BN_FLG_CONSTTIME is a ridiculous API and easy to mess up
(CVE-2016-2178). Instead, code that needs a particular algorithm which
preserves secrecy of some arguemnt should call into that algorithm
directly.
This is never set outside the library and is finally unused within the
library! Credit for all this goes almost entirely to Brian Smith. I just
took care of the last bits.
Note there was one BN_FLG_CONSTTIME check that was still reachable, the
BN_mod_inverse in RSA key generation. However, it used the same code in
both cases for even moduli and φ(n) is even if n is not a power of two.
Traditionally, RSA keys are not powers of two, even though it would make
the modular reductions a lot easier.
When reviewing, check that I didn't remove a BN_FLG_CONSTTIME that led
to a BN_mod_exp(_mont) or BN_mod_inverse call (with the exception of the
RSA one mentioned above). They should all go to functions for the
algorithms themselves like BN_mod_exp_mont_consttime.
This CL shows the checks are a no-op for all our tests:
https://boringssl-review.googlesource.com/c/12927/
BUG=125
Change-Id: I19cbb375cc75aac202bd76b51ca098841d84f337
Reviewed-on: https://boringssl-review.googlesource.com/12926
Reviewed-by: Adam Langley <alangley@gmail.com>
Most C standard library functions are undefined if passed NULL, even
when the corresponding length is zero. This gives them (and, in turn,
all functions which call them) surprising behavior on empty arrays.
Some compilers will miscompile code due to this rule. See also
https://www.imperialviolet.org/2016/06/26/nonnull.html
Add OPENSSL_memcpy, etc., wrappers which avoid this problem.
BUG=23
Change-Id: I95f42b23e92945af0e681264fffaf578e7f8465e
Reviewed-on: https://boringssl-review.googlesource.com/12928
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Android currently implements this manually (see NativeBN_putULongInt) by
reaching into BIGNUM's internals. BN_ULONG is a somewhat unfortunate API
anyway as the size is platform-dependent, so add a platform-independent
way to do this.
The other things Android needs are going to need more work, but this
one's easy.
BUG=97
Change-Id: I4af4dc29f9845bdce0f0663c379b4b5d3e1dc46e
Reviewed-on: https://boringssl-review.googlesource.com/11088
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Have |bn_correct_top| fix |bn->neg| if the input is zero so that we
don't have negative zeros lying around.
Thanks to Brian Smith for noticing.
Change-Id: I91bcadebc8e353bb29c81c4367e85853886c8e4e
Reviewed-on: https://boringssl-review.googlesource.com/9074
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
If the values of any of the coordinates in the output point |r| were
negative during nistz256 multiplication, then the calls to
|bn_set_word| would result in the wrong coordinates being returned
(the negatives of the correct coordinates would be returned instead).
Fix that.
Change-Id: I6048e62f76dca18f625650d11ef5a051c9e672a4
Reviewed-on: https://boringssl-review.googlesource.com/7442
Reviewed-by: David Benjamin <davidben@google.com>
If the function returns early due to an error, then the coordinates of the
result will have their |top| value set to a value beyond what has actually
been been written. Fix that, and make it easier to avoid such issues in the
future by refactoring the code.
As a bonus, avoid a false positive MSVC 64-bit opt build "potentially
uninitialized value used" warning.
Change-Id: I8c48deb63163a27f739c8797962414f8ca2588cd
Reviewed-on: https://boringssl-review.googlesource.com/6579
Reviewed-by: David Benjamin <davidben@google.com>
C has implicit conversion of |void *| to other pointer types so these
casts are unnecessary. Clean them up to make the code easier to read
and to make it easier to find dangerous casts.
Change-Id: I26988a672e8ed4d69c75cfbb284413999b475464
Reviewed-on: https://boringssl-review.googlesource.com/7102
Reviewed-by: David Benjamin <davidben@google.com>
Previously, both crypto/dh and crypto/ec defined |TOBN| macros that did
the same thing, but which took their arguments in the opposite order.
This change makes the code consistently use the same macro. It also
makes |STATIC_BIGNUM| available for internal use outside of crypto/bn.
Change-Id: Ide57f6a5b74ea95b3585724c7e1a630c82a864d9
Reviewed-on: https://boringssl-review.googlesource.com/6528
Reviewed-by: Adam Langley <agl@google.com>
BN_bin2bn takes a size_t as it should, but it passes that into bn_wexpand which
takes unsigned. Switch bn_wexpand and bn_expand to take size_t before they
check bounds against INT_MAX.
BIGNUM itself still uses int everywhere and we may want to audit all the
arithmetic at some point. Although I suspect having bn_expand require that the
number of bits fit in an int is sufficient to make everything happy, unless
we're doing interesting arithmetic on the number of bits somewhere.
Change-Id: Id191a4a095adb7c938cde6f5a28bee56644720c6
Reviewed-on: https://boringssl-review.googlesource.com/5680
Reviewed-by: Adam Langley <agl@google.com>
First batch of the alphabet.
Change-Id: If4e60f4fbb69e04eb4b70aa1b2240e329251bfa5
Reviewed-on: https://boringssl-review.googlesource.com/4514
Reviewed-by: Adam Langley <agl@google.com>
Including string.h in base.h causes any file that includes a BoringSSL
header to include string.h. Generally this wouldn't be a problem,
although string.h might slow down the compile if it wasn't otherwise
needed. However, it also causes problems for ipsec-tools in Android
because OpenSSL didn't have this behaviour.
This change removes string.h from base.h and, instead, adds it to each
.c file that requires it.
Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37
Reviewed-on: https://boringssl-review.googlesource.com/3200
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
