d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Capsicumize bspatch

Browse Source 
Move all of the fopen() and open() calls to the top of main()

Restrict each FD to least privilege (read/seek only, write only, etc)

cap_enter(), and make all except the output FD read/seek only.

Reviewed by:	emaste, ed, oshogbo, delphij
Approved by:	so
MFC after:	3 days
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
Differential Revision:	https://reviews.freebsd.org/D7358
This commit is contained in:
allanjude 2016-08-25 15:08:33 +00:00
parent dad1fd7735
commit 5dd28c7f85
1 changed files with 52 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
usr.bin/bsdiff/bspatch/bspatch.c
View File

@ -27,8 +27,20 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#if defined(__FreeBSD__)
#include <sys/param.h>
#if __FreeBSD_version >= 1100014
#include <sys/capsicum.h>
#define HAVE_CAPSICUM
#elif __FreeBSD_version >= 1000000
#include <sys/capability.h>
#define HAVE_CAPSICUM
#endif
#endif
#include <bzlib.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
@ -80,6 +92,9 @@ int main(int argc, char *argv[])
off_t ctrl[3];
off_t lenread;
off_t i;
#ifdef HAVE_CAPSICUM
cap_rights_t rights_ro, rights_wr;
#endif
if (argc != 4)
usage();
@ -87,6 +102,43 @@ int main(int argc, char *argv[])
/* 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 newfile */
if ((newfd = open(argv[2], O_CREAT | O_TRUNC | O_WRONLY | O_BINARY,
0666)) < 0)
err(1, "open(%s)", argv[2]);
#ifdef HAVE_CAPSICUM
if (cap_enter() < 0) {
/* Failed to sandbox, fatal if CAPABILITY_MODE enabled */
if (errno != ENOSYS)
err(1, "failed to enter security sandbox");
} else {
/* Capsicum Available */
cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
cap_rights_init(&rights_wr, CAP_WRITE);
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)
err(1, "cap_rights_limit() failed, could not restrict"
" capabilities");
}
#endif
/*
File format:
@ -123,31 +175,22 @@ int main(int argc, char *argv[])
/* Close patch file and re-open it via libbzip2 at the right places */
if (fclose(f))
err(1, "fclose(%s)", argv[3]);
if ((cpf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
if (fseeko(cpf, 32, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)32);
if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
if ((dpf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)(32 + bzctrllen));
if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
if ((epf = fopen(argv[3], "rb")) == NULL)
err(1, "fopen(%s)", argv[3]);
if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)(32 + bzctrllen + bzdatalen));
if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
oldfd = open(argv[1], O_RDONLY | O_BINARY, 0);
if (oldfd < 0)
err(1, "%s", argv[1]);
if ((oldsize = lseek(oldfd, 0, SEEK_END)) == -1 ||
(old = malloc(oldsize+1)) == NULL ||
lseek(oldfd, 0, SEEK_SET) != 0 ||
@ -215,9 +258,6 @@ int main(int argc, char *argv[])
err(1, "fclose(%s)", argv[3]);
/* Write the new file */
newfd = open(argv[2], O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0666);
if (newfd < 0)
err(1, "%s", argv[2]);
if (write(newfd, new, newsize) != newsize || close(newfd) == -1)
err(1, "%s", argv[2]);