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Run a shell in the jail when no command is specified.

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Add a new flag, -l, for a clean environment, same as jail(8) exec.clean.
Change the GET_USER_INFO macro into a function.

PR:		201300
Submitted by:	Willem Jan Withagen
MFC after:	3 days
This commit is contained in:
jamie 2015-07-12 17:03:50 +00:00
parent 084e0d801a
commit 4c3443274d
2 changed files with 101 additions and 41 deletions
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13
usr.sbin/jexec/jexec.8
View File

@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd May 27, 2009
.Dd Jul 11, 2015
.Dt JEXEC 8
.Os
.Sh NAME
@ -33,8 +33,9 @@
.Nd "execute a command inside an existing jail"
.Sh SYNOPSIS
.Nm
.Op Fl l
.Op Fl u Ar username | Fl U Ar username
.Ar jail command ...
.Ar jail Op Ar command ...
.Sh DESCRIPTION
The
.Nm
@ -43,9 +44,17 @@ utility executes
inside the
.Ar jail
identified by its jid or name.
If
.Ar command
is not specified then the user's shell is used.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl l
Execute in a clean environment.
The environment is discarded except for
.Ev HOME , SHELL , TERM , USER ,
and anything from the login class capability database for the user.
.It Fl u Ar username
The user name from host environment as whom the
.Ar command

129
usr.sbin/jexec/jexec.c
View File

@ -40,49 +40,37 @@
#include <jail.h>
#include <limits.h>
#include <login_cap.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pwd.h>
#include <unistd.h>
static void usage(void);
extern char **environ;
#define GET_USER_INFO do { \
pwd = getpwnam(username); \
if (pwd == NULL) { \
if (errno) \
err(1, "getpwnam: %s", username); \
else \
errx(1, "%s: no such user", username); \
} \
lcap = login_getpwclass(pwd); \
if (lcap == NULL) \
err(1, "getpwclass: %s", username); \
ngroups = ngroups_max; \
if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \
err(1, "getgrouplist: %s", username); \
} while (0)
static void get_user_info(const char *username, const struct passwd **pwdp,
login_cap_t **lcapp);
static void usage(void);
int
main(int argc, char *argv[])
{
int jid;
login_cap_t *lcap = NULL;
struct passwd *pwd = NULL;
gid_t *groups = NULL;
int ch, ngroups, uflag, Uflag;
long ngroups_max;
char *username;
int ch, clean, uflag, Uflag;
char *cleanenv;
const struct passwd *pwd = NULL;
const char *username, *shell, *term;
ch = uflag = Uflag = 0;
ch = clean = uflag = Uflag = 0;
username = NULL;
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
while ((ch = getopt(argc, argv, "nu:U:")) != -1) {
while ((ch = getopt(argc, argv, "lnu:U:")) != -1) {
switch (ch) {
case 'l':
clean = 1;
break;
case 'n':
/* Specified name, now unused */
break;
@ -100,12 +88,15 @@ main(int argc, char *argv[])
}
argc -= optind;
argv += optind;
if (argc < 2)
if (argc < 1)
usage();
if (uflag && Uflag)
usage();
if (uflag)
GET_USER_INFO;
if (uflag || (clean && !Uflag))
/* User info from the home environment */
get_user_info(username, &pwd, &lcap);
/* Attach to the jail */
jid = jail_getid(argv[0]);
if (jid < 0)
errx(1, "%s", jail_errmsg);
@ -113,28 +104,88 @@ main(int argc, char *argv[])
err(1, "jail_attach(%d)", jid);
if (chdir("/") == -1)
err(1, "chdir(): /");
if (username != NULL) {
/* Set up user environment */
if (clean || username != NULL) {
if (Uflag)
GET_USER_INFO;
if (setgroups(ngroups, groups) != 0)
err(1, "setgroups");
/* User info from the jail environment */
get_user_info(username, &pwd, &lcap);
if (clean) {
term = getenv("TERM");
cleanenv = NULL;
environ = &cleanenv;
setenv("PATH", "/bin:/usr/bin", 1);
if (term != NULL)
setenv("TERM", term, 1);
}
if (setgid(pwd->pw_gid) != 0)
err(1, "setgid");
if (setusercontext(lcap, pwd, pwd->pw_uid,
LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
if (setusercontext(lcap, pwd, pwd->pw_uid, username
? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN
: LOGIN_SETPATH | LOGIN_SETENV) != 0)
err(1, "setusercontext");
login_close(lcap);
setenv("USER", pwd->pw_name, 1);
setenv("HOME", pwd->pw_dir, 1);
setenv("SHELL",
*pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1);
if (clean && chdir(pwd->pw_dir) < 0)
err(1, "chdir: %s", pwd->pw_dir);
endpwent();
}
/* Run the specified command, or the shell */
if (argc > 1) {
if (execvp(argv[1], argv + 1) < 0)
err(1, "execvp: %s", argv[1]);
} else {
if (!(shell = getenv("SHELL")))
shell = _PATH_BSHELL;
if (execlp(shell, shell, "-i", NULL) < 0)
err(1, "execlp: %s", shell);
}
if (execvp(argv[1], argv + 1) == -1)
err(1, "execvp(): %s", argv[1]);
exit(0);
}
static void
get_user_info(const char *username, const struct passwd **pwdp,
login_cap_t **lcapp)
{
uid_t uid;
const struct passwd *pwd;
errno = 0;
if (username) {
pwd = getpwnam(username);
if (pwd == NULL) {
if (errno)
err(1, "getpwnam: %s", username);
else
errx(1, "%s: no such user", username);
}
} else {
uid = getuid();
pwd = getpwuid(uid);
if (pwd == NULL) {
if (errno)
err(1, "getpwuid: %d", uid);
else
errx(1, "unknown uid: %d", uid);
}
}
*pwdp = pwd;
*lcapp = login_getpwclass(pwd);
if (*lcapp == NULL)
err(1, "getpwclass: %s", pwd->pw_name);
if (initgroups(pwd->pw_name, pwd->pw_gid) < 0)
err(1, "initgroups: %s", pwd->pw_name);
}
static void
usage(void)
{
fprintf(stderr, "%s\n",
"usage: jexec [-u username | -U username] jail command ...");
"usage: jexec [-l] [-u username | -U username] jail [command ...]");
exit(1);
}