Set ReadHeaderTimeout on the HTTP server - #1626
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The &http.Server{} handed to web.ListenAndServe left ReadHeaderTimeout
unset, so request-header reads were unbounded — a Slowloris-style
connection-exhaustion vector (gosec G112). The exporter-toolkit does not
set any server timeouts either.
Set ReadHeaderTimeout to one minute via a small newServer constructor. It
bounds only header reading, not the probe handler, so it never affects
legitimate probe requests (which can run for the full scrape timeout).
Add a regression test that drives a stalled-header client against the
server built by newServer and asserts the connection is closed once the
timeout elapses, while a well-formed request still succeeds.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: randomizedcoder <dave.seddon.ca@gmail.com>
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The *http.Server built by Runner.newServer left ReadHeaderTimeout unset, so request-header reads were unbounded -- a Slowloris-style connection exhaustion vector (gosec G112). The exporter-toolkit web package does not set server timeouts either, so every bootstrap-based exporter inherited the gap. Set ReadHeaderTimeout to one minute. It bounds only header reading, not the metrics handler, so it never affects legitimate scrapes. The value is a package var so tests can shorten it. Follow-up to prometheus/blackbox_exporter#1626, which made the same change on the caller side; setting it here fixes it once for all toolkit users. go build, go vet, and go test ./... pass; gosec G112 clears. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: randomizedcoder dave.seddon.ca@gmail.com <dave.seddon.ca@gmail.com>
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The *http.Server built by Runner.newServer left ReadHeaderTimeout unset, so request-header reads were unbounded -- a Slowloris-style connection exhaustion vector (gosec G112). The exporter-toolkit web package does not set server timeouts either, so every bootstrap-based exporter inherited the gap. Add a ReadHeaderTimeout field to bootstrap.Config, defaulting to one minute when unset. It bounds only header reading, not the metrics handler, so it never affects legitimate scrapes, and -- like every other Config field -- downstream exporters can tune it to their own needs. Follow-up to prometheus/blackbox_exporter#1626, which made the same change on the caller side; setting it here fixes it once for all toolkit users. go build, go vet, and go test ./... (incl. -race) pass; gosec G112 clears. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: randomizedcoder dave.seddon.ca@gmail.com <dave.seddon.ca@gmail.com>
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The *http.Server built by Runner.newServer left ReadHeaderTimeout unset, so request-header reads were unbounded -- a Slowloris-style connection exhaustion vector (gosec G112). The exporter-toolkit web package does not set server timeouts either, so every bootstrap-based exporter inherited the gap. Add a ReadHeaderTimeout field to bootstrap.Config, defaulting to one minute when unset. It bounds only header reading, not the metrics handler, so it never affects legitimate scrapes, and -- like every other Config field -- downstream exporters can tune it to their own needs. Follow-up to prometheus/blackbox_exporter#1626, which made the same change on the caller side; setting it here fixes it once for all toolkit users. go build, go vet, and go test ./... (incl. -race) pass; gosec G112 clears. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: randomizedcoder dave.seddon.ca@gmail.com <dave.seddon.ca@gmail.com>
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The *http.Server built by Runner.newServer left ReadHeaderTimeout unset, so request-header reads were unbounded -- a Slowloris-style connection exhaustion vector (gosec G112). The exporter-toolkit web package does not set server timeouts either, so every bootstrap-based exporter inherited the gap. Add a ReadHeaderTimeout field to bootstrap.Config, defaulting to one minute when unset. It bounds only header reading, not the metrics handler, so it never affects legitimate scrapes, and -- like every other Config field -- downstream exporters can tune it to their own needs. Follow-up to prometheus/blackbox_exporter#1626, which made the same change on the caller side; setting it here fixes it once for all toolkit users. go build, go vet, and go test ./... (incl. -race) pass; gosec G112 clears. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: randomizedcoder dave.seddon.ca@gmail.com <dave.seddon.ca@gmail.com>
randomizedcoder
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The *http.Server built by Runner.newServer left ReadHeaderTimeout unset, so request-header reads were unbounded -- a Slowloris-style connection exhaustion vector (gosec G112). The exporter-toolkit web package does not set server timeouts either, so every bootstrap-based exporter inherited the gap. Add a ReadHeaderTimeout field to bootstrap.Config, defaulting to one minute when unset. It bounds only header reading, not the metrics handler, so it never affects legitimate scrapes, and -- like every other Config field -- downstream exporters can tune it to their own needs. Follow-up to prometheus/blackbox_exporter#1626, which made the same change on the caller side; setting it here fixes it once for all toolkit users. go build, go vet, and go test ./... (incl. -race) pass. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Signed-off-by: randomizedcoder dave.seddon.ca@gmail.com <dave.seddon.ca@gmail.com>
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The
&http.Server{}handed toweb.ListenAndServeleftReadHeaderTimeoutunset, so request-header reads were unbounded — a Slowloris-style connection-exhaustion vector (gosec G112). The exporter-toolkit does not set any server timeouts either.Set
ReadHeaderTimeoutto one minute. It bounds only header reading, not the probe handler, so it never affects legitimate probe requests (which can legitimately run for the full scrape timeout). Happy to adjust the value if a different bound is preferred.go build,go vet,go test ./...pass; gosec G112 clears.🤖 Generated with Claude Code