affcrypto.cpp
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affcrypto.cpp
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	/*
	* afcrypto.cpp:
	*
	* command for dealing with encryption issues
	*/

	/* Public Domain Software
	* Simson L. Garfinkel
	* Naval Postgraduate School
	*
	* The software provided here is released by the Naval Postgraduate
	* School, an agency of the U.S. Department of Navy. The software bears
	* no warranty, either expressed or implied. NPS does not assume legal
	* liability nor responsibility for a User's use of the software or the
	* results of such use.
	*
	* Please note that within the United States, copyright protection, under
	* Section 105 of the United States Code, Title 17, is not available for
	* any work of the United States Government and/or for any works created
	* by United States Government employees.
	*/



	#include "affconfig.h"
	#include "afflib.h"
	#include "afflib_i.h"
	#include "utils.h"

	#include <stdio.h>
	#include <algorithm>
	#include <vector>

	const char *progname = "afcrypto";
	#define DEFAULT_PASSPHRASE_FILE ".affpassphrase"
	int opt_debug = 0;
	int opt_verbose = 0;
	int opt_just_print_encrypted_count = 0;
	int opt_just_print_unencrypted_count = 0;
	char *opt_unsealing_private_key_file= 0;
	int opt_xml = 0;

	void change_passphrase(const char fn,const char old_passphrase,const char *new_passphrase)
	{
	int fail = 0;

	AFFILE *af = af_open(fn,O_RDWR,0666);
	if(!af) af_err(1,fn);
	if(af_change_aes_passphrase(af,old_passphrase,new_passphrase)){
	warnx("%s: af_change_aes_passphrase failed",fn);
	fail = 1;
	}
	af_close(af);
	if(!fail) printf("%s: passphrase changed.\n",fn);
	}

	void get_and_change_passphrase(const char *fn)
	{
	char old_passphrase[1024];
	char new_passphrase[1024];

	memset(old_passphrase,0,sizeof(old_passphrase));
	memset(new_passphrase,0,sizeof(new_passphrase));

	printf("Enter old passphrase: ");
	if(fgets(old_passphrase,sizeof(old_passphrase),stdin)==0) return;
	char cc = strchr(old_passphrase,'\n');if(cc) cc='\000';

	/* See if this passphrase works*/

	AFFILE *af = af_open(fn,O_RDONLY,0666);
	if(!af) af_err(1,fn);
	if(af_use_aes_passphrase(af,old_passphrase)){
	errx(1,"passphrase incorrect");
	}
	af_close(af);

	printf("Enter new passphrase: ");
	if(fgets(new_passphrase,sizeof(new_passphrase),stdin)==0) return;
	cc = strchr(new_passphrase,'\n');if(cc) *cc='\000';
	change_passphrase(fn,old_passphrase,new_passphrase);
	}

	void usage()
	{
	printf("afcrypto version %s\n",PACKAGE_VERSION);
	printf("usage: afcrypto [options] filename.aff [filename2.aff ... ]\n");
	printf(" prints if each file is encrypted or not.\n");
	printf("options:\n");
	printf(" -x --- output in XML\n");
	printf(" -j --- Just print the number of encrypted segments\n");
	printf(" -J --- Just print the number of unencrypted segments\n");

	printf("\nData conversion options:\n");
	printf(" -e --- encrypt the unencrypted non-signature segments\n");
	printf(" -d --- decrypt the encrypted non-signature segments\n");
	printf(" -r --- change passphrase (take old and new from stdin)\n");
	printf(" -O old --- specify old passphrase\n");
	printf(" -N new --- specify new passphrase\n");
	printf(" -K mykey.key -- specifies a private keyfile for unsealing (may not be repeated)\n");
	printf(" -C mycert.crt -- specifies a certificate file for sealing (may be repeated)\n");
	printf(" -S --- add symmetric encryptiong (passphrase) to AFFILE encrypted with public key\n");
	printf(" (requires a private key and a specified passphrase).\n");
	printf(" -A --- add asymmetric encryption to a AFFILE encrypted with a passphrase\n");
	printf(" (requires a certificate file spcified with the -C option\n");


	printf("\nPassword Cracking Options:\n");
	printf(" -p passphrase --- checks to see if passphrase is the passphrase of the file\n");
	printf(" exit code is 0 if it is, -1 if it is not\n");
	printf(" -k --- attempt to crack passwords by reading a list of passwords from ~/.affpassphrase\n");
	printf(" -f file --- Crack passwords but read them from file.\n");

	printf("\nDebugging:\n");
	printf(" -V --- Just print the version number and exit.\n");
	printf(" -D --- debug; print out each key as it is tried\n");
	printf(" -l --- List the installed hash and encryption algorithms \n");
	printf("Note: This program ignores the environment variables:\n");
	puts(AFFLIB_PASSPHRASE);
	puts(AFFLIB_PASSPHRASE_FILE);
	puts(AFFLIB_PASSPHRASE_FD);
	puts(AFFLIB_DECRYPTING_PRIVATE_KEYFILE);
	exit(0);
	}

	/* Try each of the passphrases in the file against the passphrase. If it is found, return it. */
	char check_file(AFFILE af,const char *passphrase_file)
	{
	char *ret = 0;
	FILE *f = fopen(passphrase_file,"r");
	if(!f) return 0;

	char buf[1024];
	memset(buf,0,sizeof(buf));
	while(fgets(buf,sizeof(buf)-1,f)){
	char *cc = strchr(buf,'\n');
	if(cc) *cc = 0;
	if(opt_debug){
	if(opt_debug) printf("checking with '%s' ... ",buf);
	fflush(stdout);
	}
	int r= af_use_aes_passphrase(af,buf);
	if(r==0){
	if(opt_debug) printf("YES!\n");
	ret = strdup(buf);
	break;
	}
	}
	fclose(f);
	return ret;
	}

	/**
	* This will eventually decrypt non-signature segments that are
	* encrypted
	*
	* @param af - the AFFILE to open
	* @param count - The number of pages actually encrypted
	*/
	int af_decrypt_encrypted_segments(AFFILE af, int count, int mode)
	{
	af_set_option(af,AF_OPTION_AUTO_ENCRYPT,0);
	af_set_option(af,AF_OPTION_AUTO_DECRYPT,0); // turn off auto decryption
	aff::seglist sl(af); // get the list of the segments
	af_set_option(af,AF_OPTION_AUTO_DECRYPT,1); // turn auto decryption back on
	for(aff::seglist::const_iterator si = sl.begin();si!=sl.end();si++){
	if(opt_debug) printf(" checking segment %s",si->name.c_str());
	if(af_is_encrypted_segment(si->name.c_str())){

	if(mode == O_RDONLY){ // if readonly, just tally
	(*count) ++;
	if(opt_debug) printf(" would decrypt segment\n");
	continue;
	}

	/* Generate the name of the unencrypted segment */
	char segname[AF_MAX_NAME_LEN];
	strcpy(segname,si->name.c_str());
	char *cc = strstr(segname,AF_AES256_SUFFIX);
	if(!cc){
	if(opt_debug) printf(" will not decrypt AFFKEY segments; will be deleted later.\n");
	continue; // something is wrong; can't find the /aes256
	}
	*cc = '\000'; // truncate off the /aes256

	/* Get the segment and put it, which will force the decryption to take place */
	if(opt_debug) printf(" decrypting segment\n");
	u_char buf = (u_char )malloc(si->len);
	if(!buf) warn("malloc(%zd) failed", si->len);
	else {
	unsigned long arg;
	size_t datalen = si->len;
	if(af_get_seg(af,segname,&arg,buf,&datalen)){
	warn("Could not read segment '%s'",segname);
	}
	else{
	/* si->datalen >= datalen.
	* si->datalen is the length of the encrypted segment.
	* datalen is the length of the decrypted segment.
	*/
	assert(si->len >= datalen);
	assert(si->arg==arg);
	if(af_update_seg(af,segname,arg,buf,datalen)){
	warn("Could not decrypt segment '%s'",si->name.c_str());
	} else {
	(*count) ++;
	}
	}
	free(buf);
	}
	} else {
	if(opt_debug) printf(" not encrypted\n");
	}
	}
	/* Delete the AF_AFFKEY segment */
	if(af_get_seg(af,AF_AFFKEY,0,0,0)==0) af_del_seg(af,AF_AFFKEY);
	/* Delete all of the EVP segments */
	for(int i=0;;i++){
	char segname[1024];
	snprintf(segname,sizeof(segname),AF_AFFKEY_EVP,i);
	if(af_get_seg(af,segname,0,0,0)!=0) break; // found the last segment
	if(af_del_seg(af,segname)) warn("Cannot delete segment %s",segname);
	}
	return 0;
	}


	/**
	* Encrypts the non-signature segments that are not encrypted.
	* There is no reason to encrypt the signature segments.
	*
	* @param af - the AFFILE to open
	* @param count - The number of pages actually encrypted
	*/

	int af_encrypt_unencrypted_nonsignature_segments(AFFILE af,int count,int mode)
	{
	af_set_option(af,AF_OPTION_AUTO_DECRYPT,0); // do not automatically decrypt
	aff::seglist sl(af);
	for(aff::seglist::const_iterator si = sl.begin();si!=sl.end();si++){
	if(si->name == AF_AFFKEY) continue; // don't encrypt the affkey!
	if(strstr(si->name.c_str(),"affkey_evp")) continue;
	if(!af_is_encrypted_segment(si->name.c_str()) &&
	!af_is_signature_segment(si->name.c_str())){

	if(mode == O_RDONLY){ // if readonly, just tally
	(*count) ++;
	continue;
	}

	/* Get the segment and put it, which will force the encryption to take place */
	if(opt_debug) printf(" encrypting segment %s\n",si->name.c_str());
	u_char buf = (u_char )malloc(si->len);
	if(!buf) warn("Cannot encrypt segment '%s' --- too large (%zd bytes) --- malloc failed",
	si->name.c_str(),si->len);
	else {
	unsigned long arg;
	size_t datalen = si->len;
	if(af_get_seg(af,si->name.c_str(),&arg,buf,&datalen)){
	warn("Could not read segment '%s'",si->name.c_str());
	}
	else{
	/* make sure that what we read is what we thought we were going to read */
	assert(si->len==datalen);
	assert(si->arg==arg);
	if(af_update_seg(af,si->name.c_str(),arg,buf,datalen)){
	warn("Could not encrypt segment '%s'",si->name.c_str());
	} else {
	(*count) ++;
	}
	}
	free(buf);
	}
	} else {
	if(opt_debug) printf(" already encrypted or signed: %s\n",si->name.c_str());
	}
	}
	af_set_option(af,AF_OPTION_AUTO_DECRYPT,1); // go back to automatically decrypting
	return 0;
	}

	void list_openssl_hashes()
	{
	const char *digests[] = {"md5","sha1","sha256",0};
	OpenSSL_add_all_algorithms();
	for(int i=0;digests[i];i++){
	printf("OpenSSL has %s: %s\n",digests[i],EVP_get_digestbyname(digests[i]) ? "YES" : "NO");
	}
	exit(0);
	}

	int main(int argc,char **argv)
	{
	int bflag, ch;
	const char *old_passphrase=0;
	const char *new_passphrase=0;
	const char *check_passphrase = 0;
	char *passphrase_file = 0;
	const char *progname = argv[0];
	int opt_encrypt = 0;
	int opt_decrypt = 0;
	int opt_add_passphrase_to_public_key = 0;
	int opt_add_public_key_to_passphrase = 0;

	int mode = O_RDONLY; // mode for opening AFF file
	const char certificates = (const char )malloc(0);
	int num_certificates = 0;
	const char *envvars[] = {AFFLIB_PASSPHRASE,AFFLIB_PASSPHRASE_FILE,AFFLIB_PASSPHRASE_FD,
	AFFLIB_DECRYPTING_PRIVATE_KEYFILE,0};
	for(int i=0;envvars[i];i++){
	/* Don't use auto-supplied passphrases */
	#ifdef HAVE_UNSETENV
	unsetenv(envvars[i]);
	#else
	if(getenv(envvars[i])){
	fprintf(stderr,"Please unset %s and restart\n",envvars[i]);
	exit(1);
	}
	#endif
	}

	bflag = 0;
	int opt_change = 0;
	const char *home = getenv("HOME");

	while ((ch = getopt(argc, argv, "zreC:SAO:N:p:f:kdDh?VK:vljJx:")) != -1) {
	switch (ch) {
	case 'x': opt_xml = 1; break;
	case 'j': opt_just_print_encrypted_count =1;break;
	case 'J': opt_just_print_unencrypted_count =1;break;

	/* These options make the mode read-write */
	case 'r': opt_change = 1; mode = O_RDWR; break;
	case 'e': opt_encrypt = 1; mode = O_RDWR; break;
	case 'd': opt_decrypt = 1; mode = O_RDWR; break;
	case 'S': opt_add_passphrase_to_public_key = 1; mode = O_RDWR; break;
	case 'A': opt_add_public_key_to_passphrase = 1; mode = O_RDWR; break;
	/* These just set up variables */
	case 'C':
	certificates = (const char *)realloc(certificates,sizeof(int )*(num_certificates+1));
	certificates[num_certificates] = optarg;
	num_certificates++;
	break;
	case 'K': opt_unsealing_private_key_file = optarg;break;
	case 'O': old_passphrase = optarg;break;
	case 'N': new_passphrase = optarg;break;
	case 'p': check_passphrase = optarg;break;
	case 'f': passphrase_file = optarg;break;
	case 'k':
	if(!home) home = "/";
	passphrase_file = (char *)malloc(strlen(home)+strlen(DEFAULT_PASSPHRASE_FILE)+2);
	strcpy(passphrase_file,home);
	strcat(passphrase_file,"/");
	strcat(passphrase_file,DEFAULT_PASSPHRASE_FILE);
	break;
	case 'D': opt_debug = 1;break;
	case 'v': opt_verbose = 1;break;
	case 'l': list_openssl_hashes(); exit(0);
	case 'h':
	case '?':
	default:
	usage();
	break;
	case 'V':
	printf("%s version %s\n",progname,PACKAGE_VERSION);
	exit(0);
	}
	}
	argc -= optind;
	argv += optind;
	if(argc<1){
	fprintf(stderr,"No image file specified\n");
	usage();
	}

	if(opt_just_print_encrypted_count && opt_just_print_unencrypted_count){
	errx(1,"Options -j and -J conflict\n");
	}

	if(num_certificates>0 && (opt_encrypt==0 && opt_decrypt==0 && opt_add_public_key_to_passphrase==0)){
	errx(1,"Encryption certificates specified but neither -e nor -d option not set. "
	"What do you want me to do with these certificates? ");
	}

	if((check_passphrase \|\| passphrase_file) && opt_encrypt){
	err(1,"Sorry, can't both encrypt and password crack. Pick one.\n");
	}

	if(opt_encrypt && (new_passphrase==0 && num_certificates==0) && mode!=O_RDONLY){
	err(1,"Currently -e requires that the passphrase be specified on the command line\n"
	"or that one or more encryption certificates be provided\n");
	}

	while(argc--){
	const char fname = argv++;

	if(opt_change){
	if(old_passphrase && new_passphrase) change_passphrase(fname,old_passphrase,new_passphrase);
	else get_and_change_passphrase(fname);
	}

	/* Get the information */
	AFFILE *af = af_open(fname,mode,0);
	if(!af) af_err(1,"af_open(%s)",fname);
	if(af_identify(af)!=AF_IDENTIFY_AFF && af_identify(af)!=AF_IDENTIFY_AFD){
	errx(1,"Cannot encrypt %s: %s only supports AFF and AFD files.",af_filename(af),progname);
	}

	if(opt_encrypt && new_passphrase){
	int r = af_establish_aes_passphrase(af,new_passphrase);
	switch(r){
	case AF_ERROR_NO_AES: errx(1,"AFFLIB: AES256 not available; cannot continue");
	case AF_ERROR_NO_SHA256: errx(1,"AFFLIB: SHA256 not available; cannot continue");
	default: err(1,"%s: cannot establish passphrase (error %d)",fname,r);
	case 0:
	case AF_ERROR_AFFKEY_EXISTS:
	/* no matter if we established it or if a phrase already exists, try to use it now */
	/* File already has a passphrase; see if this is it. */
	break;
	}
	r = af_use_aes_passphrase(af,new_passphrase);
	switch(r){
	case 0: break; // everything okay
	case AF_ERROR_WRONG_PASSPHRASE: errx(1,"%s: wrong passphrase",fname);
	default: errx(1,"%s: passphrase already established (error %d)",fname,r);
	}
	}

	if(opt_decrypt && old_passphrase){
	int r = af_use_aes_passphrase(af, old_passphrase);
	switch(r){
	case 0: printf("Passphrase is good!\n"); break;
	case AF_ERROR_WRONG_PASSPHRASE: errx(1,"%s: wrong passphrase",fname);
	}
	}

	if (opt_add_public_key_to_passphrase){
	if(!num_certificates) errx(1,"You must specify a certificate with the -C option");
	if(!check_passphrase) errx(1,"You must specify a passphrase with the -p option");
	printf("Attepmting to add public key to AFFILE...\n");
	if(af->crypto->sealing_key_set) return AF_ERROR_KEY_SET; // already enabled
	unsigned char affkey[32];
	int r = af_get_aes_key_from_passphrase(af,check_passphrase,affkey);
	if(r) errx(1, "%s: cannot get aes key. Failed to add Public Key", fname);
	af_seal_affkey_using_certificates(af, certificates, num_certificates, affkey);
	printf("...Public key added successfully.\n");
	}

	if(opt_encrypt && num_certificates){
	if(af_set_seal_certificates(af,certificates,num_certificates)){
	errx(1,"%s: can't set encryption certificate%s",fname,num_certificates==1 ? "" : "s");
	}
	}
	if(opt_encrypt){
	int count = 0;
	if(af_encrypt_unencrypted_nonsignature_segments(af,&count,mode)){
	errx(1,"%s: can't encrypt unsigned, unencrypted segments",fname);
	}
	if(mode==O_RDONLY){ // if it is readonly just print the number of segments that would be changed.
	printf("%d\n",count);
	af_close(af);
	continue;
	}
	}
	if(opt_decrypt){
	int count = 0;
	if(af_decrypt_encrypted_segments(af, &count, mode)){
	}
	if(mode==O_RDONLY){
	printf("%d\n",count);
	af_close(af);
	continue;
	}
	}

	if(opt_add_passphrase_to_public_key) {
	if(!new_passphrase) errx(1,"You must specify a new passphrase with the -N option");
	printf("Attempting to add passphrase...\n");
	u_char affkey[32];
	if(af_get_affkey_using_keyfile(af, opt_unsealing_private_key_file,affkey)){
	errx(1,"%s: cannot unseal AFFKEY",fname);
	}
	if(af_save_aes_key_with_passphrase(af,new_passphrase,affkey)){
	af_err(1,"%s: could not set the passphrase",fname);
	}
	printf("... new passphrase established.\n");
	}


	af_vnode_info vni;
	memset(&vni,0,sizeof(vni));
	if(af_vstat(af,&vni)) err(1,"%s: af_vstat failed: ",fname);
	const char *the_passphrase = 0; // the correct passphrase

	if(opt_just_print_encrypted_count){
	printf("%d\n",vni.segment_count_encrypted);
	af_close(af);
	continue;
	}

	if(opt_just_print_unencrypted_count){
	printf("%d\n",vni.segment_count_total-vni.segment_count_encrypted);
	af_close(af);
	continue;
	}


	/* were we supposed to try a check_passphrase? */
	if(check_passphrase){
	if(af_use_aes_passphrase(af,check_passphrase)==0){
	the_passphrase = check_passphrase;
	}
	af_use_aes_passphrase(af,0); // clear the passphrase
	}

	/* Is a passphrase file provided? */
	if(!the_passphrase && passphrase_file){
	the_passphrase = check_file(af,passphrase_file);
	if(the_passphrase){
	af_use_aes_passphrase(af,0); // clear the passphrase
	}
	}

	if(opt_xml){
	/* This should be replaced with our xml.cpp object */
	printf("<afcrypto>\n");
	printf(" <image_filename>%s</image_filename>\n",fname);
	printf(" <segment_count_total>%d</segment_count_total>\n",vni.segment_count_total);
	printf(" <segment_count_signed>%d</segment_count_signed>\n",vni.segment_count_signed);
	printf(" <segment_count_encrypted>%d</segment_count_encrypted>\n",vni.segment_count_encrypted);
	printf(" <page_count_total>%d</page_count_total>\n",vni.page_count_total);
	printf(" <page_count_encrypted>%d</page_count_encrypted>\n",vni.page_count_encrypted);
	if(the_passphrase){
	printf(" <passphrase correct='1'>%s</passphrase>\n",the_passphrase);
	}
	printf("</afcrypto>\n");
	}
	else{
	/* re-run vstat because counts may have changed */
	if(af_vstat(af,&vni)) err(1,"%s: af_vstat failed: ",fname);
	printf("%s: %5d segments; %5d signed; %5d encrypted; %5d pages; %5d encrypted pages",
	fname,vni.segment_count_total,vni.segment_count_signed,vni.segment_count_encrypted,
	vni.page_count_total,vni.page_count_encrypted );
	if(the_passphrase) printf("passphrase correct (\"%s\")",the_passphrase);
	putchar('\n');
	}
	af_close(af);
	}
	return(0);
	}

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