minix/usr.bin/patch/inp.c
David van Moolenbroek d8127f841f patch(1): fix arbitrary code execution bug
This is the combination of two NetBSD patches committed by Christos
Zoulas, based on the findings and Bitrig patch by Martin Natano.
The NetBSD log messages read:

  From Martin Natano @bitrig: Use execve(2) instead of system to
  apply patches that require rcs command execution instead system(3)
  to avoid malicious filenames in patches causing bad things to
  happen. In the process, lose SCCS support. It is not like we are
  shipping sccs commands for that to work.

And:

  Use absolute paths for RCS commands (Martin Natano)

Change-Id: Id44bd59a5a6bc6cd95d1e1fae468bd718cfff2db
2015-07-26 15:53:47 +00:00

519 lines
13 KiB
C

/*
* $OpenBSD: inp.c,v 1.34 2006/03/11 19:41:30 otto Exp $
* $DragonFly: src/usr.bin/patch/inp.c,v 1.6 2007/09/29 23:11:10 swildner Exp $
* $NetBSD: inp.c,v 1.24 2015/07/24 18:56:00 christos Exp $
*/
/*
* patch - a program to apply diffs to original files
*
* Copyright 1986, Larry Wall
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following condition is met:
* 1. Redistributions of source code must retain the above copyright notice,
* this condition and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* -C option added in 1998, original code by Marc Espie, based on FreeBSD
* behaviour
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: inp.c,v 1.24 2015/07/24 18:56:00 christos Exp $");
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "common.h"
#include "util.h"
#include "pch.h"
#include "inp.h"
/* Input-file-with-indexable-lines abstract type */
static off_t i_size; /* size of the input file */
static char *i_womp; /* plan a buffer for entire file */
static char **i_ptr; /* pointers to lines in i_womp */
static char empty_line[] = { '\0' };
static int tifd = -1; /* plan b virtual string array */
static char *tibuf[2]; /* plan b buffers */
static LINENUM tiline[2] = {-1, -1}; /* 1st line in each buffer */
static LINENUM lines_per_buf; /* how many lines per buffer */
static int tireclen; /* length of records in tmp file */
static bool rev_in_string(const char *);
static bool reallocate_lines(size_t *);
/* returns false if insufficient memory */
static bool plan_a(const char *);
static void plan_b(const char *);
/* New patch--prepare to edit another file. */
void
re_input(void)
{
if (using_plan_a) {
i_size = 0;
free(i_ptr);
i_ptr = NULL;
if (i_womp != NULL) {
munmap(i_womp, i_size);
i_womp = NULL;
}
} else {
using_plan_a = true; /* maybe the next one is smaller */
close(tifd);
tifd = -1;
free(tibuf[0]);
free(tibuf[1]);
tibuf[0] = tibuf[1] = NULL;
tiline[0] = tiline[1] = -1;
tireclen = 0;
}
}
/* Construct the line index, somehow or other. */
void
scan_input(const char *filename)
{
if (!plan_a(filename))
plan_b(filename);
if (verbose) {
say("Patching file %s using Plan %s...\n", filename,
(using_plan_a ? "A" : "B"));
}
}
static bool
reallocate_lines(size_t *lines_allocated)
{
char **p;
size_t new_size;
new_size = *lines_allocated * 3 / 2;
p = realloc(i_ptr, (new_size + 2) * sizeof(char *));
if (p == NULL) { /* shucks, it was a near thing */
munmap(i_womp, i_size);
i_womp = NULL;
free(i_ptr);
i_ptr = NULL;
*lines_allocated = 0;
return false;
}
*lines_allocated = new_size;
i_ptr = p;
return true;
}
/* Try keeping everything in memory. */
static bool
plan_a(const char *filename)
{
int ifd, statfailed, devnull, pstat;
char *p, *s, lbuf[MAXLINELEN];
struct stat filestat;
off_t i;
ptrdiff_t sz;
size_t iline, lines_allocated;
pid_t pid;
char *argp[4] = {NULL};
#ifdef DEBUGGING
if (debug & 8)
return false;
#endif
if (filename == NULL || *filename == '\0')
return false;
statfailed = stat(filename, &filestat);
if (statfailed && ok_to_create_file) {
if (verbose)
say("(Creating file %s...)\n", filename);
/*
* in check_patch case, we still display `Creating file' even
* though we're not. The rule is that -C should be as similar
* to normal patch behavior as possible
*/
if (check_only)
return true;
makedirs(filename, true);
close(creat(filename, 0666));
statfailed = stat(filename, &filestat);
}
if (statfailed && check_only)
fatal("%s not found, -C mode, can't probe further\n", filename);
/* For nonexistent or read-only files, look for RCS versions. */
if (statfailed ||
/* No one can write to it. */
(filestat.st_mode & 0222) == 0 ||
/* I can't write to it. */
((filestat.st_mode & 0022) == 0 && filestat.st_uid != getuid())) {
char *filebase, *filedir;
struct stat cstat;
char *tmp_filename1, *tmp_filename2;
tmp_filename1 = strdup(filename);
tmp_filename2 = strdup(filename);
if (tmp_filename1 == NULL || tmp_filename2 == NULL)
fatal("strdupping filename");
filebase = basename(tmp_filename1);
filedir = dirname(tmp_filename2);
#define try(f, a1, a2, a3) \
(snprintf(lbuf, sizeof lbuf, f, a1, a2, a3), stat(lbuf, &cstat) == 0)
/*
* else we can't write to it but it's not under a version
* control system, so just proceed.
*/
if (try("%s/RCS/%s%s", filedir, filebase, RCSSUFFIX) ||
try("%s/RCS/%s%s", filedir, filebase, "") ||
try("%s/%s%s", filedir, filebase, RCSSUFFIX)) {
if (!statfailed) {
if ((filestat.st_mode & 0222) != 0)
/* The owner can write to it. */
fatal("file %s seems to be locked "
"by somebody else under RCS\n",
filename);
/*
* It might be checked out unlocked. See if
* it's safe to check out the default version
* locked.
*/
if (verbose)
say("Comparing file %s to default "
"RCS version...\n", filename);
switch (pid = fork()) {
case -1:
fatal("can't fork: %s\n",
strerror(errno));
case 0:
devnull = open("/dev/null", O_RDONLY);
if (devnull == -1) {
fatal("can't open /dev/null: %s",
strerror(errno));
}
(void)dup2(devnull, STDOUT_FILENO);
argp[0] = __UNCONST(RCSDIFF);
argp[1] = __UNCONST(filename);
execv(RCSDIFF, argp);
exit(127);
}
pid = waitpid(pid, &pstat, 0);
if (pid == -1 || WEXITSTATUS(pstat) != 0) {
fatal("can't check out file %s: "
"differs from default RCS version\n",
filename);
}
}
if (verbose)
say("Checking out file %s from RCS...\n",
filename);
switch (pid = fork()) {
case -1:
fatal("can't fork: %s\n", strerror(errno));
case 0:
argp[0] = __UNCONST(CHECKOUT);
argp[1] = __UNCONST("-l");
argp[2] = __UNCONST(filename);
execv(CHECKOUT, argp);
exit(127);
}
pid = waitpid(pid, &pstat, 0);
if (pid == -1 || WEXITSTATUS(pstat) != 0 ||
stat(filename, &filestat)) {
fatal("can't check out file %s from RCS\n",
filename);
}
} else if (statfailed) {
fatal("can't find %s\n", filename);
}
free(tmp_filename1);
free(tmp_filename2);
}
filemode = filestat.st_mode;
if (!S_ISREG(filemode))
fatal("%s is not a normal file--can't patch\n", filename);
i_size = filestat.st_size;
if (out_of_mem) {
set_hunkmax(); /* make sure dynamic arrays are allocated */
out_of_mem = false;
return false; /* force plan b because plan a bombed */
}
if ((uintmax_t)i_size > (uintmax_t)SIZE_MAX) {
say("block too large to mmap\n");
return false;
}
if ((ifd = open(filename, O_RDONLY)) < 0)
pfatal("can't open file %s", filename);
if (i_size) {
i_womp = mmap(NULL, i_size, PROT_READ, MAP_PRIVATE, ifd, 0);
if (i_womp == MAP_FAILED) {
perror("mmap failed");
i_womp = NULL;
close(ifd);
return false;
}
} else {
i_womp = NULL;
}
close(ifd);
#if !defined(__minix)
if (i_size)
madvise(i_womp, i_size, MADV_SEQUENTIAL);
#endif /* !defined(__minix) */
/* estimate the number of lines */
lines_allocated = i_size / 25;
if (lines_allocated < 100)
lines_allocated = 100;
if (!reallocate_lines(&lines_allocated))
return false;
/* now scan the buffer and build pointer array */
iline = 1;
i_ptr[iline] = i_womp;
/* test for NUL too, to maintain the behavior of the original code */
for (s = i_womp, i = 0; i < i_size && *s != '\0'; s++, i++) {
if (*s == '\n') {
if (iline == lines_allocated) {
if (!reallocate_lines(&lines_allocated))
return false;
}
/* these are NOT NUL terminated */
i_ptr[++iline] = s + 1;
}
}
/* if the last line contains no EOL, append one */
if (i_size > 0 && i_womp[i_size - 1] != '\n') {
last_line_missing_eol = true;
/* fix last line */
sz = s - i_ptr[iline];
p = malloc(sz + 1);
if (p == NULL) {
free(i_ptr);
i_ptr = NULL;
munmap(i_womp, i_size);
i_womp = NULL;
return false;
}
memcpy(p, i_ptr[iline], sz);
p[sz] = '\n';
i_ptr[iline] = p;
/* count the extra line and make it point to some valid mem */
i_ptr[++iline] = empty_line;
} else
last_line_missing_eol = false;
input_lines = iline - 1;
/* now check for revision, if any */
if (revision != NULL) {
if (!rev_in_string(i_womp)) {
if (force) {
if (verbose)
say("Warning: this file doesn't appear "
"to be the %s version--patching anyway.\n",
revision);
} else if (batch) {
fatal("this file doesn't appear to be the "
"%s version--aborting.\n",
revision);
} else {
ask("This file doesn't appear to be the "
"%s version--patch anyway? [n] ",
revision);
if (*buf != 'y')
fatal("aborted\n");
}
} else if (verbose)
say("Good. This file appears to be the %s version.\n",
revision);
}
return true; /* plan a will work */
}
/* Keep (virtually) nothing in memory. */
static void
plan_b(const char *filename)
{
FILE *ifp;
size_t i = 0, j, maxlen = 1;
char *p;
bool found_revision = (revision == NULL);
using_plan_a = false;
if ((ifp = fopen(filename, "r")) == NULL)
pfatal("can't open file %s", filename);
unlink(TMPINNAME);
if ((tifd = open(TMPINNAME, O_EXCL | O_CREAT | O_WRONLY, 0666)) < 0)
pfatal("can't open file %s", TMPINNAME);
while (fgets(buf, buf_len, ifp) != NULL) {
if (revision != NULL && !found_revision && rev_in_string(buf))
found_revision = true;
if ((i = strlen(buf)) > maxlen)
maxlen = i; /* find longest line */
}
last_line_missing_eol = i > 0 && buf[i - 1] != '\n';
if (last_line_missing_eol && maxlen == i)
maxlen++;
if (revision != NULL) {
if (!found_revision) {
if (force) {
if (verbose)
say("Warning: this file doesn't appear "
"to be the %s version--patching anyway.\n",
revision);
} else if (batch) {
fatal("this file doesn't appear to be the "
"%s version--aborting.\n",
revision);
} else {
ask("This file doesn't appear to be the %s "
"version--patch anyway? [n] ",
revision);
if (*buf != 'y')
fatal("aborted\n");
}
} else if (verbose)
say("Good. This file appears to be the %s version.\n",
revision);
}
fseek(ifp, 0L, SEEK_SET); /* rewind file */
lines_per_buf = BUFFERSIZE / maxlen;
tireclen = maxlen;
tibuf[0] = malloc(BUFFERSIZE + 1);
if (tibuf[0] == NULL)
fatal("out of memory\n");
tibuf[1] = malloc(BUFFERSIZE + 1);
if (tibuf[1] == NULL)
fatal("out of memory\n");
for (i = 1;; i++) {
p = tibuf[0] + maxlen * (i % lines_per_buf);
if (i % lines_per_buf == 0) /* new block */
if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
pfatal("can't write temp file");
if (fgets(p, maxlen + 1, ifp) == NULL) {
input_lines = i - 1;
if (i % lines_per_buf != 0)
if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
pfatal("can't write temp file");
break;
}
j = strlen(p);
/* These are '\n' terminated strings, so no need to add a NUL */
if (j == 0 || p[j - 1] != '\n')
p[j] = '\n';
}
fclose(ifp);
close(tifd);
if ((tifd = open(TMPINNAME, O_RDONLY)) < 0)
pfatal("can't reopen file %s", TMPINNAME);
}
/*
* Fetch a line from the input file, \n terminated, not necessarily \0.
*/
char *
ifetch(LINENUM line, int whichbuf)
{
if (line < 1 || line > input_lines) {
if (warn_on_invalid_line) {
say("No such line %ld in input file, ignoring\n", line);
warn_on_invalid_line = false;
}
return NULL;
}
if (using_plan_a)
return i_ptr[line];
else {
LINENUM offline = line % lines_per_buf;
LINENUM baseline = line - offline;
if (tiline[0] == baseline)
whichbuf = 0;
else if (tiline[1] == baseline)
whichbuf = 1;
else {
tiline[whichbuf] = baseline;
if (lseek(tifd, (off_t) (baseline / lines_per_buf *
BUFFERSIZE), SEEK_SET) < 0)
pfatal("cannot seek in the temporary input file");
if (read(tifd, tibuf[whichbuf], BUFFERSIZE) < 0)
pfatal("error reading tmp file %s", TMPINNAME);
}
return tibuf[whichbuf] + (tireclen * offline);
}
}
/*
* True if the string argument contains the revision number we want.
*/
static bool
rev_in_string(const char *string)
{
const char *s;
size_t patlen;
if (revision == NULL)
return true;
patlen = strlen(revision);
if (strnEQ(string, revision, patlen) && isspace((unsigned char)string[patlen]))
return true;
for (s = string; *s; s++) {
if (isspace((unsigned char)*s) && strnEQ(s + 1, revision, patlen) &&
isspace((unsigned char)s[patlen + 1])) {
return true;
}
}
return false;
}