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1.1 root 1: static char *sccsid = "@(#)passwd.c 4.1 (Berkeley) 10/1/80";
2: /*
3: * enter a password in the password file
4: * this program should be suid with owner
5: * with an owner with write permission on /etc/passwd
6: */
7: #include <stdio.h>
8: #include <signal.h>
9: #include <pwd.h>
10:
11: char passwd[] = "/etc/passwd";
12: char temp[] = "/etc/ptmp";
13: struct passwd *pwd;
14: struct passwd *getpwent();
15: int endpwent();
16: char *strcpy();
17: char *crypt();
18: char *getpass();
19: char *getlogin();
20: char *pw;
21: char pwbuf[10];
22: char buf[BUFSIZ];
23:
24: main(argc, argv)
25: char *argv[];
26: {
27: char *p;
28: int i;
29: char saltc[2];
30: long salt;
31: int u,fi,fo;
32: int insist;
33: int ok, flags;
34: int c;
35: int pwlen;
36: FILE *tf;
37: char *uname;
38:
39: insist = 0;
40: if(argc < 2) {
41: if ((uname = getlogin()) == NULL) {
42: printf ("Usage: passwd user\n");
43: goto bex;
44: } else {
45: printf("Changing password for %s\n", uname);
46: }
47: } else {
48: uname = argv[1];
49: }
50: while(((pwd=getpwent()) != NULL)&&(strcmp(pwd->pw_name,uname)!=0));
51: u = getuid();
52: if((pwd==NULL) || (u!=0 && u != pwd->pw_uid))
53: {
54: printf("Permission denied.\n");
55: goto bex;
56: }
57: endpwent();
58: if (pwd->pw_passwd[0] && u != 0) {
59: strcpy(pwbuf, getpass("Old password:"));
60: pw = crypt(pwbuf, pwd->pw_passwd);
61: if(strcmp(pw, pwd->pw_passwd) != 0) {
62: printf("Sorry.\n");
63: goto bex;
64: }
65: }
66: tryagn:
67: strcpy(pwbuf, getpass("New password:"));
68: pwlen = strlen(pwbuf);
69: if (pwlen == 0) {
70: printf("Password unchanged.\n");
71: goto bex;
72: }
73: ok = 0;
74: flags = 0;
75: p = pwbuf;
76: while(c = *p++){
77: if(c>='a' && c<='z') flags |= 2;
78: else if(c>='A' && c<='Z') flags |= 4;
79: else if(c>='0' && c<='9') flags |= 1;
80: else flags |= 8;
81: }
82: if(flags >=7 && pwlen>= 4) ok = 1;
83: if(((flags==2)||(flags==4)) && pwlen>=6) ok = 1;
84: if(((flags==3)||(flags==5)||(flags==6))&&pwlen>=5) ok = 1;
85:
86: if((ok==0) && (insist<2)){
87: if(flags==1)
88: printf("Please use at least one non-numeric character.\n");
89: else
90: printf("Please use a longer password.\n");
91: insist++;
92: goto tryagn;
93: }
94:
95: if (strcmp(pwbuf,getpass("Retype new password:")) != 0) {
96: printf ("Mismatch - password unchanged.\n");
97: goto bex;
98: }
99:
100: time(&salt);
101: salt += getpid();
102:
103: saltc[0] = salt & 077;
104: saltc[1] = (salt>>6) & 077;
105: for(i=0;i<2;i++){
106: c = saltc[i] + '.';
107: if(c>'9') c += 7;
108: if(c>'Z') c += 6;
109: saltc[i] = c;
110: }
111: pw = crypt(pwbuf, saltc);
112: signal(SIGHUP, SIG_IGN);
113: signal(SIGINT, SIG_IGN);
114: signal(SIGQUIT, SIG_IGN);
115:
116: if(access(temp, 0) >= 0) {
117: printf("Temporary file busy -- try again\n");
118: goto bex;
119: }
120: signal(SIGTSTP, SIG_IGN);
121: close(creat(temp,0600));
122: if((tf=fopen(temp,"w")) == NULL) {
123: printf("Cannot create temporary file\n");
124: goto bex;
125: }
126:
127: /*
128: * copy passwd to temp, replacing matching lines
129: * with new password.
130: */
131:
132: while((pwd=getpwent()) != NULL) {
133: if(strcmp(pwd->pw_name,uname) == 0) {
134: u = getuid();
135: if(u != 0 && u != pwd->pw_uid) {
136: printf("Permission denied.\n");
137: goto out;
138: }
139: pwd->pw_passwd = pw;
140: if (pwd->pw_gecos[0] == '*')
141: pwd->pw_gecos++;
142: }
143: fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n",
144: pwd->pw_name,
145: pwd->pw_passwd,
146: pwd->pw_uid,
147: pwd->pw_gid,
148: pwd->pw_gecos,
149: pwd->pw_dir,
150: pwd->pw_shell);
151: }
152: endpwent();
153: fclose(tf);
154:
155: /*
156: * copy temp back to passwd file
157: */
158:
159: if((fi=open(temp,0)) < 0) {
160: printf("Temp file disappeared!\n");
161: goto out;
162: }
163: if((fo=creat(passwd, 0644)) < 0) {
164: printf("Cannot recreat passwd file.\n");
165: goto out;
166: }
167: while((u=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,u);
168:
169: out:
170: unlink(temp);
171:
172: bex:
173: exit(1);
174: }
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