* util/httputil: Benchmark newCompressedResponseWriter
This benchmark illustrates that newCompressedResponseWriter incurs a
prohibitive amount of heap allocations when handling a request containing a
malicious Accept-Encoding header.¬
Signed-off-by: jub0bs <jcretel-infosec+github@protonmail.com>
* util/httputil: Improve newCompressedResponseWriter
This change dramatically reduces the heap allocations (in bytes)
incurred when handling a request containing a malicious Accept-Encoding header.
Below are some benchmark results; for conciseness, I've omitted the name of the
benchmark function (BenchmarkNewCompressionHandler_MaliciousAcceptEncoding):
```
goos: darwin
goarch: amd64
pkg: github.com/prometheus/prometheus/util/httputil
cpu: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
│ old │ new │
│ sec/op │ sec/op vs base │
18.60m ± 2% 13.54m ± 3% -27.17% (p=0.000 n=10)
│ old │ new │
│ B/op │ B/op vs base │
16785442.50 ± 0% 32.00 ± 0% -100.00% (p=0.000 n=10)
│ old │ new │
│ allocs/op │ allocs/op vs base │
2.000 ± 0% 1.000 ± 0% -50.00% (p=0.000 n=10)
```
Signed-off-by: jub0bs <jcretel-infosec+github@protonmail.com>
---------
Signed-off-by: jub0bs <jcretel-infosec+github@protonmail.com>
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