smp_set_identity(S)

Syntax

#include <sys/types.h>
#include <prot.h>

int smp_set_identity(userp, reasonp, environp, shellp)
struct smp_user_info *userp;
char **reasonp;
char ***environp;
char **shellp;

Description

Note that this routine also checks the account lock, for the benefit of applications which do not call smp_check_pw(S) (for example, cron(C)).

environp is set to point to an appropriate environment for use in a subsequent exece, and shellp is set to point to the full pathname of the user's shell.

reasonp is used with certain return values to store a descriptive message.

Return values

SMP_NOTAUTH

The calling program does not have sufficient privileges to change the user id, or to set the account privileges.

SMP_ACCTLOCK

The account is locked, and the session should not continue.

SMP_COMPLETE

The new user's identity has been successfully assumed.

SMP_EXTFAIL

External failure; access to remote authentication information failed. reasonp points to a character string explaining the cause of the error.

SMP_FAIL

No memory was available in which to build the new environment.

SMP_OVERRIDE

Errors were encountered which would normally have resulted in the routine failing, but since the target account is root and the terminal is the console, the login process should continue. reasonp points to a character string giving the type of failure.

Diagnostics

Cannot reread protected password entry

An attempt to reread the protected password information for the account failed. SMP_EXTFAIL is returned.

Cannot reread terminal control entry

An attempt to find the terminal entry in the terminal control database failed. SMP_EXTFAIL is returned.

Cannot rewrite terminal control entry

An attempt to update the terminal control database failed. SMP_EXTFAIL is returned.

Cannot rewrite protected password entry

An attempt to update the protected password database failed. SMP_EXTFAIL is returned.

Cannot change to home directory

An attempt to change to the home directory of the account failed. SMP_EXTFAIL is returned.

Could not set default ULIMIT

The ulimit could not be set (see ulimit(S)). SMP_EXTFAIL is returned.

Bad supplemental group list

An attempt to set the supplemental group list failed. SMP_EXTFAIL is returned.

Bad login user id

The login user ID specified in userp could not be set. SMP_EXTFAIL is returned.

Bad group id

The group ID specified in userp could not be set. SMP_EXTFAIL is returned.

Bad user id

The user ID specified in userp could not be set. SMP_EXTFAIL is returned.

Unable to set kernel authorizations

An attempt to set the kernel authorizations failed (see setpriv(S)). SMP_EXTFAIL is returned.

Examples

...
    switch (smp_check_user(SMP_LOGIN, gets(line), ttyname(0), 0, &userp,
                                 &pwtries, &reason)) {
    ...
    }

    switch (smp_set_identity(userp, &reason, &environ, &shell)) {
    case SMP_COMPLETE:
        break;
    case SMP_NOTAUTH:
        put("not authorised\n");        /* not running with root perms */
        exit(1);
    case SMP_EXTFAIL:
        put(reason);
        put("\n");
        exit(1);
    case SMP_OVERRIDE:
        put(reason);
        put("\nroot login on console is allowed\n");
    }

    /* display last login messages */

    {   char *success, *unsuccess;;
        switch (smp_get_messages(userp, &success, &unsuccess, &reason)) {
        ...
        }
    }

    /* execute the user's login shell */

    {   static char minusnam[16] = "-";
        register i;

        strcpy(minusnam+1, basename(shell));
        execle(shell, minusnam, (char*)0, environ);

     /* shell not an executable binary: turn off the SHELL= env variable */
        for (i = 0; environ[i]; i++)
            if (strncmp(environ[i], "SHELL=", 6) == 0)
                environ[i][6] = 0;

        if (access(shell, 05) == 0)
            execle("/bin/sh", "sh", shell, minusnam, (char*)0, environ);
    }
    put("No shell\n");
    exit(1);

Files

/lib/libprot.a

security subsystem library routines

/usr/lib/libp/libprot.a

as above but used for profiling

/usr/include/prot.h

defines the smp_user_info structure

/etc/passwd

password file, see passwd(F)

/etc/shadow

shadow password file, see shadow(F)

/tcb/files/auth/?/*

protected password database, see prpw(F)

/etc/auth/system/ttys

terminal control database, see ttys(F)

/etc/default/login

default values for login process, see login(M)

/etc/passwd

password file, see passwd(F)

~/.hushlogin

user's hushlogin file, see login(M)

/etc/ttytype

terminal type setup, see ttytype(F)

See also

Standards conformance