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fixed crypt+sign, now the sig contains the encrypted recipient list as well and is encrypted itself

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This commit is contained in:
git@daemon.de
2014-02-05 13:09:20 +01:00
parent 5707ecbf9c
commit a89b16a15c
5 changed files with 138 additions and 38 deletions
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7
include/pcp/crypto.h
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@@ -58,8 +58,11 @@ size_t pcp_encrypt_file(FILE *in, FILE* out, pcp_key_t *s, pcp_pubkey_t *p, int
size_t pcp_decrypt_file(FILE *in, FILE* out, pcp_key_t *s, unsigned char *symkey, int verify);
size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int havehead, pcp_key_t *signkey);
size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int havehead, pcp_rec_t *recsign);
size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubkey_t *verifykey);
size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_rec_t *recverify);
pcp_rec_t *pcp_rec_new(unsigned char *cipher, size_t clen, pcp_key_t *secret, pcp_pubkey_t *pub);
void pcp_rec_free(pcp_rec_t *r);
#endif // _HAVE_PCP_CRYPTO_H

2
include/pcp/defines.h
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@@ -81,7 +81,7 @@ typedef unsigned int qbyte; // Quad byte = 32 bits
#define PCP_CRYPTO_ADD (crypto_box_ZEROBYTES - crypto_box_BOXZEROBYTES)
#define PCP_BLOCK_SIZE_IN (PCP_BLOCK_SIZE) + PCP_CRYPTO_ADD + crypto_secretbox_NONCEBYTES
#define PCP_ASYM_RECIPIENT_SIZE crypto_secretbox_KEYBYTES + PCP_CRYPTO_ADD + crypto_secretbox_NONCEBYTES
#define PCP_ASYM_RECIPIENT_SIZE crypto_secretbox_KEYBYTES + PCP_CRYPTO_ADD + crypto_secretbox_NONCEBYTES
//#define PCP_ASYM_ADD_SENDER_PUB
// used for self encryption only

15
include/pcp/key.h
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@@ -113,10 +113,25 @@ struct _pbp_pubkey_t {
char name[1024];
};
typedef struct _pcp_key_t pcp_key_t;
typedef struct _pcp_pubkey_t pcp_pubkey_t;
typedef struct _pbp_pubkey_t pbp_pubkey_t;
/*
encrypted recipient list, required for crypt+sign
contains the encrypted recipients and the secret
key required for signing the message+recipients.
*/
struct _pcp_rec_t {
size_t ciphersize;
byte *cipher;
pcp_key_t *secret;
pcp_pubkey_t *pub;
};
typedef struct _pcp_rec_t pcp_rec_t;
#define PCP_RAW_KEYSIZE sizeof(pcp_key_t) - sizeof(UT_hash_handle)
#define PCP_RAW_PUBKEYSIZE sizeof(pcp_pubkey_t) - sizeof(UT_hash_handle)

147
libpcp/crypto.c
View File

@@ -165,6 +165,7 @@ unsigned char *pcp_box_decrypt(pcp_key_t *secret, pcp_pubkey_t *pub,
size_t pcp_decrypt_file(FILE *in, FILE* out, pcp_key_t *s, unsigned char *symkey, int verify) {
pcp_pubkey_t *cur = NULL;
pcp_pubkey_t *sender = NULL;
unsigned char *reccipher = NULL;
int nrec, recmatch;
uint32_t lenrec;
byte head[1];
@@ -222,6 +223,10 @@ size_t pcp_decrypt_file(FILE *in, FILE* out, pcp_key_t *s, unsigned char *symkey
}
lenrec = be32toh(lenrec);
if(verify) {
reccipher = ucmalloc(lenrec * PCP_ASYM_RECIPIENT_SIZE);
}
// step 4, fetch recipient list and try to decrypt it for us
for(nrec=0; nrec<lenrec; nrec++) {
cur_bufsize = fread(&rec_buf, 1, PCP_ASYM_RECIPIENT_SIZE, in);
@@ -243,15 +248,23 @@ size_t pcp_decrypt_file(FILE *in, FILE* out, pcp_key_t *s, unsigned char *symkey
break;
}
}
if(recmatch == 0) {
fatal("Sorry, there's no matching public key in your vault for decryption\n");
goto errdef1;
if(verify) {
memcpy(&reccipher[nrec * (PCP_ASYM_RECIPIENT_SIZE)], &rec_buf, PCP_ASYM_RECIPIENT_SIZE);
}
}
if(recmatch == 0) {
fatal("Sorry, there's no matching public key in your vault for decryption\n");
goto errdef1;
}
// step 5, actually decrypt the file, finally
if(verify)
return pcp_decrypt_file_sym(in, out, symkey, cur);
if(verify) {
pcp_rec_t *rec = pcp_rec_new(reccipher, nrec * PCP_ASYM_RECIPIENT_SIZE, NULL, cur);
return pcp_decrypt_file_sym(in, out, symkey, rec);
pcp_rec_free(rec);
}
else
return pcp_decrypt_file_sym(in, out, symkey, NULL);
@@ -335,8 +348,11 @@ size_t pcp_encrypt_file(FILE *in, FILE* out, pcp_key_t *s, pcp_pubkey_t *p, int
// step 5, actual encrypted data
size_t sym_size = 0;
if(sign)
sym_size = pcp_encrypt_file_sym(in, out, symkey, 1, s);
if(sign) {
pcp_rec_t *rec = pcp_rec_new(recipients_cipher, rec_size * recipient_count, s, NULL);
sym_size = pcp_encrypt_file_sym(in, out, symkey, 1, rec);
pcp_rec_free(rec);
}
else
sym_size = pcp_encrypt_file_sym(in, out, symkey, 1, NULL);
@@ -361,7 +377,7 @@ size_t pcp_encrypt_file(FILE *in, FILE* out, pcp_key_t *s, pcp_pubkey_t *p, int
return 0;
}
size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int havehead, pcp_key_t *signkey) {
size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int havehead, pcp_rec_t *recsign) {
/*
havehead = 0: write the whole thing from here
havehead = 1: no header, being called from asym...
@@ -377,7 +393,7 @@ size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int have
unsigned char *hash = NULL;
byte head[1];
if(signkey != NULL) {
if(recsign != NULL) {
st = ucmalloc(sizeof(crypto_generichash_state));
hash = ucmalloc(crypto_generichash_BYTES_MAX);
crypto_generichash_init(st, NULL, 0, 0);
@@ -385,7 +401,7 @@ size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int have
if(havehead == 0) {
head[0] = PCP_SYM_CIPHER;
size_t hs = fwrite(head, 1, 1, out);
es = fwrite(head, 1, 1, out);
if(ferror(out) != 0) {
fatal("Failed to write encrypted output!\n");
return 0;
@@ -422,7 +438,7 @@ size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int have
free(buf_cipher);
out_size += crypto_secretbox_NONCEBYTES + es;
if(signkey != NULL)
if(recsign != NULL)
crypto_generichash_update(st, in_buf, cur_bufsize);
#ifdef PCP_CBC
@@ -436,11 +452,21 @@ size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int have
goto errsym1;
}
if(signkey != NULL) {
if(recsign != NULL) {
/* add encrypted recipient list to the hash */
crypto_generichash_update(st, recsign->cipher, recsign->ciphersize);
crypto_generichash_final(st, hash, crypto_generichash_BYTES_MAX);
unsigned char *signature = pcp_ed_sign(hash, crypto_generichash_BYTES_MAX, signkey);
/* generate the actual signature */
unsigned char *signature = pcp_ed_sign(hash, crypto_generichash_BYTES_MAX, recsign->secret);
size_t siglen = crypto_sign_BYTES + crypto_generichash_BYTES_MAX;
fwrite(signature, siglen, 1, out);
/* encrypt it as well */
buf_nonce = pcp_gennonce();
es = pcp_sodium_mac(&buf_cipher, signature, siglen, buf_nonce, symkey);
fwrite(buf_nonce, crypto_secretbox_NONCEBYTES, 1, out);
fwrite(buf_cipher, es, 1, out);
free(st);
free(signature);
free(hash);
@@ -461,7 +487,7 @@ size_t pcp_encrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, int have
return 0;
}
size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubkey_t *verifykey) {
size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_rec_t *recverify) {
unsigned char *buf_nonce;
unsigned char *buf_cipher;
unsigned char *buf_clear;
@@ -474,15 +500,17 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubk
out_size = 0;
unsigned char *signature = NULL;
unsigned char *signature_cr = NULL;
size_t siglen = crypto_sign_BYTES + crypto_generichash_BYTES_MAX;
size_t siglen_cr = siglen + PCP_CRYPTO_ADD + crypto_secretbox_NONCEBYTES;
crypto_generichash_state *st = NULL;
unsigned char *hash = NULL;
if(verifykey != NULL) {
if(recverify != NULL) {
st = ucmalloc(sizeof(crypto_generichash_state));
hash = ucmalloc(crypto_generichash_BYTES_MAX);
crypto_generichash_init(st, NULL, 0, 0);
signature = ucmalloc(siglen);
signature_cr = ucmalloc(siglen_cr);
}
#ifdef PCP_CBC
@@ -494,11 +522,11 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubk
if(cur_bufsize <= PCP_CRYPTO_ADD)
break; // no valid cipher block
if(verifykey != NULL) {
if(recverify != NULL) {
if(cur_bufsize < PCP_BLOCK_SIZE_IN || feof(in)) {
// pull out signature
memcpy(signature, &in_buf[cur_bufsize - siglen], siglen);
cur_bufsize -= siglen;
memcpy(signature_cr, &in_buf[cur_bufsize - siglen_cr], siglen_cr);
cur_bufsize -= siglen_cr;
}
}
@@ -527,7 +555,7 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubk
if(es == 0) {
fwrite(buf_clear, ciphersize - PCP_CRYPTO_ADD, 1, out);
if(verifykey != NULL)
if(recverify != NULL)
crypto_generichash_update(st, buf_clear, ciphersize - PCP_CRYPTO_ADD);
free(buf_clear);
@@ -553,23 +581,37 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubk
free(buf_nonce);
free(buf_cipher);
if(verifykey != NULL) {
crypto_generichash_final(st, hash, crypto_generichash_BYTES_MAX);
unsigned char *verifiedhash = NULL;
verifiedhash = pcp_ed_verify(signature, siglen, verifykey);
if(verifiedhash == NULL)
out_size = 0;
else {
if(memcmp(verifiedhash, hash, crypto_generichash_BYTES_MAX) != 0) {
// sig verified, but the hash doesn't match
fatal("signed hash doesn't match actual hash of signed decrypted file content\n");
if(recverify != NULL) {
/* decrypt the signature */
memcpy(buf_nonce, signature_cr, crypto_secretbox_NONCEBYTES);
es = pcp_sodium_verify_mac(&signature, &signature_cr[crypto_secretbox_NONCEBYTES],
siglen_cr - crypto_secretbox_NONCEBYTES, buf_nonce, symkey);
if(es == 0) {
/* add encrypted recipient list to the hash */
crypto_generichash_update(st, recverify->cipher, recverify->ciphersize);
crypto_generichash_final(st, hash, crypto_generichash_BYTES_MAX);
unsigned char *verifiedhash = NULL;
verifiedhash = pcp_ed_verify(signature, siglen, recverify->pub);
if(verifiedhash == NULL)
out_size = 0;
else {
if(memcmp(verifiedhash, hash, crypto_generichash_BYTES_MAX) != 0) {
// sig verified, but the hash doesn't match
fatal("signed hash doesn't match actual hash of signed decrypted file content\n");
out_size = 0;
}
free(verifiedhash);
}
free(verifiedhash);
}
else {
fatal("Failed to decrypt signature!\n");
out_size = 0;
}
free(st);
free(hash);
free(signature);
free(signature_cr);
}
if(fileno(in) != 0)
@@ -580,3 +622,44 @@ size_t pcp_decrypt_file_sym(FILE *in, FILE* out, unsigned char *symkey, pcp_pubk
return out_size;
}
pcp_rec_t *pcp_rec_new(unsigned char *cipher, size_t clen, pcp_key_t *secret, pcp_pubkey_t *pub) {
pcp_rec_t *r = ucmalloc(sizeof(pcp_rec_t));
r->cipher = ucmalloc(clen);
memcpy(r->cipher, cipher, clen);
r->ciphersize = clen;
if(secret != NULL) {
r->secret = ucmalloc(sizeof(pcp_key_t));
memcpy(r->secret, secret, sizeof(pcp_key_t));
}
else
r->secret = NULL;
if(pub != NULL) {
r->pub = ucmalloc(sizeof(pcp_key_t));
memcpy(r->pub, pub, sizeof(pcp_key_t));
}
else
r->pub = NULL;
return r;
}
void pcp_rec_free(pcp_rec_t *r) {
free(r->cipher);
if(r->secret != NULL) {
memset(r->secret, 0, sizeof(pcp_key_t));
free(r->secret);
}
if(r->pub != NULL) {
memset(r->pub, 0, sizeof(pcp_pubkey_t));
free(r->pub);
}
free(r);
}

5
src/encryption.c
View File

@@ -160,8 +160,7 @@ int pcpencrypt(char *id, char *infile, char *outfile, char *passwd, plist_t *rec
symkey = pcp_scrypt(passphrase, crypto_secretbox_KEYBYTES, salt, 90);
free(salt);
}
else if(id != NULL) {
// FIXME: mk id a plist_t with loop as well
else if(id != NULL && recipient == NULL) {
// lookup by id
HASH_FIND_STR(pcppubkey_hash, id, tmp);
if(tmp == NULL) {
@@ -193,7 +192,7 @@ int pcpencrypt(char *id, char *infile, char *outfile, char *passwd, plist_t *rec
plist_t *rec;
pcphash_iteratepub(tmp) {
rec = recipient->first;
while (rec->next != NULL) {
while (rec != NULL) {
_lc(rec->value);
if(strnstr(tmp->mail, rec->value, 255) != NULL || strnstr(tmp->owner, rec->value, 255) != NULL) {
pub = ucmalloc(sizeof(pcp_pubkey_t));