116 lines
2.3 KiB
C
116 lines
2.3 KiB
C
/* crypt() - one-way password encryption function Author: Kees J. Bot
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* 7 Feb 1994
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* This routine does not encrypt anything, it uses the pwdauth
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* program to do the hard work.
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*/
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#define nil ((void*)0)
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#define pipe _pipe
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#define fork _fork
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#define close _close
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#define dup2 _dup2
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#define execl _execl
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#define read _read
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#define _exit __exit
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#define write _write
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#define waitpid _waitpid
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#include <sys/types.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <sys/wait.h>
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/* Set-uid root program to read /etc/shadow or encrypt passwords. */
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static char PWDAUTH[] = "/usr/lib/pwdauth";
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#define LEN 1024
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static void tell(const char *s0, ...)
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{
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va_list ap;
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const char *s;
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va_start(ap, s0);
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s= s0;
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while (s != nil) {
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(void) write(2, s, strlen(s));
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s= va_arg(ap, const char *);
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}
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va_end(ap);
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}
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char *crypt(const char *key, const char *salt)
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{
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pid_t pid;
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int status;
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int pfd[2];
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static char pwdata[LEN];
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char *p= pwdata;
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const char *k= key;
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const char *s= salt;
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int n;
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/* Fill pwdata[] with the key and salt. */
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while ((*p++ = *k++) != 0) if (p == pwdata+LEN-1) goto fail;
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while ((*p++ = *s++) != 0) if (p == pwdata+LEN-0) goto fail;
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if (pipe(pfd) < 0) goto fail;
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/* Prefill the pipe. */
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(void) write(pfd[1], pwdata, p - pwdata);
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switch ((pid= fork())) {
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case -1:
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close(pfd[0]);
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close(pfd[1]);
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goto fail;
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case 0:
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/* Connect both input and output to the pipe. */
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if (pfd[0] != 0) {
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dup2(pfd[0], 0);
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close(pfd[0]);
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}
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if (pfd[1] != 1) {
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dup2(pfd[1], 1);
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close(pfd[1]);
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}
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execl(PWDAUTH, PWDAUTH, (char *) nil);
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tell("crypt(): ", PWDAUTH, ": ", strerror(errno), "\r\n",
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(char *) nil);
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/* No pwdauth? Fail! */
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(void) read(0, pwdata, LEN);
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_exit(1);
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}
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close(pfd[1]);
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status= -1;
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while (waitpid(pid, &status, 0) == -1 && errno == EINTR) {}
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if (status != 0) {
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close(pfd[0]);
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goto fail;
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}
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/* Read and return the result. Check if it contains exactly one
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* string.
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*/
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n= read(pfd[0], pwdata, LEN);
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close(pfd[0]);
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if (n < 0) goto fail;
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p = pwdata + n;
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n = 0;
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while (p > pwdata) if (*--p == 0) n++;
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if (n != 1) goto fail;
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return pwdata;
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fail:
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pwdata[0] = salt[0] ^ 1; /* make result != salt */
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pwdata[1] = 0;
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return pwdata;
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}
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/*
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* $PchId: crypt.c,v 1.5 1996/04/11 07:46:11 philip Exp $
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*/
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