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>
Similar to
https://boringssl-review.googlesource.com/c/boringssl/+/46405,
SHA256_Final and SHA224_Final hit array size warnings in the new GCC.
The array sizes are, strictly speaking, purely decoration, but this is a
good warning so we should be clean with it on.
That same change is difficult to apply to md32_common.h because
md32_common.h generates the functions for us. md32_common.h is already
strange in that it is multiply-included and changes behavior based on
macros defined by the caller.
Instead, replace it with inline functions, which are a bit more
conventional and typesafe. This allows each hash function to define the
function prototype. Use this to add an unsized helper for SHA-256.
Bug: 402
Change-Id: I61bc30fb58c54dd40a55c9b1ebf3fb9adde5e038
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/47807
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: Peter Foley <pefoley@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
We have loads of variations of these. Align them in one set. This avoids
the HOST_* macros defined by md32_common.h, so it'll be a little easier
to make it a more conventional header.
Change-Id: Id47fe7b51a8f961bd87839f8146d8a5aa8027aa6
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46425
Reviewed-by: Adam Langley <agl@google.com>
Although it is strictly fine to call SHA512_Final in SHA384_Final
(array sizes in C parameters are purely decorational, according to the
language), GCC 11 reportedly checks now and gets upset about the size
mismatch. Use an unsized helper function so all our code matches the
specified bounds.
Unfortunately, the bounds in all the functions are a bit misleading
because SHA512_Final really outputs based on sha->md_len (which Init
function you called) rather than which Final function. I've fixed this
places within a library where we mismatched and added asserts to the
smaller functions. SHA512_Final is assert-less because I've seen lots of
code use SHA384_Init / SHA512_Update / SHA512_Final.
This doesn't fix the SHA256 variant since that is generated by a pile of
macros in a multiply-included file. This is probably a good opportunity
to make that code less macro-heavy.
Update-Note: There is a small chance the asserts will trip something,
but hopefully not since I've left SHA512_Final alone.
Bug: 402
Change-Id: I4c9d579a63ee0a0dea103c19ef219c13bb9aa62c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46405
Reviewed-by: Adam Langley <agl@google.com>
David Benjamin
Adam Langley