From: schwarze <schwarze@openbsd.org>
Date: Tue, 21 Dec 2021 11:14:07 +0000 (+0000)
Subject: document BN_MONT_CTX_set_locked(3)
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=3de09c26cd5c245ac3554c58b815a64a4ee34f8c;p=openbsd

document BN_MONT_CTX_set_locked(3)
---

diff --git a/lib/libcrypto/man/BN_mod_mul_montgomery.3 b/lib/libcrypto/man/BN_mod_mul_montgomery.3
index 963ba8fcd46..7b22efd7f59 100644
--- a/lib/libcrypto/man/BN_mod_mul_montgomery.3
+++ b/lib/libcrypto/man/BN_mod_mul_montgomery.3
@@ -1,7 +1,25 @@
-.\"	$OpenBSD: BN_mod_mul_montgomery.3,v 1.13 2021/12/06 19:45:27 schwarze Exp $
-.\"	OpenSSL 6859cf74 Sep 25 13:33:28 2002 +0000
+.\" $OpenBSD: BN_mod_mul_montgomery.3,v 1.14 2021/12/21 11:14:07 schwarze Exp $
+.\" full merge up to: OpenSSL 6859cf74 Sep 25 13:33:28 2002 +0000
+.\" selective merge up to: OpenSSL 24a535ea Sep 22 13:14:20 2020 +0100
 .\"
-.\" This file was written by Ulf Moeller <ulf@openssl.org>.
+.\" This file is a derived work.
+.\" The changes are covered by the following Copyright and license:
+.\"
+.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
+.\"
+.\" 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.
+.\"
+.\" The original file was written by Ulf Moeller <ulf@openssl.org>.
 .\" Copyright (c) 2000 The OpenSSL Project.  All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -48,7 +66,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 .\" OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: December 6 2021 $
+.Dd $Mdocdate: December 21 2021 $
 .Dt BN_MOD_MUL_MONTGOMERY 3
 .Os
 .Sh NAME
@@ -56,6 +74,7 @@
 .Nm BN_MONT_CTX_init ,
 .Nm BN_MONT_CTX_free ,
 .Nm BN_MONT_CTX_set ,
+.Nm BN_MONT_CTX_set_locked ,
 .Nm BN_MONT_CTX_copy ,
 .Nm BN_mod_mul_montgomery ,
 .Nm BN_from_montgomery ,
@@ -82,6 +101,13 @@
 .Fa "BN_CTX *ctx"
 .Fc
 .Ft BN_MONT_CTX *
+.Fo BN_MONT_CTX_set_locked
+.Fa "BN_MONT_CTX **pmont"
+.Fa "int lock"
+.Fa "const BIGNUM *m"
+.Fa "BN_CTX *ctx"
+.Fc
+.Ft BN_MONT_CTX *
 .Fo BN_MONT_CTX_copy
 .Fa "BN_MONT_CTX *to"
 .Fa "BN_MONT_CTX *from"
@@ -133,6 +159,37 @@ structure from the modulus
 .Fa m
 by precomputing its inverse and a value R.
 .Pp
+.Fn BN_MONT_CTX_set_locked
+is a wrapper around
+.Fn BN_MONT_CTX_new
+and
+.Fn BN_MONT_CTX_set
+that is useful if more than one thread intends to use the same
+.Vt BN_MONT_CTX
+and none of these threads is exclusively responsible for creating
+and initializing the context.
+.Fn BN_MONT_CTX_set_locked
+first acquires the specified
+.Fa lock
+using
+.Xr CRYPTO_lock 3 .
+If
+.Pf * Fa pmont
+already differs from
+.Dv NULL ,
+no action occurs.
+Otherwise, a new
+.Vt BN_MONT_CTX
+is allocated with
+.Fn BN_MONT_CTX_new ,
+set up with
+.Fn BN_MONT_CTX_set ,
+and a pointer to it is stored in
+.Pf * Fa pmont .
+Finally, the
+.Fa lock
+is released.
+.Pp
 .Fn BN_MONT_CTX_copy
 copies the
 .Vt BN_MONT_CTX
@@ -207,13 +264,19 @@ or
 .Dv NULL
 on error.
 .Pp
+.Fn BN_MONT_CTX_set_locked
+returns a pointer to the existing or newly created context or
+.Dv NULL
+on error.
+.Pp
 For the other functions, 1 is returned for success or 0 on error.
 The error codes can be obtained by
 .Xr ERR_get_error 3 .
 .Sh SEE ALSO
 .Xr BN_add 3 ,
 .Xr BN_CTX_new 3 ,
-.Xr BN_new 3
+.Xr BN_new 3 ,
+.Xr CRYPTO_lock 3
 .Sh HISTORY
 .Fn BN_MONT_CTX_new ,
 .Fn BN_MONT_CTX_free ,
@@ -230,6 +293,10 @@ and
 .Fn BN_MONT_CTX_copy
 first appeared in SSLeay 0.9.1 and have been available since
 .Ox 2.6 .
+.Pp
+.Fn BN_MONT_CTX_set_locked
+first appeared in OpenSSL 0.9.8 and has been available since
+.Ox 4.0 .
 .Sh CAVEATS
 .Fn BN_MONT_CTX_init
 must not be called on a context that was used previously, or