freebsd-dev/sbin/dumpon/dumpon.c
Mark Johnston 6026dcd7ca Add support for zstd-compressed user and kernel core dumps.
This works similarly to the existing gzip compression support, but
zstd is typically faster and gives better compression ratios.

Support for this functionality must be configured by adding ZSTDIO to
one's kernel configuration file. dumpon(8)'s new -Z option is used to
configure zstd compression for kernel dumps. savecore(8) now recognizes
and saves zstd-compressed kernel dumps with a .zst extension.

Submitted by:	cem (original version)
Relnotes:	yes
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13101,
			https://reviews.freebsd.org/D13633
2018-02-13 19:28:02 +00:00

304 lines
7.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1980, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if 0
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1980, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "From: @(#)swapon.c 8.1 (Berkeley) 6/5/93";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/disk.h>
#include <sys/sysctl.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#ifdef HAVE_CRYPTO
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#endif
static int verbose;
static void
usage(void)
{
fprintf(stderr, "%s\n%s\n%s\n",
"usage: dumpon [-v] [-k public_key_file] [-Zz] special_file",
" dumpon [-v] off",
" dumpon [-v] -l");
exit(EX_USAGE);
}
static void
check_size(int fd, const char *fn)
{
int name[] = { CTL_HW, HW_PHYSMEM };
size_t namelen = nitems(name);
unsigned long physmem;
size_t len;
off_t mediasize;
int minidump;
len = sizeof(minidump);
if (sysctlbyname("debug.minidump", &minidump, &len, NULL, 0) == 0 &&
minidump == 1)
return;
len = sizeof(physmem);
if (sysctl(name, namelen, &physmem, &len, NULL, 0) != 0)
err(EX_OSERR, "can't get memory size");
if (ioctl(fd, DIOCGMEDIASIZE, &mediasize) != 0)
err(EX_OSERR, "%s: can't get size", fn);
if ((uintmax_t)mediasize < (uintmax_t)physmem) {
if (verbose)
printf("%s is smaller than physical memory\n", fn);
exit(EX_IOERR);
}
}
#ifdef HAVE_CRYPTO
static void
genkey(const char *pubkeyfile, struct diocskerneldump_arg *kda)
{
FILE *fp;
RSA *pubkey;
assert(pubkeyfile != NULL);
assert(kda != NULL);
fp = NULL;
pubkey = NULL;
fp = fopen(pubkeyfile, "r");
if (fp == NULL)
err(1, "Unable to open %s", pubkeyfile);
if (cap_enter() < 0 && errno != ENOSYS)
err(1, "Unable to enter capability mode");
pubkey = RSA_new();
if (pubkey == NULL) {
errx(1, "Unable to allocate an RSA structure: %s",
ERR_error_string(ERR_get_error(), NULL));
}
pubkey = PEM_read_RSA_PUBKEY(fp, &pubkey, NULL, NULL);
fclose(fp);
fp = NULL;
if (pubkey == NULL)
errx(1, "Unable to read data from %s.", pubkeyfile);
kda->kda_encryptedkeysize = RSA_size(pubkey);
if (kda->kda_encryptedkeysize > KERNELDUMP_ENCKEY_MAX_SIZE) {
errx(1, "Public key has to be at most %db long.",
8 * KERNELDUMP_ENCKEY_MAX_SIZE);
}
kda->kda_encryptedkey = calloc(1, kda->kda_encryptedkeysize);
if (kda->kda_encryptedkey == NULL)
err(1, "Unable to allocate encrypted key");
kda->kda_encryption = KERNELDUMP_ENC_AES_256_CBC;
arc4random_buf(kda->kda_key, sizeof(kda->kda_key));
if (RSA_public_encrypt(sizeof(kda->kda_key), kda->kda_key,
kda->kda_encryptedkey, pubkey,
RSA_PKCS1_PADDING) != (int)kda->kda_encryptedkeysize) {
errx(1, "Unable to encrypt the one-time key.");
}
RSA_free(pubkey);
}
#endif
static void
listdumpdev(void)
{
char dumpdev[PATH_MAX];
size_t len;
const char *sysctlname = "kern.shutdown.dumpdevname";
len = sizeof(dumpdev);
if (sysctlbyname(sysctlname, &dumpdev, &len, NULL, 0) != 0) {
if (errno == ENOMEM) {
err(EX_OSERR, "Kernel returned too large of a buffer for '%s'\n",
sysctlname);
} else {
err(EX_OSERR, "Sysctl get '%s'\n", sysctlname);
}
}
if (verbose) {
printf("kernel dumps on ");
}
if (strlen(dumpdev) == 0) {
printf("%s\n", _PATH_DEVNULL);
} else {
printf("%s\n", dumpdev);
}
}
int
main(int argc, char *argv[])
{
struct diocskerneldump_arg kda;
const char *pubkeyfile;
int ch;
int i, fd;
int do_listdumpdev = 0;
bool enable, gzip, zstd;
gzip = zstd = false;
pubkeyfile = NULL;
while ((ch = getopt(argc, argv, "k:lvZz")) != -1)
switch((char)ch) {
case 'k':
pubkeyfile = optarg;
break;
case 'l':
do_listdumpdev = 1;
break;
case 'v':
verbose = 1;
break;
case 'Z':
zstd = true;
break;
case 'z':
gzip = true;
break;
default:
usage();
}
if (gzip && zstd)
errx(EX_USAGE, "The -z and -Z options are mutually exclusive.");
argc -= optind;
argv += optind;
if (do_listdumpdev) {
listdumpdev();
exit(EX_OK);
}
if (argc != 1)
usage();
enable = (strcmp(argv[0], "off") != 0);
#ifndef HAVE_CRYPTO
if (pubkeyfile != NULL) {
enable = false;
warnx("Unable to use the public key. Recompile dumpon with OpenSSL support.");
}
#endif
if (enable) {
char tmp[PATH_MAX];
char *dumpdev;
if (strncmp(argv[0], _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0) {
dumpdev = argv[0];
} else {
i = snprintf(tmp, PATH_MAX, "%s%s", _PATH_DEV, argv[0]);
if (i < 0) {
err(EX_OSERR, "%s", argv[0]);
} else if (i >= PATH_MAX) {
errno = EINVAL;
err(EX_DATAERR, "%s", argv[0]);
}
dumpdev = tmp;
}
fd = open(dumpdev, O_RDONLY);
if (fd < 0)
err(EX_OSFILE, "%s", dumpdev);
if (!gzip && !zstd)
check_size(fd, dumpdev);
bzero(&kda, sizeof(kda));
kda.kda_enable = 0;
i = ioctl(fd, DIOCSKERNELDUMP, &kda);
explicit_bzero(&kda, sizeof(kda));
#ifdef HAVE_CRYPTO
if (pubkeyfile != NULL)
genkey(pubkeyfile, &kda);
#endif
kda.kda_enable = 1;
kda.kda_compression = KERNELDUMP_COMP_NONE;
if (zstd)
kda.kda_compression = KERNELDUMP_COMP_ZSTD;
else if (gzip)
kda.kda_compression = KERNELDUMP_COMP_GZIP;
i = ioctl(fd, DIOCSKERNELDUMP, &kda);
explicit_bzero(kda.kda_encryptedkey, kda.kda_encryptedkeysize);
free(kda.kda_encryptedkey);
explicit_bzero(&kda, sizeof(kda));
if (i == 0 && verbose)
printf("kernel dumps on %s\n", dumpdev);
} else {
fd = open(_PATH_DEVNULL, O_RDONLY);
if (fd < 0)
err(EX_OSFILE, "%s", _PATH_DEVNULL);
kda.kda_enable = 0;
i = ioctl(fd, DIOCSKERNELDUMP, &kda);
explicit_bzero(&kda, sizeof(kda));
if (i == 0 && verbose)
printf("kernel dumps disabled\n");
}
if (i < 0)
err(EX_OSERR, "ioctl(DIOCSKERNELDUMP)");
exit (0);
}