Converting check_autoarg from a macro to a function lost the behavior. Instead,
just move the logic into p_rsa.c which was the only EVP_PKEY implementation
that even needed the flag.
Also document this behavior on each of the functions. Make note of the out =
NULL case only returning the maximum output size, and not necessarily the
actual size.
For testing, update example_sign to determine the signature size using the NULL
behavior rather than querying the RSA key.
Change-Id: Iec6c2862028a5cfdefe8faa0e8c471755070898a
Reviewed-on: https://boringssl-review.googlesource.com/1121
Reviewed-by: Adam Langley <agl@google.com>
This change adds a new function, BN_bn2bin_padded, that attempts, as
much as possible, to serialise a BIGNUM in constant time.
This is used to avoid some timing leaks in RSA decryption.
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
