Various parts of the RSA documentation were inaccurate and out of date and

this fixes those that I'm currently aware of. In particular, the ENGINE
interference in the RSA API has hopefully been clarified. This still needs
to be done for other areas of the API ...

diff --git a/doc/crypto/RSA_new.pod b/doc/crypto/RSA_new.pod
index f16490ea6a166f2ed108645adbe969fe45e3360c..f0d996c40f5284b5c8659dc6560601af1aa23027 100644 (file)
--- a/doc/crypto/RSA_new.pod
+++ b/doc/crypto/RSA_new.pod
@@ -14,7 +14,8 @@ RSA_new, RSA_free - allocate and free RSA objects
 
 =head1 DESCRIPTION
 
-RSA_new() allocates and initializes an B<RSA> structure.
+RSA_new() allocates and initializes an B<RSA> structure. It is equivalent to
+calling RSA_new_method(NULL).
 
 RSA_free() frees the B<RSA> structure and its components. The key is
 erased before the memory is returned to the system.
@@ -29,7 +30,8 @@ RSA_free() returns no value.
 
 =head1 SEE ALSO
 
-L<err(3)|err(3)>, L<rsa(3)|rsa(3)>, L<RSA_generate_key(3)|RSA_generate_key(3)>
+L<err(3)|err(3)>, L<rsa(3)|rsa(3)>, L<RSA_generate_key(3)|RSA_generate_key(3)>,
+L<RSA_new_method(3)|RSA_new_method(3)>
 
 =head1 HISTORY
 

diff --git a/doc/crypto/RSA_set_method.pod b/doc/crypto/RSA_set_method.pod
index 14917dd35f9149c76e459542125ca1616747f0ba..7b3ebb4643969e7c99d4eecd93d5ee979386cfc7 100644 (file)
--- a/doc/crypto/RSA_set_method.pod
+++ b/doc/crypto/RSA_set_method.pod
@@ -11,52 +11,64 @@ RSA_null_method, RSA_flags, RSA_new_method - select RSA method
  #include <openssl/rsa.h>
  #include <openssl/engine.h>
 
- void RSA_set_default_openssl_method(RSA_METHOD *meth);
+ void RSA_set_default_method(const RSA_METHOD *meth);
 
- RSA_METHOD *RSA_get_default_openssl_method(void);
+ RSA_METHOD *RSA_get_default_method(void);
 
- int RSA_set_method(RSA *rsa, ENGINE *engine);
+ int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
 
- RSA_METHOD *RSA_get_method(RSA *rsa);
+ RSA_METHOD *RSA_get_method(const RSA *rsa);
 
  RSA_METHOD *RSA_PKCS1_SSLeay(void);
 
  RSA_METHOD *RSA_null_method(void);
 
- int RSA_flags(RSA *rsa);
+ int RSA_flags(const RSA *rsa);
 
  RSA *RSA_new_method(ENGINE *engine);
 
 =head1 DESCRIPTION
 
 An B<RSA_METHOD> specifies the functions that OpenSSL uses for RSA
-operations. By modifying the method, alternative implementations
-such as hardware accelerators may be used.
-
-Initially, the default is to use the OpenSSL internal implementation.
-RSA_PKCS1_SSLeay() returns a pointer to that method.
-
-RSA_set_default_openssl_method() makes B<meth> the default method for all B<RSA>
-structures created later. B<NB:> This is true only whilst the default engine
-for RSA operations remains as "openssl". ENGINEs provide an
-encapsulation for implementations of one or more algorithms at a time, and all
-the RSA functions mentioned here operate within the scope of the default
-"openssl" engine.
-
-RSA_get_default_openssl_method() returns a pointer to the current default
-method for the "openssl" engine.
-
-RSA_set_method() selects B<engine> for all operations using the key
-B<rsa>.
-
-RSA_get_method() returns a pointer to the RSA_METHOD from the currently
-selected ENGINE for B<rsa>.
-
-RSA_flags() returns the B<flags> that are set for B<rsa>'s current method.
+operations. By modifying the method, alternative implementations such as
+hardware accelerators may be used. IMPORTANT: See the NOTES section for
+important information about how these RSA API functions are affected by the
+use of B<ENGINE> API calls.
+
+Initially, the default RSA_METHOD is the OpenSSL internal implementation,
+as returned by RSA_PKCS1_SSLeay().
+
+RSA_set_default_method() makes B<meth> the default method for all <RSA>
+structures created later. B<NB>: This is true only whilst no ENGINE has
+been set as a default for RSA, so this function is no longer recommended.
+
+RSA_get_default_method() returns a pointer to the current default
+RSA_METHOD. However, the meaningfulness of this result is dependant on
+whether the ENGINE API is being used, so this function is no longer 
+recommended.
+
+RSA_set_method() selects B<meth> to perform all operations using the key
+B<rsa>. This will replace the RSA_METHOD used by the RSA key and if the
+previous method was supplied by an ENGINE, the handle to that ENGINE will
+be released during the change. It is possible to have RSA keys that only
+work with certain RSA_METHOD implementations (eg. from an ENGINE module
+that supports embedded hardware-protected keys), and in such cases
+attempting to change the RSA_METHOD for the key can have unexpected
+results.
+
+RSA_get_method() returns a pointer to the RSA_METHOD being used by B<rsa>.
+This method may or may not be supplied by an ENGINE implementation, but if
+it is, the return value can only be guaranteed to be valid as long as the
+RSA key itself is valid and does not have its implementation changed by
+RSA_set_method().
+
+RSA_flags() returns the B<flags> that are set for B<rsa>'s current
+RSA_METHOD. See the BUGS section.
 
 RSA_new_method() allocates and initializes an RSA structure so that
-B<engine> will be used for the RSA operations. If B<engine> is NULL,
-the default engine for RSA operations is used.
+B<engine> will be used for the RSA operations. If B<engine> is NULL, the
+default ENGINE for RSA operations is used, and if no default ENGINE is set,
+the RSA_METHOD controlled by RSA_set_default_method() is used.
 
 =head1 THE RSA_METHOD STRUCTURE
 
@@ -121,22 +133,45 @@ the default engine for RSA operations is used.
 
 =head1 RETURN VALUES
 
-RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_openssl_method()
+RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_method()
 and RSA_get_method() return pointers to the respective RSA_METHODs.
 
-RSA_set_default_openssl_method() returns no value.
+RSA_set_default_method() returns no value.
 
-RSA_set_method() selects B<engine> as the engine that will be responsible for
-all operations using the structure B<rsa>. If this function completes successfully,
-then the B<rsa> structure will have its own functional reference of B<engine>, so
-the caller should remember to free their own reference to B<engine> when they are
-finished with it. NB: An ENGINE's RSA_METHOD can be retrieved (or set) by
-ENGINE_get_RSA() or ENGINE_set_RSA().
+RSA_set_method() returns a pointer to the old RSA_METHOD implementation
+that was replaced. However, this return value should probably be ignored
+because if it was supplied by an ENGINE, the pointer could be invalidated
+at any time if the ENGINE is unloaded (in fact it could be unloaded as a
+result of the RSA_set_method() function releasing its handle to the
+ENGINE). For this reason, the return type may be replaced with a B<void>
+declaration in a future release.
 
-RSA_new_method() returns NULL and sets an error code that can be
-obtained by L<ERR_get_error(3)|ERR_get_error(3)> if the allocation fails. Otherwise
+RSA_new_method() returns NULL and sets an error code that can be obtained
+by L<ERR_get_error(3)|ERR_get_error(3)> if the allocation fails. Otherwise
 it returns a pointer to the newly allocated structure.
 
+=head1 NOTES
+
+As of version 0.9.7, RSA_METHOD implementations are grouped together with
+other algorithmic APIs (eg. DSA_METHOD, EVP_CIPHER, etc) into B<ENGINE>
+modules. If a default ENGINE is specified for RSA functionality using an
+ENGINE API function, that will override any RSA defaults set using the RSA
+API (ie.  RSA_set_default_method()). For this reason, the ENGINE API is the
+recommended way to control default implementations for use in RSA and other
+cryptographic algorithms.
+
+=head1 BUGS
+
+The behaviour of RSA_flags() is a mis-feature that is left as-is for now
+to avoid creating compatibility problems. RSA functionality, such as the
+encryption functions, are controlled by the B<flags> value in the RSA key
+itself, not by the B<flags> value in the RSA_METHOD attached to the RSA key
+(which is what this function returns). If the flags element of an RSA key
+is changed, the changes will be honoured by RSA functionality but will not
+be reflected in the return value of the RSA_flags() function - in effect
+RSA_flags() behaves more like an RSA_default_flags() function (which does
+not currently exist).
+
 =head1 SEE ALSO
 
 L<rsa(3)|rsa(3)>, L<RSA_new(3)|RSA_new(3)>
@@ -149,8 +184,14 @@ well as the rsa_sign and rsa_verify components of RSA_METHOD were
 added in OpenSSL 0.9.4.
 
 RSA_set_default_openssl_method() and RSA_get_default_openssl_method()
-replaced RSA_set_default_method() and RSA_get_default_method() respectively,
-and RSA_set_method() and RSA_new_method() were altered to use B<ENGINE>s
-rather than B<RSA_METHOD>s during development of OpenSSL 0.9.6.
+replaced RSA_set_default_method() and RSA_get_default_method()
+respectively, and RSA_set_method() and RSA_new_method() were altered to use
+B<ENGINE>s rather than B<RSA_METHOD>s during development of the engine
+version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the ENGINE
+API was restructured so that this change was reversed, and behaviour of the
+other functions resembled more closely the previous behaviour. The
+behaviour of defaults in the ENGINE API now transparently overrides the
+behaviour of defaults in the RSA API without requiring changing these
+function prototypes.
 
 =cut

diff --git a/doc/crypto/rsa.pod b/doc/crypto/rsa.pod
index 2b93a12b654b7dc1db144dcb8b53ae93bdd70c77..45ac53ffc1472fcbc5fdb14487dc823f7a72b51f 100644 (file)
--- a/doc/crypto/rsa.pod
+++ b/doc/crypto/rsa.pod
@@ -16,13 +16,17 @@ rsa - RSA public key cryptosystem
     unsigned char *to, RSA *rsa, int padding);
  int RSA_private_decrypt(int flen, unsigned char *from,
     unsigned char *to, RSA *rsa, int padding);
+ int RSA_private_encrypt(int flen, unsigned char *from,
+    unsigned char *to, RSA *rsa,int padding);
+ int RSA_public_decrypt(int flen, unsigned char *from, 
+    unsigned char *to, RSA *rsa,int padding);
 
  int RSA_sign(int type, unsigned char *m, unsigned int m_len,
     unsigned char *sigret, unsigned int *siglen, RSA *rsa);
  int RSA_verify(int type, unsigned char *m, unsigned int m_len,
     unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
 
- int RSA_size(RSA *rsa);
+ int RSA_size(const RSA *rsa);
 
  RSA *RSA_generate_key(int num, unsigned long e,
     void (*callback)(int,int,void *), void *cb_arg);
@@ -32,13 +36,13 @@ rsa - RSA public key cryptosystem
  int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
  void RSA_blinding_off(RSA *rsa);
 
- void RSA_set_default_openssl_method(RSA_METHOD *meth);
- RSA_METHOD *RSA_get_default_openssl_method(void);
- int RSA_set_method(RSA *rsa, ENGINE *engine);
- RSA_METHOD *RSA_get_method(RSA *rsa);
+ void RSA_set_default_method(const RSA_METHOD *meth);
+ const RSA_METHOD *RSA_get_default_method(void);
+ int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
+ const RSA_METHOD *RSA_get_method(const RSA *rsa);
  RSA_METHOD *RSA_PKCS1_SSLeay(void);
  RSA_METHOD *RSA_null_method(void);
- int RSA_flags(RSA *rsa);
+ int RSA_flags(const RSA *rsa);
  RSA *RSA_new_method(ENGINE *engine);
 
  int RSA_print(BIO *bp, RSA *x, int offset);
@@ -49,11 +53,6 @@ rsa - RSA public key cryptosystem
  int RSA_set_ex_data(RSA *r,int idx,char *arg);
  char *RSA_get_ex_data(RSA *r, int idx);
 
- int RSA_private_encrypt(int flen, unsigned char *from,
-    unsigned char *to, RSA *rsa,int padding);
- int RSA_public_decrypt(int flen, unsigned char *from, 
-    unsigned char *to, RSA *rsa,int padding);
-
  int RSA_sign_ASN1_OCTET_STRING(int dummy, unsigned char *m,
     unsigned int m_len, unsigned char *sigret, unsigned int *siglen,
     RSA *rsa);
@@ -90,6 +89,14 @@ B<p>, B<q>, B<dmp1>, B<dmq1> and B<iqmp> may be B<NULL> in private
 keys, but the RSA operations are much faster when these values are
 available.
 
+Note that RSA keys may use non-standard B<RSA_METHOD> implementations,
+either directly or by the use of B<ENGINE> modules. In some cases (eg. an
+ENGINE providing support for hardware-embedded keys), these BIGNUM values
+will not be used by the implementation or may be used for alternative data
+storage. For this reason, applications should generally avoid using RSA
+structure elements directly and instead use API functions to query or
+modify keys.
+
 =head1 CONFORMING TO
 
 SSL, PKCS #1 v2.0
@@ -101,7 +108,7 @@ RSA was covered by a US patent which expired in September 2000.
 =head1 SEE ALSO
 
 L<rsa(1)|rsa(1)>, L<bn(3)|bn(3)>, L<dsa(3)|dsa(3)>, L<dh(3)|dh(3)>,
-L<rand(3)|rand(3)>, L<RSA_new(3)|RSA_new(3)>,
+L<rand(3)|rand(3)>, L<engine(3)|engine(3)>, L<RSA_new(3)|RSA_new(3)>,
 L<RSA_public_encrypt(3)|RSA_public_encrypt(3)>,
 L<RSA_sign(3)|RSA_sign(3)>, L<RSA_size(3)|RSA_size(3)>,
 L<RSA_generate_key(3)|RSA_generate_key(3)>,