On aarch64 and x86_64 ABIs, the unused bits of 32-bit parameters have
unspecified value. That means if, say, the aarch64
aes_hw_set_encrypt_key accessed the 'bits' parameter as X1 rather than
W1, it could get a different value from what C passed in. To test this,
our ABI testing framework fills the upper half of the register with
garbage. However, set_encrypt_key just cleanly returns error on
unrecognized bit length. So, to check that this all worked correctly, we
need to assert that the return value was correct.
Looking at the assembly, they all handle it correctly, but now we'll
also test it.
(Note these functions break the usual convention and use zero as the
success value.)
Change-Id: Icaf65ea54564ebfe3696b42287488fe3f72ef138
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/54205
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
We have a ton of per-file rotation functions, often with generic names
that do not tell you whether they are uint32_t vs uint64_t, or rotl vs
rotr.
Additionally, (x >> r) | (x << (32 - r)) is UB at r = 0.
(x >> r) | (x << ((-r) & 31)) works for 0 <= r < 32, which is what
cast.c does. GCC and Clang recognize this pattern as a rotate, but MSVC
doesn't. MSVC does, however, provide functions for this.
We usually rotate by a non-zero constant, which makes this moot, but
rotation comes up often enough that it's worth extracting out. Some
particular changes to call out:
- I've switched sha256.c from rotl to rotr. There was a comment
explaining why it differed from the specification. Now that we have
both functions, it's simpler to just match the specification.
- I've dropped all the inline assembly from sha512.c. Compilers should
be able to recognize rotations in 2021.
Change-Id: Ia1030e8bfe94dad92514ed1c28777447c48b82f9
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/49765
Reviewed-by: Adam Langley <agl@google.com>
David Benjamin
Adam Langley
Adam Langley