unsigned char *p1 = b1, *p2 = b2;
+ size_t i;
+ int res = 0, done = 0;
+
+ for (i = 0; i < len; i++) {
+ /* lt is -1 if p1[i] < p2[i]; else 0. */
+ int lt = (p1[i] - p2[i]) >> CHAR_BIT;
+
+ /* gt is -1 if p1[i] > p2[i]; else 0. */
+ int gt = (p2[i] - p1[i]) >> CHAR_BIT;
+
+ /* cmp is 1 if p1[i] > p2[i]; -1 if p1[i] < p2[i]; else 0. */
+ int cmp = lt - gt;
+
+ /* set res = cmp if !done. */
+ res |= cmp & ~done;
+
+ /* set done if p1[i] != p2[i]. */
+ done |= lt | gt;
+ }
+
+ return (res);
+}
+
+__weak_reference(__timingsafe_memcmp, timingsafe_memcmp);

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