| 1 | /* crypt() - one-way password encryption function Author: Kees J. Bot
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| 2 | * 7 Feb 1994
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| 3 | * This routine does not encrypt anything, it uses the pwdauth
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| 4 | * program to do the hard work.
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| 5 | */
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| 6 | #define nil ((void*)0)
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| 7 | #define pipe _pipe
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| 8 | #define fork _fork
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| 9 | #define close _close
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| 10 | #define dup2 _dup2
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| 11 | #define execl _execl
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| 12 | #define read _read
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| 13 | #define _exit __exit
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| 14 | #define write _write
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| 15 | #define waitpid _waitpid
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| 16 | #include <sys/types.h>
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| 17 | #include <unistd.h>
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| 18 | #include <string.h>
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| 19 | #include <stdio.h>
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| 20 | #include <errno.h>
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| 21 | #include <stdarg.h>
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| 22 | #include <sys/wait.h>
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| 23 |
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| 24 | /* Set-uid root program to read /etc/shadow or encrypt passwords. */
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| 25 | static char PWDAUTH[] = "/usr/lib/pwdauth";
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| 26 | #define LEN 1024
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| 27 |
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| 28 | static void tell(const char *s0, ...)
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| 29 | {
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| 30 | va_list ap;
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| 31 | const char *s;
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| 32 |
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| 33 | va_start(ap, s0);
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| 34 | s= s0;
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| 35 | while (s != nil) {
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| 36 | (void) write(2, s, strlen(s));
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| 37 | s= va_arg(ap, const char *);
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| 38 | }
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| 39 | va_end(ap);
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| 40 | }
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| 41 |
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| 42 | char *crypt(const char *key, const char *salt)
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| 43 | {
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| 44 | pid_t pid;
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| 45 | int status;
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| 46 | int pfd[2];
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| 47 | static char pwdata[LEN];
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| 48 | char *p= pwdata;
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| 49 | const char *k= key;
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| 50 | const char *s= salt;
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| 51 | int n;
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| 52 |
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| 53 | /* Fill pwdata[] with the key and salt. */
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| 54 | while ((*p++ = *k++) != 0) if (p == pwdata+LEN-1) goto fail;
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| 55 | while ((*p++ = *s++) != 0) if (p == pwdata+LEN-0) goto fail;
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| 56 |
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| 57 | if (pipe(pfd) < 0) goto fail;
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| 58 |
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| 59 | /* Prefill the pipe. */
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| 60 | (void) write(pfd[1], pwdata, p - pwdata);
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| 61 |
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| 62 | switch ((pid= fork())) {
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| 63 | case -1:
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| 64 | close(pfd[0]);
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| 65 | close(pfd[1]);
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| 66 | goto fail;
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| 67 | case 0:
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| 68 | /* Connect both input and output to the pipe. */
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| 69 | if (pfd[0] != 0) {
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| 70 | dup2(pfd[0], 0);
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| 71 | close(pfd[0]);
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| 72 | }
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| 73 | if (pfd[1] != 1) {
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| 74 | dup2(pfd[1], 1);
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| 75 | close(pfd[1]);
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| 76 | }
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| 77 |
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| 78 | execl(PWDAUTH, PWDAUTH, (char *) nil);
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| 79 |
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| 80 | tell("crypt(): ", PWDAUTH, ": ", strerror(errno), "\r\n",
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| 81 | (char *) nil);
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| 82 | /* No pwdauth? Fail! */
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| 83 | (void) read(0, pwdata, LEN);
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| 84 | _exit(1);
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| 85 | }
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| 86 | close(pfd[1]);
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| 87 |
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| 88 | status= -1;
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| 89 | while (waitpid(pid, &status, 0) == -1 && errno == EINTR) {}
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| 90 | if (status != 0) {
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| 91 | close(pfd[0]);
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| 92 | goto fail;
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| 93 | }
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| 94 |
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| 95 | /* Read and return the result. Check if it contains exactly one
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| 96 | * string.
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| 97 | */
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| 98 | n= read(pfd[0], pwdata, LEN);
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| 99 | close(pfd[0]);
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| 100 | if (n < 0) goto fail;
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| 101 | p = pwdata + n;
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| 102 | n = 0;
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| 103 | while (p > pwdata) if (*--p == 0) n++;
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| 104 | if (n != 1) goto fail;
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| 105 | return pwdata;
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| 106 |
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| 107 | fail:
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| 108 | pwdata[0] = salt[0] ^ 1; /* make result != salt */
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| 109 | pwdata[1] = 0;
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| 110 | return pwdata;
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| 111 | }
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| 112 |
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| 113 | /*
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| 114 | * $PchId: crypt.c,v 1.5 1996/04/11 07:46:11 philip Exp $
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| 115 | */
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