The original RT request included a patch. By the time we got around to doing it, however, the callback scheme had changed. So I wrote a new function RSA_check_key_ex() that uses the BN_GENCB callback. But thanks very much to Vinet Sharma <vineet.sharma@gmail.com> for the initial implementation. Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
		
			
				
	
	
		
			78 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			78 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
=pod
 | 
						|
 | 
						|
=head1 NAME
 | 
						|
 | 
						|
RSA_check_key - validate private RSA keys
 | 
						|
 | 
						|
=head1 SYNOPSIS
 | 
						|
 | 
						|
 #include <openssl/rsa.h>
 | 
						|
 | 
						|
 int RSA_check_key_ex(RSA *rsa, BN_GENCB *cb);
 | 
						|
 | 
						|
 int RSA_check_key(RSA *rsa);
 | 
						|
 | 
						|
=head1 DESCRIPTION
 | 
						|
 | 
						|
RSA_check_key_ex() function validates RSA keys.
 | 
						|
It checks that B<p> and B<q> are
 | 
						|
in fact prime, and that B<n = p*q>.
 | 
						|
 | 
						|
It does not work on RSA public keys that have only the modulus
 | 
						|
and public exponent elements populated.
 | 
						|
It also checks that B<d*e = 1 mod (p-1*q-1)>,
 | 
						|
and that B<dmp1>, B<dmq1> and B<iqmp> are set correctly or are B<NULL>.
 | 
						|
It performs integrity checks on all
 | 
						|
the RSA key material, so the RSA key structure must contain all the private
 | 
						|
key data too.
 | 
						|
Therefore, it cannot be used with any arbitrary RSA key object,
 | 
						|
even if it is otherwise fit for regular RSA operation.
 | 
						|
 | 
						|
The B<cb> parameter is a callback that will be invoked in the same
 | 
						|
manner as L<BN_is_prime_ex(3)|BN_is_prime_ex(3)>.
 | 
						|
 | 
						|
RSA_check_key() is equivalent to RSA_check_key_ex() with a NULL B<cb>.
 | 
						|
 | 
						|
=head1 RETURN VALUE
 | 
						|
 | 
						|
RSA_check_key_ex() and RSA_check_key()
 | 
						|
return 1 if B<rsa> is a valid RSA key, and 0 otherwise.
 | 
						|
They return -1 if an error occurs while checking the key.
 | 
						|
 | 
						|
If the key is invalid or an error occurred, the reason code can be
 | 
						|
obtained using L<ERR_get_error(3)|ERR_get_error(3)>.
 | 
						|
 | 
						|
=head1 NOTES
 | 
						|
 | 
						|
Unlike most other RSA functions, this function does B<not> work
 | 
						|
transparently with any underlying ENGINE implementation because it uses the
 | 
						|
key data in the RSA structure directly. An ENGINE implementation can
 | 
						|
override the way key data is stored and handled, and can even provide
 | 
						|
support for HSM keys - in which case the RSA structure may contain B<no>
 | 
						|
key data at all! If the ENGINE in question is only being used for
 | 
						|
acceleration or analysis purposes, then in all likelihood the RSA key data
 | 
						|
is complete and untouched, but this can't be assumed in the general case.
 | 
						|
 | 
						|
=head1 BUGS
 | 
						|
 | 
						|
A method of verifying the RSA key using opaque RSA API functions might need
 | 
						|
to be considered. Right now RSA_check_key() simply uses the RSA structure
 | 
						|
elements directly, bypassing the RSA_METHOD table altogether (and
 | 
						|
completely violating encapsulation and object-orientation in the process).
 | 
						|
The best fix will probably be to introduce a "check_key()" handler to the
 | 
						|
RSA_METHOD function table so that alternative implementations can also
 | 
						|
provide their own verifiers.
 | 
						|
 | 
						|
=head1 SEE ALSO
 | 
						|
 | 
						|
L<BN_is_prime_ex(3)|BN_is_prime_ex(3)>,
 | 
						|
L<rsa(3)|rsa(3)>,
 | 
						|
L<ERR_get_error(3)|ERR_get_error(3)>
 | 
						|
 | 
						|
=head1 HISTORY
 | 
						|
 | 
						|
RSA_check_key() appeared in OpenSSL 0.9.4.
 | 
						|
RSA_check_key_ex() appeared after OpenSSL 1.0.2.
 | 
						|
 | 
						|
=cut
 |