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Update documentation of RSA_padding_check_PKCS1_OAEP_mgf1

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Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/8365)

(cherry picked from commit f0e4a860d0)
This commit is contained in:
Bernd Edlinger 2019-03-03 14:25:52 +01:00
parent 930e031052
commit f1006f188c
1 changed files with 41 additions and 19 deletions
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60
doc/man3/RSA_padding_add_PKCS1_type_1.pod
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@ -5,6 +5,7 @@
RSA_padding_add_PKCS1_type_1, RSA_padding_check_PKCS1_type_1,
RSA_padding_add_PKCS1_type_2, RSA_padding_check_PKCS1_type_2,
RSA_padding_add_PKCS1_OAEP, RSA_padding_check_PKCS1_OAEP,
RSA_padding_add_PKCS1_OAEP_mgf1, RSA_padding_check_PKCS1_OAEP_mgf1,
RSA_padding_add_SSLv23, RSA_padding_check_SSLv23,
RSA_padding_add_none, RSA_padding_check_none - asymmetric encryption
padding
@ -14,35 +15,46 @@ padding
#include <openssl/rsa.h>
int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
unsigned char *f, int fl);
const unsigned char *f, int fl);
int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
unsigned char *f, int fl, int rsa_len);
const unsigned char *f, int fl, int rsa_len);
int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
unsigned char *f, int fl);
const unsigned char *f, int fl);
int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
unsigned char *f, int fl, int rsa_len);
const unsigned char *f, int fl, int rsa_len);
int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
unsigned char *f, int fl, unsigned char *p, int pl);
const unsigned char *f, int fl,
const unsigned char *p, int pl);
int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
unsigned char *f, int fl, int rsa_len,
unsigned char *p, int pl);
const unsigned char *f, int fl, int rsa_len,
const unsigned char *p, int pl);
int RSA_padding_add_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
const unsigned char *f, int fl,
const unsigned char *p, int pl,
const EVP_MD *md, const EVP_MD *mgf1md);
int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen,
const unsigned char *f, int fl, int rsa_len,
const unsigned char *p, int pl,
const EVP_MD *md, const EVP_MD *mgf1md);
int RSA_padding_add_SSLv23(unsigned char *to, int tlen,
unsigned char *f, int fl);
const unsigned char *f, int fl);
int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
unsigned char *f, int fl, int rsa_len);
const unsigned char *f, int fl, int rsa_len);
int RSA_padding_add_none(unsigned char *to, int tlen,
unsigned char *f, int fl);
const unsigned char *f, int fl);
int RSA_padding_check_none(unsigned char *to, int tlen,
unsigned char *f, int fl, int rsa_len);
const unsigned char *f, int fl, int rsa_len);
=head1 DESCRIPTION
@ -98,6 +110,10 @@ at B<to>.
For RSA_padding_xxx_OAEP(), B<p> points to the encoding parameter
of length B<pl>. B<p> may be B<NULL> if B<pl> is 0.
For RSA_padding_xxx_OAEP_mgf1(), B<md> points to the md hash,
if B<md> is B<NULL> that means md=sha1, and B<mgf1md> points to
the mgf1 hash, if B<mgf1md> is B<NULL> that means mgf1md=md.
=head1 RETURN VALUES
The RSA_padding_add_xxx() functions return 1 on success, 0 on error.
@ -107,15 +123,21 @@ L<ERR_get_error(3)>.
=head1 WARNING
The RSA_padding_check_PKCS1_type_2() padding check leaks timing
The result of RSA_padding_check_PKCS1_type_2() is a very sensitive
information which can potentially be used to mount a Bleichenbacher
padding oracle attack. This is an inherent weakness in the PKCS #1
v1.5 padding design. Prefer PKCS1_OAEP padding. Otherwise it can
be recommended to pass zero-padded B<f>, so that B<fl> equals to
B<rsa_len>, and if fixed by protocol, B<tlen> being set to the
expected length. In such case leakage would be minimal, it would
take attacker's ability to observe memory access pattern with byte
granilarity as it occurs, post-factum timing analysis won't do.
v1.5 padding design. Prefer PKCS1_OAEP padding. If that is not
possible, the result of RSA_padding_check_PKCS1_type_2() should be
checked in constant time if it matches the expected length of the
plaintext and additionally some application specific consistency
checks on the plaintext need to be performed in constant time.
If the plaintext is rejected it must be kept secret which of the
checks caused the application to reject the message.
Do not remove the zero-padding from the decrypted raw RSA data
which was computed by RSA_private_decrypt() with B<RSA_NO_PADDING>,
as this would create a small timing side channel which could be
used to mount a Bleichenbacher attack against any padding mode
including PKCS1_OAEP.
=head1 SEE ALSO
@ -125,7 +147,7 @@ L<RSA_sign(3)>, L<RSA_verify(3)>
=head1 COPYRIGHT
Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy