(re-)added detached signature support, now with 32k-blockwise reading of files, enabled with -a.

ChangeLog

@@ -22,6 +22,12 @@
 	Armored signatures are calculated the same way but
 	output follows the pgp scheme instead.
 
+	Detached signatures are still supported as before,
+	for the user everything with them is as known, but
+	the commandline option -a (--detach) have to be
+	applied. Internally, however, inputs will be read in
+	32k blockwise as well. Detached signatures are now
+	z85 encoded always.
 
 0.1.5   Fixed a segmentation fault when using pcp1 -t on a
 	public key. I added a double free() there by purpose

include/pcp/ed.h

@@ -53,6 +53,9 @@ unsigned char * pcp_ed_verify(unsigned char *signature, size_t siglen, pcp_pubke
    sig only to the output */
 size_t pcp_ed_sign_buffered(FILE *in, FILE *out, pcp_key_t *s, int z85);
 
-unsigned char *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p);
+pcp_pubkey_t *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p);
+
+size_t pcp_ed_detachsign_buffered(FILE *in, FILE *out, pcp_key_t *s);
+pcp_pubkey_t *pcp_ed_detachverify_buffered(FILE *in, FILE *sigfd, pcp_pubkey_t *p);
 
 #endif // _HAVE_PCP_ED_H

libpcp/crypto.c

@@ -456,6 +456,4 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey) {
     fclose(out);
 
   return out_size;
-
-  
 }

libpcp/ed.c

@@ -99,7 +99,7 @@ size_t pcp_ed_sign_buffered(FILE *in, FILE *out, pcp_key_t *s, int z85) {
   return outsize;
 }
 
-unsigned char *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p) {
+pcp_pubkey_t *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p) {
   unsigned char in_buf[PCP_BLOCK_SIZE/2];
   unsigned char in_next[PCP_BLOCK_SIZE/2];
   unsigned char in_full[PCP_BLOCK_SIZE];
@@ -236,8 +236,6 @@ unsigned char *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p) {
     if(z85block == NULL)
       goto errvb1;
 
-    fprintf(stderr, "<%s>\n", z85block);
-
     size_t dstlen;
     unsigned char *z85decoded = pcp_z85_decode(z85block, &dstlen);
     if(dstlen != mlen) {
@@ -272,7 +270,7 @@ unsigned char *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p) {
     return NULL;
   }
 
-  return verifiedhash;
+  return p;
   
 
  errvb1:
@@ -280,3 +278,139 @@ unsigned char *pcp_ed_verify_buffered(FILE *in, pcp_pubkey_t *p) {
   return NULL;
 }
 
+size_t pcp_ed_detachsign_buffered(FILE *in, FILE *out, pcp_key_t *s) {
+  unsigned char in_buf[PCP_BLOCK_SIZE];
+  size_t cur_bufsize = 0;
+  size_t outsize = 0;
+  crypto_generichash_state *st = ucmalloc(sizeof(crypto_generichash_state));
+  unsigned char hash[crypto_generichash_BYTES_MAX];
+
+  crypto_generichash_init(st, NULL, 0, 0);
+
+  while(!feof(in)) {
+    cur_bufsize = fread(&in_buf, 1, PCP_BLOCK_SIZE, in);
+    if(cur_bufsize <= 0)
+      break;
+    outsize += cur_bufsize;
+    crypto_generichash_update(st, in_buf, cur_bufsize);
+  }
+
+  crypto_generichash_final(st, hash, crypto_generichash_BYTES_MAX);
+
+  unsigned char *signature = pcp_ed_sign(hash, crypto_generichash_BYTES_MAX, s);
+  size_t mlen = + crypto_sign_BYTES + crypto_generichash_BYTES_MAX;
+
+  fprintf(out, "\n%s\n Version: PCP v%d.%d.%d\n\n",
+	  PCP_SIG_START, PCP_VERSION_MAJOR, PCP_VERSION_MINOR, PCP_VERSION_PATCH);
+  size_t zlen;
+  char *z85encoded = pcp_z85_encode((unsigned char*)signature, mlen, &zlen);
+  fprintf(out, "%s\n%s\n", z85encoded, PCP_SIG_END);
+
+  if(fileno(in) != 0)
+    fclose(in);
+  if(fileno(out) != 1)
+    fclose(out);
+
+  free(st);
+
+  return outsize;
+}
+
+pcp_pubkey_t *pcp_ed_detachverify_buffered(FILE *in, FILE *sigfd, pcp_pubkey_t *p) {
+  unsigned char in_buf[PCP_BLOCK_SIZE];
+  size_t cur_bufsize = 0;
+  size_t outsize = 0;
+  crypto_generichash_state *st = ucmalloc(sizeof(crypto_generichash_state));
+  unsigned char hash[crypto_generichash_BYTES_MAX];
+  size_t mlen = + crypto_sign_BYTES + crypto_generichash_BYTES_MAX;
+
+  crypto_generichash_init(st, NULL, 0, 0);
+
+  while(!feof(in)) {
+    cur_bufsize = fread(&in_buf, 1, PCP_BLOCK_SIZE, in);
+    if(cur_bufsize <= 0)
+      break;
+    outsize += cur_bufsize;
+    crypto_generichash_update(st, in_buf, cur_bufsize);
+  }
+
+  crypto_generichash_final(st, hash, crypto_generichash_BYTES_MAX);
+
+  // read the sig
+  unsigned char *sig = NULL;
+  size_t inputBufSize = 0;
+  unsigned char byte[1];
+  
+  while(!feof(sigfd)) {
+    if(!fread(&byte, 1, 1, sigfd))
+      break;
+    unsigned char *tmp = realloc(sig, inputBufSize + 1);
+    sig = tmp;
+    memmove(&sig[inputBufSize], byte, 1);
+    inputBufSize ++;
+  }
+  fclose(sigfd);
+
+  if(sig == NULL) {
+    fatal("Invalid detached signature\n");
+    goto errdea1;
+  }
+
+
+  char *z85block = pcp_readz85string(sig, inputBufSize);
+  if(z85block == NULL)
+    goto errdea2;
+
+  size_t clen;
+  unsigned char *sighash = pcp_z85_decode(z85block, &clen);
+  if(sighash == NULL)
+    goto errdea3;
+
+  if(clen != mlen) {
+    fatal("z85 decoded signature didn't result in a proper signed hash(got: %ld, expected: %ld)\n", clen, mlen);
+    goto errdea4;
+  }
+  
+  unsigned char *verifiedhash = NULL;
+  if(p == NULL) {
+    pcphash_iteratepub(p) {
+      verifiedhash = pcp_ed_verify(sighash, mlen, p);
+      if(verifiedhash != NULL)
+	break;
+    }
+  }
+  else {
+    verifiedhash = pcp_ed_verify(sighash, mlen, p);
+  }
+
+  if(verifiedhash == NULL)
+    goto errdea4;
+
+  if(memcmp(verifiedhash, hash, crypto_generichash_BYTES_MAX) != 0) {
+    // sig verified, but the hash doesn't
+    fatal("signed hash doesn't match actual hash of signed file content\n");
+    goto errdea5;
+  }
+
+  free(verifiedhash);
+  free(sighash);
+  free(z85block);
+  free(sig);
+  return p;
+
+
+ errdea5:
+  free(verifiedhash);
+
+ errdea4:
+  free(sighash);
+  
+ errdea3:
+  free(z85block);
+  
+ errdea2:
+  free(sig);
+  
+ errdea1:
+  return NULL;
+}

src/encryption.c

@@ -259,7 +259,7 @@ int pcpencrypt(char *id, char *infile, char *outfile, char *passwd, plist_t *rec
   size_t clen = 0;
 
   if(self == 1)
-    pcp_encrypt_file_sym(in, out, symkey, 0);
+    clen = pcp_encrypt_file_sym(in, out, symkey, 0);
   else
     clen = pcp_encrypt_file(in, out, secret, pubhash);
 

src/pcp.c

@@ -44,10 +44,11 @@ char *default_vault() {
 }
 
 int main (int argc, char **argv)  {
-  int opt, mode, usevault, useid, userec, lo, armor;
+  int opt, mode, usevault, useid, userec, lo, armor, detach;
   char *vaultfile = default_vault();
   char *outfile = NULL;
   char *infile = NULL;
+  char *sigfile = NULL;
   char *keyid = NULL;
   char *id = NULL;
   char *xpass = NULL;
@@ -63,6 +64,7 @@ int main (int argc, char **argv)  {
   userec = 0;
   lo = 0;
   armor = 0;
+  detach = 0;
 
   static struct option longopts[] = {
     // generics
@@ -101,11 +103,12 @@ int main (int argc, char **argv)  {
 
     // signing
     { "sign",            no_argument,       NULL,           'g' }, 
-    { "check-signature", no_argument,       NULL,           'c' }, 
+    { "check-signature", required_argument, NULL,           'c' }, 
+    { "detach",          no_argument,       NULL,           'a' }, 
     { NULL,              0,                 NULL,            0 }
   };
 
-  while ((opt = getopt_long(argc, argv, "klV:vdehsO:i:I:pSPRtEx:DzZr:gcym",
+  while ((opt = getopt_long(argc, argv, "klV:vdehsO:i:I:pSPRtEx:DzZr:gc:yma",
 			    longopts, NULL)) != -1) {
   
     switch (opt)  {
@@ -171,12 +174,17 @@ int main (int argc, char **argv)  {
       case 'Z':
 	armor = 1;
 	break;
+      case 'a':
+	detach = 1;
+	break;
       case 'g':
 	mode += PCP_MODE_SIGN;
 	usevault = 1;
 	break;
       case 'c':
 	mode += PCP_MODE_VERIFY;
+	sigfile = ucmalloc(strlen(optarg)+1);
+	strncpy(sigfile, optarg, strlen(optarg)+1);
 	usevault = 1;
 	break;
       case 'y':
@@ -372,19 +380,19 @@ int main (int argc, char **argv)  {
 	break;	
 
       case PCP_MODE_SIGN:
-	pcpsign(infile, outfile, xpass, armor);
+	pcpsign(infile, outfile, xpass, armor, detach);
 	break;
 
       case PCP_MODE_VERIFY:
 	if(useid) {
 	  id = pcp_normalize_id(keyid);
 	  if(id != NULL) {
-	    pcpverify(infile, id);
+	    pcpverify(infile, sigfile, id, detach);
 	    free(id);
 	  }
 	}
 	else {
-	  pcpverify(infile, NULL);
+	  pcpverify(infile, sigfile, NULL, detach);
 	}
 	break;
 

src/signature.c

@@ -23,7 +23,8 @@
 #include "signature.h"
 #include "defines.h"
 
-int pcpsign(char *infile, char *outfile, char *passwd, int z85) {
+
+int pcpsign(char *infile, char *outfile, char *passwd, int z85, int detach) {
   FILE *in = NULL;
   FILE *out = NULL;
   pcp_key_t *secret = NULL;
@@ -70,7 +71,11 @@ int pcpsign(char *infile, char *outfile, char *passwd, int z85) {
       goto errs1;
   }
 
-  size_t sigsize = pcp_ed_sign_buffered(in, out, secret, z85);
+  size_t sigsize;
+  if(detach == 1)
+    sigsize = pcp_ed_detachsign_buffered(in, out, secret);
+  else
+    sigsize = pcp_ed_sign_buffered(in, out, secret, z85);
 
   if(sigsize == 0)
     goto errs1;
@@ -83,10 +88,10 @@ int pcpsign(char *infile, char *outfile, char *passwd, int z85) {
   return 1;
 }
 
-int pcpverify(char *infile, char *id) {
+int pcpverify(char *infile, char *sigfile, char *id, int detach) {
   FILE *in = NULL;
+  FILE *sigfd = NULL;
   pcp_pubkey_t *pub = NULL;
-  unsigned char *message = NULL;
 
   if(infile == NULL)
     in = stdin;
@@ -97,27 +102,24 @@ int pcpverify(char *infile, char *id) {
     }
   }
 
+  if(sigfile != NULL) {
+    if((sigfd = fopen(sigfile, "rb")) == NULL) {
+      fatal("Could not open signature file %s\n", sigfile);
+      goto errv1;
+    }
+  }
+  
   if(id != NULL)
     HASH_FIND_STR(pcppubkey_hash, id, pub);
  
-  if(pub != NULL) {
-    message = pcp_ed_verify_buffered(in, pub);
-    if(message != NULL) {
-      fprintf(stderr, "Signature verified (signed by %s <%s>).\n", pub->owner, pub->mail);
-    }
-  }
-  else {
-    // put public key as pub, so verify iterates over our keys
-    message = pcp_ed_verify_buffered(in, pub);
-    if(message != NULL) {
-      fprintf(stderr, "Signature verified (signed by %s <%s>).\n", pub->owner, pub->mail);
-    }
-  }
+  if(detach)
+    pub = pcp_ed_detachverify_buffered(in, sigfd, pub);
+  else
+    pub = pcp_ed_verify_buffered(sigfd, pub);
 
-  if(message != NULL) {
-    free(message);
-    return 0;
-  }
+  if(pub != NULL)
+    fprintf(stderr, "Signature verified (signed by %s <%s>).\n", pub->owner, pub->mail);
+  
 
  errv4:
 

src/signature.h

@@ -32,8 +32,8 @@
 #include "uthash.h"
 #include "z85.h"
 
-int pcpsign(char *infile, char *outfile, char *passwd, int z85);
-int pcpverify(char *infile, char *id);
+int pcpsign(char *infile, char *outfile, char *passwd, int z85, int detach);
+int pcpverify(char *infile, char *sigfile, char *id, int detach);
 
 
 

src/usage.txt

@@ -92,11 +92,15 @@ Signature Options:
                           -I (or from stdin) using your primary
                           secret key. If -r has been given, a derived
                           secret key will be used for signing.
-
 -c --check-signature <file> Verify a signature in file <file> against
                           the file specified with -I (or stdin).
                           The public key required for this must
                           exist in your vault file.
+-a --detach               Write a detached signature file, which doesn't
+                          contain the original content. Output will be
+                          z85 encoded always. To verify, you need to
+                          specify the original file to be verified
+                          against using -I as well (plus -a).
 
 Encoding Options:
 -z --z85-encode           Encode something to Z85 encoding. Use

tests/unittests.cfg

@@ -210,13 +210,31 @@ dxmorg@florida.cops.gov
 </test>
 
 #
-# signature test
-<test check-sign-to-bobby>
+# signature tests
+<test check-sign-detached-to-bobby>
+  cmd = $pcp -V va -g -I README -O testsig -x a -a
+  expect-file testsig
+</test>
+<test check-verify-detached-signature>
+  cmd = $pcp -V vb -c testsig -I README -i $idalicia -a
+  expect = /verified/
+</test>
+<test check-sign-armored-to-bobby>
+  prepare = rm -f testsig
+  cmd = $pcp -V va -g -I README -O testsig -x a -z
+  expect-file testsig
+</test>
+<test check-verify-armored-signature>
+  cmd = $pcp -V vb -c testsig -i $idalicia -z
+  expect = /verified/
+</test>
+<test check-sign-bin-to-bobby>
+  prepare = rm -f testsig
   cmd = $pcp -V va -g -I README -O testsig -x a
   expect-file testsig
 </test>
-<test check-verify-signature>
-  cmd = $pcp -V vb -c -I testsig -i $idalicia
+<test check-verify-bin-signature>
+  cmd = $pcp -V vb -c testsig -i $idalicia
   expect = /verified/
 </test>
 
@@ -332,12 +350,15 @@ dxmorg@florida.cops.gov
 </test>
 */
 
+/*
+ * Disabled, since z85 standalone mode currently disabled
 <test check-if-catch-nokey-behind-z85>
   prepare = ./jot 30 | while read ignore; do echo XXXXX; done \
             | $pcp -z > testfile-nokey
   cmd = $pcp -V $vault -P -I testfile-nokey
   expect = /result to a proper sized key/
 </test>
+*/
 
 <test check-if-sanity-catch-nosecret>
   cmd = $pcp -V $vault -S -I bart.pub