On Fri, Sep 07, 2012 at 01:39:49PM +0100, Pádraig Brady wrote:
> Maybe we could keep the runuser name and say
> the prefered form is to specify -u $USER, which
> will _not_ start a shell. The old interface without
> -u being retained for backwards compat?
Good idea. Implemented, see below. The su-like options -c/C, -l and -f
are mutually exclusive to -u.
(and sorry for coding style. I'm absolutely incompatible with the
original code -- when all the changes will be in master branch we'll
use indent to make it readable for lovers of the kernel-style ...)
Karel
>From 6ec71facf066ade0c42b98b274d041c6e0ed6d8c Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@xxxxxxxxxx>
Date: Thu, 13 Sep 2012 11:58:00 +0200
Subject: [PATCH] runuser: add -u to not execute shell
Signed-off-by: Karel Zak <kzak@xxxxxxxxxx>
---
login-utils/runuser.1 | 20 +++++---
login-utils/su-common.c | 138 +++++++++++++++++++++++++++++++----------------
login-utils/su.1 | 1 +
3 files changed, 105 insertions(+), 54 deletions(-)
diff --git a/login-utils/runuser.1 b/login-utils/runuser.1
index 1f21408..9a00cb6 100644
--- a/login-utils/runuser.1
+++ b/login-utils/runuser.1
@@ -3,10 +3,21 @@
runuser \- run a command with substitute user and group ID
.SH SYNOPSIS
.B runuser
-[options...] [\-] [user [args...]]
+[options] -u
+.IR user
+.IR "command " [ argument ...]
+.LP
+.B runuser
+[options] [-]
+[
+.IR "user " [ argument ...]
+]
.SH DESCRIPTION
.B runuser
allows to run commands with substitute user and group ID.
+If the option \fB\-u\fR not given, fallback to
+.B su
+compatible semantic and shell is executed.
The difference between the commands
.B runuser
and
@@ -37,12 +48,7 @@ and
.B LOGNAME
if the target
.I user
-is not root). It is recommended to always use the
-.B \-\-login
-option (instead it's shortcut
-.BR \- )
-to avoid side effects caused by mixing environments.
-.PP
+is not root).
This version of
.B runuser
uses PAM for session management.
diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index 23ad57d..c6f3389 100644
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -543,7 +543,8 @@ modify_environment (const struct passwd *pw, const char *shell)
if (term)
xsetenv ("TERM", term, 1);
xsetenv ("HOME", pw->pw_dir, 1);
- xsetenv ("SHELL", shell, 1);
+ if (shell)
+ xsetenv ("SHELL", shell, 1);
xsetenv ("USER", pw->pw_name, 1);
xsetenv ("LOGNAME", pw->pw_name, 1);
set_path(pw);
@@ -555,7 +556,8 @@ modify_environment (const struct passwd *pw, const char *shell)
if (change_environment)
{
xsetenv ("HOME", pw->pw_dir, 1);
- xsetenv ("SHELL", shell, 1);
+ if (shell)
+ xsetenv ("SHELL", shell, 1);
if (getlogindefs_bool ("ALWAYS_SET_PATH", 0))
set_path(pw);
else
@@ -690,35 +692,47 @@ restricted_shell (const char *shell)
static void __attribute__((__noreturn__))
usage (int status)
{
- if (status != EXIT_SUCCESS)
- fprintf (stderr, _("Try `%s --help' for more information.\n"),
- program_invocation_short_name);
- else
- {
- fputs(USAGE_HEADER, stdout);
- printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
- fputs (_("\n\
- Change the effective user id and group id to that of USER.\n\
- A mere - implies -l. If USER not given, assume root.\n"), stdout);
- fputs(USAGE_OPTIONS, stdout);
- fputs (_("\
- -, -l, --login make the shell a login shell\n\
- -c, --command <command> pass a single command to the shell with -c\n\
- --session-command <command> pass a single command to the shell with -c\n\
- and do not create a new session\n\
- -g --group=group specify the primary group\n\
- -G --supp-group=group specify a supplemental group\n\
- -f, --fast pass -f to the shell (for csh or tcsh)\n\
- -m, --preserve-environment do not reset environment variables\n\
- -p same as -m\n\
- -s, --shell <shell> run shell if /etc/shells allows it\n\
-"), stdout);
-
- fputs(USAGE_SEPARATOR, stdout);
- fputs(USAGE_HELP, stdout);
- fputs(USAGE_VERSION, stdout);
- printf(USAGE_MAN_TAIL("su(1)"));
- }
+ if (su_mode == RUNUSER_MODE) {
+ fputs(USAGE_HEADER, stdout);
+ printf (_(" %s [options] -u <USER> COMMAND\n"), program_invocation_short_name);
+ printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
+ fputs (_("\n"
+ "Run COMMAND with the effective <user> id and group id. If -u not\n"
+ "given, fallback to su(1) compatible semantic and shell is executed.\n"
+ "The options -l, -c, -f, -s are mutually exclusive to -u.\n"), stdout);
+
+ fputs(USAGE_OPTIONS, stdout);
+
+ fputs (_(
+ " -u, --user <user> username\n"), stdout);
+
+ } else {
+ fputs(USAGE_HEADER, stdout);
+ printf (_(" %s [options] [-] [USER [arg]...]\n"), program_invocation_short_name);
+ fputs (_("\n"
+ "Change the effective user id and group id to that of USER.\n"
+ "A mere - implies -l. If USER not given, assume root.\n"), stdout);
+
+ fputs(USAGE_OPTIONS, stdout);
+ }
+
+ fputs (_(
+ " -m, -p, --preserve-environment do not reset environment variables\n"
+ " -g, --group <group> specify the primary group\n"
+ " -G, --supp-group <group> specify a supplemental group\n\n"), stdout);
+
+ fputs (_(
+ " -, -l, --login make the shell a login shell\n"
+ " -c, --command <command> pass a single command to the shell with -c\n"
+ " --session-command <command> pass a single command to the shell with -c\n"
+ " and do not create a new session\n"
+ " -f, --fast pass -f to the shell (for csh or tcsh)\n"
+ " -s, --shell <shell> run shell if /etc/shells allows it\n"), stdout);
+
+ fputs(USAGE_SEPARATOR, stdout);
+ fputs(USAGE_HELP, stdout);
+ fputs(USAGE_VERSION, stdout);
+ printf(USAGE_MAN_TAIL(su_mode == SU_MODE ? "su(1)" : "runuser(1)"));
exit (status);
}
@@ -754,7 +768,7 @@ int
su_main (int argc, char **argv, int mode)
{
int optc;
- const char *new_user = DEFAULT_USER;
+ const char *new_user = DEFAULT_USER, *runuser_user = NULL;
char *command = NULL;
int request_same_session = 0;
char *shell = NULL;
@@ -774,6 +788,7 @@ su_main (int argc, char **argv, int mode)
{"shell", required_argument, NULL, 's'},
{"group", required_argument, NULL, 'g'},
{"supp-group", required_argument, NULL, 'G'},
+ {"user", required_argument, NULL, 'u'}, /* runuser only */
{"help", no_argument, 0, 'h'},
{"version", no_argument, 0, 'V'},
{NULL, 0, NULL, 0}
@@ -789,7 +804,7 @@ su_main (int argc, char **argv, int mode)
simulate_login = false;
change_environment = true;
- while ((optc = getopt_long (argc, argv, "c:fg:G:lmps:hV", longopts, NULL)) != -1)
+ while ((optc = getopt_long (argc, argv, "+c:fg:G:lmps:u:hV", longopts, NULL)) != -1)
{
switch (optc)
{
@@ -839,6 +854,12 @@ su_main (int argc, char **argv, int mode)
shell = optarg;
break;
+ case 'u':
+ if (su_mode != RUNUSER_MODE)
+ usage (EXIT_FAILURE);
+ runuser_user = optarg;
+ break;
+
case 'h':
usage(0);
@@ -858,8 +879,21 @@ su_main (int argc, char **argv, int mode)
simulate_login = true;
++optind;
}
- if (optind < argc)
+
+ /* if not "-u <user>" specified then fallback to classic su(1) */
+ if (!runuser_user && optind < argc)
new_user = argv[optind++];
+ else {
+ /* runuser -u <command> */
+ new_user = runuser_user;
+ if (shell || fast_startup || command || simulate_login) {
+ errx(EXIT_FAILURE,
+ _("options --{shell,fast,command,session-command,login} and "
+ "--user are mutually exclusive."));
+ }
+ if (optind == argc)
+ errx(EXIT_FAILURE, _("COMMAND not specified."));
+ }
if ((num_supp_groups || use_gid) && restricted)
errx(EXIT_FAILURE, _("only root can specify alternative groups"));
@@ -903,18 +937,23 @@ su_main (int argc, char **argv, int mode)
if (request_same_session || !command || !pw->pw_uid)
same_session = 1;
- if (!shell && !change_environment)
- shell = getenv ("SHELL");
- if (shell && getuid () != 0 && restricted_shell (pw->pw_shell))
- {
- /* The user being su'd to has a nonstandard shell, and so is
- probably a uucp account or has restricted access. Don't
- compromise the account by allowing access with a standard
- shell. */
- warnx (_("using restricted shell %s"), pw->pw_shell);
- shell = NULL;
- }
- shell = xstrdup (shell ? shell : pw->pw_shell);
+ /* initialize shell variable only if "-u <user>" not specified */
+ if (runuser_user) {
+ shell = NULL;
+ } else {
+ if (!shell && !change_environment)
+ shell = getenv ("SHELL");
+ if (shell && getuid () != 0 && restricted_shell (pw->pw_shell))
+ {
+ /* The user being su'd to has a nonstandard shell, and so is
+ probably a uucp account or has restricted access. Don't
+ compromise the account by allowing access with a standard
+ shell. */
+ warnx (_("using restricted shell %s"), pw->pw_shell);
+ shell = NULL;
+ }
+ shell = xstrdup (shell ? shell : pw->pw_shell);
+ }
init_groups (pw, groups, num_supp_groups);
@@ -933,7 +972,12 @@ su_main (int argc, char **argv, int mode)
if (simulate_login && chdir (pw->pw_dir) != 0)
warn (_("warning: cannot change directory to %s"), pw->pw_dir);
- run_shell (shell, command, argv + optind, max (0, argc - optind));
+ if (shell)
+ run_shell (shell, command, argv + optind, max (0, argc - optind));
+ else {
+ execvp(argv[optind], &argv[optind]);
+ err(EXIT_FAILURE, _("executing %s failed"), argv[optind]);
+ }
}
// vim: sw=2 cinoptions=>4,n-2,{2,^-2,\:2,=2,g0,h2,p5,t0,+2,(0,u0,w1,m1
diff --git a/login-utils/su.1 b/login-utils/su.1
index 59e1731..c82b941 100644
--- a/login-utils/su.1
+++ b/login-utils/su.1
@@ -216,6 +216,7 @@ command specific logindef config file
global logindef config file
.PD 1
.SH "SEE ALSO"
+.BR runuser (8),
.BR pam (8),
.BR shells (5),
.BR login.defs (5)
--
1.7.7.6
--
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