projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 252e456d | 1 | #ifndef lint |
| 09a58956 | 2 | static char sccsid[] = "@(#)passwd.c 4.2 (Berkeley) %G%"; |
| 252e456d SL |
3 | #endif |
| 4 | ||
| 5 | /* | |
| 6 | * enter a password in the password file | |
| 7 | * this program should be suid with owner | |
| 8 | * with an owner with write permission on /etc/passwd | |
| 9 | */ | |
| 10 | #include <sys/file.h> | |
| 11 | ||
| 12 | #include <stdio.h> | |
| 13 | #include <signal.h> | |
| 14 | #include <pwd.h> | |
| 15 | #include <errno.h> | |
| 16 | ||
| 17 | char passwd[] = "/etc/passwd"; | |
| 18 | char temp[] = "/etc/ptmp"; | |
| 19 | struct passwd *pwd; | |
| 20 | struct passwd *getpwent(); | |
| 21 | int endpwent(); | |
| 22 | char *strcpy(); | |
| 23 | char *crypt(); | |
| 24 | char *getpass(); | |
| 25 | char *getlogin(); | |
| 26 | char *pw; | |
| 27 | char pwbuf[10]; | |
| 28 | extern int errno; | |
| 29 | ||
| 30 | main(argc, argv) | |
| 31 | char *argv[]; | |
| 32 | { | |
| 33 | char *p; | |
| 34 | int i; | |
| 35 | char saltc[2]; | |
| 36 | long salt; | |
| 37 | int u; | |
| 38 | int insist; | |
| 39 | int ok, flags; | |
| 40 | int c, pwlen, fd; | |
| 41 | FILE *tf; | |
| 42 | char *uname; | |
| 43 | ||
| 44 | insist = 0; | |
| 45 | if (argc < 2) { | |
| 46 | if ((uname = getlogin()) == NULL) { | |
| 47 | printf ("Usage: passwd user\n"); | |
| 48 | exit(1); | |
| 49 | } | |
| 50 | printf("Changing password for %s\n", uname); | |
| 51 | } else | |
| 52 | uname = argv[1]; | |
| 53 | while (((pwd = getpwent()) != NULL) && strcmp(pwd->pw_name, uname)) | |
| 54 | ; | |
| 55 | u = getuid(); | |
| 56 | if (pwd == NULL || (u != 0 && u != pwd->pw_uid)) { | |
| 57 | printf("Permission denied.\n"); | |
| 58 | exit(1); | |
| 59 | } | |
| 60 | endpwent(); | |
| 61 | if (pwd->pw_passwd[0] && u != 0) { | |
| 62 | strcpy(pwbuf, getpass("Old password:")); | |
| 63 | pw = crypt(pwbuf, pwd->pw_passwd); | |
| 64 | if (strcmp(pw, pwd->pw_passwd) != 0) { | |
| 65 | printf("Sorry.\n"); | |
| 66 | exit(1); | |
| 67 | } | |
| 68 | } | |
| 69 | tryagain: | |
| 70 | strcpy(pwbuf, getpass("New password:")); | |
| 71 | pwlen = strlen(pwbuf); | |
| 72 | if (pwlen == 0) { | |
| 73 | printf("Password unchanged.\n"); | |
| 74 | exit(1); | |
| 75 | } | |
| 76 | /* | |
| 77 | * Insure password is of reasonable length and | |
| 78 | * composition. If we really wanted to make things | |
| 79 | * sticky, we could check the dictionary for common | |
| 80 | * words, but then things would really be slow. | |
| 81 | */ | |
| 82 | ok = 0; | |
| 83 | flags = 0; | |
| 84 | p = pwbuf; | |
| 85 | while (c = *p++) { | |
| 86 | if (c >= 'a' && c <= 'z') | |
| 87 | flags |= 2; | |
| 88 | else if (c >= 'A' && c <= 'Z') | |
| 89 | flags |= 4; | |
| 90 | else if (c >= '0' && c <= '9') | |
| 91 | flags |= 1; | |
| 92 | else | |
| 93 | flags |= 8; | |
| 94 | } | |
| 95 | if (flags >= 7 && pwlen >= 4) | |
| 96 | ok = 1; | |
| 97 | if ((flags == 2 || flags == 4) && pwlen >= 6) | |
| 98 | ok = 1; | |
| 99 | if ((flags == 3 || flags == 5 || flags == 6) && pwlen >= 5) | |
| 100 | ok = 1; | |
| 101 | if (!ok && insist < 2) { | |
| 252e456d SL |
102 | printf("Please use %s.\n", flags == 1 ? |
| 103 | "at least one non-numeric character" : | |
| 104 | "a longer password"); | |
| 105 | insist++; | |
| 106 | goto tryagain; | |
| 107 | } | |
| 108 | if (strcmp(pwbuf, getpass("Retype new password:")) != 0) { | |
| 109 | printf("Mismatch - password unchanged.\n"); | |
| 110 | exit(1); | |
| 111 | } | |
| 112 | time(&salt); | |
| 113 | salt = 9 * getpid(); | |
| 114 | saltc[0] = salt & 077; | |
| 115 | saltc[1] = (salt>>6) & 077; | |
| 116 | for (i = 0; i < 2; i++) { | |
| 117 | c = saltc[i] + '.'; | |
| 118 | if (c > '9') | |
| 119 | c += 7; | |
| 120 | if (c > 'Z') | |
| 121 | c += 6; | |
| 122 | saltc[i] = c; | |
| 123 | } | |
| 124 | pw = crypt(pwbuf, saltc); | |
| 125 | signal(SIGHUP, SIG_IGN); | |
| 126 | signal(SIGINT, SIG_IGN); | |
| 127 | signal(SIGQUIT, SIG_IGN); | |
| 128 | /* | |
| 129 | * The mode here could be 644 except then old versions | |
| 130 | * of passwd that don't honor the advisory locks might | |
| 131 | * sneak in and mess things up. If we could believe the | |
| 132 | * locking were honored, then we could also eliminate the | |
| 133 | * chmod below after the rename. | |
| 134 | */ | |
| 135 | fd = open(temp, FWRONLY|FCREATE|FEXLOCK|FNBLOCK, 0600); | |
| 136 | if (fd < 0) { | |
| 137 | fprintf(stderr, "passwd: "); | |
| 138 | if (errno == EBUSY) | |
| 139 | fprintf(stderr, "password file busy - try again.\n"); | |
| 140 | else | |
| 141 | perror(temp); | |
| 142 | exit(1); | |
| 143 | } | |
| 144 | signal(SIGTSTP, SIG_IGN); | |
| 145 | if ((tf = fdopen(fd, "w")) == NULL) { | |
| 146 | fprintf(stderr, "passwd: fdopen failed?\n"); | |
| 147 | exit(1); | |
| 148 | } | |
| 149 | /* | |
| 150 | * Copy passwd to temp, replacing matching lines | |
| 151 | * with new password. | |
| 152 | */ | |
| 153 | while ((pwd = getpwent()) != NULL) { | |
| 154 | if (strcmp(pwd->pw_name,uname) == 0) { | |
| 155 | u = getuid(); | |
| 156 | if (u && u != pwd->pw_uid) { | |
| 157 | fprintf(stderr, "passwd: permission denied.\n"); | |
| 158 | unlink(temp); | |
| 159 | exit(1); | |
| 160 | } | |
| 161 | pwd->pw_passwd = pw; | |
| 162 | if (pwd->pw_gecos[0] == '*') | |
| 163 | pwd->pw_gecos++; | |
| 164 | } | |
| 165 | fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n", | |
| 166 | pwd->pw_name, | |
| 167 | pwd->pw_passwd, | |
| 168 | pwd->pw_uid, | |
| 169 | pwd->pw_gid, | |
| 170 | pwd->pw_gecos, | |
| 171 | pwd->pw_dir, | |
| 172 | pwd->pw_shell); | |
| 173 | } | |
| 174 | endpwent(); | |
| 175 | if (rename(temp, passwd) < 0) { | |
| 176 | fprintf(stderr, "passwd: "); perror("rename"); | |
| 177 | unlink(temp); | |
| 178 | exit(1); | |
| 179 | } | |
| 180 | chmod(passwd, 0644); | |
| 181 | fclose(tf); | |
| 182 | } |