timing attacks.
BN_FLG_EXP_CONSTTIME requests this algorithm, and this done by default for
RSA/DSA/DH private key computations unless
RSA_FLAG_NO_EXP_CONSTTIME/DSA_FLAG_NO_EXP_CONSTTIME/
DH_FLAG_NO_EXP_CONSTTIME is set.
Submitted by: Matthew D Wood
Reviewed by: Bodo Moeller
- possibility of re-creation of the blinding parameters after a
fixed number of uses (suggested by Bodo)
- calculatition of the rsa::e in case it's absent and p and q
are present (see bug report #785)
- improve the performance when if one rsa structure is shared by
more than a thread (see bug report #555)
- fix the problem described in bug report #827
- hide the definition ot the BN_BLINDING structure in bn_blind.c
operations no longer require two distinct BN_CTX structures. This may put
more "strain" on the current BN_CTX implementation (which has a fixed limit
to the number of variables it will hold), but so far this limit is not
triggered by any of the tests pass and I will be changing BN_CTX in the
near future to avoid this problem anyway.
This also changes the default RSA implementation code to use the BN_CTX in
favour of initialising some of its variables locally in each function.
Also, I've added handling for other mod_exp calls that were not using any
cached montgomery forms. These cases matter only for special RSA keys (eg.
ones that are missing information) so are unlikely to be used in normal
circumstances.
verification step of CRT private key operations in the RSA code -
previously no montgomery form was checked or used for 'n', and so it would
be generated on the fly each time. As a result, private key operations are
now a percent or two faster.
Rather than adding this as another repetition of the nearly-identical
montgomery "check for first-use" initialisation code blocks, I've taken
this chance to create a helper function and macro-wrapper to replace them.
PR: 475
ENGINE surgery. DH, DSA, RAND, and RSA now use *both* "method" and ENGINE
pointers to manage their hooking with ENGINE. Previously their use of
"method" pointers was replaced by use of ENGINE references. See
crypto/engine/README for details.
Also, remove the ENGINE iterations from evp_test - even when the
cipher/digest code is committed in, this functionality would require a
different set of API calls.
does not contain more bytes than the RSA modulus 'n' - it does not check
that the input is strictly *less* than 'n'. Whether this should be the
case or not is open to debate - however, due to security problems with
returning miscalculated CRT results, the 'rsa_mod_exp' implementation in
rsa_eay.c now performs a public-key exponentiation to verify the CRT result
and in the event of an error will instead recalculate and return a non-CRT
(more expensive) mod_exp calculation. As the mod_exp of 'I' is equivalent
to the mod_exp of 'I mod n', and the verify result is automatically between
0 and n-1 inclusive, the verify only matches the input if 'I' was less than
'n', otherwise even a correct CRT calculation is only congruent to 'I' (ie.
they differ by a multiple of 'n'). Rather than rejecting correct
calculations and doing redundant and slower ones instead, this changes the
equality check in the verification code to a congruence check.
sure they are available in opensslconf.h, by giving them names starting
with "OPENSSL_" to avoid conflicts with other packages and by making
sure e_os2.h will cover all platform-specific cases together with
opensslconf.h.
I've checked fairly well that nothing breaks with this (apart from
external software that will adapt if they have used something like
NO_KRB5), but I can't guarantee it completely, so a review of this
change would be a good thing.
like Malloc, Realloc and especially Free conflict with already existing names
on some operating systems or other packages. That is reason enough to change
the names of the OpenSSL memory allocation macros to something that has a
better chance of being unique, like prepending them with OPENSSL_.
This change includes all the name changes needed throughout all C files.
