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Add HostSNIRegexp rule matcher for TCP

This commit is contained in:
Romain 2022-03-18 16:04:08 +01:00 committed by GitHub
parent 0d58e8d1ad
commit 2da7fa0397
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 311 additions and 7 deletions

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@ -1,11 +1,13 @@
package tcp
import (
"bytes"
"errors"
"fmt"
"net"
"regexp"
"sort"
"strconv"
"strings"
"github.com/traefik/traefik/v2/pkg/ip"
@ -17,8 +19,9 @@ import (
)
var tcpFuncs = map[string]func(*matchersTree, ...string) error{
"HostSNI": hostSNI,
"ClientIP": clientIP,
"HostSNI": hostSNI,
"HostSNIRegexp": hostSNIRegexp,
"ClientIP": clientIP,
}
// ParseHostSNI extracts the HostSNIs declared in a rule.
@ -326,3 +329,124 @@ func hostSNI(tree *matchersTree, hosts ...string) error {
return nil
}
// hostSNIRegexp checks if the SNI Host of the connection matches the matcher host regexp.
func hostSNIRegexp(tree *matchersTree, templates ...string) error {
if len(templates) == 0 {
return fmt.Errorf("empty value for \"HostSNIRegexp\" matcher is not allowed")
}
var regexps []*regexp.Regexp
for _, template := range templates {
preparedPattern, err := preparePattern(template)
if err != nil {
return fmt.Errorf("invalid pattern value for \"HostSNIRegexp\" matcher, %q is not a valid pattern: %w", template, err)
}
regexp, err := regexp.Compile(preparedPattern)
if err != nil {
return err
}
regexps = append(regexps, regexp)
}
tree.matcher = func(meta ConnData) bool {
for _, regexp := range regexps {
if regexp.MatchString(meta.serverName) {
return true
}
}
return false
}
return nil
}
// TODO: expose more of containous/mux fork to get rid of the following copied code (https://github.com/containous/mux/blob/8ffa4f6d063c/regexp.go).
// preparePattern builds a regexp pattern from the initial user defined expression.
// This function reuses the code dedicated to host matching of the newRouteRegexp func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func preparePattern(template string) (string, error) {
// Check if it is well-formed.
idxs, errBraces := braceIndices(template)
if errBraces != nil {
return "", errBraces
}
defaultPattern := "[^.]+"
pattern := bytes.NewBufferString("")
// Host SNI matching is case-insensitive
fmt.Fprint(pattern, "(?i)")
pattern.WriteByte('^')
var end int
var err error
for i := 0; i < len(idxs); i += 2 {
// Set all values we are interested in.
raw := template[end:idxs[i]]
end = idxs[i+1]
parts := strings.SplitN(template[idxs[i]+1:end-1], ":", 2)
name := parts[0]
patt := defaultPattern
if len(parts) == 2 {
patt = parts[1]
}
// Name or pattern can't be empty.
if name == "" || patt == "" {
return "", fmt.Errorf("mux: missing name or pattern in %q",
template[idxs[i]:end])
}
// Build the regexp pattern.
fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), varGroupName(i/2), patt)
// Append variable name and compiled pattern.
if err != nil {
return "", err
}
}
// Add the remaining.
raw := template[end:]
pattern.WriteString(regexp.QuoteMeta(raw))
pattern.WriteByte('$')
return pattern.String(), nil
}
// varGroupName builds a capturing group name for the indexed variable.
// This function is a copy of varGroupName func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func varGroupName(idx int) string {
return "v" + strconv.Itoa(idx)
}
// braceIndices returns the first level curly brace indices from a string.
// This function is a copy of braceIndices func from the gorilla/mux library.
// https://github.com/containous/mux/tree/8ffa4f6d063c1e2b834a73be6a1515cca3992618.
func braceIndices(s string) ([]int, error) {
var level, idx int
var idxs []int
for i := 0; i < len(s); i++ {
switch s[i] {
case '{':
if level++; level == 1 {
idx = i
}
case '}':
if level--; level == 0 {
idxs = append(idxs, idx, i+1)
} else if level < 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
}
}
if level != 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
return idxs, nil
}