dsa_mod_exp() and bn_mod_exp() handlers from dsa_do_verify() and
dsa_sign_setup(). When another DSA_METHOD implementation does not define
these lower-level handlers, it becomes impossible to do a fallback to
software on errors using a simple DSA_OpenSSL()->fn(key).
This change allows the default DSA_METHOD to function in such circumstances
by only using dsa_mod_exp() and bn_mod_exp() handlers if they exist,
otherwise using BIGNUM implementations directly (which is what those
handlers did before this change). There should be no noticable difference
for the software case, or indeed any custom case that didn't already
segfault, except perhaps that there is now one less level of indirection in
all cases.
PR: 507
Two fixes:
1. If BIO_write() fails inside enc_write() it should return the
total number of bytes successfully written.
2. If BIO_write() fails during BIO_flush() it should return immediately
with the error code: previously it would fall through to the final
encrypt, corrupting the buffer.
when reading from a non blocking BIO.
It would incorrectly interpret retries as EOF, incorrectly
buffer initial data and have no buffering at all after initial
data (data would be sent one byte at a time to EVP_DecodeUpdate).
behaviour was not quite consistent with the conventions
for d2i and i2d functions as far as handling of the 'out'
or 'in' pointer is concerned.
This patch changes this behaviour, and renames the functions to
o2i_ECPublicKey and i2o_ECPublicKey (not 'd2i' and 'i2d' because the
external encoding is just a raw object string without any DER icing).
Submitted by: Nils Larsch
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
