Document RSA accessors/writers

Reviewed-by: Matt Caswell <matt@openssl.org>

2 files changed, 93 insertions, 20 deletions

diff --git a/doc/crypto/RSA_get0_key.pod b/doc/crypto/RSA_get0_key.pod
new file mode 100644
index 0000000000..5caf9dd72e
--- /dev/null
+++ b/doc/crypto/RSA_get0_key.pod
@@ -0,0 +1,86 @@
+=pod
+
+=head1 NAME
+
+RSA_set0_key, RSA_set0_factors, RSA_set0_crt_params, RSA_get0_key,
+RSA_get0_factors, RSA_get0_crt_params, RSA_clear_flags,
+RSA_test_flags, RSA_set_flags, RSA_get0_engine - Routines for getting
+and setting data in an RSA object
+
+=head1 SYNOPSIS
+
+ #include <openssl/rsa.h>
+
+ int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d);
+ int RSA_set0_factors(RSA *r, BIGNUM *p, BIGNUM *q);
+ int RSA_set0_crt_params(RSA *r,BIGNUM *dmp1, BIGNUM *dmq1, BIGNUM *iqmp);
+ void RSA_get0_key(const RSA *r, BIGNUM **n, BIGNUM **e, BIGNUM **d);
+ void RSA_get0_factors(const RSA *r, BIGNUM **p, BIGNUM **q);
+ void RSA_get0_crt_params(const RSA *r,
+                          BIGNUM **dmp1, BIGNUM **dmq1, BIGNUM **iqmp);
+ void RSA_clear_flags(RSA *r, int flags);
+ int RSA_test_flags(const RSA *r, int flags);
+ void RSA_set_flags(RSA *r, int flags);
+ ENGINE *RSA_get0_engine(RSA *r);
+
+=head1 DESCRIPTION
+
+An RSA object contains the components for the public and private key,
+B<n>, B<e>, B<d>, B<p>, B<q>, B<dmp1>, B<dmq1> and B<iqmp>.  B<n> is
+the modulus common to both public and private key, B<e> is the public
+exponent and B<d> is the private exponent.  B<p>, B<q>, B<dmp1>,
+B<dmq1> and B<iqmp> are the factors for the second representation of a
+private key (see PKCS#1 section 3 Key Types), where B<p> and B<q> are
+the first and second factor of B<n> and B<dmp1>, B<dmq1> and B<iqmp>
+are the exponents and coefficient for CRT calculations.
+
+The B<n>, B<e> and B<d> parameters can be obtained by calling
+RSA_get0_key().  If they have not been set yet, then B<*n>, B<*e> and
+B<*d> will be set to NULL.  Otherwise, they are set to pointers to
+their respective values. These point directly to the internal
+representations of the values and therefore should not be freed
+by the caller.
+
+The B<n>, B<e> and B<d> parameter values can be set by calling
+RSA_set0_key() and passing the new values for B<n>, B<e> and B<d> as
+parameters to the function. Calling this function transfers the memory
+management of the values to the RSA object, and therefore the values
+that have been passed in should not be freed by the caller after this
+function has been called.
+
+In a similar fashion, the B<p> and B<q> parameters can be obtained and
+set with RSA_get0_factors() and RSA_set0_factors(), and the B<dmp1>,
+B<dmq1> and B<iqmp> parameters can be obtained and set with
+RSA_get0_crt_params() and RSA_set0_crt_params().
+
+RSA_set_flags() sets the flags in the B<flags> parameter on the RSA
+object. Multiple flags can be passed in one go (bitwise ORed together).
+Any flags that are already set are left set. RSA_test_flags() tests to
+see whether the flags passed in the B<flags> parameter are currently
+set in the RSA object. Multiple flags can be tested in one go. All
+flags that are currently set are returned, or zero if none of the
+flags are set. RSA_clear_flags() clears the specified flags within the
+RSA object.
+
+RSA_get0_engine() returns a handle to the ENGINE that has been set for
+this RSA object, or NULL if no such ENGINE has been set.
+
+=head1 RETURN VALUES
+
+RSA_set0_key(), RSA_set0_factors and RSA_set0_crt_params() return 1 on
+success or 0 on failure.
+
+RSA_test_flags() returns the current state of the flags in the RSA object.
+
+RSA_get0_engine() returns the ENGINE set for the RSA object or NULL if no
+ENGINE has been set.
+
+=head1 SEE ALSO
+
+L<rsa(3)>, L<RSA_new(3)>, L<RSA_size(3)>
+
+=head1 HISTORY
+
+The functions described here were added in OpenSSL version 1.1.0.
+
+=cut
diff --git a/doc/crypto/rsa.pod b/doc/crypto/rsa.pod
index 9c42923abd..a1341b8d7c 100644
--- a/doc/crypto/rsa.pod
+++ b/doc/crypto/rsa.pod
@@ -58,25 +58,12 @@ rsa - RSA public key cryptosystem
 These functions implement RSA public key encryption and signatures
 as defined in PKCS #1 v2.0 [RFC 2437].
 
-The B<RSA> structure consists of several BIGNUM components. It can
-contain public as well as private RSA keys:
-
- struct
-        {
-        BIGNUM *n;		// public modulus
-        BIGNUM *e;		// public exponent
-        BIGNUM *d;		// private exponent
-        BIGNUM *p;		// secret prime factor
-        BIGNUM *q;		// secret prime factor
-        BIGNUM *dmp1;		// d mod (p-1)
-        BIGNUM *dmq1;		// d mod (q-1)
-        BIGNUM *iqmp;		// q^-1 mod p
-	// ...
-        };
- RSA
-
-In public keys, the private exponent and the related secret values are
-B<NULL>.
+The B<RSA> structure consists of the BIGNUM components B<n>, B<e>,
+B<d>, B<p>, B<q>, B<dmp1>, B<dmq1> and B<iqmp>, which represent public
+as well as private RSA keys.
+
+In public keys, the private exponent B<d> and the related secret
+values B<p>, B<q>, B<dmp1>, B<dmq1> and B<iqmp> are B<NULL>.
 
 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
@@ -101,7 +88,7 @@ RSA was covered by a US patent which expired in September 2000.
 =head1 SEE ALSO
 
 L<rsa(1)>, L<bn(3)>, L<dsa(3)>, L<dh(3)>,
-L<rand(3)>, L<engine(3)>, L<RSA_new(3)>,
+L<rand(3)>, L<engine(3)>, L<RSA_new(3)>, L<RSA_set0_key(3)>
 L<RSA_public_encrypt(3)>,
 L<RSA_sign(3)>, L<RSA_size(3)>,
 L<RSA_generate_key(3)>,