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freebsd/usr.bin/cmp/special.c
Mark Johnston 2528b7e2cb Fix handling of rights on stdio streams, take two.
Split the rights-limiting code into two cases: if one of the input
files isn't a regular file, use caph_limit_stream(3) instead of
open-coding the same logic; if both input files are regular files,
and the initial attempts to map them succeed, we limit the rights on
those files to CAP_MMAP_R.

Add a regression test for PR 234885.

PR:		234885
Reviewed by:	delphij
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D19216
2019-02-25 19:47:27 +00:00

117 lines
3.3 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1991, 1993, 1994
* 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 char sccsid[] = "@(#)special.c 8.3 (Berkeley) 4/2/94";
#endif
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <capsicum_helpers.h>
#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include "extern.h"
void
c_special(int fd1, const char *file1, off_t skip1,
int fd2, const char *file2, off_t skip2)
{
int ch1, ch2;
off_t byte, line;
FILE *fp1, *fp2;
int dfound;
if (caph_limit_stream(fd1, CAPH_READ) < 0)
err(ERR_EXIT, "caph_limit_stream(%s)", file1);
if (caph_limit_stream(fd2, CAPH_READ) < 0)
err(ERR_EXIT, "caph_limit_stream(%s)", file2);
if (caph_enter() < 0)
err(ERR_EXIT, "unable to enter capability mode");
if ((fp1 = fdopen(fd1, "r")) == NULL)
err(ERR_EXIT, "%s", file1);
if ((fp2 = fdopen(fd2, "r")) == NULL)
err(ERR_EXIT, "%s", file2);
dfound = 0;
while (skip1--)
if (getc(fp1) == EOF)
goto eof;
while (skip2--)
if (getc(fp2) == EOF)
goto eof;
for (byte = line = 1;; ++byte) {
ch1 = getc(fp1);
ch2 = getc(fp2);
if (ch1 == EOF || ch2 == EOF)
break;
if (ch1 != ch2) {
if (xflag) {
dfound = 1;
(void)printf("%08llx %02x %02x\n",
(long long)byte - 1, ch1, ch2);
} else if (lflag) {
dfound = 1;
(void)printf("%6lld %3o %3o\n",
(long long)byte, ch1, ch2);
} else {
diffmsg(file1, file2, byte, line);
/* NOTREACHED */
}
}
if (ch1 == '\n')
++line;
}
eof: if (ferror(fp1))
err(ERR_EXIT, "%s", file1);
if (ferror(fp2))
err(ERR_EXIT, "%s", file2);
if (feof(fp1)) {
if (!feof(fp2))
eofmsg(file1);
} else
if (feof(fp2))
eofmsg(file2);
fclose(fp2);
fclose(fp1);
if (dfound)
exit(DIFF_EXIT);
}