sneak
a8b24a843b
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script/fmt now runs golines -m 77 after gofmt, repeating golines until it changes nothing, since one pass can leave a line the next splits. script/fmt-check fails when either would change a file. script/bootstrap installs golines v0.13.0 with go install, pinned to its commit, and checks the installed version with go version -m. The tree is reformatted. The longer lines this makes are fixed by hand: nolint directives moved onto their own line above the statement, one string split, and 20 functions over funlen's 80 lines shortened or split, RunWAF and limitPercentages among them. Model: opus-5-5
70 lines
1.8 KiB
Go
70 lines
1.8 KiB
Go
package waf
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// The heuristic header_limits. It reads no setting: its limits are fixed.
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import (
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"context"
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"strings"
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"time"
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"sneak.berlin/go/smallwebwaf/internal/requestlog"
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)
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// The header limits: the most cookies and header fields a request may have.
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// Real clients never reach them.
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const (
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maxCookies = 50
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maxHeaderFields = 100
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)
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// headerLimits refuses a request with more than maxHeaderFields header fields
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// or more than maxCookies cookies, with 431. Its figures are the request's
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// header fields and cookies, and the limit of each.
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type headerLimits struct{}
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func (headerLimits) name() string { return "header_limits" }
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func (headerLimits) check(
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_ context.Context,
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rq *request,
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_ time.Time,
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) *verdict {
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fields, cookies := rq.headerCounts()
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if fields <= maxHeaderFields && cookies <= maxCookies {
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return nil
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}
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return &verdict{
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action: requestlog.ActionRequestHeaderTooLarge,
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figures: map[string]any{
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"fields": fields, "fields_limit": maxHeaderFields,
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"cookies": cookies, "cookies_limit": maxCookies,
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},
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}
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}
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// headerCounts returns the request's header fields, each value of a header sent
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// twice being one, and its cookies, each part of a Cookie header between
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// semicolons being one unless it is empty or only spaces and tabs. The Core
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// Rule Set runs each of its rules on each cookie, so that thousands of small
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// cookies keep it busy for over a second. It trims only spaces and control
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// characters, of which a header value can hold only tabs, so a part of Unicode
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// spaces is a cookie to it.
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func (rq *request) headerCounts() (int, int) {
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fields, cookies := 0, 0
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for _, values := range rq.in.Header {
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fields += len(values)
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}
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for _, value := range rq.in.Header.Values("Cookie") {
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for part := range strings.SplitSeq(value, ";") {
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if strings.Trim(part, " \t") != "" {
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cookies++
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}
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}
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}
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return fields, cookies
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}
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