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CAP_PWD(3) FreeBSD Library Functions Manual CAP_PWD(3)
NAME
cap_getpwent, cap_getpwnam, cap_getpwuid, cap_getpwent_r, cap_getpwnam_r,
cap_getpwuid_r, cap_setpassent, cap_setpwent, cap_endpwent,
cap_pwd_limit_cmds, cap_pwd_limit_fields, cap_pwd_limit_users - library
for password database operations in capability mode
LIBRARY
library "libcap_pwd"
SYNOPSIS
#include <libcasper.h>
#include <casper/cap_pwd.h>
struct passwd *
cap_getpwent(cap_channel_t *chan);
struct passwd *
cap_getpwnam(cap_channel_t *chan, const char *login);
struct passwd *
cap_getpwuid(cap_channel_t *chan, uid_t uid);
int
cap_getpwent_r(cap_channel_t *chan, struct passwd *pwd, char *buffer,
size_t bufsize, struct passwd **result);
int
cap_getpwnam_r(cap_channel_t *chan, const char *name, struct passwd *pwd,
char *buffer, size_t bufsize, struct passwd **result);
int
cap_getpwuid_r(cap_channel_t *chan, uid_t uid, struct passwd *pwd,
char *buffer, size_t bufsize, struct passwd **result);
int
cap_setpassent(cap_channel_t *chan, int stayopen);
void
cap_setpwent(cap_channel_t *chan);
void
cap_endpwent(cap_channel_t *chan);
int
cap_pwd_limit_cmds(cap_channel_t *chan, const char * const *cmds,
size_t ncmds);
int
cap_pwd_limit_fields(cap_channel_t *chan, const char * const *fields,
size_t nfields);
int
cap_pwd_limit_users(cap_channel_t *chan, const char * const *names,
size_t nnames, uid_t *uids, size_t nuids);
DESCRIPTION
The functions cap_getpwent(), cap_getpwnam(), cap_getpwuid(),
service. The cmds variable can be set to getpwent, getpwnam, getpwuid,
getpwent_r, getpwnam_r, getpwuid_r, setpassent, setpwent, or endpwent
which will allow to use the function associated with the name. The ncmds
variable contains the number of cmds provided.
The cap_pwd_limit_fields() function allows limit fields returned in the
structure passwd. The fields variable can be set to pw_name, pw_passwd,
pw_uid, pw_gid, pw_change, pw_class, pw_gecos, pw_dir, pw_shell,
pw_expire or pw_fields The field which was set as the limit will be
returned, while the rest of the values not set this way will have default
values. The nfields variable contains the number of fields provided.
The cap_pwd_limit_users() function allows to limit access to users. The
names variable allows to limit users by name and the uids variable by the
user number. The nnames and nuids variables provide numbers of limited
names and uids.
EXAMPLES
The following example first opens a capability to casper and then uses
this capability to create the system.pwd casper service and uses it to
get a user name.
cap_channel_t *capcas, *cappwd;
const char *cmds[] = { "getpwuid" };
const char *fields[] = { "pw_name" };
uid_t uid[] = { 1 };
struct passwd *passwd;
/* Open capability to Casper. */
capcas = cap_init();
if (capcas == NULL)
err(1, "Unable to contact Casper");
/* Enter capability mode sandbox. */
if (cap_enter() < 0 && errno != ENOSYS)
err(1, "Unable to enter capability mode");
/* Use Casper capability to create capability to the system.pwd service. */
cappwd = cap_service_open(capcas, "system.pwd");
if (cappwd == NULL)
err(1, "Unable to open system.pwd service");
/* Close Casper capability, we don't need it anymore. */
cap_close(capcas);
/* Limit service to one single function. */
if (cap_pwd_limit_cmds(cappwd, cmds, nitems(cmds)))
err(1, "Unable to limit access to system.pwd service");
/* Limit service to one field as we only need name of the user. */
if (cap_pwd_limit_fields(cappwd, fields, nitems(fields)))
err(1, "Unable to limit access to system.pwd service");
/* Limit service to one uid. */
if (cap_pwd_limit_users(cappwd, NULL, 0, uid, nitems(uid)))
err(1, "Unable to limit access to system.pwd service");
passwd = cap_getpwuid(cappwd, uid[0]);
if (passwd == NULL)
cap_enter(2), endpwent(3), err(3), getpwent(3), getpwent_r(3),
getpwnam(3), getpwnam_r(3), getpwuid(3), getpwuid_r(3), setpassent(3),
setpwent(3), capsicum(4), nv(9)
HISTORY
The cap_pwd service first appeared in FreeBSD 10.3.
AUTHORS
The cap_pwd service was implemented by Pawel Jakub Dawidek
<pawel@dawidek.net> under sponsorship from the FreeBSD Foundation.
This manual page was written by
Mariusz Zaborski <oshogbo@FreeBSD.org>.
FreeBSD 14.0-RELEASE-p6 May 5, 2020 FreeBSD 14.0-RELEASE-p6