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hiddecohiddeco
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Add loose SSH signature implementation
Signed-off-by: Hidde Beydals <hidde@hhh.computer>
1 parent fddfecd commit e1b64bc

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5 files changed

+162
-13
lines changed

5 files changed

+162
-13
lines changed

‎go.mod

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,7 @@ require (
1212
github.com/go-git/go-billy/v5 v5.4.1
1313
github.com/go-git/go-git-fixtures/v4 v4.3.1
1414
github.com/google/go-cmp v0.5.9
15+
github.com/hiddeco/sshsig v0.1.0
1516
github.com/imdario/mergo v0.3.13
1617
github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99
1718
github.com/jessevdk/go-flags v1.5.0
@@ -21,10 +22,10 @@ require (
2122
github.com/sergi/go-diff v1.1.0
2223
github.com/skeema/knownhosts v1.1.0
2324
github.com/xanzy/ssh-agent v0.3.3
24-
golang.org/x/crypto v0.6.0
25-
golang.org/x/net v0.7.0
26-
golang.org/x/sys v0.5.0
27-
golang.org/x/text v0.7.0
25+
golang.org/x/crypto v0.7.0
26+
golang.org/x/net v0.8.0
27+
golang.org/x/sys v0.6.0
28+
golang.org/x/text v0.8.0
2829
gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
2930
gopkg.in/warnings.v0 v0.1.2 // indirect
3031
)

‎go.sum

Lines changed: 23 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -28,6 +28,8 @@ github.com/go-git/go-git-fixtures/v4 v4.3.1 h1:y5z6dd3qi8Hl+stezc8p3JxDkoTRqMAlK
2828
github.com/go-git/go-git-fixtures/v4 v4.3.1/go.mod h1:8LHG1a3SRW71ettAD/jW13h8c6AqjVSeL11RAdgaqpo=
2929
github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
3030
github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
31+
github.com/hiddeco/sshsig v0.1.0 h1:ehWA9PeBtDVAU7uULxUbQgw2e/JAB+ZKN29TIO33QUk=
32+
github.com/hiddeco/sshsig v0.1.0/go.mod h1:PtIDi8GwgjGQDK0fUF1XhC24wjOymNbyiWd0NzXxTwo=
3133
github.com/imdario/mergo v0.3.13 h1:lFzP57bqS/wsqKssCGmtLAb8A0wKjLGrve2q3PPVcBk=
3234
github.com/imdario/mergo v0.3.13/go.mod h1:4lJ1jqUDcsbIECGy0RUJAXNIhg+6ocWgb1ALK2O4oXg=
3335
github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 h1:BQSFePA1RWJOlocH6Fxy8MmwDt+yVQYULKfN0RoTN8A=
@@ -59,10 +61,15 @@ github.com/sirupsen/logrus v1.7.0/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic
5961
github.com/skeema/knownhosts v1.1.0 h1:Wvr9V0MxhjRbl3f9nMnKnFfiWTJmtECJ9Njkea3ysW0=
6062
github.com/skeema/knownhosts v1.1.0/go.mod h1:sKFq3RD6/TKZkSWn8boUbDC7Qkgcv+8XXijpFO6roag=
6163
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
64+
github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
65+
github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
6266
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
6367
github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
64-
github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
6568
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
69+
github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
70+
github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
71+
github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
72+
github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
6673
github.com/xanzy/ssh-agent v0.3.3 h1:+/15pJfg/RsTxqYcX6fHqOXZwwMP+2VyYWJeWM2qQFM=
6774
github.com/xanzy/ssh-agent v0.3.3/go.mod h1:6dzNDKs0J9rVPHPhaGCukekBHKqfl+L3KghI1Bc68Uw=
6875
github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
@@ -73,21 +80,23 @@ golang.org/x/crypto v0.0.0-20220525230936-793ad666bf5e/go.mod h1:IxCIyHEi3zRg3s0
7380
golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
7481
golang.org/x/crypto v0.0.0-20220826181053-bd7e27e6170d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
7582
golang.org/x/crypto v0.1.0/go.mod h1:RecgLatLF4+eUMCP1PoPZQb+cVrJcOPbHkTkbkB9sbw=
76-
golang.org/x/crypto v0.6.0 h1:qfktjS5LUO+fFKeJXZ+ikTRijMmljikvG68fpMMruSc=
77-
golang.org/x/crypto v0.6.0/go.mod h1:OFC/31mSvZgRz0V1QTNCzfAI1aIRzbiufJtkMIlEp58=
83+
golang.org/x/crypto v0.7.0 h1:AvwMYaRytfdeVt3u6mLaxYtErKYjxA2OXjJ1HHq6t3A=
84+
golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
7885
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
7986
golang.org/x/mod v0.6.0/go.mod h1:4mET923SAdbXp2ki8ey+zGs1SLqsuM2Y0uvdZR/fUNI=
87+
golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
8088
golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
8189
golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
8290
golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
8391
golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
8492
golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
8593
golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
8694
golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
87-
golang.org/x/net v0.7.0 h1:rJrUqqhjsgNp7KqAIc25s9pZnjU7TUcSY7HcVZjdn1g=
88-
golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
95+
golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
96+
golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
8997
golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
9098
golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
99+
golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
91100
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
92101
golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
93102
golang.org/x/sys v0.0.0-20200302150141-5c8b2ff67527/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -104,25 +113,29 @@ golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBc
104113
golang.org/x/sys v0.0.0-20220825204002-c680a09ffe64/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
105114
golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
106115
golang.org/x/sys v0.3.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
107-
golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
108116
golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
117+
golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
118+
golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
109119
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
110120
golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
111121
golang.org/x/term v0.0.0-20220722155259-a9ba230a4035/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
112122
golang.org/x/term v0.1.0/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
113-
golang.org/x/term v0.5.0 h1:n2a8QNdAb0sZNpU9R1ALUXBbY+w51fCQDN+7EdxNBsY=
114123
golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
124+
golang.org/x/term v0.6.0 h1:clScbb1cHjoCkyRbWwBEUZ5H/tIFu5TAXIqaZD0Gcjw=
125+
golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
115126
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
116127
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
117128
golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
118129
golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
119130
golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
120-
golang.org/x/text v0.7.0 h1:4BRB4x83lYWy72KwLD/qYDuTu7q9PjSagHvijDw7cLo=
121131
golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
132+
golang.org/x/text v0.8.0 h1:57P1ETyNKtuIjB4SRd15iJxuhj8Gc416Y78H3qgMh68=
133+
golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
122134
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
123135
golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
124136
golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
125137
golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
138+
golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
126139
golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
127140
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
128141
gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -134,6 +147,7 @@ gopkg.in/warnings.v0 v0.1.2/go.mod h1:jksf8JmL6Qr/oQM2OXTHunEvvTAsrWBLb6OOjuVWRN
134147
gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
135148
gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
136149
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
137-
gopkg.in/yaml.v3 v3.0.0 h1:hjy8E9ON/egN1tAYqKb61G10WtihqetD4sz2H+8nIeA=
138150
gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
151+
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
152+
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
139153
rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

‎plumbing/object/signature/ssh/entity.go

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,34 @@
1+
package ssh
2+
3+
import (
4+
"golang.org/x/crypto/ssh"
5+
6+
"github.com/go-git/go-git/v5/plumbing/object/signature"
7+
)
8+
9+
// EntityType is the SSH Entity type. It can be used to detect if a
10+
// signature.Entity is of type SSH.
11+
const EntityType signature.EntityType = "SSH"
12+
13+
// Entity is the SSH entity that signed a signature.VerifiableObject.
14+
// Using the Entity method, you can get the underlying ssh.PublicKey.
15+
type Entity struct {
16+
publicKey ssh.PublicKey
17+
}
18+
19+
// Canonical returns the canonical identifier of the Entity. Which equals to
20+
// a marshalled authorized key (as in a known_hosts file).
21+
func (s *Entity) Canonical() string {
22+
return string(ssh.MarshalAuthorizedKey(s.publicKey))
23+
}
24+
25+
// Type returns the EntityType of the Entity.
26+
func (s *Entity) Type() signature.EntityType {
27+
return EntityType
28+
}
29+
30+
// Concrete returns the underlying concrete type of the Entity. In this case
31+
// a pointer to an ssh.PublicKey.
32+
func (s *Entity) Concrete() interface{} {
33+
return s.publicKey
34+
}

‎plumbing/object/signature/ssh/signer.go

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,54 @@
1+
package ssh
2+
3+
import (
4+
"github.com/hiddeco/sshsig"
5+
"golang.org/x/crypto/ssh"
6+
7+
"github.com/go-git/go-git/v5/plumbing"
8+
"github.com/go-git/go-git/v5/plumbing/object/signature"
9+
)
10+
11+
// namespace is the Git namespace for SSH signatures.
12+
// TODO(hidde): need to confirm how this relates to defining "namespaces" in
13+
//
14+
// allowed_signers file.
15+
const namespace = "git"
16+
17+
// Signer is an SSH signer. It can sign a signature.SignableObject object using
18+
// an ssh.Signer.
19+
type Signer struct {
20+
signer ssh.Signer
21+
algorithm sshsig.HashAlgorithm
22+
}
23+
24+
// NewSigner returns a new Signer using the given ssh.Signer and hash algorithm.
25+
func NewSigner(signer ssh.Signer, algorithm sshsig.HashAlgorithm) (*Signer, error) {
26+
return &Signer{signer: signer, algorithm: algorithm}, nil
27+
}
28+
29+
// NewDefaultSigner returns a new Signer using the given ssh.Signer. It uses
30+
// sshsig.HashSHA512 as the default hash algorithm.
31+
func NewDefaultSigner(signer ssh.Signer) (*Signer, error) {
32+
return NewSigner(signer, sshsig.HashSHA512)
33+
}
34+
35+
// Sign signs a signature.SignableObject object using the Signer's ssh.Signer.
36+
// It returns the signature of the object in armored (PEM) format, or an
37+
// error.
38+
func (s *Signer) Sign(o signature.SignableObject) (string, error) {
39+
encoded := &plumbing.MemoryObject{}
40+
if err := o.Encode(encoded); err != nil {
41+
return "", err
42+
}
43+
44+
r, err := encoded.Reader()
45+
if err != nil {
46+
return "", err
47+
}
48+
49+
sig, err := sshsig.Sign(r, s.signer, s.algorithm, namespace)
50+
if err != nil {
51+
return "", err
52+
}
53+
return string(sshsig.Armor(sig)), nil
54+
}

‎plumbing/object/signature/ssh/verifier.go

Lines changed: 46 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,46 @@
1+
package ssh
2+
3+
import (
4+
"github.com/hiddeco/sshsig"
5+
"golang.org/x/crypto/ssh"
6+
7+
"github.com/go-git/go-git/v5/plumbing"
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"github.com/go-git/go-git/v5/plumbing/object/signature"
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)
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// Verifier is an SSH verifier. It can verify an SSH signature using an
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// ssh.PublicKey.
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//
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// TODO(hidde): the PGP counterpart is capable of doing "lists", mostly because
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//
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// it can do "keyrings". This is not possible with SSH, so we need to figure out
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// if we want to support multiple keys in the same verifier. The alternative
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// would potentially be a wrapper which can parse an allowed_signers file into
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// a list of verifiers.
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type Verifier struct {
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publicKey ssh.PublicKey
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}
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// Verify verifies an SSH signature using the verifier's public SSH key.
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// It returns the signature.Entity that signed the object, or an error.
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func (v *Verifier) Verify(o signature.VerifiableObject) (signature.Entity, error) {
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sig, err := sshsig.Unarmor([]byte(o.Signature()))
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if err != nil {
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return nil, err
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}
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encoded := &plumbing.MemoryObject{}
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if err := o.EncodeWithoutSignature(encoded); err != nil {
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return nil, err
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}
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er, err := encoded.Reader()
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if err != nil {
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return nil, err
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}
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if err := sshsig.Verify(er, sig, v.publicKey, sig.HashAlgorithm, sig.Namespace); err != nil {
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return nil, err
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}
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return &Entity{publicKey: v.publicKey}, nil
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}

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