boinc/lib/crypt.cpp

704 lines
19 KiB
C++

// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>.
#if defined(_WIN32) && !defined(__STDWX_H__)
#include "boinc_win.h"
#elif defined(_WIN32) && defined(__STDWX_H__)
#include "stdwx.h"
#else
#include "config.h"
#include <cctype>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#endif
#ifdef _MSC_VER
#define snprintf _snprintf
#define strdup _strdup
#endif
#include <openssl/ssl.h>
#include <openssl/md5.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/conf.h>
#include <openssl/engine.h>
#include <openssl/err.h>
#ifdef _USING_FCGI_
#include "boinc_fcgi.h"
#endif
#include "md5_file.h"
#include "cert_sig.h"
#include "filesys.h"
#include "error_numbers.h"
#include "crypt.h"
// NOTE: the fast CGI I/O library doesn't have fscanf(),
// so some of the following have been modified to use
// fgets() and sscanf() instead
// write some data in hex notation.
// NOTE: since length may not be known to the reader,
// we follow the data with a non-hex character '.'
//
int print_hex_data(FILE* f, DATA_BLOCK& x) {
unsigned int i;
for (i=0; i<x.len; i++) {
fprintf(f, "%02x", x.data[i]);
if (i%32==31) fprintf(f, "\n");
}
if (x.len%32 != 0) fprintf(f, "\n");
fprintf(f, ".\n");
return 0;
}
// same, but write to buffer
//
int sprint_hex_data(char* out_buf, DATA_BLOCK& x) {
unsigned int i;
const char hex[] = "0123456789abcdef";
char* p = out_buf;
for (i=0; i<x.len; i++) {
*p++ = hex[x.data[i]/16];
*p++ = hex[x.data[i]%16];
if (i%32==31) *p++ = '\n';
}
if (x.len%32 != 0) *p++ = '\n';
strcpy(p, ".\n");
return 0;
}
int print_raw_data(FILE* f, DATA_BLOCK& x) {
unsigned int i;
for (i=0; i<x.len; i++) {
//printf("%x ", x.data[i]);
fprintf(f, "%c", x.data[i]);
}
return 0;
}
// NOTE: buffer must be big enough; no checking is done.
int scan_raw_data(FILE *f, DATA_BLOCK& x) {
int i=0,j;
while(EOF!=(j=fgetc(f))) {
x.data[i]=j;
i++;
}
x.len = i;
return 0;
}
// scan data in hex notation.
// stop when you reach a non-parsed character.
// NOTE: buffer must be big enough; no checking is done.
//
int scan_hex_data(FILE* f, DATA_BLOCK& x) {
int n;
x.len = 0;
#if _USING_FCGI_
char *p, buf[256];
int i, j;
while (1) {
p = fgets(buf, 256, f);
if (!p) return ERR_GETS;
n = strlen(p)/2;
if (n == 0) break;
for (i=0; i<n; i++) {
sscanf(buf+i*2, "%2x", &j);
x.data[x.len] = j;
x.len++;
}
}
#else
while (1) {
int j;
n = fscanf(f, "%2x", &j);
if (n <= 0) break;
x.data[x.len] = j;
x.len++;
}
#endif
return 0;
}
// same, but read from buffer
//
static int sscan_hex_data(const char* p, DATA_BLOCK& x) {
int m, n, nleft=x.len;
x.len = 0;
while (1) {
if (isspace(*p)) {
++p;
continue;
}
n = sscanf(p, "%2x", &m);
if (n <= 0) break;
if (nleft<=0) {
fprintf(stderr, "sscan_hex_data: buffer overflow\n");
return ERR_BAD_HEX_FORMAT;
}
x.data[x.len++] = m;
nleft--;
p += 2;
}
return 0;
}
// print a key in ASCII form
//
int print_key_hex(FILE* f, KEY* key, int size) {
int len;
DATA_BLOCK x;
fprintf(f, "%d\n", key->bits);
len = size - sizeof(key->bits);
x.data = key->data;
x.len = len;
return print_hex_data(f, x);
}
int scan_key_hex(FILE* f, KEY* key, int size) {
int len, i, n;
int num_bits;
#if _USING_FCGI_
char *p, buf[256];
int j = 0, b;
fgets(buf, 256, f);
sscanf(buf, "%d", &num_bits);
key->bits = num_bits;
len = size - sizeof(key->bits);
while (1) {
p = fgets(buf, 256, f);
if (!p) break;
n = (strlen(p)-1)/2;
if (n == 0) break;
for (i=0; i<n; i++) {
sscanf(buf+i*2, "%2x", &b);
if (j == len) break;
key->data[j++] = b;
}
}
if (j != len) return ERR_NULL;
#else
fscanf(f, "%d", &num_bits);
key->bits = num_bits;
len = size - sizeof(key->bits);
for (i=0; i<len; i++) {
fscanf(f, "%2x", &n);
key->data[i] = n;
}
fscanf(f, ".");
#endif
return 0;
}
// parse a text-encoded key from a memory buffer
//
int sscan_key_hex(const char* buf, KEY* key, int size) {
int n, retval,num_bits;
DATA_BLOCK db;
//fprintf(stderr, "buf = %s\n", buf);
n = sscanf(buf, "%d", &num_bits);
key->bits = num_bits; //key->bits is a short
//fprintf(stderr, "key->bits = %d\n", key->bits);
if (n != 1) return ERR_XML_PARSE;
buf = strchr(buf, '\n');
if (!buf) return ERR_XML_PARSE;
buf += 1;
db.data = key->data;
db.len = size - sizeof(key->bits); //huh???
retval = sscan_hex_data(buf, db);
return retval;
}
// encrypt some data.
// The amount encrypted may be less than what's supplied.
// The output buffer must be at least MIN_OUT_BUFFER_SIZE.
// The output block must be decrypted in its entirety.
//
int encrypt_private(R_RSA_PRIVATE_KEY& key, DATA_BLOCK& in, DATA_BLOCK& out) {
int n, modulus_len, retval;
modulus_len = (key.bits+7)/8;
n = in.len;
if (n >= modulus_len-11) {
n = modulus_len-11;
}
RSA* rp = RSA_new();
private_to_openssl(key, rp);
retval = RSA_private_encrypt(n, in.data, out.data, rp, RSA_PKCS1_PADDING);
if (retval < 0) {
RSA_free(rp);
return ERR_CRYPTO;
}
out.len = RSA_size(rp);
RSA_free(rp);
return 0;
}
int decrypt_public(R_RSA_PUBLIC_KEY& key, DATA_BLOCK& in, DATA_BLOCK& out) {
int retval;
RSA* rp = RSA_new();
public_to_openssl(key, rp);
retval = RSA_public_decrypt(in.len, in.data, out.data, rp, RSA_PKCS1_PADDING);
if (retval < 0) {
RSA_free(rp);
return ERR_CRYPTO;
}
out.len = RSA_size(rp);
RSA_free(rp);
return 0;
}
int sign_file(const char* path, R_RSA_PRIVATE_KEY& key, DATA_BLOCK& signature) {
char md5_buf[MD5_LEN];
double file_length;
DATA_BLOCK in_block;
int retval;
retval = md5_file(path, md5_buf, file_length);
if (retval) return retval;
in_block.data = (unsigned char*)md5_buf;
in_block.len = (unsigned int)strlen(md5_buf);
retval = encrypt_private(key, in_block, signature);
if (retval) return retval;
return 0;
}
int sign_block(DATA_BLOCK& data_block, R_RSA_PRIVATE_KEY& key, DATA_BLOCK& signature) {
char md5_buf[MD5_LEN];
int retval;
DATA_BLOCK in_block;
md5_block(data_block.data, data_block.len, md5_buf);
in_block.data = (unsigned char*)md5_buf;
in_block.len = (unsigned int)strlen(md5_buf);
retval = encrypt_private(key, in_block, signature);
if (retval) {
printf("sign_block: encrypt_private returned %d\n", retval);
return retval;
}
return 0;
}
// compute an XML signature element for some text
//
int generate_signature(
char* text_to_sign, char* signature_hex, R_RSA_PRIVATE_KEY& key
) {
DATA_BLOCK block, signature_data;
unsigned char signature_buf[SIGNATURE_SIZE_BINARY];
int retval;
block.data = (unsigned char*)text_to_sign;
block.len = (unsigned int)strlen(text_to_sign);
signature_data.data = signature_buf;
signature_data.len = SIGNATURE_SIZE_BINARY;
retval = sign_block(block, key, signature_data);
if (retval) return retval;
sprint_hex_data(signature_hex, signature_data);
return 0;
}
// check a file signature
//
int check_file_signature(
const char* md5_buf, R_RSA_PUBLIC_KEY& key,
DATA_BLOCK& signature, bool& answer
) {
char clear_buf[MD5_LEN];
int n, retval;
DATA_BLOCK clear_signature;
n = (int)strlen(md5_buf);
clear_signature.data = (unsigned char*)clear_buf;
clear_signature.len = MD5_LEN;
retval = decrypt_public(key, signature, clear_signature);
if (retval) {
fprintf(stderr,
"check_file_signature: decrypt_public error %d\n", retval
);
return retval;
}
answer = !strncmp(md5_buf, clear_buf, n);
return 0;
}
// same, signature given as string
//
int check_file_signature2(
const char* md5, const char* signature_text,
const char* key_text, bool& answer
) {
R_RSA_PUBLIC_KEY key;
unsigned char signature_buf[SIGNATURE_SIZE_BINARY];
int retval;
DATA_BLOCK signature;
retval = sscan_key_hex(key_text, (KEY*)&key, sizeof(key));
if (retval) {
fprintf(stderr, "check_file_signature2: sscan_key_hex failed\n");
return retval;
}
signature.data = signature_buf;
signature.len = sizeof(signature_buf);
retval = sscan_hex_data(signature_text, signature);
if (retval) return retval;
return check_file_signature(md5, key, signature, answer);
}
// same, both text and signature are char strings
//
int check_string_signature(
const char* text, const char* signature_text, R_RSA_PUBLIC_KEY& key,
bool& answer
) {
char md5_buf[MD5_LEN];
unsigned char signature_buf[SIGNATURE_SIZE_BINARY];
char clear_buf[MD5_LEN];
int retval, n;
DATA_BLOCK signature, clear_signature;
retval = md5_block((const unsigned char*)text, (int)strlen(text), md5_buf);
if (retval) return retval;
n = (int)strlen(md5_buf);
signature.data = signature_buf;
signature.len = sizeof(signature_buf);
retval = sscan_hex_data(signature_text, signature);
if (retval) return retval;
clear_signature.data = (unsigned char*)clear_buf;
clear_signature.len = 256;
retval = decrypt_public(key, signature, clear_signature);
if (retval) return retval;
answer = !strncmp(md5_buf, clear_buf, n);
return 0;
}
// Same, where public key is also encoded as text
//
int check_string_signature2(
const char* text, const char* signature_text, const char* key_text, bool& answer
) {
R_RSA_PUBLIC_KEY key;
int retval;
retval = sscan_key_hex(key_text, (KEY*)&key, sizeof(key));
if (retval) return retval;
return check_string_signature(text, signature_text, key, answer);
}
int read_key_file(const char* keyfile, R_RSA_PRIVATE_KEY& key) {
int retval;
#ifndef _USING_FCGI_
FILE* fkey = fopen(keyfile, "r");
#else
FCGI_FILE* fkey = FCGI::fopen(keyfile, "r");
#endif
if (!fkey) {
fprintf(stderr, "can't open key file (%s)\n", keyfile);
return ERR_FOPEN;
}
retval = scan_key_hex(fkey, (KEY*)&key, sizeof(key));
fclose(fkey);
if (retval) {
fprintf(stderr, "can't parse key\n");
return retval;
}
return 0;
}
static void bn_to_bin(BIGNUM* bn, unsigned char* bin, int n) {
memset(bin, 0, n);
int m = BN_num_bytes(bn);
BN_bn2bin(bn, bin+n-m);
}
void openssl_to_keys(
RSA* rp, int nbits, R_RSA_PRIVATE_KEY& priv, R_RSA_PUBLIC_KEY& pub
) {
pub.bits = nbits;
bn_to_bin(rp->n, pub.modulus, sizeof(pub.modulus));
bn_to_bin(rp->e, pub.exponent, sizeof(pub.exponent));
memset(&priv, 0, sizeof(priv));
priv.bits = nbits;
bn_to_bin(rp->n, priv.modulus, sizeof(priv.modulus));
bn_to_bin(rp->e, priv.publicExponent, sizeof(priv.publicExponent));
bn_to_bin(rp->d, priv.exponent, sizeof(priv.exponent));
bn_to_bin(rp->p, priv.prime[0], sizeof(priv.prime[0]));
bn_to_bin(rp->q, priv.prime[1], sizeof(priv.prime[1]));
bn_to_bin(rp->dmp1, priv.primeExponent[0], sizeof(priv.primeExponent[0]));
bn_to_bin(rp->dmq1, priv.primeExponent[1], sizeof(priv.primeExponent[1]));
bn_to_bin(rp->iqmp, priv.coefficient, sizeof(priv.coefficient));
}
void private_to_openssl(R_RSA_PRIVATE_KEY& priv, RSA* rp) {
rp->n = BN_bin2bn(priv.modulus, sizeof(priv.modulus), 0);
rp->e = BN_bin2bn(priv.publicExponent, sizeof(priv.publicExponent), 0);
rp->d = BN_bin2bn(priv.exponent, sizeof(priv.exponent), 0);
rp->p = BN_bin2bn(priv.prime[0], sizeof(priv.prime[0]), 0);
rp->q = BN_bin2bn(priv.prime[1], sizeof(priv.prime[1]), 0);
rp->dmp1 = BN_bin2bn(priv.primeExponent[0], sizeof(priv.primeExponent[0]), 0);
rp->dmq1 = BN_bin2bn(priv.primeExponent[1], sizeof(priv.primeExponent[1]), 0);
rp->iqmp = BN_bin2bn(priv.coefficient, sizeof(priv.coefficient), 0);
}
void public_to_openssl(R_RSA_PUBLIC_KEY& pub, RSA* rp) {
rp->n = BN_bin2bn(pub.modulus, sizeof(pub.modulus), 0);
rp->e = BN_bin2bn(pub.exponent, sizeof(pub.exponent), 0);
}
static int _bn2bin(BIGNUM *from, unsigned char *to, int max) {
int i;
i=BN_num_bytes(from);
if (i > max) {
return(0);
}
memset(to,0,(unsigned int)max);
if (!BN_bn2bin(from,&(to[max-i])))
return(0);
return(1);
}
int openssl_to_private(RSA *from, R_RSA_PRIVATE_KEY *to) {
to->bits = BN_num_bits(from->n);
if (!_bn2bin(from->n,to->modulus,MAX_RSA_MODULUS_LEN))
return(0);
if (!_bn2bin(from->e,to->publicExponent,MAX_RSA_MODULUS_LEN))
return(0);
if (!_bn2bin(from->d,to->exponent,MAX_RSA_MODULUS_LEN))
return(0);
if (!_bn2bin(from->p,to->prime[0],MAX_RSA_PRIME_LEN))
return(0);
if (!_bn2bin(from->q,to->prime[1],MAX_RSA_PRIME_LEN))
return(0);
if (!_bn2bin(from->dmp1,to->primeExponent[0],MAX_RSA_PRIME_LEN))
return(0);
if (!_bn2bin(from->dmq1,to->primeExponent[1],MAX_RSA_PRIME_LEN))
return(0);
if (!_bn2bin(from->iqmp,to->coefficient,MAX_RSA_PRIME_LEN))
return(0);
return 1;
}
int check_validity_of_cert(
const char *cFile, const unsigned char *md5_md, unsigned char *sfileMsg,
const int sfsize, const char* caPath
) {
int retval = 0;
X509 *cert;
X509_STORE *store;
X509_LOOKUP *lookup;
X509_STORE_CTX *ctx = 0;
EVP_PKEY *pubKey;
BIO *bio;
bio = BIO_new(BIO_s_file());
BIO_read_filename(bio, cFile);
if (NULL == (cert = PEM_read_bio_X509(bio, NULL, 0, NULL))) {
BIO_vfree(bio);
return 0;
}
// verify certificate
store = X509_STORE_new();
lookup = X509_STORE_add_lookup(store, X509_LOOKUP_hash_dir());
X509_LOOKUP_add_dir(lookup, (char *)caPath, X509_FILETYPE_PEM);
if ((ctx = X509_STORE_CTX_new()) != 0) {
if (X509_STORE_CTX_init(ctx, store, cert, 0) == 1)
retval = X509_verify_cert(ctx);
X509_STORE_CTX_free(ctx);
}
X509_STORE_free(store);
if (retval != 1) {
fprintf(stderr,"ERROR: Cannot verify certificate ('%s')\n", cFile);
return 0;
}
pubKey = X509_get_pubkey(cert);
if (!pubKey) {
X509_free(cert);
BIO_vfree(bio);
return 0;
}
if (pubKey->type == EVP_PKEY_RSA) {
BN_CTX *c = BN_CTX_new();
if (!c) {
X509_free(cert);
EVP_PKEY_free(pubKey);
BIO_vfree(bio);
return 0;
}
if (!RSA_blinding_on(pubKey->pkey.rsa, c)) {
X509_free(cert);
EVP_PKEY_free(pubKey);
BIO_vfree(bio);
BN_CTX_free(c);
return 0;
}
retval = RSA_verify(NID_md5, md5_md, MD5_DIGEST_LENGTH, sfileMsg, sfsize, pubKey->pkey.rsa);
RSA_blinding_off(pubKey->pkey.rsa);
BN_CTX_free(c);
}
if (pubKey->type == EVP_PKEY_DSA) {
fprintf(stderr, "ERROR: DSA keys are not supported.\n");
return 0;
}
EVP_PKEY_free(pubKey);
X509_free(cert);
BIO_vfree(bio);
return retval;
}
char *check_validity(
const char *certPath, const char *origFile, unsigned char *signature,
char* caPath
) {
MD5_CTX md5CTX;
int rbytes;
unsigned char md5_md[MD5_DIGEST_LENGTH], rbuf[2048];
SSL_load_error_strings();
SSL_library_init();
if (!is_file(origFile)) {
return NULL;
}
FILE* of = boinc_fopen(origFile, "r");
if (!of) return NULL;
MD5_Init(&md5CTX);
while (0 != (rbytes = (int)fread(rbuf, 1, sizeof(rbuf), of))) {
MD5_Update(&md5CTX, rbuf, rbytes);
}
MD5_Final(md5_md, &md5CTX);
fclose(of);
DIRREF dir = dir_open(certPath);
char file[MAXPATHLEN];
while (!dir_scan(file, dir, sizeof(file))) {
char fpath[MAXPATHLEN];
snprintf(fpath, sizeof(fpath), "%s/%s", certPath, file);
// TODO : replace '128'
if (check_validity_of_cert(fpath, md5_md, signature, 128, caPath)) {
dir_close(dir);
return strdup(fpath);
}
}
dir_close(dir);
return NULL;
}
int cert_verify_file(
CERT_SIGS* signatures, const char* origFile, const char* trustLocation
) {
MD5_CTX md5CTX;
int rbytes;
unsigned char md5_md[MD5_DIGEST_LENGTH], rbuf[2048];
char buf[256];
char fbuf[MAXPATHLEN];
int verified = false;
int file_counter = 0;
DATA_BLOCK sig_db;
BIO *bio;
X509 *cert;
X509_NAME *subj;
if (signatures->signatures.size() == 0) {
printf("No signatures available for file ('%s').\n", origFile);
fflush(stdout);
return false;
}
SSL_library_init();
if (!is_file(origFile)) return false;
FILE* of = boinc_fopen(origFile, "r");
if (!of) return false;
MD5_Init(&md5CTX);
while (0 != (rbytes = (int)fread(rbuf, 1, sizeof(rbuf), of))) {
MD5_Update(&md5CTX, rbuf, rbytes);
}
MD5_Final(md5_md, &md5CTX);
fclose(of);
for(unsigned int i=0;i < signatures->signatures.size(); i++) {
sig_db.data = (unsigned char*)calloc(128, sizeof(char));
if (sig_db.data == NULL) {
printf("Cannot allocate 128 bytes for signature buffer\n");
return false;
}
sig_db.len=128;
sscan_hex_data(signatures->signatures.at(i).signature, sig_db);
file_counter = 0;
while (1) {
snprintf(fbuf, MAXPATHLEN, "%s/%s.%d", trustLocation, signatures->signatures.at(i).hash,
file_counter);
#ifndef _USING_FCGI_
FILE *f = fopen(fbuf, "r");
#else
FCGI_FILE *f = FCGI::fopen(fbuf, "r");
#endif
if (f==NULL)
break;
fclose(f);
bio = BIO_new(BIO_s_file());
BIO_read_filename(bio, fbuf);
if (NULL == (cert = PEM_read_bio_X509(bio, NULL, 0, NULL))) {
BIO_vfree(bio);
printf("Cannot read certificate ('%s')\n", fbuf);
file_counter++;
continue;
}
fflush(stdout);
subj = X509_get_subject_name(cert);
X509_NAME_oneline(subj, buf, 256);
// ???
//X509_NAME_free(subj);
X509_free(cert);
BIO_vfree(bio);
if (strcmp(buf, signatures->signatures.at(i).subject)) {
printf("Subject does not match ('%s' <-> '%s')\n", buf, signatures->signatures.at(i).subject);
file_counter++;
continue;
}
verified = check_validity_of_cert(fbuf, md5_md, sig_db.data, 128, trustLocation);
if (verified)
break;
file_counter++;
}
free(sig_db.data);
if (!verified)
return false;
}
return verified;
}