internal/cpe: add binding and tests

3 files changed, 251 insertions, 1 deletions

diff --git a/internal/cpe/binding.go b/internal/cpe/binding.go
new file mode 100644
index 0000000..8c51d7d
--- /dev/null
+++ b/internal/cpe/binding.go
@@ -0,0 +1,118 @@
+package cpe
+
+import (
+  "encoding/json"
+  "errors"
+  "fmt"
+  "strings"
+)
+
+// Common Platform Enumeration binding.
+type Binding struct {
+  Part      Part      // Part attribute (NISTIR7695 5.3.3.1).
+  Vendor    AvString  // Vendor attribute (NISTIR7695 5.3.3.2).
+  Product   AvString  // Product attribute (NISTIR7695 5.3.3.3).
+  Version   AvString  // Version attribute (NISTIR7695 5.3.3.4).
+  Update    AvString  // Update attribute (NISTIR7695 5.3.3.5).
+  Edition   AvString  // Edition attribute (NISTIR7695 5.3.3.6).
+  SwEdition AvString  // Software edition attribute (NISTIR7695 5.3.3.7).
+  TargetSw  AvString  // Target software attribute (NISTIR7695 5.3.3.8).
+  TargetHw  AvString  // Target hardware attribute (NISTIR7695 5.3.3.9).
+  Lang      AvString  // Language attribute (NISTIR7695 5.3.3.10).
+  Other     AvString  // Other attribute (NISTIR7695 5.3.3.11).
+}
+
+// cpe 2.3 formatted string prefix
+var cpe23Prefix = "cpe:2.3:"
+
+// missing prefix error
+var missingPrefix = errors.New("missing CPE 2.3 prefix")
+
+// Create CPE 2.3 binding from formatted string.
+func NewBinding(s string) (Binding, error) {
+  // check prefix
+  if s[0:len(cpe23Prefix)] != cpe23Prefix {
+    return Binding{}, missingPrefix
+  }
+
+  // tokenize string, check for error
+  toks, err := tokenize([]byte(s[len(cpe23Prefix):]))
+  if err != nil {
+    return Binding{}, err
+  }
+
+  // check token count
+  if len(toks) != 11 {
+    err = fmt.Errorf("invalid attribute count: %d != 11", len(toks))
+    return Binding{}, err
+  }
+
+  // create part
+  part, err := newPart(toks[0])
+  if err != nil {
+    return Binding{}, err
+  }
+
+  // parse tokens into strings
+  strs := make([]AvString, len(toks) - 1)
+  for i, t := range(toks[1:]) {
+    if strs[i], err = newAvString(t); err != nil {
+      return Binding{}, err
+    }
+  }
+
+  // build and return result
+  return Binding {
+    Part: part,
+    Vendor: strs[0],
+    Product: strs[1],
+    Version: strs[2],
+    Update: strs[3],
+    Edition: strs[4],
+    Lang: strs[5],
+    SwEdition: strs[6],
+    TargetSw: strs[7],
+    TargetHw: strs[8],
+    Other: strs[9],
+  }, nil
+}
+
+func (v Binding) String() string {
+  return cpe23Prefix + strings.Join([]string {
+    v.Part.String(),
+    v.Vendor.String(),
+    v.Product.String(),
+    v.Version.String(),
+    v.Update.String(),
+    v.Edition.String(),
+    v.Lang.String(),
+    v.SwEdition.String(),
+    v.TargetSw.String(),
+    v.TargetHw.String(),
+    v.Other.String(),
+  }, ":")
+}
+
+// Unmarshal CPE formatted string from JSON string.
+func (me *Binding) UnmarshalJSON(b []byte) error {
+  // decode json string
+  var s string
+  if err := json.Unmarshal(b, &s); err != nil {
+    return err
+  }
+
+  // create binding
+  binding, err := NewBinding(s)
+  if err != nil {
+    return err
+  }
+
+  // save result, return success
+  *me = binding
+  return nil
+}
+
+// Marshal CPE formatted string as JSON string.
+func (v Binding) MarshalJSON() ([]byte, error) {
+  return json.Marshal(v.String())
+}
diff --git a/internal/cpe/binding_test.go b/internal/cpe/binding_test.go
new file mode 100644
index 0000000..7c5154a
--- /dev/null
+++ b/internal/cpe/binding_test.go
@@ -0,0 +1,132 @@
+package cpe
+
+import (
+  "encoding/json"
+  "testing"
+)
+
+func TestNewBinding(t *testing.T) {
+  passTests := []string {
+    "cpe:2.3:o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*",
+  }
+
+  for _, val := range(passTests) {
+    t.Run(val, func(t *testing.T) {
+      if _, err := NewBinding(val); err != nil {
+        t.Error(err)
+      }
+    })
+  }
+
+  failTests := []struct {
+    val string
+    exp string
+  } {{
+    val: "o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*",
+    exp: "missing CPE 2.3 prefix",
+  }, {
+    val: "cpe:2.3:\n",
+    exp: "invalid byte: 0x0a",
+  }, {
+    val: "cpe:2.3:o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*",
+    exp: "invalid attribute count: 10 != 11",
+  }, {
+    val: "cpe:2.3:foo:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*",
+    exp: "unknown part: \"foo\"",
+  }}
+
+  for _, test := range(failTests) {
+    t.Run(test.val, func(t *testing.T) {
+      got, err := NewBinding(test.val)
+      if err == nil {
+        t.Errorf("got %v, exp error", got)
+      } else if err.Error() != test.exp {
+        t.Errorf("got \"%s\", exp \"%s\"", err.Error(), test.exp)
+      }
+    })
+  }
+}
+
+func TestBindingString(t *testing.T) {
+  tests := []string {
+    "cpe:2.3:o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*",
+  }
+
+  for _, val := range(tests) {
+    t.Run(val, func(t *testing.T) {
+      if got, err := NewBinding(val); err != nil {
+        t.Error(err)
+      } else if got.String() != val {
+        t.Errorf("got \"%s\", exp \"%s\"", got.String(), val)
+      }
+    })
+  }
+}
+
+func TestBindingUnmarshalJSON(t *testing.T) {
+  passTests := []string {
+    `"cpe:2.3:o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*"`,
+  }
+
+  for _, val := range(passTests) {
+    t.Run(val, func(t *testing.T) {
+      var b Binding
+      if err := json.Unmarshal([]byte(val), &b); err != nil {
+        t.Error(err)
+      }
+    })
+  }
+
+  failTests := []struct {
+    val string
+    exp string
+  } {{
+    val: `"o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*`,
+    exp: "unexpected end of JSON input",
+  }, {
+    val: `"o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*"`,
+    exp: "missing CPE 2.3 prefix",
+  }}
+
+  for _, test := range(failTests) {
+    t.Run(test.val, func(t *testing.T) {
+      var got Binding
+      if err := json.Unmarshal([]byte(test.val), &got); err == nil {
+        t.Errorf("got %v, exp error", got)
+      } else if err.Error() != test.exp {
+        t.Errorf("got \"%s\", exp \"%s\"", err.Error(), test.exp)
+      }
+    })
+  }
+}
+
+func TestBindingMarshalJSON(t *testing.T) {
+  tests := []string {
+    "cpe:2.3:o:intel:ethernet_controller_e810_firmware:*:*:*:*:*:*:*:*",
+  }
+
+  for _, val := range(tests) {
+    t.Run(val, func(t *testing.T) {
+      // create binding, check for error
+      b, err := NewBinding(val)
+      if err != nil {
+        t.Error(err)
+        return
+      }
+
+      // marshal json, check for error
+      got, err := json.Marshal(b)
+      if err != nil {
+        t.Error(err)
+        return
+      }
+
+      // build/check expected value
+      exp := "\"" + val + "\""
+      if string(got) != exp {
+        t.Errorf("got \"%s\", exp \"%s\"", string(got), exp)
+        return
+      }
+    })
+  }
+}
diff --git a/internal/cpe/cpe.go b/internal/cpe/cpe.go
index 331f315..dc38419 100644
--- a/internal/cpe/cpe.go
+++ b/internal/cpe/cpe.go
@@ -1,5 +1,5 @@
 // CPE 2.3 formatted string parser.
 //
-// Source: NISTIR 7605, figure 6-3:
+// Source: NISTIR 7695, figure 6-3:
 // https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nistir7695.pdf
 package cpe