/* su.c - switch user * * Copyright 2013 CE Strake <strake888@gmail.com> * * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/su.html * TODO: log su attempts * TODO: suid support * Supports undocumented compatibility options: -m synonym for -p, - for -l USE_SU(NEWTOY(su, "^lmpu:g:c:s:[!lmp]", TOYFLAG_BIN|TOYFLAG_ROOTONLY)) config SU bool "su" default y depends on TOYBOX_SHADOW help usage: su [-lp] [-u UID] [-g GID,...] [-s SHELL] [-c CMD] [USER [COMMAND...]] Switch user, prompting for password of new user when not run as root. With one argument, switch to USER and run user's shell from /etc/passwd. With no arguments, USER is root. If COMMAND line provided after USER, exec() it as new USER (bypasing shell). If -u or -g specified, first argument (if any) isn't USER (it's COMMAND). first argument is USER name to switch to (which must exist). Non-root users are prompted for new user's password. -s Shell to use (default is user's shell from /etc/passwd) -c Command line to pass to -s shell (ala sh -c "CMD") -l Reset environment as if new login. -u Switch to UID instead of USER -g Switch to GID (only root allowed, can be comma separated list) -p Preserve environment (except for $PATH and $IFS) */ #define FOR_su #include "toys.h" GLOBALS( char *s; char *c; ) void su_main() { char *name, *passhash = 0, **argu, **argv; struct passwd *up; struct spwd *shp; if (*toys.optargs && !strcmp("-", *toys.optargs)) { toys.optflags |= FLAG_l; toys.optargs++; } if (*toys.optargs) name = *(toys.optargs++); else name = "root"; loggit(LOG_NOTICE, "%s->%s", getusername(getuid()), name); if (!(shp = getspnam(name))) perror_exit("no '%s'", name); if (getuid()) { if (*shp->sp_pwdp != '$') goto deny; if (read_password(toybuf, sizeof(toybuf), "Password: ")) goto deny; passhash = crypt(toybuf, shp->sp_pwdp); memset(toybuf, 0, sizeof(toybuf)); if (!passhash || strcmp(passhash, shp->sp_pwdp)) goto deny; } closelog(); xsetuser(up = xgetpwnam(name)); if (FLAG(m)||FLAG(p)) { unsetenv("IFS"); setenv("PATH", _PATH_DEFPATH, 1); } else reset_env(up, FLAG(l)); argv = argu = xmalloc(sizeof(char *)*(toys.optc + 4)); *(argv++) = TT.s ? TT.s : up->pw_shell; loggit(LOG_NOTICE, "run %s", *argu); if (FLAG(l)) *(argv++) = "-l"; if (FLAG(c)) { *(argv++) = "-c"; *(argv++) = TT.c; } while ((*(argv++) = *(toys.optargs++))); xexec(argu); deny: syslog(LOG_NOTICE, "No."); puts("No."); toys.exitval = 1; }