e9ac27430c
The general idea here is to provide userspace programs with well-defined sources of entropy, in a fashion that doesn't require opening a new file descriptor (ulimits) or accessing paths (/dev/urandom may be restricted by chroot or capsicum). getrandom(2) is the more general API, and comes from the Linux world. Since our urandom and random devices are identical, the GRND_RANDOM flag is ignored. getentropy(3) is added as a compatibility shim for the OpenBSD API. truss(1) support is included. Tests for both system calls are provided. Coverage is believed to be at least as comprehensive as LTP getrandom(2) test coverage. Additionally, instructions for running the LTP tests directly against FreeBSD are provided in the "Test Plan" section of the Differential revision linked below. (They pass, of course.) PR: 194204 Reported by: David CARLIER <david.carlier AT hardenedbsd.org> Discussed with: cperciva, delphij, jhb, markj Relnotes: maybe Differential Revision: https://reviews.freebsd.org/D14500
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/random.h>
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#include <errno.h>
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#include <stdlib.h>
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#include "libc_private.h"
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int
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getentropy(void *buf, size_t buflen)
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{
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ssize_t rd;
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if (buflen > 256) {
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errno = EIO;
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return (-1);
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}
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while (buflen > 0) {
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rd = getrandom(buf, buflen, 0);
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if (rd == -1) {
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if (errno == EINTR)
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continue;
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else if (errno == ENOSYS)
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abort();
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else
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return (-1);
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}
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/* This cannot happen. */
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if (rd == 0)
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abort();
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buf = (char *)buf + rd;
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buflen -= rd;
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}
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return (0);
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}
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