net/mail: parseAddressList doesn't allow commas with empty email address #36959

timmydo · 2020-02-01T06:58:03Z

What version of Go are you using (`go version`)?

$ go version
go version go1.13.5 linux/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (`go env`)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/timmy/.cache/go-build"
GOENV="/home/timmy/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/timmy/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build645469531=/tmp/go-build -gno-record-gcc-switches"

What did you do?

net/mail/message.go parseAddressList doesn't allow commas with empty email address. I use an email client that uses this library and it fails to parse some emails.

Here is an example from a mailing list:

Cc: , emacs-devel@gnu.org

What did you expect to see?

I think parseAddressList should filter out empty entries.

RFC 5322 has a section about this. I think it would be nice if empty spaces between commas were passed over.

4.4.  Obsolete Addressing

   There are four primary differences in addressing.  First, mailbox
   addresses were allowed to have a route portion before the addr-spec
   when enclosed in "<" and ">".  The route is simply a comma-separated
   list of domain names, each preceded by "@", and the list terminated
   by a colon.  Second, CFWS were allowed between the period-separated
   elements of local-part and domain (i.e., dot-atom was not used).  In
   addition, local-part is allowed to contain quoted-string in addition
   to just atom.  Third, mailbox-list and address-list were allowed to
   have "null" members.  That is, there could be two or more commas in
   such a list with nothing in between them, or commas at the beginning
   or end of the list.  Finally, US-ASCII control characters and quoted-
   pairs were allowed in domain literals and are added here.

   obs-angle-addr  =   [CFWS] "<" obs-route addr-spec ">" [CFWS]

   obs-route       =   obs-domain-list ":"

   obs-domain-list =   *(CFWS / ",") "@" domain
                       *("," [CFWS] ["@" domain])

   obs-mbox-list   =   *([CFWS] ",") mailbox *("," [mailbox / CFWS])

   obs-addr-list   =   *([CFWS] ",") address *("," [address / CFWS])

What did you see instead?

--- FAIL: TestAddressParsing (0.00s)
message_test.go:527: Failed parsing (single) " , joe@where.test": mail: no angle-addr

The text was updated successfully, but these errors were encountered:

timmydo · 2020-02-01T06:59:31Z

--- /usr/local/go/src/net/mail/message.go	2019-12-04 14:53:53.000000000 -0800
+++ message.go	2020-01-31 22:42:03.184647817 -0800
@@ -251,6 +251,16 @@
 	var list []*Address
 	for {
 		p.skipSpace()
+
+		// obs-addr-list: allow skipping over empty entries
+		if p.consume(',') {
+			p.skipSpace();
+		}
+
+		if p.empty() {
+			break
+		}
+		
 		addrs, err := p.parseAddress(true)
 		if err != nil {
 			return nil, err


--- /usr/local/go/src/net/mail/message_test.go	2019-12-04 14:53:53.000000000 -0800
+++ message_test.go	2020-01-31 22:40:55.724863690 -0800
@@ -281,6 +281,19 @@
 			},
 		},
 		{
+			` , joe@where.test,,John <jdoe@one.test>,`,
+			[]*Address{
+				{
+					Name:    "",
+					Address: "joe@where.test",
+				},
+				{
+					Name:    "John",
+					Address: "jdoe@one.test",
+				},
+			},
+		},
+		{
 			`Group1: <addr1@example.com>;, Group 2: addr2@example.com;, John <addr3@example.com>`,
 			[]*Address{
 				{

mvdan · 2020-02-01T13:53:55Z

@timmydo I think this is reasonable. Want to send the patch above as a CL? See https://tip.golang.org/doc/contribute.html; I'd be happy to review.

RFC 5322 has a section 4.4 where it says that address-list could have "null" members: "That is, there could be two or more commas in such a list with nothing in between them, or commas at the beginning or end of the list." This change handles such a case so that mail clients using this method on actual email messages get a reasonable return value when they parse email. Fixes golang#36959

timmydo · 2020-02-01T18:29:04Z

Thanks @mvdan . I created one

gopherbot · 2020-02-01T18:29:22Z

Change https://golang.org/cl/217377 mentions this issue: net/mail: skip empty entries in parseAddressList

RFC 5322 has a section 4.4 where it says that address-list could have "null" members: "That is, there could be two or more commas in such a list with nothing in between them, or commas at the beginning or end of the list." This change handles such a case so that mail clients using this method on actual email messages get a reasonable return value when they parse email. Fixes golang#36959

gofish · 2020-08-12T20:42:47Z

@mvdan This change appears to have had the side-effect of returning the empty slice and a nil error when the address list is empty. Previously, mail.ParseAddressList("") would return the error "mail: no address". Was this change intentional?

go/src/net/mail/message.go

Line 330 in 30e3bf2

return nil, errors.New("mail: no address")

https://play.golang.org/p/R2VdisTd4Wz

If this change in behavior was not intended, a fix might be as simple as

		if p.empty() && len(list) > 0 {
			break
		}

gopherbot · 2020-08-14T20:31:10Z

Change https://golang.org/cl/248598 mentions this issue: net/mail: return error on empty address list

This restores the handling accidentally changed in CL 217377. Fixes #40803 For #36959 Change-Id: If77fbc0c2a1dde4799f760affdfb8dde9bcaf458 Reviewed-on: https://go-review.googlesource.com/c/go/+/248598 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Jeremy Fishman <jfishman@cloudflare.com>

gopherbot · 2020-08-27T23:26:47Z

Change https://golang.org/cl/251167 mentions this issue: [release-branch.go1.15] net/mail: return error on empty address list

This restores the handling accidentally changed in CL 217377. Fixes #40804 For #40803 For #36959 Change-Id: If77fbc0c2a1dde4799f760affdfb8dde9bcaf458 Reviewed-on: https://go-review.googlesource.com/c/go/+/248598 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Jeremy Fishman <jfishman@cloudflare.com> (cherry picked from commit 3e636ab) Reviewed-on: https://go-review.googlesource.com/c/go/+/251167

mvdan changed the title ~~net/mail/message.go parseAddressList doesn't allow commas with empty email address~~ net/mail: parseAddressList doesn't allow commas with empty email address Feb 1, 2020

timmydo mentioned this issue Feb 1, 2020

net/mail: skip empty entries in parseAddressList #36966

Closed

odeke-em added this to the Go1.15 milestone Feb 5, 2020

odeke-em assigned timmydo and mvdan Feb 5, 2020

gopherbot closed this as completed in 30e3bf2 Feb 21, 2020

ianlancetaylor mentioned this issue Aug 14, 2020

net/mail: change in behavior of ParseAddressList("") in 1.15 #40803

Closed

ddvk mentioned this issue Nov 9, 2020

Sending emails fails due to trailing ", " ddvk/rmfakecloud#18

Closed

golang locked and limited conversation to collaborators Aug 27, 2021

gopherbot added the FrozenDueToAge label Aug 27, 2021

rsc unassigned timmydo and mvdan Jun 23, 2022

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net/mail: parseAddressList doesn't allow commas with empty email address #36959

net/mail: parseAddressList doesn't allow commas with empty email address #36959

timmydo commented Feb 1, 2020

timmydo commented Feb 1, 2020

mvdan commented Feb 1, 2020

timmydo commented Feb 1, 2020

gopherbot commented Feb 1, 2020

gofish commented Aug 12, 2020

gopherbot commented Aug 14, 2020

gopherbot commented Aug 27, 2020

net/mail: parseAddressList doesn't allow commas with empty email address #36959

net/mail: parseAddressList doesn't allow commas with empty email address #36959

Comments

timmydo commented Feb 1, 2020

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

timmydo commented Feb 1, 2020

mvdan commented Feb 1, 2020

timmydo commented Feb 1, 2020

gopherbot commented Feb 1, 2020

gofish commented Aug 12, 2020

gopherbot commented Aug 14, 2020

gopherbot commented Aug 27, 2020

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?