DH_check is used to test the validity of Diffie-Hellman parameter sets (p, q, g). Among the tests performed are primality tests on p and q, for this BN_is_prime_ex is called with the rounds of Miller-Rabin set as default. This will therefore use the average case error estimates derived from the function BN_prime_checks_for_size based on the bit size of the number tested.
However, these bounds are only accurate on testing random input. Within this testing scenario, where we are checking the validity of a DH parameter set, we can not assert that these parameters are randomly generated. Thus we must treat them as if they are adversarial in nature and increase the rounds of Miller-Rabin performed.
Generally, each round of Miller-Rabin can declare a composite number prime with probability at most (1/4), thus 64 rounds is sufficient in thwarting known generation techniques (even in safe prime settings - see https://eprint.iacr.org/2019/032 for full analysis). The choice of 64 rounds is also consistent with SRP_NUMBER_ITERATIONS_FOR_PRIME 64 as used in srp_Verify_N_and_g in openssl/apps/s_client.c.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8593)
EVP_PKEY_public_check() and EVP_PKEY_param_check()
Doc and test cases are added
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4647)
Since return is inconsistent, I removed unnecessary parentheses and
unified them.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4541)
To make it consistent in the code base
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/3749)
When the client reads DH parameters from the TLS stream, we only
checked that they all are non-zero. This change updates the check to
use DH_check_params()
DH_check_params() is a new function for light weight checking of the p
and g parameters:
check that p is odd
check that 1 < g < p - 1
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
As of 37258dadaa and the corresponding upstream
change, BN_mod_word may fail, like BN_div_word. Handle this properly. Thanks to
Brian Smith for pointing this out. See BoringSSL's
44bedc348d9491e63c7ed1438db100a4b8a830be.
Signed-off-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #1251
This function returns a tri-state -1 on error. See BoringSSL's
53409ee3d7595ed37da472bc73b010cd2c8a5ffd.
Signed-off-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #1251
Move the dh_st structure into an internal header file and provide
relevant accessors for the internal fields.
Reviewed-by: Richard Levitte <levitte@openssl.org>
The function DH_check_pub_key() was missing some return value checks in
some calls to BN functions.
RT#4278
Reviewed-by: Andy Polyakov <appro@openssl.org>
Historically OpenSSL only ever generated DH parameters based on "safe"
primes. More recently (in version 1.0.2) support was provided for
generating X9.42 style parameter files such as those required for RFC
5114 support. The primes used in such files may not be "safe". Where an
application is using DH configured with parameters based on primes that
are not "safe" then an attacker could use this fact to find a peer's
private DH exponent. This attack requires that the attacker complete
multiple handshakes in which the peer uses the same DH exponent.
A simple mitigation is to ensure that y^q (mod p) == 1
CVE-2016-0701
Issue reported by Antonio Sanso.
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
This was done by the following
find . -name '*.[ch]' | /tmp/pl
where /tmp/pl is the following three-line script:
print unless $. == 1 && m@/\* .*\.[ch] \*/@;
close ARGV if eof; # Close file to reset $.
And then some hand-editing of other files.
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
There are header files in crypto/ that are used by a number of crypto/
submodules. Move those to crypto/include/internal and adapt the
affected source code and Makefiles.
The header files that got moved are:
crypto/cryptolib.h
crypto/md32_common.h
Reviewed-by: Rich Salz <rsalz@openssl.org>
This gets BN_.*free:
BN_BLINDING_free BN_CTX_free BN_FLG_FREE BN_GENCB_free
BN_MONT_CTX_free BN_RECP_CTX_free BN_clear_free BN_free BUF_MEM_free
Also fix a call to DSA_SIG_free to ccgost engine and remove some #ifdef'd
dead code in engines/e_ubsec.
Reviewed-by: Richard Levitte <levitte@openssl.org>
key-generation and prime-checking functions. Rather than explicitly passing
callback functions and caller-defined context data for the callbacks, a new
structure BN_GENCB is defined that encapsulates this; a pointer to the
structure is passed to all such functions instead.
This wrapper structure allows the encapsulation of "old" and "new" style
callbacks - "new" callbacks return a boolean result on the understanding
that returning FALSE should terminate keygen/primality processing. The
BN_GENCB abstraction will allow future callback modifications without
needing to break binary compatibility nor change the API function
prototypes. The new API functions have been given names ending in "_ex" and
the old functions are implemented as wrappers to the new ones. The
OPENSSL_NO_DEPRECATED symbol has been introduced so that, if defined,
declaration of the older functions will be skipped. NB: Some
openssl-internal code will stick with the older callbacks for now, so
appropriate "#undef" logic will be put in place - this is in case the user
is *building* openssl (rather than *including* its headers) with this
symbol defined.
There is another change in the new _ex functions; the key-generation
functions do not return key structures but operate on structures passed by
the caller, the return value is a boolean. This will allow for a smoother
transition to having key-generation as "virtual function" in the various
***_METHOD tables.
