diff --git a/dummy-chain-cert.pem b/dummy-chain-cert.pem new file mode 100644 index 0000000..4daceaa --- /dev/null +++ b/dummy-chain-cert.pem @@ -0,0 +1,62 @@ +-----BEGIN CERTIFICATE----- +MIIFWjCCA0KgAwIBAgIUAi7P4JOR4g8b5DMERUtZQEtw+igwDQYJKoZIhvcNAQEL +BQAwRTELMAkGA1UEBhMCQVUxEzARBgNVBAgMClNvbWUtU3RhdGUxITAfBgNVBAoM +GEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDAeFw0yNDA5MjYxNDU0MDlaFw0yNTA5 +MjYxNDU0MDlaMEUxCzAJBgNVBAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEw +HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwggIiMA0GCSqGSIb3DQEB +AQUAA4ICDwAwggIKAoICAQCiLh0JJTRRBhmUyiMKALHtTOK7T20Bwy+fG0SO6RlB +c+hSuuX/n6znXcNgOBlQ2Gg3+p1on/bmcKnGN/SCiVBLpROiwxg3blQbZ7B7Jors +/MopGk0LIBOXHPtAuYbF4J6ND5Ol6sgeGjMnomwRjZlfeuBlHY345MqvcwH/lPhO +lKme+tWD+bsFh08NGS+3NdQGP6dA2bRVrPXhLXStHEmqfKO9EMVLWv+77tYhZESD +6XgnA8pWjbdr9jajCsrQWrCG3jqHtzHNxtwf7xfRwwgoUhLEvue6SBVokZGVmDhv +WdRt2sjtLcWWJCI3p7M+NXRt5qf6iu24wLBdzIDuWfgooWu5vBzNZjSTh2if6R1a +s9BdwASwy1n2HMvqpzgA+f/rXDFbvVc7WIKiuGzfWApBrL0qTCQBuSyepH0G4rQ2 +sJtI5U8QOKBO76nQJq5WDQgefBX4GDI8aJ6qX+teQq1AqERUmLWx4WlTwxSo5X+d +1jY9I8f61CRKVfIRgMvAZUhm2h6RnoVIgq7G7W3HdC3RT/f758njI7oIv5bhiyqp +gyKr3cYhmn0enjP+YtjY85m51q005qzRLfaTYiwMR4qyJW4ZOEPntPs20CD+e+Pi +2JLONpRdcsSrkqZusVjm5PFy2e5RyNFXTupUH2KVrgTRHL3GG2KWF5PmBdkhQfGG +1QIDAQABo0IwQDAdBgNVHQ4EFgQUS8+HouVQ94SdgI3kV3L8Jm53P6YwHwYDVR0j +BBgwFoAUY1u7KerT8m01BvAg77PUaot2S0EwDQYJKoZIhvcNAQELBQADggIBAE14 +YBa/stYwrsy/1iQ44NeQyYMPMdOC8TI1xrbW/9u1FllipECnFEGDK1N6mZ7xDEfG +un5dQ3jXQ7156Ge672374yUsN7FQ37mTyZos3Q2N/mOpVOnYJt5mIukx2MXBU3r3 +UP1Jpnf9rB4kdtWXa7b1CSTkM4kraige3wZhPELwESnm4t8C34MIzHBWPbHpft05 +WheDv9Zizfw+0pbJ+WNGnHF4PjR/wq9ymkLf89cqsbS9mOdPpWva8i0e7pqKnxzo +iz2ueQB4Z2Tbgp0G9ResA+2Zxk1iIQPbhtqNUZv6ROPiLAWdiVRysFJJf/19V+nZ +LIC0xw+amF6P51/fA95EGqElO4OLJTIGY27H761g7+FhTwfryLMHKknSxcfk7xoq +BMyBr7ARYnmpjee7yKOBUgSdpxb6YUcdGZwjCUIiIHlBII83DzcNILa5QvUkzMCh +xHYmPvvftJOjF8hwMfjA9MDFML9yWVm+CBNraNPh25U5uMOuIuyUBtSB5yEdPRhY +BJGrZEew0lLAWAqqASmGPDaWNBaA0HYqO70g4IyqBwIGNnaHSLVr/vT23BFRMyXf +wh5mtJmyyR3+c0po3vDX39mkIAZ2gZWprWa3Jw0dVs6cEujcVNdqeZlQw0RCa9wm +xioBxb1md2AplUQ2fG/KHnu2ZuxHA6MNYcwMJNgv +-----END CERTIFICATE----- +-----BEGIN CERTIFICATE----- +MIIFazCCA1OgAwIBAgIUKU+ta2rnJE/79L2Uxg4vFoF0RxYwDQYJKoZIhvcNAQEL +BQAwRTELMAkGA1UEBhMCQVUxEzARBgNVBAgMClNvbWUtU3RhdGUxITAfBgNVBAoM +GEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDAeFw0yNDA5MjYxNDUzMzlaFw0zNDA5 +MjQxNDUzMzlaMEUxCzAJBgNVBAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEw +HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwggIiMA0GCSqGSIb3DQEB +AQUAA4ICDwAwggIKAoICAQDSOuYqxNsP4Gm/EDauon/SAVWj8PIKFB1OpuguHm13 +b2l2G6hRuNnAmR6ewP22H/YoyYz1qRchH2qw1uizwnnSS0OY74CsJhd0PV6f4XRR +Y+6PotGDPu1fJJM4XI3HjWGdBkJSawZNWjP1dQRJPUHNRttSOrPsG3XT7TjfLjoK +jOelTqgwHUGE2n0AtQP7ZFQVn7LLBrukve8zMgivwEL1JFSlKppWFf0SUgpmQVE6 +3jTAQPPrI/B5z5Ys1j2jv7mJt3/UATcTGmvPTNv94SUrO6nC3TJxKHtR30MALteo +EgH/s2O0Ax44iDENgm9p6eb+GCyTWS/eHBAJ6SU76PRymiE57/0GOqyYewuEOuIU +FYd6+gglCMe+ayfhI20njHP6RTiQpRjFy+DM8+bkcS89q0sfFSFHR5oFNbAgUgyI +bGiaWb+DmUCwSFnS0HusSU2AECqzuwiyObD3rkoqBQMj+xl6SnJU6TTcB+WD/Z5G +tqu1zTMXpo3VRts3AQSGUuSaqbeG/S+38LX+fbjeTLa6SEGJfB7/H2s64vCO/0hR +M0KEXAaTyjx0PnNKYSlCIJyA9lYea21oByNc31tkUXQjmUQpSXYayrDwzR2JAXVY +rFJLNu1Q6sZ0WqT9fj06oTas7g1g3gcl18tIapeael2jJohth0RizBxKYuLYc6Pv +1QIDAQABo1MwUTAdBgNVHQ4EFgQUY1u7KerT8m01BvAg77PUaot2S0EwHwYDVR0j +BBgwFoAUY1u7KerT8m01BvAg77PUaot2S0EwDwYDVR0TAQH/BAUwAwEB/zANBgkq +hkiG9w0BAQsFAAOCAgEAB8BpmI3v2cNlXUjhf+rldaqDfq/IJ7Ri23kCBJW4VaoW +c0UrtvLC+K5m61I1iWSUYEK85/bPw2K5dn1e8w3Q2J460Yvc7/ZT7mucZlXQxfl3 +V7yqqQI7OMsY6FochYUL3+c32WQg5jllsLPlHAHBJlagf3uEqmVrvSExHNBQOVyE +/cs1i9DcTJF2A8JNPKilIObvRT103Qp2eFnW+EY9OUBb+TdQvPjxroLfK1SuOAe6 +bLPBxdgvA/0raHuXeDTNsNRICIU1X5eBfZwCXKe9lRVJpIsKTYeHDN/rEmfTtehB +vz8/KkCWqwPDn/YFkNAdg3TRjqW4oW2wZ+XqbTlR2qA7szE7oMAfHxNkintxMnNm +vD2/AAP6RUw16HZk0najFWPIG9gc+O1gSks6hwn9JilAPy8mn40H2D7cedU6Ew+T +CQ02+dw2+2FLKYr1eiYPlIELsAu8kmbrjwvwy2sCf3L4fxLtPRqXFuXB2Uer9zvy +tn+RK5hJkKo/YY37I9Y9x57rpCqUfFIeYWBub07x1620ujRkL1pJPxfRNBfyh42t +beuk/XQGIvPcIkbPnmsb4gGaiRMuw+mZ7isJDoQwHUmfqL1EpOYb5mLYHkIqKaCz +8t8wTdkimIVIFSxedy7cJCCWdQ/BCyTJoQpXD69PLPzxEi/YK9pB9S8qBtfefu4= +-----END CERTIFICATE----- diff --git a/dummy-child-key.pem b/dummy-child-key.pem new file mode 100644 index 0000000..2a8639b --- /dev/null +++ b/dummy-child-key.pem @@ -0,0 +1,52 @@ +-----BEGIN PRIVATE KEY----- +MIIJQAIBADANBgkqhkiG9w0BAQEFAASCCSowggkmAgEAAoICAQCiLh0JJTRRBhmU +yiMKALHtTOK7T20Bwy+fG0SO6RlBc+hSuuX/n6znXcNgOBlQ2Gg3+p1on/bmcKnG +N/SCiVBLpROiwxg3blQbZ7B7Jors/MopGk0LIBOXHPtAuYbF4J6ND5Ol6sgeGjMn +omwRjZlfeuBlHY345MqvcwH/lPhOlKme+tWD+bsFh08NGS+3NdQGP6dA2bRVrPXh +LXStHEmqfKO9EMVLWv+77tYhZESD6XgnA8pWjbdr9jajCsrQWrCG3jqHtzHNxtwf +7xfRwwgoUhLEvue6SBVokZGVmDhvWdRt2sjtLcWWJCI3p7M+NXRt5qf6iu24wLBd +zIDuWfgooWu5vBzNZjSTh2if6R1as9BdwASwy1n2HMvqpzgA+f/rXDFbvVc7WIKi +uGzfWApBrL0qTCQBuSyepH0G4rQ2sJtI5U8QOKBO76nQJq5WDQgefBX4GDI8aJ6q +X+teQq1AqERUmLWx4WlTwxSo5X+d1jY9I8f61CRKVfIRgMvAZUhm2h6RnoVIgq7G +7W3HdC3RT/f758njI7oIv5bhiyqpgyKr3cYhmn0enjP+YtjY85m51q005qzRLfaT +YiwMR4qyJW4ZOEPntPs20CD+e+Pi2JLONpRdcsSrkqZusVjm5PFy2e5RyNFXTupU +H2KVrgTRHL3GG2KWF5PmBdkhQfGG1QIDAQABAoICAAL3IruL6/zP5DPZ9RkiL1m/ +lHPhP7/sWKTfWMPf4ChX6XAHWeYraqNPvx8/bESdstLAvx3piyvcapRupN9DsVTu +SrKytjXft6OEVWFLEveHk3F8B+9ewbMY4BmsQOjpVR9J7+6SZmpUB2MdD3lpdY07 +YSuamff0dcNdV2+NEZth6bit++iJFc9rTI/OwBZLMTVsp+oVpKh7w72h1DfboaF/ +oU9tYHWFWTRUfSzoqm7Q4POKmII4BhA+1QWIUIX1OLQocepzgfw72Tj+GlRQ7WAu +IToIBqbRxfsNflaWDSv15UrE7OCDLUdlXILOd0GgtJaYTsX7X7ZMU1mIoqX0IBsk +KRCep+7BTA8VYXOlW26tPEcsj2Vp7tdghptTaEtdx05delaYaX18rxdprNz+VV0Z +jNVIgShJC4vMEVQtOSOyznavF9OONScBG4e0E9rSHbYudtvrp8WOoaDK6mzAwo6w +wShYwwzFmf0Y2FbsENvNiNw5cqKT4WQoCXM6WS9BjPfJqz4M7V8pYa3pCE4M+oXP +sfQDgkpyXg88Dez1N78cbpr4GKsI9odFmphivQngXF1H3N8UKLCjW/EQNKHoydTn +nTtIfSY1G5hlDS0nCqTn6LvI2W887Da+ASWGtgGn0opLUW5Kg5fPurFjoCEP4mNg +JQ8nX9q2N5AogHld0h1ZAoIBAQDVRSty2Q7+oQh0qWGI0eDESeAHd/OKnwELAsMx +pfXABhB/CjO0/Iy4MgBL1dMb1S64gHhHi816CfxoSQuaUNjOcAWxhLTbnPEx8eaS +SFvdnd3itEC0T6Cg1r8mklHXrz6WH8vtLfu3pc8svGp+xJ5Rmlg1G3rhYFce6csg +lgeP4n4vjxOZtds3Jr8oHiW0/KYrLUK8/TgFOwYvWZQ8Lk92Oz+Fcd+RkegSkzIB +hHpqIMQz4T5uirjmxKX9573X17cVO3LuCBSite1uiyXRAIrGEOOyHwv3xC2h/bV1 +6IYSiuwJOxDxZAmYuWYBtlvfWrOypEuWogZQv8C/zxDpkDSLAoIBAQDCrHxmh5NI +ksWQg0W6176uktwyypFBh8REE1VfCgoxJ84TVOQzEBiNQpRj/FUCe4e7ZElIAks+ +N9mh8smJLvHDVo7033NIfAZCfCbLve8uWSGAm5x+aKS7kG5gynojKT8vl0y88m5o +Nm+BfvpQKjb6n6jibZZRsQsyz5KBct+Gb9gyA81jjrFudBmYy9WZeEm6pjzQtkuq +I0xCbQFwB+It/utjz7okuAWk5fPU0LRqOvvEMJjf2DyvIK45FDsBF3zGlG8Zunnh +q3o28zXdQCvYxY5Ik8zRuSTTAQnaJ3/zUvqR2g3PoSF8d7/WSkzNK+ZhTANqPkq1 +SOg515Na9L4fAoH/Vc5+rLaoUcp4nHeJxoKq7E7M1DRuyFcxFD0IS/F57siB2ptA +MpFqDLIRbHGbfpdHNPR7cE3PXkqmQ08gW/YrROPNZp7+JV3/rRimrDRwwbnCjHP5 +lJJ1DkFYpyw3wY/AnqYsZkEaBcmwkU89icOR70MqOjPUPNmGM+nc0D+My1dVbc0j +FbUVfhsYzgtTIH6GXNjZATDgWTpmQqbH/W6kie1MoWQvj2Ik/VQ7ymCC4DBOwJDf +jZpCypZUMtQKjc083E4O77ZQlyabYN6bWHvfWdFxyziyl/1WXta1K7tiNhOu5Aff +yT92nPv7DrVQQY08v6NaxkBqShLcek/VfiOHAoIBAAtzd/HUAb7gG0zv29csv6On +Mdqu/bJcGRhkBr6LaaQQkleiw7WZOch9ZRsoiZuWxpooQQNCV0i2ok+bZ21xXHlA +CzKuPirCWN/qS6HqbzpLtePJw3/QCfiae1OoNV0CHRxgivwGSqZIpXB5lqHGiete +HuIKzi/J+T2o5hZFOo6+33m5rYgwqZE0tRi+zLa1U6juBF/GiVbdsqupm88KN6y6 +9P+vBWUJihN0D06yZBpnk82riiKIprEqe/URkpLy3b0UmCBsTqUOoCbBUabNEocy +v7bXMtIXUOo0gm7ZqfYXKHQR3oQbF0wqAxfI0RG0hl2syfqi5WQagMZ+PsW35cMC +ggEBAM6kIM/zUnNBFla+oTiPCyoII7nGmGz8dT9IhH0+6T5nNzG4O6D28A3MJcs1 +C3pfukCCeWOnDNCIQ7C9Hx5XcCDoI4eD6zCRy+7zXxn0FxYS+O6lczB2mXGE69Yp +n3qb7P4XqZYex3dT72czJUlY6nFB2e0FmyvSoez8fsH9Ws78c4JGO953klam/emA +Hc8nB3CyM8rb2JlM3WeQbmo+Sbi0Yvj+MWM2AnTXx0xyaFXKP4WGD8hAxTvf9tSX +3NAPVBXku4zRpvoXyyrcBVd9vwE0qBr3eWCuci8aDD6RAAJgb8HHX9RjRF/phFpY +S++xGnGHEUSEl7cWnO8k0RyJzzc= +-----END PRIVATE KEY----- diff --git a/encoding.go b/encoding.go index 47213da..77243fc 100644 --- a/encoding.go +++ b/encoding.go @@ -149,6 +149,7 @@ const ( TypePGPEncrypted ContentType = "application/pgp-encrypted" TypeTextHTML ContentType = "text/html" TypeTextPlain ContentType = "text/plain" + typeSMimeSigned ContentType = `application/pkcs7-signature; name="smime.p7s"` ) // List of MIMETypes @@ -156,6 +157,7 @@ const ( MIMEAlternative MIMEType = "alternative" MIMEMixed MIMEType = "mixed" MIMERelated MIMEType = "related" + MIMESMime MIMEType = `signed; protocol="application/pkcs7-signature"; micalg=sha256` ) // String is a standard method to convert an Charset into a printable format diff --git a/encoding_test.go b/encoding_test.go index 14711b7..11bf991 100644 --- a/encoding_test.go +++ b/encoding_test.go @@ -61,6 +61,11 @@ func TestContentType_String(t *testing.T) { "ContentType: application/pgp-encrypted", TypePGPEncrypted, "application/pgp-encrypted", }, + + { + "ContentType: pkcs7-signature", typeSMimeSigned, + `application/pkcs7-signature; name="smime.p7s"`, + }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { diff --git a/go.mod b/go.mod index b155b9b..a59f78a 100644 --- a/go.mod +++ b/go.mod @@ -5,3 +5,5 @@ module github.com/wneessen/go-mail go 1.16 + +require go.mozilla.org/pkcs7 v0.9.0 diff --git a/go.sum b/go.sum index e69de29..4ca3691 100644 --- a/go.sum +++ b/go.sum @@ -0,0 +1,2 @@ +go.mozilla.org/pkcs7 v0.9.0 h1:yM4/HS9dYv7ri2biPtxt8ikvB37a980dg69/pKmS+eI= +go.mozilla.org/pkcs7 v0.9.0/go.mod h1:SNgMg+EgDFwmvSmLRTNKC5fegJjB7v23qTQ0XLGUNHk= diff --git a/msg.go b/msg.go index b66bffe..1dbceca 100644 --- a/msg.go +++ b/msg.go @@ -7,6 +7,7 @@ package mail import ( "bytes" "context" + "crypto/tls" "embed" "errors" "fmt" @@ -120,6 +121,9 @@ type Msg struct { // noDefaultUserAgent indicates whether the default User Agent will be excluded for the Msg when it's sent. noDefaultUserAgent bool + + // SMime represents a middleware used to sign messages with S/MIME + sMime *SMime } // SendmailPath is the default system path to the sendmail binary @@ -202,6 +206,16 @@ func WithNoDefaultUserAgent() MsgOption { } } +// SignWithSMime configures the Msg to be signed with S/MIME +func (m *Msg) SignWithSMime(keyPair *tls.Certificate) error { + sMime, err := newSMime(keyPair) + if err != nil { + return err + } + m.sMime = sMime + return nil +} + // SetCharset sets the encoding charset of the Msg func (m *Msg) SetCharset(c Charset) { m.charset = c @@ -979,10 +993,50 @@ func (m *Msg) applyMiddlewares(msg *Msg) *Msg { return msg } +// signMessage sign the Msg with S/MIME +func (m *Msg) signMessage(msg *Msg) (*Msg, error) { + signedPart := msg.GetParts()[0] + body, err := signedPart.GetContent() + if err != nil { + return nil, err + } + + signaturePart, err := m.createSignaturePart(signedPart.GetEncoding(), signedPart.GetContentType(), signedPart.GetCharset(), body) + if err != nil { + return nil, err + } + + m.parts = append(m.parts, signaturePart) + + return m, err +} + +func (m *Msg) createSignaturePart(encoding Encoding, contentType ContentType, charSet Charset, body []byte) (*Part, error) { + message := m.sMime.createMessage(encoding, contentType, charSet, body) + signaturePart := m.newPart(typeSMimeSigned, WithPartEncoding(EncodingB64), WithSMimeSinging()) + + if err := m.sMime.sign(signaturePart, message); err != nil { + return nil, err + } + + return signaturePart, nil +} + // WriteTo writes the formated Msg into a give io.Writer and satisfies the io.WriteTo interface func (m *Msg) WriteTo(writer io.Writer) (int64, error) { mw := &msgWriter{writer: writer, charset: m.charset, encoder: m.encoder} - mw.writeMsg(m.applyMiddlewares(m)) + msg := m.applyMiddlewares(m) + + if m.hasSMime() { + signedMsg, err := m.signMessage(msg) + if err != nil { + return 0, err + } + msg = signedMsg + } + + mw.writeMsg(msg) + return mw.bytesWritten, mw.err } @@ -1169,7 +1223,7 @@ func (m *Msg) hasAlt() bool { count++ } } - return count > 1 && m.pgptype == 0 + return count > 1 && m.pgptype == 0 && !m.hasSMime() } // hasMixed returns true if the Msg has mixed parts @@ -1177,6 +1231,11 @@ func (m *Msg) hasMixed() bool { return m.pgptype == 0 && ((len(m.parts) > 0 && len(m.attachments) > 0) || len(m.attachments) > 1) } +// hasSMime returns true if the Msg has should be signed with S/MIME +func (m *Msg) hasSMime() bool { + return m.sMime != nil +} + // hasRelated returns true if the Msg has related parts func (m *Msg) hasRelated() bool { return m.pgptype == 0 && ((len(m.parts) > 0 && len(m.embeds) > 0) || len(m.embeds) > 1) diff --git a/msg_test.go b/msg_test.go index f570b02..881ff55 100644 --- a/msg_test.go +++ b/msg_test.go @@ -1907,6 +1907,23 @@ func TestMsg_hasAlt(t *testing.T) { } } +// TestMsg_hasAlt tests the hasAlt() method of the Msg with active S/MIME +func TestMsg_hasAltWithSMime(t *testing.T) { + keyPair, err := getDummyCertificate() + if err != nil { + t.Errorf("failed to load dummy certificate. Cause: %v", err) + } + m := NewMsg() + m.SetBodyString(TypeTextPlain, "Plain") + m.AddAlternativeString(TypeTextHTML, "HTML") + if err := m.SignWithSMime(keyPair); err != nil { + t.Errorf("set of certificate was not successful") + } + if m.hasAlt() { + t.Errorf("mail has alternative parts and S/MIME is active, but hasAlt() returned true") + } +} + // TestMsg_hasRelated tests the hasRelated() method of the Msg func TestMsg_hasRelated(t *testing.T) { m := NewMsg() @@ -3246,6 +3263,37 @@ func TestNewMsgWithNoDefaultUserAgent(t *testing.T) { } } +// TestSignWithSMime_ValidKeyPair tests WithSMimeSinging with given key pair +func TestSignWithSMime_ValidKeyPair(t *testing.T) { + keyPair, err := getDummyCertificate() + if err != nil { + t.Errorf("failed to load dummy certificate. Cause: %v", err) + } + m := NewMsg() + if err := m.SignWithSMime(keyPair); err != nil { + t.Errorf("failed to set sMime. Cause: %v", err) + } + if m.sMime.privateKey == nil { + t.Errorf("WithSMimeSinging() - no private key is given") + } + if m.sMime.certificate == nil { + t.Errorf("WithSMimeSinging() - no certificate is given") + } + if len(m.sMime.parentCertificates) != len(keyPair.Certificate[:1]) { + t.Errorf("WithSMimeSinging() - no certificate is given") + } +} + +// TestSignWithSMime_InvalidKeyPair tests WithSMimeSinging with given invalid key pair +func TestSignWithSMime_InvalidKeyPair(t *testing.T) { + m := NewMsg() + + err := m.SignWithSMime(nil) + if !errors.Is(err, ErrInvalidKeyPair) { + t.Errorf("failed to check sMimeAuthConfig values correctly: %s", err) + } +} + // Fuzzing tests func FuzzMsg_Subject(f *testing.F) { f.Add("Testsubject") @@ -3273,3 +3321,84 @@ func FuzzMsg_From(f *testing.F) { m.Reset() }) } + +// TestMsg_createSignaturePart tests the Msg.createSignaturePart method +func TestMsg_createSignaturePart(t *testing.T) { + keyPair, err := getDummyCertificate() + if err != nil { + t.Errorf("failed to load dummy certificate. Cause: %v", err) + } + m := NewMsg() + if err := m.SignWithSMime(keyPair); err != nil { + t.Errorf("set of certificate was not successful") + } + body := []byte("This is the body") + part, err := m.createSignaturePart(EncodingQP, TypeTextPlain, CharsetUTF7, body) + if err != nil { + t.Errorf("createSignaturePart() method failed.") + } + + if part.GetEncoding() != EncodingB64 { + t.Errorf("createSignaturePart() method failed. Expected encoding: %s, got: %s", EncodingB64, part.GetEncoding()) + } + if part.GetContentType() != typeSMimeSigned { + t.Errorf("createSignaturePart() method failed. Expected content type: %s, got: %s", typeSMimeSigned, part.GetContentType()) + } + if part.GetCharset() != CharsetUTF8 { + t.Errorf("createSignaturePart() method failed. Expected charset: %s, got: %s", CharsetUTF8, part.GetCharset()) + } + if content, err := part.GetContent(); err != nil || len(content) == len(body) { + t.Errorf("createSignaturePart() method failed. Expected content should not be equal: %s, got: %s", body, part.GetEncoding()) + } +} + +// TestMsg_signMessage tests the Msg.signMessage method +func TestMsg_signMessage(t *testing.T) { + keyPair, err := getDummyCertificate() + if err != nil { + t.Errorf("failed to load dummy certificate. Cause: %v", err) + } + body := []byte("This is the body") + m := NewMsg() + m.SetBodyString(TypeTextPlain, string(body)) + if err := m.SignWithSMime(keyPair); err != nil { + t.Errorf("set of certificate was not successful") + } + msg, err := m.signMessage(m) + if err != nil { + t.Errorf("createSignaturePart() method failed.") + } + + parts := msg.GetParts() + if len(parts) != 2 { + t.Errorf("createSignaturePart() method failed. Expected 2 parts, got: %d", len(parts)) + } + + signedPart := parts[0] + if signedPart.GetEncoding() != EncodingQP { + t.Errorf("createSignaturePart() method failed. Expected encoding: %s, got: %s", EncodingB64, signedPart.GetEncoding()) + } + if signedPart.GetContentType() != TypeTextPlain { + t.Errorf("createSignaturePart() method failed. Expected content type: %s, got: %s", typeSMimeSigned, signedPart.GetContentType()) + } + if signedPart.GetCharset() != CharsetUTF8 { + t.Errorf("createSignaturePart() method failed. Expected charset: %s, got: %s", CharsetUTF8, signedPart.GetCharset()) + } + if content, err := signedPart.GetContent(); err != nil || len(content) != len(body) { + t.Errorf("createSignaturePart() method failed. Expected content should be equal: %s, got: %s", body, content) + } + + signaturePart := parts[1] + if signaturePart.GetEncoding() != EncodingB64 { + t.Errorf("createSignaturePart() method failed. Expected encoding: %s, got: %s", EncodingB64, signaturePart.GetEncoding()) + } + if signaturePart.GetContentType() != typeSMimeSigned { + t.Errorf("createSignaturePart() method failed. Expected content type: %s, got: %s", typeSMimeSigned, signaturePart.GetContentType()) + } + if signaturePart.GetCharset() != CharsetUTF8 { + t.Errorf("createSignaturePart() method failed. Expected charset: %s, got: %s", CharsetUTF8, signaturePart.GetCharset()) + } + if content, err := signaturePart.GetContent(); err != nil || len(content) == len(body) { + t.Errorf("createSignaturePart() method failed. Expected content should not be equal: %s, got: %s", body, signaturePart.GetEncoding()) + } +} diff --git a/msgwriter.go b/msgwriter.go index ff1b47b..7c1e88e 100644 --- a/msgwriter.go +++ b/msgwriter.go @@ -88,6 +88,10 @@ func (mw *msgWriter) writeMsg(msg *Msg) { } } + if msg.hasSMime() { + mw.startMP(MIMESMime, msg.boundary) + mw.writeString(DoubleNewLine) + } if msg.hasMixed() { mw.startMP(MIMEMixed, msg.boundary) mw.writeString(DoubleNewLine) @@ -237,7 +241,7 @@ func (mw *msgWriter) addFiles(files []*File, isAttachment bool) { } if mw.err == nil { - mw.writeBody(file.Writer, encoding) + mw.writeBody(file.Writer, encoding, false) } } } @@ -269,7 +273,7 @@ func (mw *msgWriter) writePart(part *Part, charset Charset) { mimeHeader.Add(string(HeaderContentTransferEnc), contentTransferEnc) mw.newPart(mimeHeader) } - mw.writeBody(part.writeFunc, part.encoding) + mw.writeBody(part.writeFunc, part.encoding, part.smime) } // writeString writes a string into the msgWriter's io.Writer interface @@ -318,7 +322,7 @@ func (mw *msgWriter) writeHeader(key Header, values ...string) { } // writeBody writes an io.Reader into an io.Writer using provided Encoding -func (mw *msgWriter) writeBody(writeFunc func(io.Writer) (int64, error), encoding Encoding) { +func (mw *msgWriter) writeBody(writeFunc func(io.Writer) (int64, error), encoding Encoding, singingWithSMime bool) { var writer io.Writer var encodedWriter io.WriteCloser var n int64 @@ -333,12 +337,11 @@ func (mw *msgWriter) writeBody(writeFunc func(io.Writer) (int64, error), encodin lineBreaker := Base64LineBreaker{} lineBreaker.out = &writeBuffer - switch encoding { - case EncodingQP: + if encoding == EncodingQP { encodedWriter = quotedprintable.NewWriter(&writeBuffer) - case EncodingB64: + } else if encoding == EncodingB64 && !singingWithSMime { encodedWriter = base64.NewEncoder(base64.StdEncoding, &lineBreaker) - case NoEncoding: + } else if encoding == NoEncoding { _, err = writeFunc(&writeBuffer) if err != nil { mw.err = fmt.Errorf("bodyWriter function: %w", err) @@ -351,7 +354,7 @@ func (mw *msgWriter) writeBody(writeFunc func(io.Writer) (int64, error), encodin mw.bytesWritten += n } return - default: + } else { encodedWriter = quotedprintable.NewWriter(writer) } diff --git a/msgwriter_test.go b/msgwriter_test.go index a41e5d3..ca1a982 100644 --- a/msgwriter_test.go +++ b/msgwriter_test.go @@ -154,3 +154,26 @@ func TestMsgWriter_writeMsg_PGP(t *testing.T) { t.Errorf("writeMsg failed. Expected PGP encoding header but didn't find it in message output") } } + +// TestMsgWriter_writeMsg_SMime tests the writeMsg method of the msgWriter with S/MIME types set +func TestMsgWriter_writeMsg_SMime(t *testing.T) { + keyPair, err := getDummyCertificate() + if err != nil { + t.Errorf("failed to load dummy certificate. Cause: %v", err) + } + m := NewMsg() + if err := m.SignWithSMime(keyPair); err != nil { + t.Errorf("set of certificate was not successful") + } + _ = m.From(`"Toni Tester" `) + _ = m.To(`"Toni Receiver" `) + m.Subject("This is a subject") + m.SetBodyString(TypeTextPlain, "This is the body") + buf := bytes.Buffer{} + mw := &msgWriter{writer: &buf, charset: CharsetUTF8, encoder: mime.QEncoding} + mw.writeMsg(m) + ms := buf.String() + if !strings.Contains(ms, `multipart/signed; protocol="application/pkcs7-signature"; micalg=sha256;`) { + t.Errorf("writeMsg failed. Expected PGP encoding header but didn't find it in message output") + } +} diff --git a/part.go b/part.go index 7c76b7d..035b342 100644 --- a/part.go +++ b/part.go @@ -20,6 +20,7 @@ type Part struct { encoding Encoding isDeleted bool writeFunc func(io.Writer) (int64, error) + smime bool } // GetContent executes the WriteFunc of the Part and returns the content as byte slice @@ -56,6 +57,11 @@ func (p *Part) GetDescription() string { return p.description } +// IsSMimeSigned returns true if the Part should be singed with S/MIME +func (p *Part) IsSMimeSigned() bool { + return p.smime +} + // SetContent overrides the content of the Part with the given string func (p *Part) SetContent(content string) { buffer := bytes.NewBufferString(content) @@ -82,6 +88,11 @@ func (p *Part) SetDescription(description string) { p.description = description } +// SetIsSMimeSigned sets the flag for signing the Part with S/MIME +func (p *Part) SetIsSMimeSigned(smime bool) { + p.smime = smime +} + // SetWriteFunc overrides the WriteFunc of the Part func (p *Part) SetWriteFunc(writeFunc func(io.Writer) (int64, error)) { p.writeFunc = writeFunc @@ -113,3 +124,10 @@ func WithPartContentDescription(description string) PartOption { p.description = description } } + +// WithSMimeSinging overrides the flag for signing the Part with S/MIME +func WithSMimeSinging() PartOption { + return func(p *Part) { + p.smime = true + } +} diff --git a/part_test.go b/part_test.go index a196986..c1a8ac7 100644 --- a/part_test.go +++ b/part_test.go @@ -102,6 +102,24 @@ func TestPart_WithPartContentDescription(t *testing.T) { } } +// TestPart_WithSMimeSinging tests the WithSMimeSinging method +func TestPart_WithSMimeSinging(t *testing.T) { + m := NewMsg() + part := m.newPart(TypeTextPlain, WithSMimeSinging()) + if part == nil { + t.Errorf("newPart() WithSMimeSinging() failed: no part returned") + return + } + if part.smime != true { + t.Errorf("newPart() WithSMimeSinging() failed: expected: %v, got: %v", true, part.smime) + } + part.smime = true + part.SetIsSMimeSigned(false) + if part.smime != false { + t.Errorf("newPart() SetIsSMimeSigned() failed: expected: %v, got: %v", false, part.smime) + } +} + // TestPartContentType tests Part.SetContentType func TestPart_SetContentType(t *testing.T) { tests := []struct { @@ -245,6 +263,33 @@ func TestPart_GetContentBroken(t *testing.T) { } } +// TestPart_IsSMimeSigned tests Part.IsSMimeSigned +func TestPart_IsSMimeSigned(t *testing.T) { + tests := []struct { + name string + want bool + }{ + {"smime:", true}, + {"smime:", false}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + m := NewMsg() + m.SetBodyString(TypeTextPlain, "This is a body!") + pl, err := getPartList(m) + if err != nil { + t.Errorf("failed: %s", err) + return + } + pl[0].SetIsSMimeSigned(tt.want) + smime := pl[0].IsSMimeSigned() + if smime != tt.want { + t.Errorf("SetContentType failed. Got: %v, expected: %v", smime, tt.want) + } + }) + } +} + // TestPart_SetWriteFunc tests Part.SetWriteFunc func TestPart_SetWriteFunc(t *testing.T) { c := "This is a test with ümläutß" diff --git a/sime.go b/sime.go new file mode 100644 index 0000000..fe05158 --- /dev/null +++ b/sime.go @@ -0,0 +1,159 @@ +package mail + +import ( + "bytes" + "crypto/rsa" + "crypto/tls" + "crypto/x509" + "encoding/pem" + "errors" + "fmt" + "go.mozilla.org/pkcs7" + "strings" +) + +var ( + // ErrInvalidKeyPair should be used if key pair is invalid + ErrInvalidKeyPair = errors.New("invalid key pair") + + // ErrCouldNotInitialize should be used if the signed data could not initialize + ErrCouldNotInitialize = errors.New("could not initialize signed data") + + // ErrCouldNotAddSigner should be used if the signer could not be added + ErrCouldNotAddSigner = errors.New("could not add signer message") + + // ErrCouldNotFinishSigning should be used if the signing could not be finished + ErrCouldNotFinishSigning = errors.New("could not finish signing") + + // ErrCouldNoEncodeToPEM should be used if the signature could not be encoded to PEM + ErrCouldNoEncodeToPEM = errors.New("could not encode to PEM") +) + +// SMime is used to sign messages with S/MIME +type SMime struct { + privateKey *rsa.PrivateKey + certificate *x509.Certificate + parentCertificates []*x509.Certificate +} + +// NewSMime construct a new instance of SMime with a provided *tls.Certificate +func newSMime(keyPair *tls.Certificate) (*SMime, error) { + if keyPair == nil { + return nil, ErrInvalidKeyPair + } + + parentCertificates := make([]*x509.Certificate, 0) + for _, cert := range keyPair.Certificate[1:] { + c, err := x509.ParseCertificate(cert) + if err != nil { + return nil, err + } + parentCertificates = append(parentCertificates, c) + } + + return &SMime{ + privateKey: keyPair.PrivateKey.(*rsa.PrivateKey), + certificate: keyPair.Leaf, + parentCertificates: parentCertificates, + }, nil +} + +// sign with the S/MIME method the message of the actual *Part +func (sm *SMime) sign(signaturePart *Part, message string) error { + lines := parseLines([]byte(message)) + toBeSigned := lines.bytesFromLines([]byte("\r\n")) + + tmp, err := pkcs7.NewSignedData(toBeSigned) + tmp.SetDigestAlgorithm(pkcs7.OIDDigestAlgorithmSHA256) + if err != nil { + return ErrCouldNotInitialize + } + + if err = tmp.AddSignerChain(sm.certificate, sm.privateKey, sm.parentCertificates, pkcs7.SignerInfoConfig{}); err != nil { + return ErrCouldNotAddSigner + } + + signatureDER, err := tmp.Finish() + if err != nil { + return ErrCouldNotFinishSigning + } + + pemMsg, err := encodeToPEM(signatureDER) + if err != nil { + return ErrCouldNoEncodeToPEM + } + signaturePart.SetContent(*pemMsg) + + return nil +} + +// createMessage prepares the message that will be used for the sign method later +func (sm *SMime) createMessage(encoding Encoding, contentType ContentType, charset Charset, body []byte) string { + return fmt.Sprintf("Content-Transfer-Encoding: %v\r\nContent-Type: %v; charset=%v\r\n\r\n%v", encoding, contentType, charset, string(body)) +} + +// encodeToPEM uses the method pem.Encode from the standard library but cuts the typical PEM preamble +func encodeToPEM(msg []byte) (*string, error) { + block := &pem.Block{Bytes: msg} + + var arrayBuffer bytes.Buffer + if err := pem.Encode(&arrayBuffer, block); err != nil { + return nil, err + } + + r := arrayBuffer.String() + r = strings.ReplaceAll(r, "-----BEGIN -----\n", "") + r = strings.ReplaceAll(r, "-----END -----\n", "") + + return &r, nil +} + +// line is the representation of one line of the message that will be used for signing purposes +type line struct { + line []byte + endOfLine []byte +} + +// lines is the representation of a message that will be used for signing purposes +type lines []line + +// bytesFromLines creates the line representation with the given endOfLine char +func (ls lines) bytesFromLines(sep []byte) []byte { + var raw []byte + for i := range ls { + raw = append(raw, ls[i].line...) + if len(ls[i].endOfLine) != 0 && sep != nil { + raw = append(raw, sep...) + } else { + raw = append(raw, ls[i].endOfLine...) + } + } + return raw +} + +// parseLines constructs the lines representation of a given message +func parseLines(raw []byte) lines { + oneLine := line{raw, nil} + lines := lines{oneLine} + lines = lines.splitLine([]byte("\r\n")) + lines = lines.splitLine([]byte("\r")) + lines = lines.splitLine([]byte("\n")) + return lines +} + +// splitLine uses the given endOfLine to split the given line +func (ls lines) splitLine(sep []byte) lines { + nl := lines{} + for _, l := range ls { + split := bytes.Split(l.line, sep) + if len(split) > 1 { + for i := 0; i < len(split)-1; i++ { + nl = append(nl, line{split[i], sep}) + } + nl = append(nl, line{split[len(split)-1], l.endOfLine}) + } else { + nl = append(nl, l) + } + } + return nl +} diff --git a/util_test.go b/util_test.go new file mode 100644 index 0000000..47bac43 --- /dev/null +++ b/util_test.go @@ -0,0 +1,22 @@ +package mail + +import ( + "crypto/tls" + "crypto/x509" +) + +const ( + certFilePath = "dummy-chain-cert.pem" + keyFilePath = "dummy-child-key.pem" +) + +func getDummyCertificate() (*tls.Certificate, error) { + keyPair, err := tls.LoadX509KeyPair(certFilePath, keyFilePath) + if err != nil { + return nil, err + } + + keyPair.Leaf, err = x509.ParseCertificate(keyPair.Certificate[0]) + + return &keyPair, nil +}