121 lines
3.0 KiB
Go
121 lines
3.0 KiB
Go
// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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// PERFORMANCE OF THIS SOFTWARE.
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package security
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import (
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"context"
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"fmt"
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"strings"
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"codeberg.org/miekg/dns"
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"go.probo.inc/probo/pkg/agent"
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)
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type (
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spfParams struct {
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Domain string `json:"domain" jsonschema:"The domain to check SPF record for (e.g. example.com)"`
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}
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spfResult struct {
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Found bool `json:"found"`
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RawRecord string `json:"raw_record,omitempty"`
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Policy string `json:"policy,omitempty"`
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Mechanisms string `json:"mechanisms,omitempty"`
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ErrorDetail string `json:"error_detail,omitempty"`
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}
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)
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func parseSPFPolicy(record string) string {
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for part := range strings.FieldsSeq(strings.ToLower(record)) {
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switch part {
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case "-all":
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return "fail"
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case "~all":
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return "softfail"
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case "?all":
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return "neutral"
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case "+all":
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return "pass"
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}
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}
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return ""
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}
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func CheckSPFTool() agent.Tool {
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return agent.FunctionTool(
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"check_spf",
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"Check the SPF (Sender Policy Framework) DNS record for a domain, returning the raw record and its policy qualifier.",
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func(ctx context.Context, p spfParams) (agent.ToolResult, error) {
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fqdn := p.Domain
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if !strings.HasSuffix(fqdn, ".") {
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fqdn = fqdn + "."
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}
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client := dns.NewClient()
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answers, err := queryDNS(
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ctx,
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client,
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&dns.TXT{
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Hdr: dns.Header{
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Name: fqdn,
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Class: dns.ClassINET,
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},
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},
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)
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if err != nil {
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return agent.ResultJSON(spfResult{
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Found: false,
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ErrorDetail: fmt.Sprintf("cannot lookup SPF record: %s", err),
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}), nil
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}
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var spfRecords []string
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for _, answer := range answers {
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txt, ok := answer.(*dns.TXT)
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if !ok {
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continue
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}
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record := strings.Join(txt.Txt, "")
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if !strings.HasPrefix(strings.ToLower(record), "v=spf1") {
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continue
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}
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spfRecords = append(spfRecords, record)
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}
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if len(spfRecords) > 1 {
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return agent.ResultJSON(spfResult{
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Found: true,
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ErrorDetail: fmt.Sprintf("multiple SPF records found (%d); this is an invalid configuration per RFC 7208", len(spfRecords)),
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}), nil
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}
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if len(spfRecords) == 1 {
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record := spfRecords[0]
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return agent.ResultJSON(spfResult{
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Found: true,
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RawRecord: record,
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Policy: parseSPFPolicy(record),
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Mechanisms: record,
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}), nil
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}
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return agent.ResultJSON(spfResult{Found: false}), nil
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},
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)
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}
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