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Code Issues Releases Activity

Capsicum-ize soelim(1).

Browse Source 
As a trick to be able to access all files passed in arguments (readonly) within
the sandbox we first open the root directory, then consider all files as
relative to this file descriptor.

This might be improved once casper add supports for filesystem.

MFC after:	1 month
Reviewed by:	allanjude
Differential Revision:	https://reviews.freebsd.org/D7936
This commit is contained in:
Baptiste Daroussin 2016-09-18 16:25:41 +00:00
parent f902d06ce3
commit 224d9e3ed2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=305936
1 changed files with 59 additions and 13 deletions
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72
usr.bin/soelim/soelim.c
View File

@ -27,15 +27,19 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/capsicum.h>
#include <sys/types.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stringlist.h>
#include <termios.h>
#include <unistd.h>
#define C_OPTION 0x1
@ -51,18 +55,27 @@ usage(void)
exit(EXIT_FAILURE);
}
static FILE *
soelim_fopen(const char *name)
static const char *
relpath(const char *path)
{
while (*path == '/' && *path != '\0')
path++;
return (path);
}
static FILE *
soelim_fopen(int rootfd, const char *name)
{
FILE *f;
char path[PATH_MAX];
size_t i;
int fd;
if (strcmp(name, "-") == 0)
return (stdin);
if ((f = fopen(name, "r")) != NULL)
return (f);
if ((fd = openat(rootfd, relpath(name), O_RDONLY)) != -1)
return (fdopen(fd, "r"));
if (*name == '/') {
warn("can't open '%s'", name);
@ -72,17 +85,17 @@ soelim_fopen(const char *name)
for (i = 0; i < includes->sl_cur; i++) {
snprintf(path, sizeof(path), "%s/%s", includes->sl_str[i],
name);
if ((f = fopen(path, "r")) != NULL)
return (f);
if ((fd = openat(rootfd, relpath(path), O_RDONLY)) != -1)
return (fdopen(fd, "r"));
}
warn("can't open '%s'", name);
return (f);
return (NULL);
}
static int
soelim_file(FILE *f, int flag)
soelim_file(int rootfd, FILE *f, int flag)
{
char *line = NULL;
char *walk, *cp;
@ -118,7 +131,7 @@ soelim_file(FILE *f, int flag)
printf("%s", line);
continue;
}
if (soelim_file(soelim_fopen(walk), flag) == 1) {
if (soelim_file(rootfd, soelim_fopen(rootfd, walk), flag) == 1) {
free(line);
return (1);
}
@ -135,11 +148,15 @@ soelim_file(FILE *f, int flag)
int
main(int argc, char **argv)
{
int ch, i;
int ch, i, rootfd;
int ret = 0;
int flags = 0;
unsigned long cmd;
char cwd[MAXPATHLEN];
cap_rights_t rights;
includes = sl_init();
sl_add(includes, getcwd(cwd, sizeof(cwd)));
if (includes == NULL)
err(EXIT_FAILURE, "sl_init()");
@ -165,13 +182,42 @@ main(int argc, char **argv)
argc -= optind;
argv += optind;
cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_IOCTL);
/*
* EBADF in case stdin is closed by the caller
*/
if (cap_rights_limit(STDIN_FILENO, &rights) < 0 && errno != ENOSYS
&& errno != EBADF)
err(EXIT_FAILURE, "unable to limit rights for stdin");
cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT, CAP_IOCTL);
if (cap_rights_limit(STDOUT_FILENO, &rights) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit rights for stdout");
if (cap_rights_limit(STDERR_FILENO, &rights) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit rights for stderr");
rootfd = open("/", O_DIRECTORY | O_RDONLY);
cap_rights_init(&rights, CAP_READ, CAP_LOOKUP, CAP_FSTAT, CAP_FCNTL);
if (cap_rights_limit(rootfd, &rights) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit rights");
cmd = TIOCGETA;
if (cap_ioctls_limit(STDOUT_FILENO, &cmd, 1) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit ioctls for stdout");
if (cap_ioctls_limit(STDERR_FILENO, &cmd, 1) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit ioctls for stderr");
if (cap_ioctls_limit(STDIN_FILENO, &cmd, 1) < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to limit ioctls for stdin");
if (cap_enter() < 0 && errno != ENOSYS)
err(EXIT_FAILURE, "unable to enter capability mode");
if (argc == 0)
ret = soelim_file(stdin, flags);
ret = soelim_file(rootfd, stdin, flags);
for (i = 0; i < argc; i++)
ret = soelim_file(soelim_fopen(argv[i]), flags);
ret = soelim_file(rootfd, soelim_fopen(rootfd, argv[i]), flags);
sl_free(includes, 0);
close(rootfd);
return (ret);
}