/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright 2003-2005 Colin Percival
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing 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 AUTHOR 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/cdefs.h>
#ifndef WITHOUT_CAPSICUM
#include <sys/capsicum.h>
#endif
#include <bzlib.h>
#include <err.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef O_BINARY
#define O_BINARY 0
#endif
#define HEADER_SIZE 32
static char *newfile;
static int dirfd = -1;
static void
exit_cleanup(void)
{
if (dirfd != -1 && newfile != NULL)
if (unlinkat(dirfd, newfile, 0))
warn("unlinkat");
}
static inline off_t
add_off_t(off_t a, off_t b)
{
off_t result;
#if __GNUC__ >= 5 || \
(defined(__has_builtin) && __has_builtin(__builtin_add_overflow))
if (__builtin_add_overflow(a, b, &result))
errx(1, "Corrupt patch");
#else
if ((b > 0 && a > OFF_MAX - b) || (b < 0 && a < OFF_MIN - b))
errx(1, "Corrupt patch");
result = a + b;
#endif
return result;
}
static off_t offtin(u_char *buf)
{
off_t y;
y = buf[7] & 0x7F;
y = y * 256; y += buf[6];
y = y * 256; y += buf[5];
y = y * 256; y += buf[4];
y = y * 256; y += buf[3];
y = y * 256; y += buf[2];
y = y * 256; y += buf[1];
y = y * 256; y += buf[0];
if (buf[7] & 0x80)
y = -y;
return (y);
}
static void
usage(void)
{
fprintf(stderr, "usage: bspatch oldfile newfile patchfile\n");
exit(1);
}
int main(int argc, char *argv[])
{
FILE *f, *cpf, *dpf, *epf;
BZFILE *cpfbz2, *dpfbz2, *epfbz2;
char *directory, *namebuf;
int cbz2err, dbz2err, ebz2err;
int newfd, oldfd;
off_t oldsize, newsize;
off_t bzctrllen, bzdatalen;
u_char header[HEADER_SIZE], buf[8];
u_char *old, *new;
off_t oldpos, newpos;
off_t ctrl[3];
off_t i, lenread, offset;
#ifndef WITHOUT_CAPSICUM
cap_rights_t rights_dir, rights_ro, rights_wr;
#endif
if (argc != 4)
usage();
/* Open patch file */
if ((f = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
/* Open patch file for control block */
if ((cpf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
/* open patch file for diff block */
if ((dpf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
/* open patch file for extra block */
if ((epf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
/* open oldfile */
if ((oldfd = open(argv[1], O_RDONLY | O_BINARY, 0)) < 0)
err(1, "open(%s)", argv[1]);
/* open directory where we'll write newfile */
if ((namebuf = strdup(argv[2])) == NULL ||
(directory = dirname(namebuf)) == NULL ||
(dirfd = open(directory, O_DIRECTORY)) < 0)
err(1, "open %s", argv[2]);
free(namebuf);
if ((newfile = basename(argv[2])) == NULL)
err(1, "basename");
/* open newfile */
if ((newfd = openat(dirfd, newfile,
O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666)) < 0)
err(1, "open(%s)", argv[2]);
atexit(exit_cleanup);
#ifndef WITHOUT_CAPSICUM
if (cap_enter() < 0)
err(1, "failed to enter security sandbox");
cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
cap_rights_init(&rights_wr, CAP_WRITE);
cap_rights_init(&rights_dir, CAP_UNLINKAT);
if (cap_rights_limit(fileno(f), &rights_ro) < 0 ||
cap_rights_limit(fileno(cpf), &rights_ro) < 0 ||
cap_rights_limit(fileno(dpf), &rights_ro) < 0 ||
cap_rights_limit(fileno(epf), &rights_ro) < 0 ||
cap_rights_limit(oldfd, &rights_ro) < 0 ||
cap_rights_limit(newfd, &rights_wr) < 0 ||
cap_rights_limit(dirfd, &rights_dir) < 0)
err(1, "cap_rights_limit() failed, could not restrict"
" capabilities");
#endif
/*
File format:
0 8 "BSDIFF40"
8 8 X
16 8 Y
24 8 sizeof(newfile)
32 X bzip2(control block)
32+X Y bzip2(diff block)
32+X+Y ??? bzip2(extra block)
with control block a set of triples (x,y,z) meaning "add x bytes
from oldfile to x bytes from the diff block; copy y bytes from the
extra block; seek forwards in oldfile by z bytes".
*/
/* Read header */
if (fread(header, 1, HEADER_SIZE, f) < HEADER_SIZE) {
if (feof(f))
errx(1, "Corrupt patch");
err(1, "fread(%s)", argv[3]);
}
/* Check for appropriate magic */
if (memcmp(header, "BSDIFF40", 8) != 0)
errx(1, "Corrupt patch");
/* Read lengths from header */
bzctrllen = offtin(header + 8);
bzdatalen = offtin(header + 16);
newsize = offtin(header + 24);
if (bzctrllen < 0 || bzctrllen > OFF_MAX - HEADER_SIZE ||
bzdatalen < 0 || bzctrllen + HEADER_SIZE > OFF_MAX - bzdatalen ||
newsize < 0 || newsize > SSIZE_MAX)
errx(1, "Corrupt patch");
/* Close patch file and re-open it via libbzip2 at the right places */
if (fclose(f))
err(1, "fclose(%s)", argv[3]);
offset = HEADER_SIZE;
if (fseeko(cpf, offset, SEEK_SET))
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
offset = add_off_t(offset, bzctrllen);
if (fseeko(dpf, offset, SEEK_SET))
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
offset = add_off_t(offset, bzdatalen);
if (fseeko(epf, offset, SEEK_SET))
err(1, "fseeko(%s, %jd)", argv[3], (intmax_t)offset);
if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
oldsize > SSIZE_MAX ||
(old = malloc(oldsize)) == NULL ||
lseek(oldfd, 0, SEEK_SET) != 0 ||
read(oldfd, old, oldsize) != oldsize ||
close(oldfd) == -1)
err(1, "%s", argv[1]);
if ((new = malloc(newsize)) == NULL)
err(1, NULL);
oldpos = 0;
newpos = 0;
while (newpos < newsize) {
/* Read control data */
for (i = 0; i <= 2; i++) {
lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
if ((lenread < 8) || ((cbz2err != BZ_OK) &&
(cbz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch");
ctrl[i] = offtin(buf);
}
/* Sanity-check */
if (ctrl[0] < 0 || ctrl[0] > INT_MAX ||
ctrl[1] < 0 || ctrl[1] > INT_MAX)
errx(1, "Corrupt patch");
/* Sanity-check */
if (add_off_t(newpos, ctrl[0]) > newsize)
errx(1, "Corrupt patch");
/* Read diff string */
lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
if ((lenread < ctrl[0]) ||
((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch");
/* Add old data to diff string */
for (i = 0; i < ctrl[0]; i++)
if (add_off_t(oldpos, i) < oldsize)
new[newpos + i] += old[oldpos + i];
/* Adjust pointers */
newpos = add_off_t(newpos, ctrl[0]);
oldpos = add_off_t(oldpos, ctrl[0]);
/* Sanity-check */
if (add_off_t(newpos, ctrl[1]) > newsize)
errx(1, "Corrupt patch");
/* Read extra string */
lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
if ((lenread < ctrl[1]) ||
((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch");
/* Adjust pointers */
newpos = add_off_t(newpos, ctrl[1]);
oldpos = add_off_t(oldpos, ctrl[2]);
}
/* Clean up the bzip2 reads */
BZ2_bzReadClose(&cbz2err, cpfbz2);
BZ2_bzReadClose(&dbz2err, dpfbz2);
BZ2_bzReadClose(&ebz2err, epfbz2);
if (fclose(cpf) || fclose(dpf) || fclose(epf))
err(1, "fclose(%s)", argv[3]);
/* Write the new file */
if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
err(1, "%s", argv[2]);
/* Disable atexit cleanup */
newfile = NULL;
free(new);
free(old);
return (0);
}
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