freebsd-skq/usr.bin/uudecode/uudecode.c
fanf 4bb74a4762 The POSIXly-correct /dev/stdout handling added in rev 1.44 makes
careless users vulnerable to terminal control sequence attacks,
since they expect uudecode to just drop (or overwrite) a file in
the current directory. POSIX also says that the full pathname from
the input should be used when writing a file, which we only do if
the -s (shoot me in the foot) option is specified; therefore this
revision means that you now need to use -s for standard /dev/stdout
handling.
2003-03-18 14:19:26 +00:00

440 lines
9.8 KiB
C

/*-
* Copyright (c) 1983, 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#if 0
#ifndef lint
static char sccsid[] = "@(#)uudecode.c 8.2 (Berkeley) 4/2/94";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* uudecode [file ...]
*
* create the specified file, decoding as you go.
* used with uuencode.
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <pwd.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static const char *infile, *outfile;
static FILE *infp, *outfp;
static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
static void usage(void);
static int decode(void);
static int decode2(void);
static int uu_decode(void);
static int base64_decode(void);
int
main(int argc, char *argv[])
{
int rval, ch;
if (strcmp(basename(argv[0]), "b64decode") == 0)
base64 = 1;
while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
switch(ch) {
case 'c':
if (oflag || rflag)
usage();
cflag = 1; /* multiple uudecode'd files */
break;
case 'i':
iflag = 1; /* ask before override files */
break;
case 'm':
base64 = 1;
break;
case 'o':
if (cflag || pflag || rflag || sflag)
usage();
oflag = 1; /* output to the specified file */
sflag = 1; /* do not strip pathnames for output */
outfile = optarg; /* set the output filename */
break;
case 'p':
if (oflag)
usage();
pflag = 1; /* print output to stdout */
break;
case 'r':
if (cflag || oflag)
usage();
rflag = 1; /* decode raw data */
break;
case 's':
if (oflag)
usage();
sflag = 1; /* do not strip pathnames for output */
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (*argv) {
rval = 0;
do {
infp = fopen(infile = *argv, "r");
if (infp == NULL) {
warn("%s", *argv);
rval = 1;
continue;
}
rval |= decode();
fclose(infp);
} while (*++argv);
} else {
infile = "stdin";
infp = stdin;
rval = decode();
}
exit(rval);
}
static int
decode(void)
{
int r, v;
if (rflag) {
/* relaxed alternative to decode2() */
outfile = "/dev/stdout";
outfp = stdout;
if (base64)
return (base64_decode());
else
return (uu_decode());
}
v = decode2();
if (v == EOF) {
warnx("%s: missing or bad \"begin\" line", infile);
return (1);
}
for (r = v; cflag; r |= v) {
v = decode2();
if (v == EOF)
break;
}
return (r);
}
static int
decode2(void)
{
int flags, fd, mode;
size_t n, m;
char *p, *q;
void *handle;
struct passwd *pw;
struct stat st;
char buf[MAXPATHLEN+1];
base64 = 0;
/* search for header line */
for (;;) {
if (fgets(buf, sizeof(buf), infp) == NULL)
return (EOF);
p = buf;
if (strncmp(p, "begin-base64 ", 13) == 0) {
base64 = 1;
p += 13;
} else if (strncmp(p, "begin ", 6) == 0)
p += 6;
else
continue;
/* p points to mode */
q = strchr(p, ' ');
if (q == NULL)
continue;
*q++ = '\0';
/* q points to filename */
n = strlen(q);
while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
q[--n] = '\0';
/* found valid header? */
if (n > 0)
break;
}
handle = setmode(p);
if (handle == NULL) {
warnx("%s: unable to parse file mode", infile);
return (1);
}
mode = getmode(handle, 0) & 0666;
free(handle);
if (sflag) {
/* don't strip, so try ~user/file expansion */
p = NULL;
pw = NULL;
if (*q == '~')
p = strchr(q, '/');
if (p != NULL) {
*p = '\0';
pw = getpwnam(q + 1);
*p = '/';
}
if (pw != NULL) {
n = strlen(pw->pw_dir);
if (buf + n > p) {
/* make room */
m = strlen(p);
if (sizeof(buf) < n + m) {
warnx("%s: bad output filename",
infile);
return (1);
}
p = memmove(buf + n, p, m);
}
q = memcpy(p - n, pw->pw_dir, n);
}
} else {
/* strip down to leaf name */
p = strrchr(q, '/');
if (p != NULL)
q = p + 1;
}
if (!oflag)
outfile = q;
/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
if (pflag || strcmp(outfile, "/dev/stdout") == 0)
outfp = stdout;
else {
flags = O_WRONLY|O_CREAT|O_EXCL;
if (lstat(outfile, &st) == 0) {
if (iflag) {
warnc(EEXIST, "%s: %s", infile, outfile);
return (0);
}
switch (st.st_mode & S_IFMT) {
case S_IFREG:
case S_IFLNK:
/* avoid symlink attacks */
if (unlink(outfile) == 0 || errno == ENOENT)
break;
warn("%s: unlink %s", infile, outfile);
return (1);
case S_IFDIR:
warnc(EISDIR, "%s: %s", infile, outfile);
return (1);
default:
if (oflag) {
/* trust command-line names */
flags &= ~O_EXCL;
break;
}
warnc(EEXIST, "%s: %s", infile, outfile);
return (1);
}
} else if (errno != ENOENT) {
warn("%s: %s", infile, outfile);
return (1);
}
if ((fd = open(outfile, flags, mode)) < 0 ||
(outfp = fdopen(fd, "w")) == NULL) {
warn("%s: %s", infile, outfile);
return (1);
}
}
if (base64)
return (base64_decode());
else
return (uu_decode());
}
static int
getline(char *buf, size_t size)
{
if (fgets(buf, size, infp) != NULL)
return (2);
if (rflag)
return (0);
warnx("%s: %s: short file", infile, outfile);
return (1);
}
static int
checkend(const char *ptr, const char *end, const char *msg)
{
size_t n;
n = strlen(end);
if (strncmp(ptr, end, n) != 0 ||
strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
warnx("%s: %s: %s", infile, outfile, msg);
return (1);
}
if (fclose(outfp) != 0) {
warn("%s: %s", infile, outfile);
return (1);
}
return (0);
}
static int
uu_decode(void)
{
int i, ch;
char *p;
char buf[MAXPATHLEN+1];
/* for each input line */
for (;;) {
switch (getline(buf, sizeof(buf))) {
case 0: return (0);
case 1: return (1);
}
#define DEC(c) (((c) - ' ') & 077) /* single character decode */
#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
#define OUT_OF_RANGE do { \
warnx("%s: %s: character out of range: [%d-%d]", \
infile, outfile, 1 + ' ', 077 + ' ' + 1); \
return (1); \
} while (0)
/*
* `i' is used to avoid writing out all the characters
* at the end of the file.
*/
p = buf;
if ((i = DEC(*p)) <= 0)
break;
for (++p; i > 0; p += 4, i -= 3)
if (i >= 3) {
if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
OUT_OF_RANGE;
ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
putc(ch, outfp);
ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
putc(ch, outfp);
ch = DEC(p[2]) << 6 | DEC(p[3]);
putc(ch, outfp);
}
else {
if (i >= 1) {
if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
OUT_OF_RANGE;
ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
putc(ch, outfp);
}
if (i >= 2) {
if (!(IS_DEC(*(p + 1)) &&
IS_DEC(*(p + 2))))
OUT_OF_RANGE;
ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
putc(ch, outfp);
}
if (i >= 3) {
if (!(IS_DEC(*(p + 2)) &&
IS_DEC(*(p + 3))))
OUT_OF_RANGE;
ch = DEC(p[2]) << 6 | DEC(p[3]);
putc(ch, outfp);
}
}
}
switch (getline(buf, sizeof(buf))) {
case 0: return (0);
case 1: return (1);
default: return (checkend(buf, "end", "no \"end\" line"));
}
}
static int
base64_decode(void)
{
int n;
char inbuf[MAXPATHLEN+1];
unsigned char outbuf[MAXPATHLEN * 4];
for (;;) {
switch (getline(inbuf, sizeof(inbuf))) {
case 0: return (0);
case 1: return (1);
}
n = b64_pton(inbuf, outbuf, sizeof(outbuf));
if (n < 0)
break;
fwrite(outbuf, 1, n, outfp);
}
return (checkend(inbuf, "====",
"error decoding base64 input stream"));
}
static void
usage(void)
{
(void)fprintf(stderr,
"usage: uudecode [-cimprs] [file ...]\n"
" uudecode [-i] -o output_file [file]\n"
" b64decode [-cimprs] [file ...]\n"
" b64decode [-i] -o output_file [file]\n");
exit(1);
}