added signature support (doesn't work yet)

src/signature.c

@@ -0,0 +1,224 @@
+/*
+    This file is part of Pretty Curved Privacy (pcp1).
+
+    Copyright (C) 2013 T.Linden.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    You can contact me by mail: <tlinden AT cpan DOT org>.
+*/
+
+
+#include "signature.h"
+#include "defines.h"
+
+int pcpsign(char *infile, char *outfile, char *passwd) {
+  FILE *in = NULL;
+  FILE *out = NULL;
+  pcp_key_t *secret = NULL;
+
+  secret = pcp_find_primary_secret();
+  if(secret == NULL) {
+    fatal("Could not find a secret key in vault %s!\n", vault->filename);
+    goto errs1;
+  }
+
+  if(infile == NULL)
+    in = stdin;
+  else {
+    if((in = fopen(infile, "rb")) == NULL) {
+      fatal("Could not open input file %s\n", infile);
+      goto errs2;
+    }
+  }
+
+  if(outfile == NULL)
+    out = stdout;
+  else {
+    if((out = fopen(outfile, "wb+")) == NULL) {
+      fatal("Could not open output file %s\n", outfile);
+      goto errs2;
+    }
+  }
+
+  if(secret->secret[0] == 0) {
+    // encrypted, decrypt it
+    char *passphrase;
+    if(passwd == NULL) {
+      pcp_readpass(&passphrase,
+		   "Enter passphrase to decrypt your secret key", NULL, 1);
+    }
+    else {
+      passphrase = ucmalloc(strlen(passwd)+1);
+      strncpy(passphrase, passwd, strlen(passwd)+1);
+    }
+
+    secret = pcpkey_decrypt(secret, passphrase);
+    if(secret == NULL)
+      goto errs3;
+  }
+
+  unsigned char *input = NULL;
+  size_t inputBufSize = 0;
+  unsigned char byte[1];
+  
+  while(!feof(in)) {
+    if(!fread(&byte, 1, 1, in))
+      break;
+    unsigned char *tmp = realloc(input, inputBufSize + 1);
+    input = tmp;
+    memmove(&input[inputBufSize], byte, 1);
+    inputBufSize ++;
+  }
+  fclose(in);
+
+  if(inputBufSize == 0) {
+    fatal("Input file is empty!\n");
+    goto errs4;
+  }
+
+  size_t zlen;
+  pcp_sig_t *signature = pcp_ed_sign(input, inputBufSize, secret);
+
+  if(signature == NULL)
+    goto errs5;
+
+  sig2be(signature);
+  char *encoded = pcp_z85_encode((unsigned char *)signature, sizeof(pcp_sig_t), &zlen);
+
+  if(encoded == NULL)
+    goto errs6;
+
+  fprintf(out, "%s\n%s\n%s\n", PCP_SIG_HEADER, encoded, PCP_SIG_FOOTER);
+  if(ferror(out) != 0) {
+    fatal("Failed to write encrypted output!\n");
+    goto errs7;
+  }
+
+  fprintf(stderr, "Signed %d bytes successfully\n",
+	  (int)inputBufSize);
+
+  fclose(out);
+  free(encoded);
+  free(signature);
+
+  return 0;
+
+ errs7:
+  free(encoded);
+  
+ errs6:
+  free(signature);
+
+ errs5:
+
+ errs4:
+  free(input);
+
+ errs3:
+
+ errs2:
+
+ errs1:
+  return 1;
+}
+
+int pcpverify(char *infile, char *sigfile) {
+  FILE *in = NULL;
+  FILE *sigin = NULL;
+  pcp_pubkey_t *public = NULL;
+
+  if(infile == NULL)
+    in = stdin;
+  else {
+    if((in = fopen(infile, "rb")) == NULL) {
+      fatal("Could not open input file %s\n", infile);
+      goto errv1;
+    }
+  }
+
+ if((sigin = fopen(sigfile, "rb")) == NULL) {
+   fatal("Could not open signature file %s\n", sigfile);
+   goto errv1;
+ }
+
+  char *encoded = pcp_readz85file(sigin);
+  if(encoded == NULL)
+    goto errv1;
+
+  size_t clen;
+  unsigned char *decoded = pcp_z85_decode((char *)encoded, &clen);
+
+  if(decoded == NULL)
+    goto errv2;
+
+  if(clen != sizeof(pcp_sig_t)) {
+    fatal("Error: decoded signature file didn't result to a proper sized sig! (got %d bytes)\n", clen);
+    goto errv2;
+  }
+
+  pcp_sig_t *sig = (pcp_sig_t *)decoded;
+  sig2native(sig);
+
+  HASH_FIND_STR(pcppubkey_hash, sig->id, public);
+ 
+  if(public == NULL) {
+    fatal("Could not find a usable public key in vault %s!\n",
+	  vault->filename);
+      goto errv3;
+  }
+
+  unsigned char *input = NULL;
+  size_t inputBufSize = 0;
+  unsigned char byte[1];
+  
+  while(!feof(in)) {
+    if(!fread(&byte, 1, 1, in))
+      break;
+    unsigned char *tmp = realloc(input, inputBufSize + 1);
+    input = tmp;
+    memmove(&input[inputBufSize], byte, 1);
+    inputBufSize ++;
+  }
+  fclose(in);
+
+  if(inputBufSize == 0) {
+    fatal("Input file is empty!\n");
+    goto errv4;
+  }
+
+ 
+  if(pcp_ed_verify(input, inputBufSize, sig, public) == 0) {
+    fprintf(stderr, "Signature verified.\n");
+  }
+
+  free(decoded);
+  free(encoded);
+  free(sig);
+  free(input);
+  return 0;
+
+ errv4:
+  free(input);
+
+ errv3:
+  free(decoded);
+  free(sig);
+
+ errv2:
+  //  free(encoded); why???
+
+ errv1:
+  return 1;
+}