NAME

LIBRARY

SYNOPSIS

fileargs_t *
fileargs_init(int argc, char *argv[], int flags, mode_t mode, cap_rights_t *rightsp, int operations);

fileargs_t *
fileargs_cinit(cap_channel_t *cas, int argc, char *argv[], int flags, mode_t mode, cap_rights_t *rightsp, int operations);

fileargs_t *
fileargs_cinitnv(cap_channel_t *cas, nvlist_t *limits);

fileargs_t *
fileargs_initnv(nvlist_t *limits);

void
fileargs_free(fileargs_t *fa);

int
fileargs_lstat(fileargs_t *fa, const char *path, struct stat *sb);

int
fileargs_open(fileargs_t *fa, const char *name);

FILE *
fileargs_fopen(fileargs_t *fa, const char *name, const char *mode);

char *
fileargs_realpath(fileargs_t *fa, const char *pathname, char *reserved_path);

DESCRIPTION

The function fileargs_init() create a service to the system.fileargs. The argv contains a list of files that should be opened. The argument can be set to NULL which will not create a service and all files will be prohibited to be opened. The argc argument contains a number of passed files. The flags argument limits opened files for either execution or reading and/or writing. The mode argument tells which what mode file should be created if the O_CREATE flag is present . For more details of the flags and mode arguments see open(2). The rightsp argument contains a list of the capability rights which file should be limited to. For more details of the capability rights see cap_rights_init(3). The operations argument limits the operations that are available using system.fileargs. operations is a combination of:

FA_OPEN

Allow fileargs_open() and fileargs_fopen().

FA_LSTAT

Allow fileargs_lstat().

FA_REALPATH

Allow fileargs_realpath().

The function fileargs_cinit() is equivalent to fileargs_init() except that the connection to the Casper needs to be provided.

The functions fileargs_initnv() and fileargs_cinitnv() are respectively equivalent to fileargs_init() and fileargs_cinit() expect that all arguments all provided as nvlist(9). For details see LIMITS.

The fileargs_free close connection to the system.fileargs service and free are structures. The function handle NULL argument.

The function fileargs_lstat() is equivalent to lstat(2).

The functions fileargs_open() and fileargs_fopen() are respectively equivalent to open(2) and fopen(3) expect that all arguments are fetched from the fileargs_t structure.

The function fileargs_realpath() is equivalent to realpath(3).

LIMITS

flags (NV_TYPE_NUMBER)

The flags limits opened files for either execution or reading and/or writing.

mode (NV_TYPE_NUMBER)

If in the flags argument the O_CREATE flag was defined the nvlist(9) must contain the mode. The mode argument tells which what mode file should be created.

operations (NV_TYPE_NUMBER)

The operations limits the usable operations for system.fileargs. The possible values are explained as operations argument with fileargs_init().

The nvlist(9) for that functions may contain the following values and types:

cap_rights (NV_TYPE_BINARY)

The cap_rights argument contains a list of the capability rights which file should be limited to.

(

NV_TYPE_NULL)

Any number of NV_TYPE_NULL where the name of the element is name of the file which can be opened.

EXAMPLES

int ch, fd, i;
cap_rights_t rights;
fileargs_t *fa;

while ((ch = getopt(argc, argv, "h")) != -1) {
	switch (ch) {
		case 'h':
		default:
			usage();
	}
}

argc -= optind;
argv += optind;

/* Create capability to the system.fileargs service. */
fa = fileargs_init(argc, argv, O_RDONLY, 0,
    cap_rights_init(&rights, CAP_READ), FA_OPEN);
if (fa == NULL)
	err(1, "unable to open system.fileargs service");

/* Enter capability mode sandbox. */
if (cap_enter() < 0 && errno != ENOSYS)
	err(1, "unable to enter capability mode");

/* Open files. */
for (i = 0; i < argc; i++) {
	fd = fileargs_open(fa, argv[i]);
	if (fd < 0)
		err(1, "unable to open file %s", argv[i]);
	printf("File %s opened in capability mode\n", argv[i]);
	close(fd);
}

fileargs_free(fa);

SEE ALSO

HISTORY

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