Write example code for generating, storing, and verifying a password

1 files changed, 65 insertions, 9 deletions

diff --git a/src/encryption.c b/src/encryption.c
index 052b9aa..692b46a 100644
--- a/src/encryption.c
+++ b/src/encryption.c
@@ -8,12 +8,14 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <stdarg.h>
+#include <string.h>
 #include <unistd.h>
 #include <errno.h>
 #include <error.h>
 #include <fcntl.h>
 #include <stdio.h>
 
+
 #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
 void naclfaildefault(void *none) {
     none = none; // Makes gcc happy    
@@ -60,17 +62,20 @@ void checksodium(void) {
 // 2- Encrypt the file's contents to the temp file                                                      -- 
     // 2.1- Open the file                                                                                   -- 
     // 2.2- Stream the file's contents into some encryption algo                                            -- 
+        // 2.2.1- Pick which encryption algo to use                                                              -- 
+        // 2.2.2- Generate a key                                                                                 -- 
+            // 2.2.2.1- Create a password to derrive a key from                                                     -- DONE 
     // 2.3- Pipe the output of the encryption into the temp file                                            -- 
 // 3- Once the file has been encrypted, hard link it back to the original location, with the right name -- 
 // 4- Delete the original file                                                                          -- 
 // 5- Delete the temp file                                                                              --
 
 
-int maketmp(const char *dest) {
+int maketmp(const char * const dest) {
     return open(dest, (O_TMPFILE | O_WRONLY | O_CLOEXEC | O_SYNC), (S_IRUSR | S_IWUSR));
 }
 
-int encrypttotmp(const char *toencrypt) {
+int encrypttotmp(const char * const toencrypt) {
     #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
         checksodium();
     #endif
@@ -110,6 +115,7 @@ int genpassword(char **str, unsigned int words) {
     int ret;
     for(unsigned int i = 1; i < words; i++) {    
         ret = asprintf(&tmp, "%s %s", lstr, PASSWORD_WORDS[randombytes_uniform(PASSWORD_WORDS_LEN)]);
+        sodium_memzero(lstr, strlen(lstr) + 1);
         free(lstr);
         if(ret < 0)
             return -1;
@@ -119,18 +125,29 @@ int genpassword(char **str, unsigned int words) {
 
     *str = lstr;
     return words;
-
-    // This function was exploding because of some weird conflict with using my buggy implementation of asprintf instead of the 
-    // _GNU_SOURCE version. Don't know why it wasn't using the _GNU_SOURCE version, as I had a define macro put in place to 
-    // prevent it from being compiled if _GNU_SOURCE was defined, but whatever
 }
 
+// sodium_malloc wrapper. Calls `error()` or `abort()` depnding on the value of `___VXGG___XALLOC_EXIT_ON_ERROR___`. Will make sure libsodium is initialized if `___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0`
+void* xsodium_malloc(size_t size) {
+    #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
+        checksodium();
+    #endif
+
+    void *mem = sodium_malloc(size);
+    if(mem == NULL) {
+        #if defined ___VXGG___XALLOC_EXIT_ON_ERROR___ && ___VXGG___XALLOC_EXIT_ON_ERROR___ > 0
+            error(1, errno, "xsodium_malloc: could not allocate memory... Quitting");
+        #endif
+
+        abort();
+    }
+
+    return mem;
+}
 
 #define TESTING
 #ifdef TESTING
 
-#include <string.h>
-
 int main(void) {
     /*// Example code for creating a temp file, writing to it, then linking it back into the fs
     const char *dir = ".", *testmsg = "we do a little testing\n";
@@ -153,7 +170,7 @@ int main(void) {
         error(1, errno, "close broke");
     //*///
 
-    //*// Example code for getting a password using genpassword
+    /*// Example code for getting a password using genpassword
     checksodium();
 
     char *password = NULL;
@@ -162,6 +179,45 @@ int main(void) {
     free(password);
     //*///
 
+    //*// Example code for generating a password, derriving a secret key from it, and storing things properly
+    
+    // Initialization
+    checksodium();
+    char *pass = NULL, hpass[crypto_pwhash_STRBYTES];
+
+    if(genpassword(&pass, 20) < 0) {
+        error(1, 0, "Could not generate password, quitting...");
+        abort(); // Makes gcc happy. Not sure why gcc randomly decides that error() isn't a proper exit, but hey whatever
+    }
+    sodium_mlock(pass, strlen(pass) + 1);
+    printf("Password:%s\n", pass);
+
+    // Store the password
+    if(crypto_pwhash_str(hpass, pass, strlen(pass) + 1, crypto_pwhash_OPSLIMIT_MODERATE, crypto_pwhash_MEMLIMIT_MODERATE) != 0)
+        error(1, errno, "Couldn't generate password, quitting...");
+        /* Don't know if I want to use MODERATE or SENSITIVE for this. SENSITIVE takes a little bit on my laptop, which honestly 
+        // shouldn't be a problem, but it annoys me. MODERATE is quick and snappy, or at least quick enough that the slowdown is
+        // barely noticable. I might do MODERATE for testing and SENSITIVE for release */
+
+    sodium_munlock(pass, strlen(pass) + 1);
+    free(pass);
+
+    printf("Hashed password: %s\n", hpass);
+
+    // Check if the password from the user is correct
+    char *uin = NULL; int size = -1;
+    if((size = readwholebuffer(&uin, 20, STDIN_FILENO)) < 0)
+        error(1, errno, "Could not read from stdin");
+    sodium_mlock(uin, size);
+
+    printf("Valid password? %s\n", (crypto_pwhash_str_verify(hpass, uin, size) == 0) ? "True" : "False");
+
+
+    sodium_munlock(uin, strlen(uin) + 1);
+    free(uin);
+
+    //*///
+
     return 0;
 }