Password function

src/pam_panic_pw/Makefile

@@ -0,0 +1,6 @@
+LDFLAGS = -lc -lcrypt 
+CFLAGS = $(LDFLAGS) --std=gnu11 -Wall -O2 -DPPASSFILE=\"$(PPASSFILE)\"
+
+all:
+	mkdir -p ../../build/
+	gcc $(CFLAGS) pam_panic_pw.c -o ../../build/pam_panic_pw

src/pam_panic_pw/pam_panic_pw.c

@@ -0,0 +1,88 @@
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <crypt.h>
+
+
+int writePasswords(char pw[][99]){
+
+  FILE *f = fopen(PPASSFILE, "w");
+  if(f == NULL){
+    fprintf(stderr, "ERROR opening file!\n");
+    return 2;
+  }
+
+  fprintf(f, "%s\n%s\n", pw[0], pw[1]);
+
+  fclose(f);
+
+  chmod(PPASSFILE, 0600);
+
+  return 0;
+}
+
+
+int main(void){
+
+  time_t t;
+  srand((unsigned) time(&t));
+  unsigned long seed[2];
+  char salt[] = "$6$........";
+  const char *const seedchars =
+    "./0123456789ABCDEFGHIJKLMNOPQRST"
+    "UVWXYZabcdefghijklmnopqrstuvwxyz";
+  char *password[2];
+  char *pwvrf[2];
+  
+  char pw[2][99];
+  char pwv[2][99];
+
+  char *prompt[4] = {"Key password: ",  "Panic password: ", "Retype key password: ","Retype panic password: "};
+
+  int i;
+
+  if(getuid() != 0){
+    printf("Please run this program under root. Write access to %s is mandatory.\n", PPASSFILE);    return 1;
+  }
+  
+  for(int j=0; j<2; j++){ 
+
+    seed[0] = time(&t);
+    seed[1] = rand() ^ (seed[0] >> 14 & 0x30000);
+    
+    /* Turn it into printable characters from ‘seedchars’. */
+    for (i = 0; i < 8; i++)
+      salt[3+i] = seedchars[(seed[i/5] >> (i%5)*6) & 0x3f];
+
+    /* Read in the user’s password and encrypt it. */
+    password[j] = crypt(getpass(prompt[j]), salt);
+  
+    strcpy(pw[j], password[j]);
+
+    int ok;
+    for(int k=0; k<3; k++){
+      pwvrf[j] = crypt(getpass(prompt[j+2]), pw[j]);
+      strcpy(pwv[j], pwvrf[j]);
+      ok = strcmp(pw[j], pwv[j]) == 0;
+      if(!ok){
+        if(k==2){
+          printf("Didn't work. Bye.\n");
+          return 1;
+        }else
+          printf("Password didn't match. Try again.\n");
+      }else
+        break;
+    }
+  
+  }
+
+  /* Save the results. */
+  
+  return writePasswords(pw);
+}