@@ -213,7 +213,10 @@ SMTP server and if it is supported by the utilized SASL library, the mechanism
is used for authentication. If neither 'sendemail.smtpAuth' nor `--smtp-auth`
is specified, all mechanisms supported by the SASL library can be used. The
special value 'none' maybe specified to completely disable authentication
-independently of `--smtp-user`
+independently of `--smtp-user`. Specifying `OAUTHBEARER` or `XOAUTH2` will
+bypass SASL negotiation and force bearer authentication. In this case the
+bearer token must be provided with `--smtp-pass` or using a credential helper
+and `--smtp-encryption=tls` must be set.
--smtp-pass[=<password>]::
Password for SMTP-AUTH. The argument is optional: If no
@@ -1398,6 +1398,63 @@ sub smtp_host_string {
}
}
+sub generate_oauthbearer_string {
+ # This will generate the oauthbearer string used for authentication.
+ #
+ # "n,a=" {User} ",^Ahost=" {Host} "^Aport=" {Port} "^Aauth=Bearer " {Access Token} "^A^A
+ #
+ # The first part `n,a=" {User} ",` is the gs2 header described in RFC5801.
+ # * gs2-cb-flag `n` -> client does not support CB
+ # * gs2-authzid `a=" {User} "`
+ #
+ # The second part are key value pairs containing host, port and auth as
+ # described in RFC7628.
+ #
+ # https://datatracker.ietf.org/doc/html/rfc5801
+ # https://datatracker.ietf.org/doc/html/rfc7628
+ my $username = shift;
+ my $token = shift;
+ return "n,a=$username,\001port=$smtp_server_port\001auth=Bearer $token\001\001";
+}
+
+sub generate_xoauth2_string {
+ # "user=" {User} "^Aauth=Bearer " {Access Token} "^A^A"
+ # https://developers.google.com/gmail/imap/xoauth2-protocol#initial_client_response
+ my $username = shift;
+ my $token = shift;
+ return "user=$username\001auth=Bearer $token\001\001";
+}
+
+sub smtp_bearer_auth {
+ my $username = shift;
+ my $token = shift;
+ my $auth_string;
+ if ($smtp_encryption ne "tls") {
+ # As described in RFC7628 TLS is required and will be enforced
+ # at this point.
+ #
+ # https://datatracker.ietf.org/doc/html/rfc7628#section-3
+ die __("For $smtp_auth TLS is required.")
+ }
+ if ($smtp_auth eq "OAUTHBEARER") {
+ $auth_string = generate_oauthbearer_string($username, $token);
+ } elsif ($smtp_auth eq "XOAUTH2") {
+ $auth_string = generate_xoauth2_string($username, $token);
+ }
+ my $encoded_auth_string = MIME::Base64::encode($auth_string, "");
+ $smtp->command("AUTH $smtp_auth $encoded_auth_string\r\n");
+ use Net::Cmd qw(CMD_OK);
+ if ($smtp->response() == CMD_OK){
+ return 1;
+ } else {
+ # Send dummy request on authentication failure according to rfc7628.
+ # https://datatracker.ietf.org/doc/html/rfc7628#section-3.2.3
+ $smtp->command(MIME::Base64::encode("\001"));
+ $smtp->response();
+ return 0;
+ }
+}
+
# Returns 1 if authentication succeeded or was not necessary
# (smtp_user was not specified), and 0 otherwise.
@@ -1431,8 +1488,12 @@ sub smtp_auth_maybe {
'password' => $smtp_authpass
}, sub {
my $cred = shift;
-
- if ($smtp_auth) {
+ if (defined $smtp_auth && ($smtp_auth eq "OAUTHBEARER" || $smtp_auth eq "XOAUTH2")) {
+ # Since Authen:SASL does not support XOAUTH2 nor OAUTHBEARER we will
+ # manually authenticate for these types. The password field should
+ # contain the auth token at this point.
+ return smtp_bearer_auth($cred->{'username'}, $cred->{'password'});
+ } elsif ($smtp_auth) {
my $sasl = Authen::SASL->new(
mechanism => $smtp_auth,
callback => {
Manually send SMTP AUTH command for auth type OAUTHBEARER and XOAUTH2. This is necessary since they are currently not supported by the Perls Authen::SASL module. The bearer token needs to be passed in as the password. This can be done with git-credential-oauth[0] after minor modifications[1]. Which will allow using git send-email with Gmail and oauth2 authentication: [credential] helper = cache --timeout 7200 # two hours helper = oauth [sendemail] smtpEncryption = tls smtpServer = smtp.gmail.com smtpUser = example@gmail.com smtpServerPort = 587 smtpauth = OAUTHBEARER As well as Office 365 accounts: [credential] helper = cache --timeout 7200 # two hours helper = oauth [sendemail] smtpEncryption = tls smtpServer = smtp.office365.com smtpUser = example@example.com smtpServerPort = 587 smtpauth = XOAUTH2 [0] https://github.com/hickford/git-credential-oauth [1] https://github.com/hickford/git-credential-oauth/issues/48 Tested-by: M Hickford <mirth.hickford@gmail.com> Signed-off-by: Julian Swagemakers <julian@swagemakers.org> --- Documentation/git-send-email.txt | 5 ++- git-send-email.perl | 65 +++++++++++++++++++++++++++++++- 2 files changed, 67 insertions(+), 3 deletions(-) Range-diff against v1: 1: ab3ba94099 ! 1: 7532a1ee0a send-email: implement SMTP bearer authentication @@ Commit message with git-credential-oauth[0] after minor modifications[1]. Which will allow using git send-email with Gmail and oauth2 authentication: - ``` - [credential] - helper = cache --timeout 7200 # two hours + [credential] + helper = cache --timeout 7200 # two hours helper = oauth - [sendemail] - smtpEncryption = tls - smtpServer = smtp.gmail.com - smtpUser = example@gmail.com - smtpServerPort = 587 - smtpauth = OAUTHBEARER - ``` + [sendemail] + smtpEncryption = tls + smtpServer = smtp.gmail.com + smtpUser = example@gmail.com + smtpServerPort = 587 + smtpauth = OAUTHBEARER As well as Office 365 accounts: - ``` - [credential] + [credential] helper = cache --timeout 7200 # two hours helper = oauth - [sendemail] - smtpEncryption = tls - smtpServer = smtp.office365.com - smtpUser = example@example.com - smtpServerPort = 587 - smtpauth = XOAUTH2 - ``` + [sendemail] + smtpEncryption = tls + smtpServer = smtp.office365.com + smtpUser = example@example.com + smtpServerPort = 587 + smtpauth = XOAUTH2 [0] https://github.com/hickford/git-credential-oauth [1] https://github.com/hickford/git-credential-oauth/issues/48 + Tested-by: M Hickford <mirth.hickford@gmail.com> Signed-off-by: Julian Swagemakers <julian@swagemakers.org> + ## Documentation/git-send-email.txt ## +@@ Documentation/git-send-email.txt: SMTP server and if it is supported by the utilized SASL library, the mechanism + is used for authentication. If neither 'sendemail.smtpAuth' nor `--smtp-auth` + is specified, all mechanisms supported by the SASL library can be used. The + special value 'none' maybe specified to completely disable authentication +-independently of `--smtp-user` ++independently of `--smtp-user`. Specifying `OAUTHBEARER` or `XOAUTH2` will ++bypass SASL negotiation and force bearer authentication. In this case the ++bearer token must be provided with `--smtp-pass` or using a credential helper ++and `--smtp-encryption=tls` must be set. + + --smtp-pass[=<password>]:: + Password for SMTP-AUTH. The argument is optional: If no + ## git-send-email.perl ## @@ git-send-email.perl: sub smtp_host_string { } @@ git-send-email.perl: sub smtp_host_string { + my $token = shift; + my $auth_string; + if ($smtp_encryption ne "tls") { -+ # As described in RFC7628 TLS is required and will be will -+ # be enforced at this point. ++ # As described in RFC7628 TLS is required and will be enforced ++ # at this point. + # + # https://datatracker.ietf.org/doc/html/rfc7628#section-3 + die __("For $smtp_auth TLS is required.") @@ git-send-email.perl: sub smtp_auth_maybe { my $cred = shift; - - if ($smtp_auth) { -+ if ($smtp_auth eq "OAUTHBEARER" or $smtp_auth eq "XOAUTH2") { ++ if (defined $smtp_auth && ($smtp_auth eq "OAUTHBEARER" || $smtp_auth eq "XOAUTH2")) { + # Since Authen:SASL does not support XOAUTH2 nor OAUTHBEARER we will -+ # manuall authenticate for tese types. The password field should ++ # manually authenticate for these types. The password field should + # contain the auth token at this point. + return smtp_bearer_auth($cred->{'username'}, $cred->{'password'}); + } elsif ($smtp_auth) {