328 lines
6.8 KiB
C
328 lines
6.8 KiB
C
/* Login code for S/KEY Authentication. S/KEY is a trademark
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* of Bellcore.
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*
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* Mink is the former name of the S/KEY authentication system.
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* Many references for mink may still be found in this program.
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*/
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <time.h>
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#include <errno.h>
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#include "skey.h"
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#include "pathnames.h"
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char *skipspace();
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int skeylookup __P((struct skey *mp,char *name));
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#define setpriority(x,y,z) /* nothing */
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/* Issue a skey challenge for user 'name'. If successful,
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* fill in the caller's skey structure and return 0. If unsuccessful
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* (e.g., if name is unknown) return -1.
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*
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* The file read/write pointer is left at the start of the
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* record.
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*/
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int
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getskeyprompt(mp,name,prompt)
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struct skey *mp;
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char *name;
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char *prompt;
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{
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int rval;
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sevenbit(name);
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rval = skeylookup(mp,name);
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strcpy(prompt,"s/key 55 latour1\n");
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switch(rval){
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case -1: /* File error */
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return -1;
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case 0: /* Lookup succeeded, return challenge */
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sprintf(prompt,"s/key %d %s\n",mp->n - 1,mp->seed);
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return 0;
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case 1: /* User not found */
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fclose(mp->keyfile);
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return -1;
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}
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return -1; /* Can't happen */
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}
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/* Return a skey challenge string for user 'name'. If successful,
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* fill in the caller's skey structure and return 0. If unsuccessful
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* (e.g., if name is unknown) return -1.
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*
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* The file read/write pointer is left at the start of the
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* record.
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*/
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int
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skeychallenge(mp,name, ss)
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struct skey *mp;
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char *name;
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char *ss;
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{
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int rval;
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rval = skeylookup(mp,name);
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switch(rval){
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case -1: /* File error */
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return -1;
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case 0: /* Lookup succeeded, issue challenge */
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sprintf(ss, "s/key %d %s",mp->n - 1,mp->seed);
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return 0;
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case 1: /* User not found */
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fclose(mp->keyfile);
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return -1;
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}
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return -1; /* Can't happen */
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}
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/* Find an entry in the One-time Password database.
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* Return codes:
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* -1: error in opening database
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* 0: entry found, file R/W pointer positioned at beginning of record
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* 1: entry not found, file R/W pointer positioned at EOF
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*/
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int
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skeylookup(mp,name)
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struct skey *mp;
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char *name;
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{
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int found;
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int len;
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long recstart;
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char *cp;
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struct stat statbuf;
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/* See if the _PATH_SKEYFILE exists, and create it if not */
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if(stat(_PATH_SKEYFILE,&statbuf) == -1 && errno == ENOENT){
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mp->keyfile = fopen(_PATH_SKEYFILE,"w+");
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(void) chmod(_PATH_SKEYFILE, 0644);
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} else {
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/* Otherwise open normally for update */
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mp->keyfile = fopen(_PATH_SKEYFILE,"r+");
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}
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if(mp->keyfile == NULL)
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return -1;
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/* Look up user name in database */
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len = strlen(name);
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if( len > 8 ) len = 8; /* Added 8/2/91 - nmh */
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found = 0;
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while(!feof(mp->keyfile)){
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recstart = ftell(mp->keyfile);
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mp->recstart = recstart;
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if(fgets(mp->buf,sizeof(mp->buf),mp->keyfile) != mp->buf){
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break;
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}
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rip(mp->buf);
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if(mp->buf[0] == '#')
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continue; /* Comment */
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if((mp->logname = strtok(mp->buf," \t")) == NULL)
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continue;
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if((cp = strtok(NULL," \t")) == NULL)
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continue;
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mp->n = atoi(cp);
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if((mp->seed = strtok(NULL," \t")) == NULL)
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continue;
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if((mp->val = strtok(NULL," \t")) == NULL)
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continue;
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if(strlen(mp->logname) == len
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&& strncmp(mp->logname,name,len) == 0){
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found = 1;
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break;
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}
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}
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if(found){
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fseek(mp->keyfile,recstart,0);
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return 0;
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} else
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return 1;
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}
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/* Verify response to a s/key challenge.
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*
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* Return codes:
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* -1: Error of some sort; database unchanged
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* 0: Verify successful, database updated
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* 1: Verify failed, database unchanged
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*
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* The database file is always closed by this call.
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*/
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int
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skeyverify(mp,response)
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struct skey *mp;
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char *response;
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{
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struct timeval startval;
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struct timeval endval;
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long microsec;
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char key[8];
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char fkey[8];
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char filekey[8];
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time_t now;
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struct tm *tm;
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char tbuf[27],buf[60];
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char me[80];
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int rval;
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char *cp;
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time(&now);
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tm = localtime(&now);
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strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm);
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if(response == NULL){
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fclose(mp->keyfile);
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return -1;
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}
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rip(response);
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/* Convert response to binary */
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if(etob(key,response) != 1 && atob8(key,response) != 0){
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/* Neither english words or ascii hex */
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fclose(mp->keyfile);
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return -1;
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}
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/* Compute fkey = f(key) */
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memcpy(fkey,key,sizeof(key));
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f(fkey);
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/* in order to make the window of update as short as possible
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we must do the comparison here and if OK write it back
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other wise the same password can be used twice to get in
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to the system
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*/
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setpriority(PRIO_PROCESS, 0, -4);
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/*
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gettimeofday(&startval, (char *)0 );
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*/
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/* reread the file record NOW*/
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fseek(mp->keyfile,mp->recstart,0);
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if(fgets(mp->buf,sizeof(mp->buf),mp->keyfile) != mp->buf){
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setpriority(PRIO_PROCESS, 0, 0);
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fclose(mp->keyfile);
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return -1;
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}
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rip(mp->buf);
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mp->logname = strtok(mp->buf," \t");
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cp = strtok(NULL," \t") ;
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mp->seed = strtok(NULL," \t");
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mp->val = strtok(NULL," \t");
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/* And convert file value to hex for comparison */
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atob8(filekey,mp->val);
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/* Do actual comparison */
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if(memcmp(filekey,fkey,8) != 0){
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/* Wrong response */
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setpriority(PRIO_PROCESS, 0, 0);
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fclose(mp->keyfile);
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return 1;
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}
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/* Update key in database by overwriting entire record. Note
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* that we must write exactly the same number of bytes as in
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* the original record (note fixed width field for N)
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*/
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btoa8(mp->val,key);
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mp->n--;
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fseek(mp->keyfile,mp->recstart,0);
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fprintf(mp->keyfile,"%s %04d %-16s %s %-21s\n",mp->logname,mp->n,mp->seed,
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mp->val, tbuf);
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/*
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gettimeofday(&endval, (char *)0 );
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microsec = (endval.tv_sec - startval.tv_sec) * 1000000 + (endval.tv_usec - startval.tv_usec);
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fprintf(stderr, "window= %d micro seconds \n" , microsec);
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*/
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fclose(mp->keyfile);
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setpriority(PRIO_PROCESS, 0, 0);
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return 0;
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}
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/* Convert 8-byte hex-ascii string to binary array
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* Returns 0 on success, -1 on error
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*/
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atob8(out,in)
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register char *out,*in;
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{
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register int i;
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register int val;
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if(in == NULL || out == NULL)
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return -1;
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for(i=0;i<8;i++){
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if((in = skipspace(in)) == NULL)
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return -1;
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if((val = htoi(*in++)) == -1)
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return -1;
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*out = val << 4;
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if((in = skipspace(in)) == NULL)
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return -1;
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if((val = htoi(*in++)) == -1)
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return -1;
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*out++ |= val;
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}
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return 0;
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}
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char *
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skipspace(cp)
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register char *cp;
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{
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while(*cp == ' ' || *cp == '\t')
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cp++;
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if(*cp == '\0')
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return NULL;
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else
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return cp;
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}
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/* Convert 8-byte binary array to hex-ascii string */
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int
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btoa8(out,in)
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register char *out,*in;
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{
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register int i;
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if(in == NULL || out == NULL)
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return -1;
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for(i=0;i<8;i++){
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sprintf(out,"%02x",*in++ & 0xff);
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out += 2;
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}
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return 0;
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}
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/* Convert hex digit to binary integer */
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int
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htoi(c)
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register char c;
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{
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if('0' <= c && c <= '9')
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return c - '0';
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if('a' <= c && c <= 'f')
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return 10 + c - 'a';
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if('A' <= c && c <= 'F')
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return 10 + c - 'A';
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return -1;
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}
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