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net/http/httputil: fix leaks and data loss in ReverseProxy protocol upgrade - #80924

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net/http/httputil: fix leaks and data loss in ReverseProxy protocol upgrade#80924
wentaoxu-boop wants to merge 1 commit into
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wentaoxu-boop:fix-reverseproxy-upgrade

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@wentaoxu-boop

@wentaoxu-boop wentaoxu-boop commented Aug 17, 2026

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In handleUpgradeResponse:

  • Close res.Body on early validation errors and when hijacking fails to
    prevent leaking backend connections and file descriptors.
  • Strip hop-by-hop headers from backend 101 Switching Protocols
    responses while preserving Connection and Upgrade headers.
  • Read from the Hijacker's bufio.Reader when copying data to the
    backend to avoid losing client data buffered during or immediately
    after the handshake.
  • Increase error channel buffer capacity to 2 to ensure neither copy
    goroutine blocks on channel send when exiting early on error.

Fixes #80875

@wentaoxu-boop
net/http/httputil: fix leaks and data loss in ReverseProxy protocol u…
7fa5d2c 
…pgrade

In handleUpgradeResponse:
- Close res.Body on early validation errors and when hijacking fails to
  prevent leaking backend connections and file descriptors.
- Strip hop-by-hop headers from backend 101 Switching Protocols
  responses while preserving Connection and Upgrade headers.
- Read from the Hijacker's bufio.Reader when copying data to the
  backend to avoid losing client data buffered during or immediately
  after the handshake.
- Increase error channel buffer capacity to 2 to ensure neither copy
  goroutine blocks on channel send when exiting early on error.

Fixes golang#80875
@gopherbot

gopherbot commented Aug 17, 2026

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This PR (HEAD: 7fa5d2c) has been imported to Gerrit for code review.

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gopherbot commented Aug 17, 2026

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Message from Gopher Robot:

Patch Set 1:

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net/http/httputil: ReverseProxy.handleUpgradeResponse has FD leaks on validation failure, data loss from bufio.Reader, and leaks hop-by-hop headers

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