mirror of
https://github.com/foxcpp/maddy.git
synced 2025-04-04 21:47:40 +03:00
Preliminary milter client implementation
Based on github.com/foxcpp/go-milter fork
This commit is contained in:
fox.cpp
parent
1fca7f62c9
commit
d0e7df023c
5 changed files with 448 additions and 0 deletions
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@ -747,3 +747,48 @@ the message pipeline action.
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Two codes are defined implicitly, exit code 1 causes the message to be rejected
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with a permanent error, exit code 2 causes the message to be quarantined. Both
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action can be overriden using the 'code' directive.
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## Milter protocol check (milter)
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The 'milter' implements subset of Sendmail's milter protocol that can be used
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to integrate external software in maddy.
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Notable limitations of protocol implementation in maddy include:
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1. Changes of envelope sender address are not supported
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2. Removal and addition of envelope recipients is not supported
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3. Removal and replacement of header fields is not supported
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4. Headers fields can be inserted only on top
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5. Milter does not receive some "macros" provided by sendmail.
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Restrictions 1 and 2 are inherent to the maddy checks interface and cannot be
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removed without major changes to it. Restrictions 3, 4 and 5 are temporary due to
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incomplete implementation.
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```
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milter {
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endpoint <endpoint>
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fail_open false
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}
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milter <endpoint>
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```
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## Arguments
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When defined inline, the first argument specifies endpoint to access milter
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via. See below.
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## Configuration directives
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**Syntax:** endpoint _scheme://path_ ++
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**Default:** not set
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Specifies milter protocol endpoint to use.
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The endpoit is specified in standard URL-like format:
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'tcp://127.0.0.1:6669' or 'unix:///var/lib/milter/filter.sock'
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**Syntax:** fail_open _boolean_ ++
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**Default:** false
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Toggles behavior on milter I/O errors. If false ("fail closed") - message is
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rejected with temporary error code. If true ("fail open") - check is skipped.
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3
go.mod
3
go.mod
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@ -14,6 +14,7 @@ require (
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github.com/emersion/go-imap-specialuse v0.0.0-20161227184202-ba031ced6a62
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github.com/emersion/go-imap-unselect v0.0.0-20171113212723-b985794e5f26
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github.com/emersion/go-message v0.11.2
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github.com/emersion/go-milter v0.1.0
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github.com/emersion/go-msgauth v0.4.1-0.20200429175443-e4c87369d72f
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github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b
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github.com/emersion/go-smtp v0.12.2-0.20200219094142-f9be832b5554
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@ -36,3 +37,5 @@ require (
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golang.org/x/text v0.3.2
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gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
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)
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replace github.com/emersion/go-milter => github.com/foxcpp/go-milter v0.1.1-0.20200502214548-312001df0b51
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5
go.sum
5
go.sum
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@ -38,6 +38,8 @@ github.com/emersion/go-message v0.11.1/go.mod h1:C4jnca5HOTo4bGN9YdqNQM9sITuT3Y0
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github.com/emersion/go-message v0.11.2 h1:oxO9SQ+3wgBAQRdk07eqfkCJ26Tl8ZHF7CcpGVoE00o=
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github.com/emersion/go-message v0.11.2/go.mod h1:C4jnca5HOTo4bGN9YdqNQM9sITuT3Y0K6bSUw9RklvY=
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github.com/emersion/go-milter v0.0.0-20190311184326-c3095a41a6fe/go.mod h1:aEaq7U51ARlk+2UeXTtdrDYeYWAUn/QjEwWzs7lD8OU=
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github.com/emersion/go-milter v0.1.0 h1:61u1N/QaHCcQpryDrH5icX2pO1hmU/1g3YID209JKc4=
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github.com/emersion/go-milter v0.1.0/go.mod h1:Ys4s0SSEt4H2jEl3kDbupNQq61wH4ztM9VHZMBfYKqw=
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github.com/emersion/go-msgauth v0.4.0 h1:LM9vNyaecGbhWiwKCAnzql7sVfgL072/QL5ZsIaHSL8=
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github.com/emersion/go-msgauth v0.4.0/go.mod h1:7r9HUSXL1dq+KK7Xqg0JlyBxNFGf5+JouRvSz4wBZCQ=
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github.com/emersion/go-msgauth v0.4.1-0.20200429121350-af2e57960c76 h1:lH/JVE7BLxJweku8z15q/w9N4Fk/GYy8NqJy/dCmOfU=
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@ -60,6 +62,9 @@ github.com/foxcpp/go-imap-i18nlevel v0.0.0-20200208001533-d6ec88553005 h1:pfoFtk
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github.com/foxcpp/go-imap-i18nlevel v0.0.0-20200208001533-d6ec88553005/go.mod h1:34FwxnjC2N+EFs2wMtsHevrZLWRKRuVU8wEcHWKq/nE=
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github.com/foxcpp/go-imap-sql v0.4.1-0.20200426175844-c3172a53940a h1:7IHua8lv9Qouf/TnjzB/8eYtjzws5zcn8Zxvf49ZJOo=
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github.com/foxcpp/go-imap-sql v0.4.1-0.20200426175844-c3172a53940a/go.mod h1:DISGTnTW4OX3qgG8xP5lI+qYRb97b8NvEHV7TSlUy5g=
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github.com/foxcpp/go-milter v0.1.1-0.20200430224718-2b7763a588dc/go.mod h1:ablHK0pbLB83kMFBznp/Rj8aV+Kc3jw8cxzzmCNLIOY=
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github.com/foxcpp/go-milter v0.1.1-0.20200502214548-312001df0b51 h1:njk1z7faETtQRTr+l9kSgXtUoAS6FghmAC7N8SSA3Ac=
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github.com/foxcpp/go-milter v0.1.1-0.20200502214548-312001df0b51/go.mod h1:ablHK0pbLB83kMFBznp/Rj8aV+Kc3jw8cxzzmCNLIOY=
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github.com/foxcpp/go-mockdns v0.0.0-20191216195825-5eabd8dbfe1f h1:b/CFmrdqIGU6eV774xeaQwd1VfgiLuR/8jiY3LyLiMc=
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github.com/foxcpp/go-mockdns v0.0.0-20191216195825-5eabd8dbfe1f/go.mod h1:tPg4cp4nseejPd+UKxtCVQ2hUxNTZ7qQZJa7CLriIeo=
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github.com/foxcpp/go-mockdns v0.0.0-20200218175156-e3faeb733052 h1:a9cMhXBc4p7TUqjHvqUWbhpLmRx+mgpRRPZB7L648GY=
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394
internal/check/milter/milter.go
Normal file
394
internal/check/milter/milter.go
Normal file
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@ -0,0 +1,394 @@
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package milter
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import (
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"context"
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"crypto/tls"
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"errors"
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"fmt"
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"net"
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"github.com/emersion/go-message/textproto"
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"github.com/emersion/go-milter"
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"github.com/foxcpp/maddy/internal/buffer"
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"github.com/foxcpp/maddy/internal/config"
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"github.com/foxcpp/maddy/internal/exterrors"
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"github.com/foxcpp/maddy/internal/log"
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"github.com/foxcpp/maddy/internal/module"
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"github.com/foxcpp/maddy/internal/target"
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)
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const modName = "milter"
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type Check struct {
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cl *milter.Client
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milterUrl string
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failOpen bool
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instName string
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log log.Logger
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}
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func New(_, instName string, _, inlineArgs []string) (module.Module, error) {
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c := &Check{
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instName: instName,
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log: log.Logger{Name: modName, Debug: log.DefaultLogger.Debug},
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}
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switch len(inlineArgs) {
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case 1:
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c.milterUrl = inlineArgs[0]
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case 0:
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default:
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return nil, fmt.Errorf("%s: unexpected amount of arguments, want 1 or 0", modName)
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}
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return c, nil
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}
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func (c *Check) Name() string {
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return modName
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}
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func (c *Check) InstanceName() string {
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return c.instName
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}
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func (c *Check) Init(cfg *config.Map) error {
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cfg.String("endpoint", false, false, c.milterUrl, &c.milterUrl)
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cfg.Bool("fail_open", false, false, &c.failOpen)
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if _, err := cfg.Process(); err != nil {
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return err
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}
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if c.milterUrl == "" {
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return fmt.Errorf("%s: milter endpoint is not set", modName)
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}
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endp, err := config.ParseEndpoint(c.milterUrl)
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if err != nil {
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return fmt.Errorf("%s: %v", modName, err)
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}
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switch endp.Scheme {
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case "tcp", "unix":
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default:
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return fmt.Errorf("%s: scheme unsupported: %v", modName, endp.Scheme)
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}
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if endp.Path != "" {
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return fmt.Errorf("%s: stray path in endpoint: %v", modName, endp)
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}
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c.cl = milter.NewClient(endp.Scheme, endp.Host)
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return nil
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}
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type state struct {
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c *Check
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session *milter.ClientSession
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msgMeta *module.MsgMetadata
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skipChecks bool
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discarded bool
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log log.Logger
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}
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func (c *Check) CheckStateForMsg(msgMeta *module.MsgMetadata) (module.CheckState, error) {
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const supportedActions = milter.OptAddHeader | milter.OptQuarantine
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protocolOpts := milter.OptProtocol(0)
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if msgMeta.Conn == nil {
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protocolOpts = milter.OptNoConnect | milter.OptNoHelo
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}
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session, err := c.cl.Session(supportedActions, protocolOpts)
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if err != nil {
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return nil, err
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}
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return &state{
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c: c,
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session: session,
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msgMeta: msgMeta,
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log: target.DeliveryLogger(c.log, msgMeta),
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}, nil
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}
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func (s *state) handleAction(act *milter.Action) module.CheckResult {
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switch act.Code {
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case milter.ActAccept:
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s.skipChecks = true
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return module.CheckResult{}
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case milter.ActContinue:
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return module.CheckResult{}
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case milter.ActReplyCode:
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return module.CheckResult{
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Reject: true,
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Reason: &exterrors.SMTPError{
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Code: act.SMTPCode,
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EnhancedCode: exterrors.EnhancedCode{5, 7, 1},
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Message: "Message rejected due to local policy",
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Reason: "reply code action",
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CheckName: "milter",
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Misc: map[string]interface{}{
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"milter": s.c.milterUrl,
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},
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},
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}
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case milter.ActDiscard:
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s.log.Msg("silent discard is not supported, rejecting message")
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fallthrough
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case milter.ActReject:
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return module.CheckResult{
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Reject: true,
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Reason: &exterrors.SMTPError{
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Code: 550,
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EnhancedCode: exterrors.EnhancedCode{5, 7, 1},
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Message: "Message rejected due to local policy",
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Reason: "reject action",
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CheckName: "milter",
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Misc: map[string]interface{}{
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"milter": s.c.milterUrl,
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},
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},
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}
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default:
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s.log.Msg("unknown action code ignored", "code", act.Code, "milter", s.c.milterUrl)
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return module.CheckResult{}
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}
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}
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// apply applies the modification actions returned by milter to the check results object.
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func (s *state) apply(modifyActs []milter.ModifyAction, res module.CheckResult) module.CheckResult {
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out := res
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for _, act := range modifyActs {
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switch act.Code {
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case milter.ActAddRcpt, milter.ActDelRcpt:
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s.log.Msg("envelope changes are not supported", "rcpt", act.Rcpt, "code", act.Code, "milter", s.c.milterUrl)
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case milter.ActChangeFrom:
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s.log.Msg("envelope changes are not supported", "from", act.From, "code", act.Code, "milter", s.c.milterUrl)
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case milter.ActChangeHeader:
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s.log.Msg("header field changes are not supported", "field", act.HdrName, "milter", s.c.milterUrl)
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case milter.ActInsertHeader:
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if act.HdrIndex != 1 {
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s.log.Msg("header inserting not on top is not supported, prepending instead", "field", act.HdrName, "milter", s.c.milterUrl)
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}
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fallthrough
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case milter.ActAddHeader:
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// Header field might be arbitarly folded by the caller and we want
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// to preserve that exact format in case it is important (DKIM
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// signature is added by milter).
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field := make([]byte, 0, len(act.HdrName)+2+len(act.HdrValue)+2)
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field = append(field, act.HdrName...)
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field = append(field, ':', ' ')
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field = append(field, act.HdrValue...)
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field = append(field, '\r', '\n')
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out.Header.AddRaw(field)
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case milter.ActQuarantine:
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out.Quarantine = true
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out.Reason = exterrors.WithFields(errors.New("milter quarantine action"), map[string]interface{}{
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"check": "milter",
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"milter": s.c.milterUrl,
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"reason": act.Reason,
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})
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}
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}
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return out
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}
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func (s *state) CheckConnection(ctx context.Context) module.CheckResult {
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if s.msgMeta.Conn == nil {
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return module.CheckResult{}
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}
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if !s.session.ProtocolOption(milter.OptNoConnect) {
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if err := s.session.Macros(milter.CodeConn,
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"daemon_name", "maddy",
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"if_name", "unknown",
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"if_addr", "0.0.0.0",
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// TODO: $j
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// TODO: $_
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); err != nil {
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return s.ioError(err)
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}
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var (
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protoFamily milter.ProtoFamily
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port uint16
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addr string
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)
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switch rAddr := s.msgMeta.Conn.RemoteAddr.(type) {
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case *net.TCPAddr:
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port = uint16(rAddr.Port)
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if v4 := rAddr.IP.To4(); v4 != nil {
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// Make sure to not accidentally send IPv6-mapped IPv4 address.
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protoFamily = milter.FamilyInet
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addr = v4.String()
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} else {
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protoFamily = milter.FamilyInet6
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addr = rAddr.IP.String()
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}
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case *net.UnixAddr:
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protoFamily = milter.FamilyUnix
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addr = rAddr.Name
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default:
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protoFamily = milter.FamilyUnknown
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}
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act, err := s.session.Conn(s.msgMeta.Conn.Hostname, protoFamily, port, addr)
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if err != nil {
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return s.ioError(err)
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}
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if act.Code != milter.ActContinue {
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return s.handleAction(act)
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}
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}
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if !s.session.ProtocolOption(milter.OptNoHelo) {
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if s.msgMeta.Conn.TLS.HandshakeComplete {
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fields := make([]string, 0, 4*2)
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tlsState := s.msgMeta.Conn.TLS
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switch tlsState.Version {
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case tls.VersionTLS10:
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fields = append(fields, "tls_version", "TLSv1")
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case tls.VersionTLS11:
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fields = append(fields, "tls_version", "TLSv1.1")
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case tls.VersionTLS12:
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fields = append(fields, "tls_version", "TLSv1.2")
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case tls.VersionTLS13:
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fields = append(fields, "tls_version", "TLSv1.3")
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}
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fields = append(fields, "cipher", tls.CipherSuiteName(tlsState.CipherSuite))
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if len(tlsState.PeerCertificates) != 0 {
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fields = append(fields, "cert_subject",
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tlsState.PeerCertificates[len(tlsState.PeerCertificates)-1].Subject.String())
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fields = append(fields, "cert_issuer",
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tlsState.PeerCertificates[len(tlsState.PeerCertificates)-1].Issuer.String())
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}
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if err := s.session.Macros(milter.CodeHelo, fields...); err != nil {
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return s.ioError(err)
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}
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}
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act, err := s.session.Helo(s.msgMeta.Conn.Hostname)
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if err != nil {
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return s.ioError(err)
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}
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return s.handleAction(act)
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}
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return module.CheckResult{}
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}
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func (s *state) ioError(err error) module.CheckResult {
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if s.c.failOpen {
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s.skipChecks = true // silently permit processing to continue
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s.c.log.Error("I/O error", err)
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return module.CheckResult{}
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}
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return module.CheckResult{
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Reject: true,
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Reason: &exterrors.SMTPError{
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Code: 451,
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EnhancedCode: exterrors.EnhancedCode{4, 7, 1},
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Message: "I/O error during policy check",
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Err: err,
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CheckName: "milter",
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Misc: map[string]interface{}{
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"milter": s.c.milterUrl,
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},
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},
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}
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}
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func (s *state) CheckSender(ctx context.Context, mailFrom string) module.CheckResult {
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if s.skipChecks || s.session.ProtocolOption(milter.OptNoMailFrom) {
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return module.CheckResult{}
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}
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fields := make([]string, 0, 2)
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fields = append(fields, "i", s.msgMeta.ID)
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// TODO: fields = append(fields, "auth_type", s.msgMeta.???)
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if s.msgMeta.Conn.AuthUser != "" {
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fields = append(fields, "auth_authen", s.msgMeta.Conn.AuthUser)
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}
|
||||
s.session.Macros(milter.CodeMail, fields...)
|
||||
|
||||
esmtpArgs := make([]string, 0, 2)
|
||||
if s.msgMeta.SMTPOpts.UTF8 {
|
||||
esmtpArgs = append(esmtpArgs, "SMTPUTF8")
|
||||
}
|
||||
|
||||
act, err := s.session.Mail(mailFrom, esmtpArgs)
|
||||
if err != nil {
|
||||
return s.ioError(err)
|
||||
}
|
||||
return s.handleAction(act)
|
||||
}
|
||||
|
||||
func (s *state) CheckRcpt(ctx context.Context, rcptTo string) module.CheckResult {
|
||||
if s.skipChecks {
|
||||
return module.CheckResult{}
|
||||
}
|
||||
|
||||
act, err := s.session.Rcpt(rcptTo, nil)
|
||||
if err != nil {
|
||||
return s.ioError(err)
|
||||
}
|
||||
return s.handleAction(act)
|
||||
}
|
||||
|
||||
func (s *state) CheckBody(ctx context.Context, header textproto.Header, body buffer.Buffer) module.CheckResult {
|
||||
if s.skipChecks {
|
||||
return module.CheckResult{}
|
||||
}
|
||||
|
||||
act, err := s.session.Header(header)
|
||||
if err != nil {
|
||||
return s.ioError(err)
|
||||
}
|
||||
if act.Code != milter.ActContinue {
|
||||
return s.handleAction(act)
|
||||
}
|
||||
|
||||
var modifyAct []milter.ModifyAction
|
||||
|
||||
if !s.session.ProtocolOption(milter.OptNoBody) {
|
||||
// body.Open can be expensive for on-disk buffering.
|
||||
r, err := body.Open()
|
||||
if err != nil {
|
||||
// Not ioError(err) because fail_open directive is applied only for external I/O.
|
||||
return module.CheckResult{
|
||||
Reject: true,
|
||||
Reason: &exterrors.SMTPError{
|
||||
Code: 451,
|
||||
EnhancedCode: exterrors.EnhancedCode{4, 7, 1},
|
||||
Message: "Internal error during policy check",
|
||||
Err: err,
|
||||
CheckName: "milter",
|
||||
Misc: map[string]interface{}{
|
||||
"milter": s.c.milterUrl,
|
||||
},
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
modifyAct, act, err = s.session.Body(r)
|
||||
if err != nil {
|
||||
return s.ioError(err)
|
||||
}
|
||||
} else {
|
||||
modifyAct, act, err = s.session.End()
|
||||
if err != nil {
|
||||
return s.ioError(err)
|
||||
}
|
||||
}
|
||||
|
||||
result := s.handleAction(act)
|
||||
return s.apply(modifyAct, result)
|
||||
}
|
||||
|
||||
func (s *state) Close() error {
|
||||
return s.session.Close()
|
||||
}
|
||||
|
||||
func init() {
|
||||
module.Register(modName, New)
|
||||
}
|
||||
1
maddy.go
1
maddy.go
|
|
@ -28,6 +28,7 @@ import (
|
|||
_ "github.com/foxcpp/maddy/internal/check/dkim"
|
||||
_ "github.com/foxcpp/maddy/internal/check/dns"
|
||||
_ "github.com/foxcpp/maddy/internal/check/dnsbl"
|
||||
_ "github.com/foxcpp/maddy/internal/check/milter"
|
||||
_ "github.com/foxcpp/maddy/internal/check/requiretls"
|
||||
_ "github.com/foxcpp/maddy/internal/check/spf"
|
||||
_ "github.com/foxcpp/maddy/internal/endpoint/imap"
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue