1 /* su.c - switch user
2 *
3 * Copyright 2013 CE Strake <strake888@gmail.com>
4 *
5 * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/su.html
6 * TODO: log su attempts
7
8 USE_SU(NEWTOY(su, "lmpc:s:", TOYFLAG_BIN|TOYFLAG_ROOTONLY))
9
10 config SU
11 bool "su"
12 default y
13 depends on TOYBOX_SHADOW
14 help
15 usage: su [-lmp] [-c CMD] [-s SHELL] [USER [ARGS...]]
16
17 Switch to user (or root) and run shell (with optional command line).
18
19 -s shell to use
20 -c command to pass to shell with -c
21 -l login shell
22 -(m|p) preserve environment
23 */
24
25 #define FOR_su
26 #include "toys.h"
27
GLOBALS(char * s;char * c;)28 GLOBALS(
29 char *s;
30 char *c;
31 )
32
33 static char *snapshot_env(char *name)
34 {
35 char *s = getenv(name);
36
37 if (s) return xmprintf("%s=%s", name, s);
38
39 return 0;
40 }
41
su_main()42 void su_main()
43 {
44 char *name, *passhash = 0, **argu, **argv;
45 struct passwd *up;
46 struct spwd *shp;
47
48 if (*toys.optargs && !strcmp("-", *toys.optargs)) {
49 toys.optflags |= FLAG_l;
50 toys.optargs++;
51 }
52
53 if (*toys.optargs) name = *(toys.optargs++);
54 else name = "root";
55
56 if (!(shp = getspnam(name))) perror_exit("no '%s'", name);
57 if (getuid()) {
58 if (*shp->sp_pwdp != '$') goto deny;
59 if (read_password(toybuf, sizeof(toybuf), "Password: ")) goto deny;
60 passhash = crypt(toybuf, shp->sp_pwdp);
61 memset(toybuf, 0, sizeof(toybuf));
62 if (!passhash || strcmp(passhash, shp->sp_pwdp)) goto deny;
63 }
64
65 up = xgetpwnam(name);
66 xsetuser(up);
67
68 argv = argu = xmalloc(sizeof(char *)*(toys.optc + 4));
69 *(argv++) = TT.s ? TT.s : up->pw_shell;
70
71 if (toys.optflags & FLAG_l) {
72 int i;
73 char *stuff[] = {snapshot_env("TERM"), snapshot_env("DISPLAY"),
74 snapshot_env("COLORTERM"), snapshot_env("XAUTHORITY")};
75
76 clearenv();
77 for (i=0; i < ARRAY_LEN(stuff); i++) if (stuff[i]) putenv(stuff[i]);
78 *(argv++) = "-l";
79 xchdir(up->pw_dir);
80 } else unsetenv("IFS");
81 setenv("PATH", "/sbin:/bin:/usr/sbin:/usr/bin", 1);
82 if (!(toys.optflags & (FLAG_m|FLAG_p))) {
83 setenv("HOME", up->pw_dir, 1);
84 setenv("SHELL", up->pw_shell, 1);
85 setenv("USER", up->pw_name, 1);
86 setenv("LOGNAME", up->pw_name, 1);
87 } else unsetenv("IFS");
88
89 if (toys.optflags & FLAG_c) {
90 *(argv++) = "-c";
91 *(argv++) = TT.c;
92 }
93 while ((*(argv++) = *(toys.optargs++)));
94 xexec(argu);
95
96 deny:
97 puts("No.");
98 toys.exitval = 1;
99 }
100