75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
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package protocol
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import (
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"encoding/asn1"
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)
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// Attribute ::= SEQUENCE {
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// attrType OBJECT IDENTIFIER,
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// attrValues SET OF AttributeValue }
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//
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// AttributeValue ::= ANY
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type Attribute struct {
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Type asn1.ObjectIdentifier
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// This should be a SET OF ANY, but Go's asn1 parser can't handle slices of
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// RawValues. Use value() to get an AnySet of the value.
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RawValue []asn1.RawValue `asn1:"set"`
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}
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// NewAttribute creates a single-value Attribute.
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func NewAttribute(attrType asn1.ObjectIdentifier, val interface{}) (attr Attribute, err error) {
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var rv asn1.RawValue
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if rv, err = RawValue(val); err != nil {
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return
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}
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attr = Attribute{attrType, []asn1.RawValue{rv}}
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return
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}
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// Attributes is a common Go type for SignedAttributes and UnsignedAttributes.
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//
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// SignedAttributes ::= SET SIZE (1..MAX) OF Attribute
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//
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// UnsignedAttributes ::= SET SIZE (1..MAX) OF Attribute
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type Attributes []Attribute
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// GetOnlyAttributeValueBytes gets an attribute value, returning an error if the
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// attribute occurs multiple times or has multiple values.
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func (attrs Attributes) GetOnlyAttributeValueBytes(oid asn1.ObjectIdentifier) (rv asn1.RawValue, err error) {
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var vals [][]asn1.RawValue
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if vals, err = attrs.GetValues(oid); err != nil {
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return
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}
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if len(vals) != 1 {
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err = ASN1Error{"bad attribute count"}
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return
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}
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if len(vals[0]) != 1 {
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err = ASN1Error{"bad attribute element count"}
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return
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}
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return vals[0][0], nil
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}
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// GetValues retreives the attributes with the given OID. A nil value is
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// returned if the OPTIONAL SET of Attributes is missing from the SignerInfo. An
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// empty slice is returned if the specified attribute isn't in the set.
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func (attrs Attributes) GetValues(oid asn1.ObjectIdentifier) ([][]asn1.RawValue, error) {
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if attrs == nil {
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return nil, nil
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}
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vals := [][]asn1.RawValue{}
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for _, attr := range attrs {
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if attr.Type.Equal(oid) {
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vals = append(vals, attr.RawValue)
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}
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}
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return vals, nil
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}
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