bin/95777: [patch] -u|-U options in jexec

[Cheng-Lung Sung]

>Number:         95777
>Category:       bin
>Synopsis:       [patch] -u|-U options in jexec
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          update
>Submitter-Id:   current-users
>Arrival-Date:   Sat Apr 15 02:40:17 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Cheng-Lung Sung
>Release:        FreeBSD 6.1-PRERELEASE i386
>Organization:
FreeBSD @ Taiwan
>Environment:
System: FreeBSD going04.iis.sinica.edu.tw 6.1-PRERELEASE FreeBSD 6.1-PRERELEASE #2: Fri Apr 7 12:57:51 CST 2006 root at going04.iis.sinica.edu.tw:/usr/obj/usr/src/sys/GENERIC i386


>Description:
    I think jexec command should be executed in different user,
just like what jail(8) do.

also refer to 
http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/94730
>How-To-Repeat:
    jexec <jid> cmd...
    jexec -u|-U username <jid> cmd...
>Fix:

--- /usr/src/usr.sbin/jexec/jexec.c	Sat Jul  5 03:14:27 2003
+++ jexec/jexec.c	Sat Apr 15 01:12:12 2006
@@ -30,26 +30,84 @@
 #include <sys/jail.h>
 
 #include <err.h>
+#include <errno.h>
+#include <login_cap.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <pwd.h>
 #include <unistd.h>
 
 static void	usage(void);
 
+#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;						\
+	if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)	\
+		err(1, "getgrouplist: %s", username);			\
+} while (0)
+
 int
 main(int argc, char *argv[])
 {
 	int jid;
+	login_cap_t *lcap = NULL;
+	struct passwd *pwd = NULL;
+	gid_t groups[NGROUPS];
+	int ch, ngroups, uflag, Uflag;
+	char *username;
+	ch = uflag = Uflag = 0;
+	username = NULL;
 
-	if (argc < 3)
+	while ((ch = getopt(argc, argv, "u:U:")) != -1) {
+		switch (ch) {
+		case 'u':
+			username = optarg;
+			uflag = 1;
+			break;
+		case 'U':
+			username = optarg;
+			Uflag = 1;
+			break;
+		default:
+			usage();
+		}
+	}
+	argc -= optind;
+	argv += optind;
+	if (argc < 2)
+		usage();
+	if (uflag && Uflag)
 		usage();
-	jid = (int)strtol(argv[1], NULL, 10);
+	if (uflag)
+		GET_USER_INFO;
+	jid = (int)strtol(argv[0], NULL, 10);
 	if (jail_attach(jid) == -1)
 		err(1, "jail_attach(): %d", jid);
 	if (chdir("/") == -1)
 		err(1, "chdir(): /");
-	if (execvp(argv[2], argv + 2) == -1)
-		err(1, "execvp(): %s", argv[2]);
+	if (username != NULL) {
+		if (Uflag)
+			GET_USER_INFO;
+		if (setgroups(ngroups, groups) != 0)
+			err(1, "setgroups");
+		if (setgid(pwd->pw_gid) != 0)
+			err(1, "setgid");
+		if (setusercontext(lcap, pwd, pwd->pw_uid,
+		    LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
+			err(1, "setusercontext");
+		login_close(lcap);
+	}
+	if (execvp(argv[1], argv + 1) == -1)
+		err(1, "execvp(): %s", argv[1]);
 	exit(0);
 }
 
@@ -57,6 +115,8 @@
 usage(void)
 {
 
-	fprintf(stderr, "usage: jexec jid command [...]\n");
+	fprintf(stderr, "%s%s\n",
+		"usage: jexec [-u username | -U username]",
+		" jid command [...]");
 	exit(1); 
 }
>Release-Note:
>Audit-Trail:
>Unformatted: