mirror of
https://github.com/libssh2/libssh2.git
synced 2025-11-21 14:00:51 +03:00
userauth: derive publickey from private
Pass a NULL pointer for the publickey parameter of libssh2_userauth_publickey_fromfile and libssh2_userauth_hostbased_fromfile functions. In this case, the functions recompute the public key from the private key file data. This is work done by Jean-Louis CHARTON <Jean-Louis.CHARTON@oikialog.com>, then adapted by Mark Smith and slightly edited further by me Daniel. WARNING: this does leave the feature NOT WORKING when libssh2 is built to use libgcrypt instead of OpenSSL simply due to lack of implementation.
This commit is contained in:
Mark Smith
committed by
Daniel Stenberg
Daniel Stenberg
parent
5ee38702a0
commit
5b1a7ec2f1
292
src/openssl.c
292
src/openssl.c
@@ -225,17 +225,17 @@ aes_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
|
||||
return 0;
|
||||
|
||||
switch (ctx->key_len) {
|
||||
case 16:
|
||||
aes_cipher = EVP_aes_128_ecb();
|
||||
break;
|
||||
case 24:
|
||||
aes_cipher = EVP_aes_192_ecb();
|
||||
break;
|
||||
case 32:
|
||||
aes_cipher = EVP_aes_256_ecb();
|
||||
break;
|
||||
default:
|
||||
return 0;
|
||||
case 16:
|
||||
aes_cipher = EVP_aes_128_ecb();
|
||||
break;
|
||||
case 24:
|
||||
aes_cipher = EVP_aes_192_ecb();
|
||||
break;
|
||||
case 32:
|
||||
aes_cipher = EVP_aes_256_ecb();
|
||||
break;
|
||||
default:
|
||||
return 0;
|
||||
}
|
||||
c->aes_ctx = malloc(sizeof(EVP_CIPHER_CTX));
|
||||
if (c->aes_ctx == NULL)
|
||||
@@ -515,4 +515,274 @@ libssh2_md5(const unsigned char *message, unsigned long len,
|
||||
EVP_DigestFinal(&ctx, out, NULL);
|
||||
}
|
||||
|
||||
static unsigned char *
|
||||
write_bn(unsigned char *buf, const BIGNUM *bn, int bn_bytes)
|
||||
{
|
||||
unsigned char *p = buf;
|
||||
|
||||
/* Left space for bn size which will be written below. */
|
||||
p += 4;
|
||||
|
||||
*p = 0;
|
||||
BN_bn2bin(bn, p + 1);
|
||||
if (!(*(p + 1) & 0x80)) {
|
||||
memmove(p, p + 1, --bn_bytes);
|
||||
}
|
||||
_libssh2_htonu32(p - 4, bn_bytes); /* Post write bn size. */
|
||||
|
||||
return p + bn_bytes;
|
||||
}
|
||||
|
||||
static unsigned char *
|
||||
gen_publickey_from_rsa(LIBSSH2_SESSION *session, RSA *rsa,
|
||||
size_t *key_len)
|
||||
{
|
||||
int e_bytes, n_bytes;
|
||||
unsigned long len;
|
||||
unsigned char* key;
|
||||
unsigned char* p;
|
||||
|
||||
e_bytes = BN_num_bytes(rsa->e) + 1;
|
||||
n_bytes = BN_num_bytes(rsa->n) + 1;
|
||||
|
||||
/* Key form is "ssh-rsa" + e + n. */
|
||||
len = 4 + 7 + 4 + e_bytes + 4 + n_bytes;
|
||||
|
||||
key = LIBSSH2_ALLOC(session, len);
|
||||
if (key == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/* Process key encoding. */
|
||||
p = key;
|
||||
|
||||
_libssh2_htonu32(p, 7); /* Key type. */
|
||||
p += 4;
|
||||
memcpy(p, "ssh-rsa", 7);
|
||||
p += 7;
|
||||
|
||||
p = write_bn(p, rsa->e, e_bytes);
|
||||
p = write_bn(p, rsa->n, n_bytes);
|
||||
|
||||
*key_len = (size_t)(p - key);
|
||||
return key;
|
||||
}
|
||||
|
||||
static unsigned char *
|
||||
gen_publickey_from_dsa(LIBSSH2_SESSION* session, DSA *dsa,
|
||||
size_t *key_len)
|
||||
{
|
||||
int p_bytes, q_bytes, g_bytes, k_bytes;
|
||||
unsigned long len;
|
||||
unsigned char* key;
|
||||
unsigned char* p;
|
||||
|
||||
p_bytes = BN_num_bytes(dsa->p) + 1;
|
||||
q_bytes = BN_num_bytes(dsa->q) + 1;
|
||||
g_bytes = BN_num_bytes(dsa->g) + 1;
|
||||
k_bytes = BN_num_bytes(dsa->pub_key) + 1;
|
||||
|
||||
/* Key form is "ssh-dss" + p + q + g + pub_key. */
|
||||
len = 4 + 7 + 4 + p_bytes + 4 + q_bytes + 4 + g_bytes + 4 + k_bytes;
|
||||
|
||||
key = LIBSSH2_ALLOC(session, len);
|
||||
if (key == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/* Process key encoding. */
|
||||
p = key;
|
||||
|
||||
_libssh2_htonu32(p, 7); /* Key type. */
|
||||
p += 4;
|
||||
memcpy(p, "ssh-dss", 7);
|
||||
p += 7;
|
||||
|
||||
p = write_bn(p, dsa->p, p_bytes);
|
||||
p = write_bn(p, dsa->q, q_bytes);
|
||||
p = write_bn(p, dsa->g, g_bytes);
|
||||
p = write_bn(p, dsa->pub_key, k_bytes);
|
||||
|
||||
*key_len = (size_t)(p - key);
|
||||
return key;
|
||||
}
|
||||
|
||||
static int
|
||||
gen_publickey_from_rsa_evp(LIBSSH2_SESSION *session,
|
||||
unsigned char **method,
|
||||
size_t *method_len,
|
||||
unsigned char **pubkeydata,
|
||||
size_t *pubkeydata_len,
|
||||
EVP_PKEY *pk)
|
||||
{
|
||||
RSA* rsa = NULL;
|
||||
unsigned char* key;
|
||||
unsigned char* method_buf = NULL;
|
||||
size_t key_len;
|
||||
|
||||
_libssh2_debug(session,
|
||||
LIBSSH2_TRACE_AUTH,
|
||||
"Computing public key from RSA private key envelop");
|
||||
|
||||
rsa = EVP_PKEY_get1_RSA(pk);
|
||||
if (rsa == NULL) {
|
||||
/* Assume memory allocation error... what else could it be ? */
|
||||
goto __alloc_error;
|
||||
}
|
||||
|
||||
method_buf = LIBSSH2_ALLOC(session, 7); /* ssh-rsa. */
|
||||
if (method_buf == NULL) {
|
||||
goto __alloc_error;
|
||||
}
|
||||
|
||||
key = gen_publickey_from_rsa(session, rsa, &key_len);
|
||||
if (key == NULL) {
|
||||
goto __alloc_error;
|
||||
}
|
||||
RSA_free(rsa);
|
||||
|
||||
memcpy(method_buf, "ssh-rsa", 7);
|
||||
*method = method_buf;
|
||||
*method_len = 7;
|
||||
*pubkeydata = key;
|
||||
*pubkeydata_len = key_len;
|
||||
return 0;
|
||||
|
||||
__alloc_error:
|
||||
if (rsa != NULL) {
|
||||
RSA_free(rsa);
|
||||
}
|
||||
if (method_buf != NULL) {
|
||||
LIBSSH2_FREE(session, method_buf);
|
||||
}
|
||||
|
||||
_libssh2_error(session,
|
||||
LIBSSH2_ERROR_ALLOC,
|
||||
"Unable to allocate memory for private key data");
|
||||
return -1;
|
||||
}
|
||||
|
||||
static int
|
||||
gen_publickey_from_dsa_evp(LIBSSH2_SESSION *session,
|
||||
unsigned char **method,
|
||||
size_t *method_len,
|
||||
unsigned char **pubkeydata,
|
||||
size_t *pubkeydata_len,
|
||||
EVP_PKEY *pk)
|
||||
{
|
||||
DSA* dsa = NULL;
|
||||
unsigned char* key;
|
||||
unsigned char* method_buf = NULL;
|
||||
size_t key_len;
|
||||
|
||||
_libssh2_debug(session,
|
||||
LIBSSH2_TRACE_AUTH,
|
||||
"Computing public key from DSA private key envelop");
|
||||
|
||||
dsa = EVP_PKEY_get1_DSA(pk);
|
||||
if (dsa == NULL) {
|
||||
/* Assume memory allocation error... what else could it be ? */
|
||||
goto __alloc_error;
|
||||
}
|
||||
|
||||
method_buf = LIBSSH2_ALLOC(session, 7); /* ssh-dss. */
|
||||
if (method_buf == NULL) {
|
||||
goto __alloc_error;
|
||||
}
|
||||
|
||||
key = gen_publickey_from_dsa(session, dsa, &key_len);
|
||||
if (key == NULL) {
|
||||
goto __alloc_error;
|
||||
}
|
||||
DSA_free(dsa);
|
||||
|
||||
memcpy(method_buf, "ssh-dss", 7);
|
||||
*method = method_buf;
|
||||
*method_len = 7;
|
||||
*pubkeydata = key;
|
||||
*pubkeydata_len = key_len;
|
||||
return 0;
|
||||
|
||||
__alloc_error:
|
||||
if (dsa != NULL) {
|
||||
DSA_free(dsa);
|
||||
}
|
||||
if (method_buf != NULL) {
|
||||
LIBSSH2_FREE(session, method_buf);
|
||||
}
|
||||
|
||||
_libssh2_error(session,
|
||||
LIBSSH2_ERROR_ALLOC,
|
||||
"Unable to allocate memory for private key data");
|
||||
return -1;
|
||||
}
|
||||
|
||||
int
|
||||
_libssh2_pub_priv_keyfile(LIBSSH2_SESSION *session,
|
||||
unsigned char **method,
|
||||
size_t *method_len,
|
||||
unsigned char **pubkeydata,
|
||||
size_t *pubkeydata_len,
|
||||
const char *privatekey,
|
||||
const char *passphrase)
|
||||
{
|
||||
int st;
|
||||
BIO* bp;
|
||||
EVP_PKEY* pk;
|
||||
|
||||
_libssh2_debug(session,
|
||||
LIBSSH2_TRACE_AUTH,
|
||||
"Computing public key from private key file: %s",
|
||||
privatekey);
|
||||
|
||||
bp = BIO_new_file(privatekey, "r");
|
||||
if (bp == NULL) {
|
||||
_libssh2_error(session,
|
||||
LIBSSH2_ERROR_FILE,
|
||||
"Unable to open private key file");
|
||||
return -1;
|
||||
}
|
||||
if (!EVP_get_cipherbyname("des")) {
|
||||
/* If this cipher isn't loaded it's a pretty good indication that none
|
||||
* are. I have *NO DOUBT* that there's a better way to deal with this
|
||||
* ($#&%#$(%$#( Someone buy me an OpenSSL manual and I'll read up on
|
||||
* it.
|
||||
*/
|
||||
OpenSSL_add_all_ciphers();
|
||||
}
|
||||
BIO_reset(bp);
|
||||
pk = PEM_read_bio_PrivateKey(bp, NULL, NULL, (void*)passphrase);
|
||||
BIO_free(bp);
|
||||
|
||||
if (pk == NULL) {
|
||||
_libssh2_error(session,
|
||||
LIBSSH2_ERROR_FILE,
|
||||
"Wrong passphrase or invalid/unrecognized "
|
||||
"private key file format");
|
||||
return -1;
|
||||
}
|
||||
|
||||
switch (pk->type) {
|
||||
case EVP_PKEY_RSA :
|
||||
st = gen_publickey_from_rsa_evp(
|
||||
session, method, method_len, pubkeydata, pubkeydata_len, pk);
|
||||
break;
|
||||
|
||||
case EVP_PKEY_DSA :
|
||||
st = gen_publickey_from_dsa_evp(
|
||||
session, method, method_len, pubkeydata, pubkeydata_len, pk);
|
||||
break;
|
||||
|
||||
default :
|
||||
st = -1;
|
||||
_libssh2_error(session,
|
||||
LIBSSH2_ERROR_FILE,
|
||||
"Unsupported private key file format");
|
||||
break;
|
||||
}
|
||||
|
||||
EVP_PKEY_free(pk);
|
||||
return st;
|
||||
}
|
||||
|
||||
#endif /* !LIBSSH2_LIBGCRYPT */
|
||||
|
||||
Reference in New Issue
Block a user