Add support for controlling whether utmp is updated and which user is

listed in the entry.

doc/sudo_plugin.pod

@@ -591,6 +591,20 @@ Allocate a pseudo-tty to run the command in, regardless of whether
 or not I/O logging is in use.  By default, B<sudo> will only run
 the command in a pty when an I/O log plugin is loaded.
 
+=item set_utmp=bool
+
+Create a utmp (or utmpx) entry when a pseudo-tty is allocated.  By
+default, the new entry will be a copy of the user's existing utmp
+entry (if any), with the tty, time, type and pid fields updated.
+
+=item utmp_user=string
+
+User name to use when constructing a new utmp (or utmpx) entry when
+I<set_utmp> is enabled.  This option can be used to set the user
+field in the utmp entry to the user the command runs as rather than
+the invoking user.  If not set, B<sudo> will base the new entry on
+the invoking user's existing entry.
+
 =back
 
 Unsupported values will be ignored.

plugins/sudoers/def_data.c

@@ -338,6 +338,14 @@ struct sudo_defs_types sudo_defs_table[] = {
 	"iolog_file", T_STR,
 	"File in which to store the input/output log",
 	NULL,
+    }, {
+	"set_utmp", T_FLAG,
+	"Add an entry to the utmp/utmpx file when allocating a pty",
+	NULL,
+    }, {
+	"utmp_runas", T_FLAG,
+	"Set the user in utmp to the runas user, not the invoking user",
+	NULL,
     }, {
 	NULL, 0, NULL
     }

plugins/sudoers/def_data.h

@@ -156,6 +156,10 @@
 #define I_IOLOG_DIR             77
 #define def_iolog_file          (sudo_defs_table[78].sd_un.str)
 #define I_IOLOG_FILE            78
+#define def_set_utmp            (sudo_defs_table[79].sd_un.flag)
+#define I_SET_UTMP              79
+#define def_utmp_runas          (sudo_defs_table[80].sd_un.flag)
+#define I_UTMP_RUNAS            80
 
 enum def_tuple {
 	never,

plugins/sudoers/def_data.in

@@ -250,3 +250,9 @@ iolog_dir
 iolog_file
 	T_STR
 	"File in which to store the input/output log"
+set_utmp
+	T_FLAG
+	"Add an entry to the utmp/utmpx file when allocating a pty"
+utmp_runas
+	T_FLAG
+	"Set the user in utmp to the runas user, not the invoking user"

plugins/sudoers/defaults.c

@@ -498,6 +498,7 @@ init_defaults(void)
     def_secure_path = estrdup(SECURE_PATH);
 #endif
     def_editor = estrdup(EDITOR);
+    def_set_utmp = TRUE;
 
     /* Finally do the lists (currently just environment tables). */
     init_envtables();

plugins/sudoers/sudoers.c

@@ -646,6 +646,10 @@ sudoers_policy_main(int argc, char * const argv[], int pwflag, char *env_add[],
 	command_info[info_len++] = estrdup("noexec=true");
     if (def_noexec_file)
 	command_info[info_len++] = fmt_string("noexec_file", def_noexec_file);
+    if (def_set_utmp)
+	command_info[info_len++] = estrdup("set_utmp=true");
+    if (def_utmp_runas)
+	command_info[info_len++] = fmt_string("utmp_user", runas_pw->pw_name);
 #ifdef HAVE_LOGIN_CAP_H
     if (lc != NULL)
 	command_info[info_len++] = fmt_string("login_class", lc->lc_class);

src/exec.c

@@ -203,6 +203,7 @@ int
 sudo_execve(struct command_details *details, struct command_status *cstat)
 {
     int maxfd, n, nready, sv[2], log_io = FALSE;
+    const char *utmp_user = NULL;
     fd_set *fdsr, *fdsw;
     sigaction_t sa;
     pid_t child;
@@ -231,8 +232,10 @@ sudo_execve(struct command_details *details, struct command_status *cstat)
     if (!tq_empty(&io_plugins) || ISSET(details->flags, CD_USE_PTY)) {
 	log_io = TRUE;
 	if (!ISSET(details->flags, CD_BACKGROUND)) {
+	    if (ISSET(details->flags, CD_SET_UTMP))
+		utmp_user = details->utmp_user ? details->utmp_user : user_details.username;
 	    sudo_debug(8, "allocate pty for I/O logging");
-	    pty_setup(details->euid, user_details.tty);
+	    pty_setup(details->euid, user_details.tty, utmp_user);
 	}
     }
 

src/exec_pty.c

@@ -118,7 +118,7 @@ cleanup(int gotsignal)
 #ifdef HAVE_SELINUX
     selinux_restore_tty();
 #endif
-    utmp_logout(slavename);
+    utmp_logout(slavename); /* XXX - only if CD_SET_UTMP */
 }
 
 /*
@@ -127,17 +127,16 @@ cleanup(int gotsignal)
  * and slavename globals.
  */
 void
-pty_setup(uid_t uid, const char *tty)
+pty_setup(uid_t uid, const char *tty, const char *utmp_user)
 {
     io_fds[SFD_USERTTY] = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
     if (io_fds[SFD_USERTTY] != -1) {
 	if (!get_pty(&io_fds[SFD_MASTER], &io_fds[SFD_SLAVE],
 	    slavename, sizeof(slavename), uid))
 	    error(1, "Can't get pty");
-	/*
-	 * Add entry to utmp/utmpx.
-	 */
-	utmp_login(tty, slavename, io_fds[SFD_SLAVE]);
+	/* Add entry to utmp/utmpx? */
+	if (utmp_user != NULL)
+	    utmp_login(tty, slavename, io_fds[SFD_SLAVE], utmp_user);
     }
 }
 
@@ -656,7 +655,7 @@ pty_close(struct command_status *cstat)
 	    }
 	}
     }
-    utmp_logout(slavename);
+    utmp_logout(slavename); /* XXX - only if CD_SET_UTMP */
 }
 
 /*

src/sudo.c

@@ -605,6 +605,11 @@ command_info_to_details(char * const info[], struct command_details *details)
 	    case 's':
 		SET_STRING("selinux_role=", selinux_role)
 		SET_STRING("selinux_type=", selinux_type)
+		if (strncmp("set_utmp=", info[i], sizeof("set_utmp=") - 1) == 0) {
+		    if (atobool(info[i] + sizeof("set_utmp=") - 1) == TRUE)
+			SET(details->flags, CD_SET_UTMP);
+		    break;
+		}
 		if (strncmp("sudoedit=", info[i], sizeof("sudoedit=") - 1) == 0) {
 		    if (atobool(info[i] + sizeof("sudoedit=") - 1) == TRUE)
 			SET(details->flags, CD_SUDOEDIT);
@@ -647,6 +652,7 @@ command_info_to_details(char * const info[], struct command_details *details)
 			SET(details->flags, CD_USE_PTY);
 		    break;
 		}
+		SET_STRING("utmp_user=", utmp_user)
 		break;
 	}
     }

src/sudo.h

@@ -120,6 +120,7 @@ struct user_details {
 #define CD_BACKGROUND		0x0400
 #define CD_RBAC_ENABLED		0x0800
 #define CD_USE_PTY		0x1000
+#define CD_SET_UTMP		0x2000
 
 struct command_details {
     uid_t uid;
@@ -139,6 +140,7 @@ struct command_details {
     const char *chroot;
     const char *selinux_role;
     const char *selinux_type;
+    const char *utmp_user;
     char **argv;
     char **envp;
 };

src/sudo_exec.h

@@ -38,12 +38,13 @@ int suspend_parent(int signo);
 void fd_set_iobs(fd_set *fdsr, fd_set *fdsw);
 void handler(int s);
 void pty_close(struct command_status *cstat);
-void pty_setup(uid_t uid, const char *tty);
+void pty_setup(uid_t uid, const char *tty, const char *utmp_user);
 void terminate_child(pid_t pid, int use_pgrp);
 extern int signal_pipe[2];
 
 /* utmp.c */
-int utmp_login(const char *from_line, const char *to_line, int ttyfd);
+int utmp_login(const char *from_line, const char *to_line, int ttyfd,
+    const char *user);
 int utmp_logout(const char *line);
 
 #endif /* _SUDO_EXEC_H */

src/utmp.c

@@ -125,14 +125,20 @@ utmp_settime(sudo_utmp_t *ut)
  * Fill in a utmp entry, using an old entry as a template if there is one.
  */
 static void
-utmp_fill(const char *line, sudo_utmp_t *ut_old, sudo_utmp_t *ut_new)
+utmp_fill(const char *line, const char *user, sudo_utmp_t *ut_old,
+    sudo_utmp_t *ut_new)
 {
     if (ut_old == NULL) {
 	memset(ut_new, 0, sizeof(*ut_new));
-	strncpy(ut_new->ut_user, user_details.username, sizeof(ut_new->ut_user));
+	if (user == NULL) {
+	    strncpy(ut_new->ut_user, user_details.username,
+		sizeof(ut_new->ut_user));
+	}
     } else if (ut_old != ut_new) {
 	memcpy(ut_new, ut_old, sizeof(*ut_new));
     }
+    if (user != NULL)
+	strncpy(ut_new->ut_user, user, sizeof(ut_new->ut_user));
     strncpy(ut_new->ut_line, line, sizeof(ut_new->ut_line));
 #if defined(HAVE_STRUCT_UTMPX_UT_ID) || defined(HAVE_STRUCT_UTMP_UT_ID)
     utmp_setid(ut_old, ut_new);
@@ -156,7 +162,8 @@ utmp_fill(const char *line, sudo_utmp_t *ut_old, sudo_utmp_t *ut_new)
  */
 #if defined(HAVE_GETUTXID) || defined(HAVE_GETUTID)
 int
-utmp_login(const char *from_line, const char *to_line, int ttyfd)
+utmp_login(const char *from_line, const char *to_line, int ttyfd,
+    const char *user)
 {
     sudo_utmp_t utbuf, *ut_old = NULL;
     int rval = FALSE;
@@ -174,7 +181,7 @@ utmp_login(const char *from_line, const char *to_line, int ttyfd)
 	strncpy(utbuf.ut_line, from_line, sizeof(utbuf.ut_line));
 	ut_old = getutxline(&utbuf);
     }
-    utmp_fill(to_line, ut_old, &utbuf);
+    utmp_fill(to_line, user, ut_old, &utbuf);
     if (pututxline(&utbuf) != NULL)
 	rval = TRUE;
     endutxent();
@@ -253,7 +260,8 @@ utmp_slot(const char *line, int ttyfd)
 # endif /* HAVE_GETTTYENT */
 
 int
-utmp_login(const char *from_line, const char *to_line, int ttyfd)
+utmp_login(const char *from_line, const char *to_line, int ttyfd,
+    const char *user)
 {
     sudo_utmp_t utbuf, *ut_old = NULL;
     int slot, rval = FALSE;
@@ -288,7 +296,7 @@ utmp_login(const char *from_line, const char *to_line, int ttyfd)
 	    }
 	}
     }
-    utmp_fill(to_line, ut_old, &utbuf);
+    utmp_fill(to_line, user, ut_old, &utbuf);
     if (fseek(fp, slot * (long)sizeof(utbuf), SEEK_SET) == 0) {
 	if (fwrite(&utbuf, sizeof(utbuf), 1, fp) == 1)
 	    rval = TRUE;