IABSD.fr/src/sys/stand/boot/boot.c

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• Author : deraadt
  Date : 2019-10-29 02:55:49
  Hash : f65494e6
  Message : Use arc4 to bit-spread the 512-byte random buffer over the .openbsd.randomdata section, which has grown a fair bit with the introduction of retguard. Mortimer discovered the repeated 512-byte sequence as retguard keys, and this resolves the issue. (Chacha does not fit on the media, so 1.5K early drop RC4 is hopefully sufficient in our KARL link universe) Version crank the bootblocks. sysupgrade -s will install new bootblocks. ok djm mortimer

• sys/stand/boot/boot.c

• /*	$OpenBSD: boot.c,v 1.50 2019/10/29 02:55:50 deraadt Exp $	*/
  
  /*
   * Copyright (c) 2003 Dale Rahn
   * Copyright (c) 1997,1998 Michael Shalayeff
   * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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.
   *
   */
  
  #include <sys/param.h>
  #include <sys/reboot.h>
  #include <sys/stat.h>
  #include <libsa.h>
  #include <lib/libsa/loadfile.h>
  #include <lib/libkern/funcs.h>
  #include <lib/libsa/arc4.h>
  
  #include <stand/boot/bootarg.h>
  
  #include "cmd.h"
  
  #ifndef KERNEL
  #define KERNEL "/bsd"
  #endif
  
  char prog_ident[40];
  char *progname = "BOOT";
  
  extern	const char version[];
  struct cmd_state cmd;
  
  /* bootprompt can be set by MD code to avoid prompt first time round */
  int bootprompt = 1;
  char *kernelfile = KERNEL;		/* can be changed by MD code */
  int boottimeout = 5;			/* can be changed by MD code */
  
  char	rnddata[BOOTRANDOM_MAX];
  struct rc4_ctx randomctx;
  
  void
  boot(dev_t bootdev)
  {
  	int fd, isupgrade = 0;
  	int try = 0, st;
  	uint64_t marks[MARK_MAX];
  
  	machdep();
  
  	snprintf(prog_ident, sizeof(prog_ident),
  	    ">> OpenBSD/" MACHINE " %s %s", progname, version);
  	printf("%s\n", prog_ident);
  
  	devboot(bootdev, cmd.bootdev);
  	strlcpy(cmd.image, kernelfile, sizeof(cmd.image));
  	cmd.boothowto = 0;
  	cmd.conf = "/etc/boot.conf";
  	cmd.addr = (void *)DEFAULT_KERNEL_ADDRESS;
  	cmd.timeout = boottimeout;
  
  	if (upgrade()) {
  		strlcpy(cmd.image, "/bsd.upgrade", sizeof(cmd.image));
  		printf("upgrade detected: switching to %s\n", cmd.image);
  		isupgrade = 1;
  	}
  
  	st = read_conf();
  
  #ifdef HIBERNATE
  	int bootdev_has_hibernate(void);
  
  	if (bootdev_has_hibernate()) {
  		strlcpy(cmd.image, "/bsd.booted", sizeof(cmd.image));
  		printf("unhibernate detected: switching to %s\n", cmd.image);
  	}
  #endif
  
  	if (!bootprompt)
  		snprintf(cmd.path, sizeof cmd.path, "%s:%s",
  		    cmd.bootdev, cmd.image);
  
  	while (1) {
  		/* no boot.conf, or no boot cmd in there */
  		if (bootprompt && st <= 0) {
  			do {
  				printf("boot> ");
  			} while(!getcmd());
  		}
  
  		loadrandom(BOOTRANDOM, rnddata, sizeof(rnddata));
  #ifdef MDRANDOM
  		mdrandom(rnddata, sizeof(rnddata));
  #endif
  #ifdef FWRANDOM
  		fwrandom(rnddata, sizeof(rnddata));
  #endif
  		rc4_keysetup(&randomctx, rnddata, sizeof rnddata);
  		rc4_skip(&randomctx, 1536);
  
  		st = 0;
  		bootprompt = 1;	/* allow reselect should we fail */
  
  		printf("booting %s: ", cmd.path);
  		marks[MARK_START] = (u_long)cmd.addr;
  		if ((fd = loadfile(cmd.path, marks, LOAD_ALL)) != -1) {
  
  		        /* Prevent re-upgrade: chmod a-x bsd.upgrade */
  			if (isupgrade) {
  				struct stat st;
  
  				if (fstat(fd, &st) == 0) {
  					st.st_mode &= ~(S_IXUSR|S_IXGRP|S_IXOTH);
  					if (fchmod(fd, st.st_mode) == -1)
  						printf("fchmod a-x %s: failed\n",
  						    cmd.path);
  				}
  			}
  			close(fd);
  			break;
  		}
  
  		kernelfile = KERNEL;
  		try++;
  		strlcpy(cmd.image, kernelfile, sizeof(cmd.image));
  		printf(" failed(%d). will try %s\n", errno, kernelfile);
  
  		if (try < 2) {
  			if (cmd.timeout > 0)
  				cmd.timeout++;
  		} else {
  			if (cmd.timeout)
  				printf("Turning timeout off.\n");
  			cmd.timeout = 0;
  		}
  	}
  
  	/* exec */
  	run_loadfile(marks, cmd.boothowto);
  }
  
  void
  loadrandom(char *name, char *buf, size_t buflen)
  {
  	char path[MAXPATHLEN];
  	struct stat sb;
  	int fd, i;
  
  #define O_RDONLY	0
  
  	/* Extract the device name from the kernel we are loading. */
  	for (i = 0; i < sizeof(cmd.path); i++) {
  		if (cmd.path[i] == ':') {
  			strlcpy(path, cmd.path, i + 1);
  			snprintf(path + i, sizeof(path) - i, ":%s", name);
  			break;
  		} else if (cmd.path[i] == '\0') {
  			snprintf(path, sizeof path, "%s:%s",
  			    cmd.bootdev, name);
  			break;
  		}
  	}
  
  	fd = open(path, O_RDONLY);
  	if (fd == -1) {
  		if (errno != EPERM)
  			printf("cannot open %s: %s\n", path, strerror(errno));
  		return;
  	}
  	if (fstat(fd, &sb) == -1 ||
  	    sb.st_uid != 0 ||
  	    (sb.st_mode & (S_IWOTH|S_IROTH)))
  		goto fail;
  	(void) read(fd, buf, buflen);
  fail:
  	close(fd);
  }