x/crypto/poly1305: fix memory alignment fault in ARM
The current ARM implementation assumes that the input message
is memory aligned and so it can cause alignment fault when it
is not enabled. Also it may generate incorrect outputs in ARMv5.
This change fixes this issue by temporarily copying the input
to a local aligned space. Although there may be a better way
to handle unaligned access, this would be a safe way in all
ARM versions.
This change also added a test and benchmarks with unaligned
data. The benchmark result on RasberryPI 2 is
Benchmark64 2000000 812 ns/op 78.81 MB/s
Benchmark1K 200000 7809 ns/op 131.12 MB/s
Benchmark64Unaligned 2000000 967 ns/op 66.13 MB/s
Benchmark1KUnaligned 200000 10316 ns/op 99.26 MB/s
Change-Id: I189cc1b7bb6c67a04c9877271fb27326f2896e82
Reviewed-on: https://go-review.googlesource.com/12797
Reviewed-by: Adam Langley <agl@golang.org>
2 files changed
