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Extract openssl RSA functionality into its own file.

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This commit is contained in:
Nick Mathewson 2018-07-19 08:53:40 -04:00
parent e56f0c9d33
commit 752ffa2197
3 changed files with 816 additions and 795 deletions
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795
src/lib/crypt_ops/crypto_rsa.c
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@ -21,33 +21,11 @@
#include "lib/log/util_bug.h" #include "lib/log/util_bug.h"
#include "lib/fs/files.h" #include "lib/fs/files.h"
DISABLE_GCC_WARNING(redundant-decls)
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/engine.h>
#include <openssl/rand.h>
#include <openssl/bn.h>
#include <openssl/dh.h>
#include <openssl/conf.h>
#include <openssl/hmac.h>
ENABLE_GCC_WARNING(redundant-decls)
#include "lib/log/log.h" #include "lib/log/log.h"
#include "lib/encoding/binascii.h" #include "lib/encoding/binascii.h"
#include <string.h> #include <string.h>
/** Declaration for crypto_pk_t structure. */
struct crypto_pk_t
{
int refs; /**< reference count, so we don't have to copy keys */
RSA *key; /**< The key itself */
};
/** Return the number of bytes added by padding method <b>padding</b>. /** Return the number of bytes added by padding method <b>padding</b>.
*/ */
int int
@ -72,442 +50,6 @@ crypto_get_rsa_padding(int padding)
} }
} }
/** used internally: quicly validate a crypto_pk_t object as a private key.
* Return 1 iff the public key is valid, 0 if obviously invalid.
*/
static int
crypto_pk_private_ok(const crypto_pk_t *k)
{
#ifdef OPENSSL_1_1_API
if (!k || !k->key)
return 0;
const BIGNUM *p, *q;
RSA_get0_factors(k->key, &p, &q);
return p != NULL; /* XXX/yawning: Should we check q? */
#else /* !(defined(OPENSSL_1_1_API)) */
return k && k->key && k->key->p;
#endif /* defined(OPENSSL_1_1_API) */
}
/** used by tortls.c: wrap an RSA* in a crypto_pk_t. */
crypto_pk_t *
crypto_new_pk_from_rsa_(RSA *rsa)
{
crypto_pk_t *env;
tor_assert(rsa);
env = tor_malloc(sizeof(crypto_pk_t));
env->refs = 1;
env->key = rsa;
return env;
}
/** Helper, used by tor-gencert.c. Return the RSA from a
* crypto_pk_t. */
RSA *
crypto_pk_get_rsa_(crypto_pk_t *env)
{
return env->key;
}
/** used by tortls.c: get an equivalent EVP_PKEY* for a crypto_pk_t. Iff
* private is set, include the private-key portion of the key. Return a valid
* pointer on success, and NULL on failure. */
MOCK_IMPL(EVP_PKEY *,
crypto_pk_get_evp_pkey_,(crypto_pk_t *env, int private))
{
RSA *key = NULL;
EVP_PKEY *pkey = NULL;
tor_assert(env->key);
if (private) {
if (!(key = RSAPrivateKey_dup(env->key)))
goto error;
} else {
if (!(key = RSAPublicKey_dup(env->key)))
goto error;
}
if (!(pkey = EVP_PKEY_new()))
goto error;
if (!(EVP_PKEY_assign_RSA(pkey, key)))
goto error;
return pkey;
error:
if (pkey)
EVP_PKEY_free(pkey);
if (key)
RSA_free(key);
return NULL;
}
/** Allocate and return storage for a public key. The key itself will not yet
* be set.
*/
MOCK_IMPL(crypto_pk_t *,
crypto_pk_new,(void))
{
RSA *rsa;
rsa = RSA_new();
tor_assert(rsa);
return crypto_new_pk_from_rsa_(rsa);
}
/** Release a reference to an asymmetric key; when all the references
* are released, free the key.
*/
void
crypto_pk_free_(crypto_pk_t *env)
{
if (!env)
return;
if (--env->refs > 0)
return;
tor_assert(env->refs == 0);
if (env->key)
RSA_free(env->key);
tor_free(env);
}
/** Generate a <b>bits</b>-bit new public/private keypair in <b>env</b>.
* Return 0 on success, -1 on failure.
*/
MOCK_IMPL(int,
crypto_pk_generate_key_with_bits,(crypto_pk_t *env, int bits))
{
tor_assert(env);
if (env->key) {
RSA_free(env->key);
env->key = NULL;
}
{
BIGNUM *e = BN_new();
RSA *r = NULL;
if (!e)
goto done;
if (! BN_set_word(e, 65537))
goto done;
r = RSA_new();
if (!r)
goto done;
if (RSA_generate_key_ex(r, bits, e, NULL) == -1)
goto done;
env->key = r;
r = NULL;
done:
if (e)
BN_clear_free(e);
if (r)
RSA_free(r);
}
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "generating RSA key");
return -1;
}
return 0;
}
/** A PEM callback that always reports a failure to get a password */
static int
pem_no_password_cb(char *buf, int size, int rwflag, void *u)
{
(void)buf;
(void)size;
(void)rwflag;
(void)u;
return -1;
}
/** Read a PEM-encoded private key from the <b>len</b>-byte string <b>s</b>
* into <b>env</b>. Return 0 on success, -1 on failure. If len is -1,
* the string is nul-terminated.
*/
int
crypto_pk_read_private_key_from_string(crypto_pk_t *env,
const char *s, ssize_t len)
{
BIO *b;
tor_assert(env);
tor_assert(s);
tor_assert(len < INT_MAX && len < SSIZE_T_CEILING);
/* Create a read-only memory BIO, backed by the string 's' */
b = BIO_new_mem_buf((char*)s, (int)len);
if (!b)
return -1;
if (env->key)
RSA_free(env->key);
env->key = PEM_read_bio_RSAPrivateKey(b,NULL,pem_no_password_cb,NULL);
BIO_free(b);
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "Error parsing private key");
return -1;
}
return 0;
}
/** Read a PEM-encoded private key from the file named by
* <b>keyfile</b> into <b>env</b>. Return 0 on success, -1 on failure.
*/
int
crypto_pk_read_private_key_from_filename(crypto_pk_t *env,
const char *keyfile)
{
char *contents;
int r;
/* Read the file into a string. */
contents = read_file_to_str(keyfile, 0, NULL);
if (!contents) {
log_warn(LD_CRYPTO, "Error reading private key from \"%s\"", keyfile);
return -1;
}
/* Try to parse it. */
r = crypto_pk_read_private_key_from_string(env, contents, -1);
memwipe(contents, 0, strlen(contents));
tor_free(contents);
if (r)
return -1; /* read_private_key_from_string already warned, so we don't.*/
/* Make sure it's valid. */
if (crypto_pk_check_key(env) <= 0)
return -1;
return 0;
}
/** Helper function to implement crypto_pk_write_*_key_to_string. Return 0 on
* success, -1 on failure. */
static int
crypto_pk_write_key_to_string_impl(crypto_pk_t *env, char **dest,
size_t *len, int is_public)
{
BUF_MEM *buf;
BIO *b;
int r;
tor_assert(env);
tor_assert(env->key);
tor_assert(dest);
b = BIO_new(BIO_s_mem()); /* Create a memory BIO */
if (!b)
return -1;
/* Now you can treat b as if it were a file. Just use the
* PEM_*_bio_* functions instead of the non-bio variants.
*/
if (is_public)
r = PEM_write_bio_RSAPublicKey(b, env->key);
else
r = PEM_write_bio_RSAPrivateKey(b, env->key, NULL,NULL,0,NULL,NULL);
if (!r) {
crypto_openssl_log_errors(LOG_WARN, "writing RSA key to string");
BIO_free(b);
return -1;
}
BIO_get_mem_ptr(b, &buf);
*dest = tor_malloc(buf->length+1);
memcpy(*dest, buf->data, buf->length);
(*dest)[buf->length] = 0; /* nul terminate it */
*len = buf->length;
BIO_free(b);
return 0;
}
/** PEM-encode the public key portion of <b>env</b> and write it to a
* newly allocated string. On success, set *<b>dest</b> to the new
* string, *<b>len</b> to the string's length, and return 0. On
* failure, return -1.
*/
int
crypto_pk_write_public_key_to_string(crypto_pk_t *env, char **dest,
size_t *len)
{
return crypto_pk_write_key_to_string_impl(env, dest, len, 1);
}
/** PEM-encode the private key portion of <b>env</b> and write it to a
* newly allocated string. On success, set *<b>dest</b> to the new
* string, *<b>len</b> to the string's length, and return 0. On
* failure, return -1.
*/
int
crypto_pk_write_private_key_to_string(crypto_pk_t *env, char **dest,
size_t *len)
{
return crypto_pk_write_key_to_string_impl(env, dest, len, 0);
}
/** Read a PEM-encoded public key from the first <b>len</b> characters of
* <b>src</b>, and store the result in <b>env</b>. Return 0 on success, -1 on
* failure.
*/
int
crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src,
size_t len)
{
BIO *b;
tor_assert(env);
tor_assert(src);
tor_assert(len<INT_MAX);
b = BIO_new(BIO_s_mem()); /* Create a memory BIO */
if (!b)
return -1;
BIO_write(b, src, (int)len);
if (env->key)
RSA_free(env->key);
env->key = PEM_read_bio_RSAPublicKey(b, NULL, pem_no_password_cb, NULL);
BIO_free(b);
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "reading public key from string");
return -1;
}
return 0;
}
/** Write the private key from <b>env</b> into the file named by <b>fname</b>,
* PEM-encoded. Return 0 on success, -1 on failure.
*/
int
crypto_pk_write_private_key_to_filename(crypto_pk_t *env,
const char *fname)
{
BIO *bio;
char *cp;
long len;
char *s;
int r;
tor_assert(crypto_pk_private_ok(env));
if (!(bio = BIO_new(BIO_s_mem())))
return -1;
if (PEM_write_bio_RSAPrivateKey(bio, env->key, NULL,NULL,0,NULL,NULL)
== 0) {
crypto_openssl_log_errors(LOG_WARN, "writing private key");
BIO_free(bio);
return -1;
}
len = BIO_get_mem_data(bio, &cp);
tor_assert(len >= 0);
s = tor_malloc(len+1);
memcpy(s, cp, len);
s[len]='\0';
r = write_str_to_file(fname, s, 0);
BIO_free(bio);
memwipe(s, 0, strlen(s));
tor_free(s);
return r;
}
/** Return true iff <b>env</b> has a valid key.
*/
int
crypto_pk_check_key(crypto_pk_t *env)
{
int r;
tor_assert(env);
r = RSA_check_key(env->key);
if (r <= 0)
crypto_openssl_log_errors(LOG_WARN,"checking RSA key");
return r;
}
/** Return true iff <b>key</b> contains the private-key portion of the RSA
* key. */
int
crypto_pk_key_is_private(const crypto_pk_t *key)
{
tor_assert(key);
return crypto_pk_private_ok(key);
}
/** Return true iff <b>env</b> contains a public key whose public exponent
* equals 65537.
*/
int
crypto_pk_public_exponent_ok(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
const BIGNUM *e;
#ifdef OPENSSL_1_1_API
const BIGNUM *n, *d;
RSA_get0_key(env->key, &n, &e, &d);
#else
e = env->key->e;
#endif /* defined(OPENSSL_1_1_API) */
return BN_is_word(e, 65537);
}
/** Compare the public-key components of a and b. Return less than 0
* if a\<b, 0 if a==b, and greater than 0 if a\>b. A NULL key is
* considered to be less than all non-NULL keys, and equal to itself.
*
* Note that this may leak information about the keys through timing.
*/
int
crypto_pk_cmp_keys(const crypto_pk_t *a, const crypto_pk_t *b)
{
int result;
char a_is_non_null = (a != NULL) && (a->key != NULL);
char b_is_non_null = (b != NULL) && (b->key != NULL);
char an_argument_is_null = !a_is_non_null | !b_is_non_null;
result = tor_memcmp(&a_is_non_null, &b_is_non_null, sizeof(a_is_non_null));
if (an_argument_is_null)
return result;
const BIGNUM *a_n, *a_e;
const BIGNUM *b_n, *b_e;
#ifdef OPENSSL_1_1_API
const BIGNUM *a_d, *b_d;
RSA_get0_key(a->key, &a_n, &a_e, &a_d);
RSA_get0_key(b->key, &b_n, &b_e, &b_d);
#else
a_n = a->key->n;
a_e = a->key->e;
b_n = b->key->n;
b_e = b->key->e;
#endif /* defined(OPENSSL_1_1_API) */
tor_assert(a_n != NULL && a_e != NULL);
tor_assert(b_n != NULL && b_e != NULL);
result = BN_cmp(a_n, b_n);
if (result)
return result;
return BN_cmp(a_e, b_e);
}
/** Compare the public-key components of a and b. Return non-zero iff /** Compare the public-key components of a and b. Return non-zero iff
* a==b. A NULL key is considered to be distinct from all non-NULL * a==b. A NULL key is considered to be distinct from all non-NULL
* keys, and equal to itself. * keys, and equal to itself.
@ -520,98 +62,6 @@ crypto_pk_eq_keys(const crypto_pk_t *a, const crypto_pk_t *b)
return (crypto_pk_cmp_keys(a, b) == 0); return (crypto_pk_cmp_keys(a, b) == 0);
} }
/** Return the size of the public key modulus in <b>env</b>, in bytes. */
size_t
crypto_pk_keysize(const crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
return (size_t) RSA_size((RSA*)env->key);
}
/** Return the size of the public key modulus of <b>env</b>, in bits. */
int
crypto_pk_num_bits(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
#ifdef OPENSSL_1_1_API
/* It's so stupid that there's no other way to check that n is valid
* before calling RSA_bits().
*/
const BIGNUM *n, *e, *d;
RSA_get0_key(env->key, &n, &e, &d);
tor_assert(n != NULL);
return RSA_bits(env->key);
#else /* !(defined(OPENSSL_1_1_API)) */
tor_assert(env->key->n);
return BN_num_bits(env->key->n);
#endif /* defined(OPENSSL_1_1_API) */
}
/** Increase the reference count of <b>env</b>, and return it.
*/
crypto_pk_t *
crypto_pk_dup_key(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
env->refs++;
return env;
}
#ifdef TOR_UNIT_TESTS
/** For testing: replace dest with src. (Dest must have a refcount
* of 1) */
void
crypto_pk_assign_(crypto_pk_t *dest, const crypto_pk_t *src)
{
tor_assert(dest);
tor_assert(dest->refs == 1);
tor_assert(src);
RSA_free(dest->key);
dest->key = RSAPrivateKey_dup(src->key);
}
#endif /* defined(TOR_UNIT_TESTS) */
/** Make a real honest-to-goodness copy of <b>env</b>, and return it.
* Returns NULL on failure. */
crypto_pk_t *
crypto_pk_copy_full(crypto_pk_t *env)
{
RSA *new_key;
int privatekey = 0;
tor_assert(env);
tor_assert(env->key);
if (crypto_pk_private_ok(env)) {
new_key = RSAPrivateKey_dup(env->key);
privatekey = 1;
} else {
new_key = RSAPublicKey_dup(env->key);
}
if (!new_key) {
/* LCOV_EXCL_START
*
* We can't cause RSA*Key_dup() to fail, so we can't really test this.
*/
log_err(LD_CRYPTO, "Unable to duplicate a %s key: openssl failed.",
privatekey?"private":"public");
crypto_openssl_log_errors(LOG_ERR,
privatekey ? "Duplicating a private key" :
"Duplicating a public key");
tor_fragile_assert();
return NULL;
/* LCOV_EXCL_STOP */
}
return crypto_new_pk_from_rsa_(new_key);
}
/** Perform a hybrid (public/secret) encryption on <b>fromlen</b> /** Perform a hybrid (public/secret) encryption on <b>fromlen</b>
* bytes of data from <b>from</b>, with padding type 'padding', * bytes of data from <b>from</b>, with padding type 'padding',
* storing the results on <b>to</b>. * storing the results on <b>to</b>.
@ -754,179 +204,6 @@ crypto_pk_obsolete_private_hybrid_decrypt(crypto_pk_t *env,
return -1; return -1;
} }
/** Encrypt <b>fromlen</b> bytes from <b>from</b> with the public key
* in <b>env</b>, using the padding method <b>padding</b>. On success,
* write the result to <b>to</b>, and return the number of bytes
* written. On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_public_encrypt(crypto_pk_t *env, char *to, size_t tolen,
const char *from, size_t fromlen, int padding)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen<INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
r = RSA_public_encrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, crypto_get_rsa_padding(padding));
if (r<0) {
crypto_openssl_log_errors(LOG_WARN, "performing RSA encryption");
return -1;
}
return r;
}
/** Decrypt <b>fromlen</b> bytes from <b>from</b> with the private key
* in <b>env</b>, using the padding method <b>padding</b>. On success,
* write the result to <b>to</b>, and return the number of bytes
* written. On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_private_decrypt(crypto_pk_t *env, char *to,
size_t tolen,
const char *from, size_t fromlen,
int padding, int warnOnFailure)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(env->key);
tor_assert(fromlen<INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
if (!crypto_pk_key_is_private(env))
/* Not a private key */
return -1;
r = RSA_private_decrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, crypto_get_rsa_padding(padding));
if (r<0) {
crypto_openssl_log_errors(warnOnFailure?LOG_WARN:LOG_DEBUG,
"performing RSA decryption");
return -1;
}
return r;
}
/** Check the signature in <b>from</b> (<b>fromlen</b> bytes long) with the
* public key in <b>env</b>, using PKCS1 padding. On success, write the
* signed data to <b>to</b>, and return the number of bytes written.
* On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
MOCK_IMPL(int,
crypto_pk_public_checksig,(const crypto_pk_t *env, char *to,
size_t tolen,
const char *from, size_t fromlen))
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen < INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
r = RSA_public_decrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, RSA_PKCS1_PADDING);
if (r<0) {
crypto_openssl_log_errors(LOG_INFO, "checking RSA signature");
return -1;
}
return r;
}
/** Sign <b>fromlen</b> bytes of data from <b>from</b> with the private key in
* <b>env</b>, using PKCS1 padding. On success, write the signature to
* <b>to</b>, and return the number of bytes written. On failure, return
* -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_private_sign(const crypto_pk_t *env, char *to, size_t tolen,
const char *from, size_t fromlen)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen < INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
if (!crypto_pk_key_is_private(env))
/* Not a private key */
return -1;
r = RSA_private_encrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
(RSA*)env->key, RSA_PKCS1_PADDING);
if (r<0) {
crypto_openssl_log_errors(LOG_WARN, "generating RSA signature");
return -1;
}
return r;
}
/** ASN.1-encode the public portion of <b>pk</b> into <b>dest</b>.
* Return -1 on error, or the number of characters used on success.
*/
int
crypto_pk_asn1_encode(const crypto_pk_t *pk, char *dest, size_t dest_len)
{
int len;
unsigned char *buf = NULL;
len = i2d_RSAPublicKey(pk->key, &buf);
if (len < 0 || buf == NULL)
return -1;
if ((size_t)len > dest_len || dest_len > SIZE_T_CEILING) {
OPENSSL_free(buf);
return -1;
}
/* We don't encode directly into 'dest', because that would be illegal
* type-punning. (C99 is smarter than me, C99 is smarter than me...)
*/
memcpy(dest,buf,len);
OPENSSL_free(buf);
return len;
}
/** Decode an ASN.1-encoded public key from <b>str</b>; return the result on
* success and NULL on failure.
*/
crypto_pk_t *
crypto_pk_asn1_decode(const char *str, size_t len)
{
RSA *rsa;
unsigned char *buf;
const unsigned char *cp;
cp = buf = tor_malloc(len);
memcpy(buf,str,len);
rsa = d2i_RSAPublicKey(NULL, &cp, len);
tor_free(buf);
if (!rsa) {
crypto_openssl_log_errors(LOG_WARN,"decoding public key");
return NULL;
}
return crypto_new_pk_from_rsa_(rsa);
}
/** Given a private or public key <b>pk</b>, put a fingerprint of the /** Given a private or public key <b>pk</b>, put a fingerprint of the
* public key into <b>fp_out</b> (must have at least FINGERPRINT_LEN+1 bytes of * public key into <b>fp_out</b> (must have at least FINGERPRINT_LEN+1 bytes of
* space). Return 0 on success, -1 on failure. * space). Return 0 on success, -1 on failure.
@ -1111,75 +388,3 @@ crypto_pk_get_common_digests(crypto_pk_t *pk, common_digests_t *digests_out)
tor_free(buf); tor_free(buf);
return rv; return rv;
} }
/** Given a crypto_pk_t <b>pk</b>, allocate a new buffer containing the
* Base64 encoding of the DER representation of the private key as a NUL
* terminated string, and return it via <b>priv_out</b>. Return 0 on
* success, -1 on failure.
*
* It is the caller's responsibility to sanitize and free the resulting buffer.
*/
int
crypto_pk_base64_encode(const crypto_pk_t *pk, char **priv_out)
{
unsigned char *der = NULL;
int der_len;
int ret = -1;
*priv_out = NULL;
der_len = i2d_RSAPrivateKey(pk->key, &der);
if (der_len < 0 || der == NULL)
return ret;
size_t priv_len = base64_encode_size(der_len, 0) + 1;
char *priv = tor_malloc_zero(priv_len);
if (base64_encode(priv, priv_len, (char *)der, der_len, 0) >= 0) {
*priv_out = priv;
ret = 0;
} else {
tor_free(priv);
}
memwipe(der, 0, der_len);
OPENSSL_free(der);
return ret;
}
/** Given a string containing the Base64 encoded DER representation of the
* private key <b>str</b>, decode and return the result on success, or NULL
* on failure.
*/
crypto_pk_t *
crypto_pk_base64_decode(const char *str, size_t len)
{
crypto_pk_t *pk = NULL;
char *der = tor_malloc_zero(len + 1);
int der_len = base64_decode(der, len, str, len);
if (der_len <= 0) {
log_warn(LD_CRYPTO, "Stored RSA private key seems corrupted (base64).");
goto out;
}
const unsigned char *dp = (unsigned char*)der; /* Shut the compiler up. */
RSA *rsa = d2i_RSAPrivateKey(NULL, &dp, der_len);
if (!rsa) {
crypto_openssl_log_errors(LOG_WARN, "decoding private key");
goto out;
}
pk = crypto_new_pk_from_rsa_(rsa);
/* Make sure it's valid. */
if (crypto_pk_check_key(pk) <= 0) {
crypto_pk_free(pk);
pk = NULL;
goto out;
}
out:
memwipe(der, 0, len + 1);
tor_free(der);
return pk;
}

815
src/lib/crypt_ops/crypto_rsa_openssl.c Normal file
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@ -0,0 +1,815 @@
/* Copyright (c) 2001, Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file crypto_rsa.c
* \brief OpenSSL implementations of our RSA code.
**/
#include "lib/crypt_ops/compat_openssl.h"
#include "lib/crypt_ops/crypto_rsa.h"
#include "lib/crypt_ops/crypto_util.h"
#include "lib/ctime/di_ops.h"
#include "lib/log/util_bug.h"
#include "lib/fs/files.h"
DISABLE_GCC_WARNING(redundant-decls)
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/engine.h>
#include <openssl/rand.h>
#include <openssl/bn.h>
#include <openssl/conf.h>
ENABLE_GCC_WARNING(redundant-decls)
#include "lib/log/log.h"
#include "lib/encoding/binascii.h"
#include <string.h>
/** Declaration for crypto_pk_t structure. */
struct crypto_pk_t
{
int refs; /**< reference count, so we don't have to copy keys */
RSA *key; /**< The key itself */
};
/** used internally: quicly validate a crypto_pk_t object as a private key.
* Return 1 iff the public key is valid, 0 if obviously invalid.
*/
static int
crypto_pk_private_ok(const crypto_pk_t *k)
{
#ifdef OPENSSL_1_1_API
if (!k || !k->key)
return 0;
const BIGNUM *p, *q;
RSA_get0_factors(k->key, &p, &q);
return p != NULL; /* XXX/yawning: Should we check q? */
#else /* !(defined(OPENSSL_1_1_API)) */
return k && k->key && k->key->p;
#endif /* defined(OPENSSL_1_1_API) */
}
/** used by tortls.c: wrap an RSA* in a crypto_pk_t. */
crypto_pk_t *
crypto_new_pk_from_rsa_(RSA *rsa)
{
crypto_pk_t *env;
tor_assert(rsa);
env = tor_malloc(sizeof(crypto_pk_t));
env->refs = 1;
env->key = rsa;
return env;
}
/** Helper, used by tor-gencert.c. Return the RSA from a
* crypto_pk_t. */
RSA *
crypto_pk_get_rsa_(crypto_pk_t *env)
{
return env->key;
}
/** used by tortls.c: get an equivalent EVP_PKEY* for a crypto_pk_t. Iff
* private is set, include the private-key portion of the key. Return a valid
* pointer on success, and NULL on failure. */
MOCK_IMPL(EVP_PKEY *,
crypto_pk_get_evp_pkey_,(crypto_pk_t *env, int private))
{
RSA *key = NULL;
EVP_PKEY *pkey = NULL;
tor_assert(env->key);
if (private) {
if (!(key = RSAPrivateKey_dup(env->key)))
goto error;
} else {
if (!(key = RSAPublicKey_dup(env->key)))
goto error;
}
if (!(pkey = EVP_PKEY_new()))
goto error;
if (!(EVP_PKEY_assign_RSA(pkey, key)))
goto error;
return pkey;
error:
if (pkey)
EVP_PKEY_free(pkey);
if (key)
RSA_free(key);
return NULL;
}
/** Allocate and return storage for a public key. The key itself will not yet
* be set.
*/
MOCK_IMPL(crypto_pk_t *,
crypto_pk_new,(void))
{
RSA *rsa;
rsa = RSA_new();
tor_assert(rsa);
return crypto_new_pk_from_rsa_(rsa);
}
/** Release a reference to an asymmetric key; when all the references
* are released, free the key.
*/
void
crypto_pk_free_(crypto_pk_t *env)
{
if (!env)
return;
if (--env->refs > 0)
return;
tor_assert(env->refs == 0);
if (env->key)
RSA_free(env->key);
tor_free(env);
}
/** Generate a <b>bits</b>-bit new public/private keypair in <b>env</b>.
* Return 0 on success, -1 on failure.
*/
MOCK_IMPL(int,
crypto_pk_generate_key_with_bits,(crypto_pk_t *env, int bits))
{
tor_assert(env);
if (env->key) {
RSA_free(env->key);
env->key = NULL;
}
{
BIGNUM *e = BN_new();
RSA *r = NULL;
if (!e)
goto done;
if (! BN_set_word(e, 65537))
goto done;
r = RSA_new();
if (!r)
goto done;
if (RSA_generate_key_ex(r, bits, e, NULL) == -1)
goto done;
env->key = r;
r = NULL;
done:
if (e)
BN_clear_free(e);
if (r)
RSA_free(r);
}
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "generating RSA key");
return -1;
}
return 0;
}
/** A PEM callback that always reports a failure to get a password */
static int
pem_no_password_cb(char *buf, int size, int rwflag, void *u)
{
(void)buf;
(void)size;
(void)rwflag;
(void)u;
return -1;
}
/** Read a PEM-encoded private key from the <b>len</b>-byte string <b>s</b>
* into <b>env</b>. Return 0 on success, -1 on failure. If len is -1,
* the string is nul-terminated.
*/
int
crypto_pk_read_private_key_from_string(crypto_pk_t *env,
const char *s, ssize_t len)
{
BIO *b;
tor_assert(env);
tor_assert(s);
tor_assert(len < INT_MAX && len < SSIZE_T_CEILING);
/* Create a read-only memory BIO, backed by the string 's' */
b = BIO_new_mem_buf((char*)s, (int)len);
if (!b)
return -1;
if (env->key)
RSA_free(env->key);
env->key = PEM_read_bio_RSAPrivateKey(b,NULL,pem_no_password_cb,NULL);
BIO_free(b);
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "Error parsing private key");
return -1;
}
return 0;
}
/** Read a PEM-encoded private key from the file named by
* <b>keyfile</b> into <b>env</b>. Return 0 on success, -1 on failure.
*/
int
crypto_pk_read_private_key_from_filename(crypto_pk_t *env,
const char *keyfile)
{
char *contents;
int r;
/* Read the file into a string. */
contents = read_file_to_str(keyfile, 0, NULL);
if (!contents) {
log_warn(LD_CRYPTO, "Error reading private key from \"%s\"", keyfile);
return -1;
}
/* Try to parse it. */
r = crypto_pk_read_private_key_from_string(env, contents, -1);
memwipe(contents, 0, strlen(contents));
tor_free(contents);
if (r)
return -1; /* read_private_key_from_string already warned, so we don't.*/
/* Make sure it's valid. */
if (crypto_pk_check_key(env) <= 0)
return -1;
return 0;
}
/** Helper function to implement crypto_pk_write_*_key_to_string. Return 0 on
* success, -1 on failure. */
static int
crypto_pk_write_key_to_string_impl(crypto_pk_t *env, char **dest,
size_t *len, int is_public)
{
BUF_MEM *buf;
BIO *b;
int r;
tor_assert(env);
tor_assert(env->key);
tor_assert(dest);
b = BIO_new(BIO_s_mem()); /* Create a memory BIO */
if (!b)
return -1;
/* Now you can treat b as if it were a file. Just use the
* PEM_*_bio_* functions instead of the non-bio variants.
*/
if (is_public)
r = PEM_write_bio_RSAPublicKey(b, env->key);
else
r = PEM_write_bio_RSAPrivateKey(b, env->key, NULL,NULL,0,NULL,NULL);
if (!r) {
crypto_openssl_log_errors(LOG_WARN, "writing RSA key to string");
BIO_free(b);
return -1;
}
BIO_get_mem_ptr(b, &buf);
*dest = tor_malloc(buf->length+1);
memcpy(*dest, buf->data, buf->length);
(*dest)[buf->length] = 0; /* nul terminate it */
*len = buf->length;
BIO_free(b);
return 0;
}
/** PEM-encode the public key portion of <b>env</b> and write it to a
* newly allocated string. On success, set *<b>dest</b> to the new
* string, *<b>len</b> to the string's length, and return 0. On
* failure, return -1.
*/
int
crypto_pk_write_public_key_to_string(crypto_pk_t *env, char **dest,
size_t *len)
{
return crypto_pk_write_key_to_string_impl(env, dest, len, 1);
}
/** PEM-encode the private key portion of <b>env</b> and write it to a
* newly allocated string. On success, set *<b>dest</b> to the new
* string, *<b>len</b> to the string's length, and return 0. On
* failure, return -1.
*/
int
crypto_pk_write_private_key_to_string(crypto_pk_t *env, char **dest,
size_t *len)
{
return crypto_pk_write_key_to_string_impl(env, dest, len, 0);
}
/** Read a PEM-encoded public key from the first <b>len</b> characters of
* <b>src</b>, and store the result in <b>env</b>. Return 0 on success, -1 on
* failure.
*/
int
crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src,
size_t len)
{
BIO *b;
tor_assert(env);
tor_assert(src);
tor_assert(len<INT_MAX);
b = BIO_new(BIO_s_mem()); /* Create a memory BIO */
if (!b)
return -1;
BIO_write(b, src, (int)len);
if (env->key)
RSA_free(env->key);
env->key = PEM_read_bio_RSAPublicKey(b, NULL, pem_no_password_cb, NULL);
BIO_free(b);
if (!env->key) {
crypto_openssl_log_errors(LOG_WARN, "reading public key from string");
return -1;
}
return 0;
}
/** Write the private key from <b>env</b> into the file named by <b>fname</b>,
* PEM-encoded. Return 0 on success, -1 on failure.
*/
int
crypto_pk_write_private_key_to_filename(crypto_pk_t *env,
const char *fname)
{
BIO *bio;
char *cp;
long len;
char *s;
int r;
tor_assert(crypto_pk_private_ok(env));
if (!(bio = BIO_new(BIO_s_mem())))
return -1;
if (PEM_write_bio_RSAPrivateKey(bio, env->key, NULL,NULL,0,NULL,NULL)
== 0) {
crypto_openssl_log_errors(LOG_WARN, "writing private key");
BIO_free(bio);
return -1;
}
len = BIO_get_mem_data(bio, &cp);
tor_assert(len >= 0);
s = tor_malloc(len+1);
memcpy(s, cp, len);
s[len]='\0';
r = write_str_to_file(fname, s, 0);
BIO_free(bio);
memwipe(s, 0, strlen(s));
tor_free(s);
return r;
}
/** Return true iff <b>env</b> has a valid key.
*/
int
crypto_pk_check_key(crypto_pk_t *env)
{
int r;
tor_assert(env);
r = RSA_check_key(env->key);
if (r <= 0)
crypto_openssl_log_errors(LOG_WARN,"checking RSA key");
return r;
}
/** Return true iff <b>key</b> contains the private-key portion of the RSA
* key. */
int
crypto_pk_key_is_private(const crypto_pk_t *key)
{
tor_assert(key);
return crypto_pk_private_ok(key);
}
/** Return true iff <b>env</b> contains a public key whose public exponent
* equals 65537.
*/
int
crypto_pk_public_exponent_ok(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
const BIGNUM *e;
#ifdef OPENSSL_1_1_API
const BIGNUM *n, *d;
RSA_get0_key(env->key, &n, &e, &d);
#else
e = env->key->e;
#endif /* defined(OPENSSL_1_1_API) */
return BN_is_word(e, 65537);
}
/** Compare the public-key components of a and b. Return less than 0
* if a\<b, 0 if a==b, and greater than 0 if a\>b. A NULL key is
* considered to be less than all non-NULL keys, and equal to itself.
*
* Note that this may leak information about the keys through timing.
*/
int
crypto_pk_cmp_keys(const crypto_pk_t *a, const crypto_pk_t *b)
{
int result;
char a_is_non_null = (a != NULL) && (a->key != NULL);
char b_is_non_null = (b != NULL) && (b->key != NULL);
char an_argument_is_null = !a_is_non_null | !b_is_non_null;
result = tor_memcmp(&a_is_non_null, &b_is_non_null, sizeof(a_is_non_null));
if (an_argument_is_null)
return result;
const BIGNUM *a_n, *a_e;
const BIGNUM *b_n, *b_e;
#ifdef OPENSSL_1_1_API
const BIGNUM *a_d, *b_d;
RSA_get0_key(a->key, &a_n, &a_e, &a_d);
RSA_get0_key(b->key, &b_n, &b_e, &b_d);
#else
a_n = a->key->n;
a_e = a->key->e;
b_n = b->key->n;
b_e = b->key->e;
#endif /* defined(OPENSSL_1_1_API) */
tor_assert(a_n != NULL && a_e != NULL);
tor_assert(b_n != NULL && b_e != NULL);
result = BN_cmp(a_n, b_n);
if (result)
return result;
return BN_cmp(a_e, b_e);
}
/** Return the size of the public key modulus in <b>env</b>, in bytes. */
size_t
crypto_pk_keysize(const crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
return (size_t) RSA_size((RSA*)env->key);
}
/** Return the size of the public key modulus of <b>env</b>, in bits. */
int
crypto_pk_num_bits(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
#ifdef OPENSSL_1_1_API
/* It's so stupid that there's no other way to check that n is valid
* before calling RSA_bits().
*/
const BIGNUM *n, *e, *d;
RSA_get0_key(env->key, &n, &e, &d);
tor_assert(n != NULL);
return RSA_bits(env->key);
#else /* !(defined(OPENSSL_1_1_API)) */
tor_assert(env->key->n);
return BN_num_bits(env->key->n);
#endif /* defined(OPENSSL_1_1_API) */
}
/** Increase the reference count of <b>env</b>, and return it.
*/
crypto_pk_t *
crypto_pk_dup_key(crypto_pk_t *env)
{
tor_assert(env);
tor_assert(env->key);
env->refs++;
return env;
}
#ifdef TOR_UNIT_TESTS
/** For testing: replace dest with src. (Dest must have a refcount
* of 1) */
void
crypto_pk_assign_(crypto_pk_t *dest, const crypto_pk_t *src)
{
tor_assert(dest);
tor_assert(dest->refs == 1);
tor_assert(src);
RSA_free(dest->key);
dest->key = RSAPrivateKey_dup(src->key);
}
#endif /* defined(TOR_UNIT_TESTS) */
/** Make a real honest-to-goodness copy of <b>env</b>, and return it.
* Returns NULL on failure. */
crypto_pk_t *
crypto_pk_copy_full(crypto_pk_t *env)
{
RSA *new_key;
int privatekey = 0;
tor_assert(env);
tor_assert(env->key);
if (crypto_pk_private_ok(env)) {
new_key = RSAPrivateKey_dup(env->key);
privatekey = 1;
} else {
new_key = RSAPublicKey_dup(env->key);
}
if (!new_key) {
/* LCOV_EXCL_START
*
* We can't cause RSA*Key_dup() to fail, so we can't really test this.
*/
log_err(LD_CRYPTO, "Unable to duplicate a %s key: openssl failed.",
privatekey?"private":"public");
crypto_openssl_log_errors(LOG_ERR,
privatekey ? "Duplicating a private key" :
"Duplicating a public key");
tor_fragile_assert();
return NULL;
/* LCOV_EXCL_STOP */
}
return crypto_new_pk_from_rsa_(new_key);
}
/** Encrypt <b>fromlen</b> bytes from <b>from</b> with the public key
* in <b>env</b>, using the padding method <b>padding</b>. On success,
* write the result to <b>to</b>, and return the number of bytes
* written. On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_public_encrypt(crypto_pk_t *env, char *to, size_t tolen,
const char *from, size_t fromlen, int padding)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen<INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
r = RSA_public_encrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, crypto_get_rsa_padding(padding));
if (r<0) {
crypto_openssl_log_errors(LOG_WARN, "performing RSA encryption");
return -1;
}
return r;
}
/** Decrypt <b>fromlen</b> bytes from <b>from</b> with the private key
* in <b>env</b>, using the padding method <b>padding</b>. On success,
* write the result to <b>to</b>, and return the number of bytes
* written. On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_private_decrypt(crypto_pk_t *env, char *to,
size_t tolen,
const char *from, size_t fromlen,
int padding, int warnOnFailure)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(env->key);
tor_assert(fromlen<INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
if (!crypto_pk_key_is_private(env))
/* Not a private key */
return -1;
r = RSA_private_decrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, crypto_get_rsa_padding(padding));
if (r<0) {
crypto_openssl_log_errors(warnOnFailure?LOG_WARN:LOG_DEBUG,
"performing RSA decryption");
return -1;
}
return r;
}
/** Check the signature in <b>from</b> (<b>fromlen</b> bytes long) with the
* public key in <b>env</b>, using PKCS1 padding. On success, write the
* signed data to <b>to</b>, and return the number of bytes written.
* On failure, return -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
MOCK_IMPL(int,
crypto_pk_public_checksig,(const crypto_pk_t *env, char *to,
size_t tolen,
const char *from, size_t fromlen))
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen < INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
r = RSA_public_decrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
env->key, RSA_PKCS1_PADDING);
if (r<0) {
crypto_openssl_log_errors(LOG_INFO, "checking RSA signature");
return -1;
}
return r;
}
/** Sign <b>fromlen</b> bytes of data from <b>from</b> with the private key in
* <b>env</b>, using PKCS1 padding. On success, write the signature to
* <b>to</b>, and return the number of bytes written. On failure, return
* -1.
*
* <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be
* at least the length of the modulus of <b>env</b>.
*/
int
crypto_pk_private_sign(const crypto_pk_t *env, char *to, size_t tolen,
const char *from, size_t fromlen)
{
int r;
tor_assert(env);
tor_assert(from);
tor_assert(to);
tor_assert(fromlen < INT_MAX);
tor_assert(tolen >= crypto_pk_keysize(env));
if (!crypto_pk_key_is_private(env))
/* Not a private key */
return -1;
r = RSA_private_encrypt((int)fromlen,
(unsigned char*)from, (unsigned char*)to,
(RSA*)env->key, RSA_PKCS1_PADDING);
if (r<0) {
crypto_openssl_log_errors(LOG_WARN, "generating RSA signature");
return -1;
}
return r;
}
/** ASN.1-encode the public portion of <b>pk</b> into <b>dest</b>.
* Return -1 on error, or the number of characters used on success.
*/
int
crypto_pk_asn1_encode(const crypto_pk_t *pk, char *dest, size_t dest_len)
{
int len;
unsigned char *buf = NULL;
len = i2d_RSAPublicKey(pk->key, &buf);
if (len < 0 || buf == NULL)
return -1;
if ((size_t)len > dest_len || dest_len > SIZE_T_CEILING) {
OPENSSL_free(buf);
return -1;
}
/* We don't encode directly into 'dest', because that would be illegal
* type-punning. (C99 is smarter than me, C99 is smarter than me...)
*/
memcpy(dest,buf,len);
OPENSSL_free(buf);
return len;
}
/** Decode an ASN.1-encoded public key from <b>str</b>; return the result on
* success and NULL on failure.
*/
crypto_pk_t *
crypto_pk_asn1_decode(const char *str, size_t len)
{
RSA *rsa;
unsigned char *buf;
const unsigned char *cp;
cp = buf = tor_malloc(len);
memcpy(buf,str,len);
rsa = d2i_RSAPublicKey(NULL, &cp, len);
tor_free(buf);
if (!rsa) {
crypto_openssl_log_errors(LOG_WARN,"decoding public key");
return NULL;
}
return crypto_new_pk_from_rsa_(rsa);
}
/** Given a crypto_pk_t <b>pk</b>, allocate a new buffer containing the
* Base64 encoding of the DER representation of the private key as a NUL
* terminated string, and return it via <b>priv_out</b>. Return 0 on
* success, -1 on failure.
*
* It is the caller's responsibility to sanitize and free the resulting buffer.
*/
int
crypto_pk_base64_encode(const crypto_pk_t *pk, char **priv_out)
{
unsigned char *der = NULL;
int der_len;
int ret = -1;
*priv_out = NULL;
der_len = i2d_RSAPrivateKey(pk->key, &der);
if (der_len < 0 || der == NULL)
return ret;
size_t priv_len = base64_encode_size(der_len, 0) + 1;
char *priv = tor_malloc_zero(priv_len);
if (base64_encode(priv, priv_len, (char *)der, der_len, 0) >= 0) {
*priv_out = priv;
ret = 0;
} else {
tor_free(priv);
}
memwipe(der, 0, der_len);
OPENSSL_free(der);
return ret;
}
/** Given a string containing the Base64 encoded DER representation of the
* private key <b>str</b>, decode and return the result on success, or NULL
* on failure.
*/
crypto_pk_t *
crypto_pk_base64_decode(const char *str, size_t len)
{
crypto_pk_t *pk = NULL;
char *der = tor_malloc_zero(len + 1);
int der_len = base64_decode(der, len, str, len);
if (der_len <= 0) {
log_warn(LD_CRYPTO, "Stored RSA private key seems corrupted (base64).");
goto out;
}
const unsigned char *dp = (unsigned char*)der; /* Shut the compiler up. */
RSA *rsa = d2i_RSAPrivateKey(NULL, &dp, der_len);
if (!rsa) {
crypto_openssl_log_errors(LOG_WARN, "decoding private key");
goto out;
}
pk = crypto_new_pk_from_rsa_(rsa);
/* Make sure it's valid. */
if (crypto_pk_check_key(pk) <= 0) {
crypto_pk_free(pk);
pk = NULL;
goto out;
}
out:
memwipe(der, 0, len + 1);
tor_free(der);
return pk;
}

1
src/lib/crypt_ops/include.am
View File

@ -19,6 +19,7 @@ src_lib_libtor_crypt_ops_a_SOURCES = \
src/lib/crypt_ops/crypto_pwbox.c \ src/lib/crypt_ops/crypto_pwbox.c \
src/lib/crypt_ops/crypto_rand.c \ src/lib/crypt_ops/crypto_rand.c \
src/lib/crypt_ops/crypto_rsa.c \ src/lib/crypt_ops/crypto_rsa.c \
src/lib/crypt_ops/crypto_rsa_openssl.c \
src/lib/crypt_ops/crypto_s2k.c \ src/lib/crypt_ops/crypto_s2k.c \
src/lib/crypt_ops/crypto_util.c \ src/lib/crypt_ops/crypto_util.c \
src/lib/crypt_ops/digestset.c src/lib/crypt_ops/digestset.c