Move the temporary packages to thirdparty

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

validate.go

+package verifcid
+
+import (
+	"fmt"
+
+	mh "gx/ipfs/QmZyZDi491cCNTLfAhwcaDii2Kg4pwKRkhqQzURGDvY6ua/go-multihash"
+	cid "gx/ipfs/QmcZfnkapfECQGcLZaf9B79NRg7cRa9EnZh4LSbkCzwNvY/go-cid"
+)
+
+var ErrPossiblyInsecureHashFunction = fmt.Errorf("potentially insecure hash functions not allowed")
+var ErrBelowMinimumHashLength = fmt.Errorf("hashes must be at %d least bytes long", minimumHashLength)
+
+const minimumHashLength = 20
+
+var goodset = map[uint64]bool{
+	mh.SHA2_256:     true,
+	mh.SHA2_512:     true,
+	mh.SHA3_224:     true,
+	mh.SHA3_256:     true,
+	mh.SHA3_384:     true,
+	mh.SHA3_512:     true,
+	mh.SHAKE_256:    true,
+	mh.DBL_SHA2_256: true,
+	mh.KECCAK_224:   true,
+	mh.KECCAK_256:   true,
+	mh.KECCAK_384:   true,
+	mh.KECCAK_512:   true,
+	mh.ID:           true,
+
+	mh.SHA1: true, // not really secure but still useful
+}
+
+func IsGoodHash(code uint64) bool {
+	good, found := goodset[code]
+	if good {
+		return true
+	}
+
+	if !found {
+		if code >= mh.BLAKE2B_MIN+19 && code <= mh.BLAKE2B_MAX {
+			return true
+		}
+		if code >= mh.BLAKE2S_MIN+19 && code <= mh.BLAKE2S_MAX {
+			return true
+		}
+	}
+
+	return false
+}
+
+func ValidateCid(c *cid.Cid) error {
+	pref := c.Prefix()
+	if !IsGoodHash(pref.MhType) {
+		return ErrPossiblyInsecureHashFunction
+	}
+
+	if pref.MhType != mh.ID && pref.MhLength < minimumHashLength {
+		return ErrBelowMinimumHashLength
+	}
+
+	return nil
+}

validate_test.go

+package verifcid
+
+import (
+	"testing"
+
+	mh "gx/ipfs/QmZyZDi491cCNTLfAhwcaDii2Kg4pwKRkhqQzURGDvY6ua/go-multihash"
+
+	cid "gx/ipfs/QmcZfnkapfECQGcLZaf9B79NRg7cRa9EnZh4LSbkCzwNvY/go-cid"
+)
+
+func TestValidateCids(t *testing.T) {
+	assertTrue := func(v bool) {
+		t.Helper()
+		if !v {
+			t.Fatal("expected success")
+		}
+	}
+	assertFalse := func(v bool) {
+		t.Helper()
+		if v {
+			t.Fatal("expected failure")
+		}
+	}
+
+	assertTrue(IsGoodHash(mh.SHA2_256))
+	assertTrue(IsGoodHash(mh.BLAKE2B_MIN + 32))
+	assertTrue(IsGoodHash(mh.DBL_SHA2_256))
+	assertTrue(IsGoodHash(mh.KECCAK_256))
+	assertTrue(IsGoodHash(mh.SHA3))
+
+	assertTrue(IsGoodHash(mh.SHA1))
+
+	assertFalse(IsGoodHash(mh.BLAKE2B_MIN + 5))
+
+	mhcid := func(code uint64, length int) *cid.Cid {
+		mhash, err := mh.Sum([]byte{}, code, length)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return cid.NewCidV1(cid.DagCBOR, mhash)
+	}
+
+	cases := []struct {
+		cid *cid.Cid
+		err error
+	}{
+		{mhcid(mh.SHA2_256, 32), nil},
+		{mhcid(mh.SHA2_256, 16), ErrBelowMinimumHashLength},
+		{mhcid(mh.MURMUR3, 4), ErrPossiblyInsecureHashFunction},
+	}
+
+	for i, cas := range cases {
+		if ValidateCid(cas.cid) != cas.err {
+			t.Errorf("wrong result in case of %s (index %d). Expected: %s, got %s",
+				cas.cid, i, cas.err, ValidateCid(cas.cid))
+		}
+	}
+
+}