606 lines
14 KiB
C
606 lines
14 KiB
C
/*
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* Copyright (C) 2004-2008 Internet Systems Consortium, Inc. ("ISC")
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* Copyright (C) 2000-2003 Internet Software Consortium.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/* $Id: entropy.c,v 1.82 2008/12/01 23:47:45 tbox Exp $ */
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/* \file unix/entropy.c
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* \brief
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* This is the system dependent part of the ISC entropy API.
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*/
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#include <config.h>
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#include <sys/param.h> /* Openserver 5.0.6A and FD_SETSIZE */
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#ifdef HAVE_NANOSLEEP
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#include <time.h>
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#endif
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#include <unistd.h>
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#include <isc/platform.h>
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#include <isc/strerror.h>
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#ifdef ISC_PLATFORM_NEEDSYSSELECTH
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#include <sys/select.h>
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#endif
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#include "errno2result.h"
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/*%
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* There is only one variable in the entropy data structures that is not
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* system independent, but pulling the structure that uses it into this file
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* ultimately means pulling several other independent structures here also to
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* resolve their interdependencies. Thus only the problem variable's type
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* is defined here.
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*/
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#define FILESOURCE_HANDLE_TYPE int
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typedef struct {
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int handle;
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enum {
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isc_usocketsource_disconnected,
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isc_usocketsource_connecting,
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isc_usocketsource_connected,
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isc_usocketsource_ndesired,
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isc_usocketsource_wrote,
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isc_usocketsource_reading
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} status;
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size_t sz_to_recv;
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} isc_entropyusocketsource_t;
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#include "../entropy.c"
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static unsigned int
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get_from_filesource(isc_entropysource_t *source, isc_uint32_t desired) {
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isc_entropy_t *ent = source->ent;
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unsigned char buf[128];
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int fd = source->sources.file.handle;
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ssize_t n, ndesired;
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unsigned int added;
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if (source->bad)
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return (0);
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desired = desired / 8 + (((desired & 0x07) > 0) ? 1 : 0);
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added = 0;
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while (desired > 0) {
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ndesired = ISC_MIN(desired, sizeof(buf));
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n = read(fd, buf, ndesired);
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if (n < 0) {
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if (errno == EAGAIN || errno == EINTR)
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goto out;
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goto err;
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}
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if (n == 0)
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goto err;
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entropypool_adddata(ent, buf, n, n * 8);
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added += n * 8;
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desired -= n;
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}
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goto out;
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err:
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(void)close(fd);
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source->sources.file.handle = -1;
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source->bad = ISC_TRUE;
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out:
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return (added);
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}
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static unsigned int
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get_from_usocketsource(isc_entropysource_t *source, isc_uint32_t desired) {
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isc_entropy_t *ent = source->ent;
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unsigned char buf[128];
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int fd = source->sources.usocket.handle;
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ssize_t n = 0, ndesired;
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unsigned int added;
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size_t sz_to_recv = source->sources.usocket.sz_to_recv;
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if (source->bad)
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return (0);
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desired = desired / 8 + (((desired & 0x07) > 0) ? 1 : 0);
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added = 0;
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while (desired > 0) {
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ndesired = ISC_MIN(desired, sizeof(buf));
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eagain_loop:
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switch ( source->sources.usocket.status ) {
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case isc_usocketsource_ndesired:
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buf[0] = ndesired;
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if ((n = sendto(fd, buf, 1, 0, NULL, 0)) < 0) {
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if (errno == EWOULDBLOCK || errno == EINTR ||
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errno == ECONNRESET)
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goto out;
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goto err;
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}
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INSIST(n == 1);
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source->sources.usocket.status =
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isc_usocketsource_wrote;
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goto eagain_loop;
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case isc_usocketsource_connecting:
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case isc_usocketsource_connected:
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buf[0] = 1;
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buf[1] = ndesired;
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if ((n = sendto(fd, buf, 2, 0, NULL, 0)) < 0) {
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if (errno == EWOULDBLOCK || errno == EINTR ||
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errno == ECONNRESET)
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goto out;
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goto err;
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}
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if (n == 1) {
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source->sources.usocket.status =
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isc_usocketsource_ndesired;
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goto eagain_loop;
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}
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INSIST(n == 2);
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source->sources.usocket.status =
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isc_usocketsource_wrote;
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/*FALLTHROUGH*/
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case isc_usocketsource_wrote:
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if (recvfrom(fd, buf, 1, 0, NULL, NULL) != 1) {
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if (errno == EAGAIN) {
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/*
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* The problem of EAGAIN (try again
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* later) is a major issue on HP-UX.
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* Solaris actually tries the recvfrom
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* call again, while HP-UX just dies.
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* This code is an attempt to let the
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* entropy pool fill back up (at least
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* that's what I think the problem is.)
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* We go to eagain_loop because if we
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* just "break", then the "desired"
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* amount gets borked.
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*/
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#ifdef HAVE_NANOSLEEP
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struct timespec ts;
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ts.tv_sec = 0;
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ts.tv_nsec = 1000000;
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nanosleep(&ts, NULL);
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#else
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usleep(1000);
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#endif
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goto eagain_loop;
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}
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if (errno == EWOULDBLOCK || errno == EINTR)
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goto out;
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goto err;
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}
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source->sources.usocket.status =
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isc_usocketsource_reading;
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sz_to_recv = buf[0];
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source->sources.usocket.sz_to_recv = sz_to_recv;
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if (sz_to_recv > sizeof(buf))
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goto err;
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/*FALLTHROUGH*/
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case isc_usocketsource_reading:
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if (sz_to_recv != 0U) {
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n = recv(fd, buf, sz_to_recv, 0);
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if (n < 0) {
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if (errno == EWOULDBLOCK ||
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errno == EINTR)
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goto out;
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goto err;
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}
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} else
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n = 0;
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break;
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default:
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goto err;
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}
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if ((size_t)n != sz_to_recv)
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source->sources.usocket.sz_to_recv -= n;
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else
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source->sources.usocket.status =
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isc_usocketsource_connected;
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if (n == 0)
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goto out;
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entropypool_adddata(ent, buf, n, n * 8);
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added += n * 8;
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desired -= n;
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}
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goto out;
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err:
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close(fd);
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source->bad = ISC_TRUE;
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source->sources.usocket.status = isc_usocketsource_disconnected;
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source->sources.usocket.handle = -1;
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out:
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return (added);
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}
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/*
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* Poll each source, trying to get data from it to stuff into the entropy
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* pool.
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*/
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static void
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fillpool(isc_entropy_t *ent, unsigned int desired, isc_boolean_t blocking) {
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unsigned int added;
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unsigned int remaining;
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unsigned int needed;
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unsigned int nsource;
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isc_entropysource_t *source;
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REQUIRE(VALID_ENTROPY(ent));
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needed = desired;
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/*
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* This logic is a little strange, so an explanation is in order.
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*
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* If needed is 0, it means we are being asked to "fill to whatever
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* we think is best." This means that if we have at least a
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* partially full pool (say, > 1/4th of the pool) we probably don't
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* need to add anything.
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*
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* Also, we will check to see if the "pseudo" count is too high.
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* If it is, try to mix in better data. Too high is currently
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* defined as 1/4th of the pool.
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*
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* Next, if we are asked to add a specific bit of entropy, make
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* certain that we will do so. Clamp how much we try to add to
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* (DIGEST_SIZE * 8 < needed < POOLBITS - entropy).
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*
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* Note that if we are in a blocking mode, we will only try to
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* get as much data as we need, not as much as we might want
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* to build up.
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*/
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if (needed == 0) {
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REQUIRE(!blocking);
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if ((ent->pool.entropy >= RND_POOLBITS / 4)
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&& (ent->pool.pseudo <= RND_POOLBITS / 4))
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return;
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needed = THRESHOLD_BITS * 4;
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} else {
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needed = ISC_MAX(needed, THRESHOLD_BITS);
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needed = ISC_MIN(needed, RND_POOLBITS);
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}
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/*
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* In any case, clamp how much we need to how much we can add.
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*/
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needed = ISC_MIN(needed, RND_POOLBITS - ent->pool.entropy);
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/*
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* But wait! If we're not yet initialized, we need at least
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* THRESHOLD_BITS
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* of randomness.
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*/
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if (ent->initialized < THRESHOLD_BITS)
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needed = ISC_MAX(needed, THRESHOLD_BITS - ent->initialized);
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/*
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* Poll each file source to see if we can read anything useful from
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* it. XXXMLG When where are multiple sources, we should keep a
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* record of which one we last used so we can start from it (or the
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* next one) to avoid letting some sources build up entropy while
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* others are always drained.
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*/
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added = 0;
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remaining = needed;
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if (ent->nextsource == NULL) {
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ent->nextsource = ISC_LIST_HEAD(ent->sources);
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if (ent->nextsource == NULL)
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return;
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}
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source = ent->nextsource;
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again_file:
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for (nsource = 0; nsource < ent->nsources; nsource++) {
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unsigned int got;
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if (remaining == 0)
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break;
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got = 0;
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switch ( source->type ) {
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case ENTROPY_SOURCETYPE_FILE:
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got = get_from_filesource(source, remaining);
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break;
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case ENTROPY_SOURCETYPE_USOCKET:
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got = get_from_usocketsource(source, remaining);
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break;
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}
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added += got;
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remaining -= ISC_MIN(remaining, got);
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source = ISC_LIST_NEXT(source, link);
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if (source == NULL)
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source = ISC_LIST_HEAD(ent->sources);
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}
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ent->nextsource = source;
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if (blocking && remaining != 0) {
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int fds;
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fds = wait_for_sources(ent);
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if (fds > 0)
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goto again_file;
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}
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/*
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* Here, if there are bits remaining to be had and we can block,
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* check to see if we have a callback source. If so, call them.
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*/
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source = ISC_LIST_HEAD(ent->sources);
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while ((remaining != 0) && (source != NULL)) {
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unsigned int got;
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got = 0;
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if (source->type == ENTROPY_SOURCETYPE_CALLBACK)
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got = get_from_callback(source, remaining, blocking);
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added += got;
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remaining -= ISC_MIN(remaining, got);
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if (added >= needed)
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break;
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source = ISC_LIST_NEXT(source, link);
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}
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/*
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* Mark as initialized if we've added enough data.
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*/
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if (ent->initialized < THRESHOLD_BITS)
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ent->initialized += added;
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}
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static int
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wait_for_sources(isc_entropy_t *ent) {
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isc_entropysource_t *source;
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int maxfd, fd;
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int cc;
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fd_set reads;
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fd_set writes;
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maxfd = -1;
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FD_ZERO(&reads);
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FD_ZERO(&writes);
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source = ISC_LIST_HEAD(ent->sources);
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while (source != NULL) {
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if (source->type == ENTROPY_SOURCETYPE_FILE) {
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fd = source->sources.file.handle;
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if (fd >= 0) {
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maxfd = ISC_MAX(maxfd, fd);
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FD_SET(fd, &reads);
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}
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}
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if (source->type == ENTROPY_SOURCETYPE_USOCKET) {
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fd = source->sources.usocket.handle;
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if (fd >= 0) {
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switch (source->sources.usocket.status) {
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case isc_usocketsource_disconnected:
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break;
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case isc_usocketsource_connecting:
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case isc_usocketsource_connected:
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case isc_usocketsource_ndesired:
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maxfd = ISC_MAX(maxfd, fd);
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FD_SET(fd, &writes);
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break;
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case isc_usocketsource_wrote:
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case isc_usocketsource_reading:
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maxfd = ISC_MAX(maxfd, fd);
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FD_SET(fd, &reads);
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break;
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}
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}
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}
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source = ISC_LIST_NEXT(source, link);
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}
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if (maxfd < 0)
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return (-1);
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cc = select(maxfd + 1, &reads, &writes, NULL, NULL);
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if (cc < 0)
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return (-1);
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return (cc);
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}
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static void
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destroyfilesource(isc_entropyfilesource_t *source) {
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(void)close(source->handle);
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}
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static void
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destroyusocketsource(isc_entropyusocketsource_t *source) {
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close(source->handle);
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}
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/*
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* Make a fd non-blocking
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*/
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static isc_result_t
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make_nonblock(int fd) {
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int ret;
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int flags;
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char strbuf[ISC_STRERRORSIZE];
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#ifdef USE_FIONBIO_IOCTL
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int on = 1;
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ret = ioctl(fd, FIONBIO, (char *)&on);
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#else
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flags = fcntl(fd, F_GETFL, 0);
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flags |= PORT_NONBLOCK;
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ret = fcntl(fd, F_SETFL, flags);
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#endif
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if (ret == -1) {
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isc__strerror(errno, strbuf, sizeof(strbuf));
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UNEXPECTED_ERROR(__FILE__, __LINE__,
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#ifdef USE_FIONBIO_IOCTL
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"ioctl(%d, FIONBIO, &on): %s", fd,
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#else
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"fcntl(%d, F_SETFL, %d): %s", fd, flags,
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#endif
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strbuf);
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return (ISC_R_UNEXPECTED);
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}
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return (ISC_R_SUCCESS);
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}
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isc_result_t
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isc_entropy_createfilesource(isc_entropy_t *ent, const char *fname) {
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int fd;
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struct stat _stat;
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isc_boolean_t is_usocket = ISC_FALSE;
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isc_boolean_t is_connected = ISC_FALSE;
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isc_result_t ret;
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isc_entropysource_t *source;
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REQUIRE(VALID_ENTROPY(ent));
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REQUIRE(fname != NULL);
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LOCK(&ent->lock);
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if (stat(fname, &_stat) < 0) {
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ret = isc__errno2result(errno);
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goto errout;
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}
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/*
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* Solaris 2.5.1 does not have support for sockets (S_IFSOCK),
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* but it does return type S_IFIFO (the OS believes that
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* the socket is a fifo). This may be an issue if we tell
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* the program to look at an actual FIFO as its source of
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* entropy.
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*/
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#if defined(S_ISSOCK)
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if (S_ISSOCK(_stat.st_mode))
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is_usocket = ISC_TRUE;
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#endif
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#if defined(S_ISFIFO) && defined(sun)
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if (S_ISFIFO(_stat.st_mode))
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is_usocket = ISC_TRUE;
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#endif
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if (is_usocket)
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fd = socket(PF_UNIX, SOCK_STREAM, 0);
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else
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fd = open(fname, O_RDONLY | PORT_NONBLOCK, 0);
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if (fd < 0) {
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ret = isc__errno2result(errno);
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goto errout;
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}
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ret = make_nonblock(fd);
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if (ret != ISC_R_SUCCESS)
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goto closefd;
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if (is_usocket) {
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struct sockaddr_un sname;
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memset(&sname, 0, sizeof(sname));
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sname.sun_family = AF_UNIX;
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strncpy(sname.sun_path, fname, sizeof(sname.sun_path));
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sname.sun_path[sizeof(sname.sun_path)-1] = '0';
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#ifdef ISC_PLATFORM_HAVESALEN
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#if !defined(SUN_LEN)
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#define SUN_LEN(su) \
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(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
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#endif
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|
sname.sun_len = SUN_LEN(&sname);
|
|
#endif
|
|
|
|
if (connect(fd, (struct sockaddr *) &sname,
|
|
sizeof(struct sockaddr_un)) < 0) {
|
|
if (errno != EINPROGRESS) {
|
|
ret = isc__errno2result(errno);
|
|
goto closefd;
|
|
}
|
|
} else
|
|
is_connected = ISC_TRUE;
|
|
}
|
|
|
|
source = isc_mem_get(ent->mctx, sizeof(isc_entropysource_t));
|
|
if (source == NULL) {
|
|
ret = ISC_R_NOMEMORY;
|
|
goto closefd;
|
|
}
|
|
|
|
/*
|
|
* From here down, no failures can occur.
|
|
*/
|
|
source->magic = SOURCE_MAGIC;
|
|
source->ent = ent;
|
|
source->total = 0;
|
|
source->bad = ISC_FALSE;
|
|
memset(source->name, 0, sizeof(source->name));
|
|
ISC_LINK_INIT(source, link);
|
|
if (is_usocket) {
|
|
source->sources.usocket.handle = fd;
|
|
if (is_connected)
|
|
source->sources.usocket.status =
|
|
isc_usocketsource_connected;
|
|
else
|
|
source->sources.usocket.status =
|
|
isc_usocketsource_connecting;
|
|
source->sources.usocket.sz_to_recv = 0;
|
|
source->type = ENTROPY_SOURCETYPE_USOCKET;
|
|
} else {
|
|
source->sources.file.handle = fd;
|
|
source->type = ENTROPY_SOURCETYPE_FILE;
|
|
}
|
|
|
|
/*
|
|
* Hook it into the entropy system.
|
|
*/
|
|
ISC_LIST_APPEND(ent->sources, source, link);
|
|
ent->nsources++;
|
|
|
|
UNLOCK(&ent->lock);
|
|
return (ISC_R_SUCCESS);
|
|
|
|
closefd:
|
|
(void)close(fd);
|
|
|
|
errout:
|
|
UNLOCK(&ent->lock);
|
|
|
|
return (ret);
|
|
}
|