61 lines
1.7 KiB
Go
61 lines
1.7 KiB
Go
package stupidgcm
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import (
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"runtime"
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"golang.org/x/sys/cpu"
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)
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// PreferOpenSSLAES256GCM tells us if OpenSSL AES-256-GCM is faster than Go stdlib
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// on this machine.
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//
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// Go GCM is only faster if the CPU either:
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//
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// 1. Is X86_64 && has AES instructions && Go is v1.6 or higher
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// 2. Is ARM64 && has AES instructions && Go is v1.11 or higher
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// (commit https://github.com/golang/go/commit/4f1f503373cda7160392be94e3849b0c9b9ebbda)
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//
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// See https://github.com/rfjakob/gocryptfs/wiki/CPU-Benchmarks
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// for benchmarks.
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func PreferOpenSSLAES256GCM() bool {
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if BuiltWithoutOpenssl {
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return false
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}
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// If the CPU has AES acceleration, Go stdlib is faster
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if CpuHasAES() {
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return false
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}
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// Otherwise OpenSSL is probably faster
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return true
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}
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// PreferOpenSSLXchacha20poly1305 returns true if OpenSSL Xchacha20poly1305 is
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// faster than Go stdlib on this machine.
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func PreferOpenSSLXchacha20poly1305() bool {
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if BuiltWithoutOpenssl {
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return false
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}
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// Go x/crypto has optimized assembly for amd64:
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// https://github.com/golang/crypto/blob/master/chacha20poly1305/chacha20poly1305_amd64.s
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if runtime.GOARCH == "amd64" {
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return false
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}
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// On arm64 and arm, OpenSSL is faster. Probably everywhere else too.
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return true
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}
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// CpuHasAES tells you if the CPU we are running has AES acceleration that is
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// usable by the Go crypto library.
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func CpuHasAES() bool {
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// Safe to call on other architectures - will just read false.
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if cpu.X86.HasAES || cpu.ARM64.HasAES {
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return true
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}
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// On the Apple M1, the CPU has AES acceleration, despite cpu.ARM64.HasAES
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// reading false: https://github.com/rfjakob/gocryptfs/issues/556#issuecomment-848079309
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if runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" {
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return true
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}
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return false
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}
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