fix(blob): add fixes along with the fuzzers that discovered them

This changes adds fuzzers+corpra that found some bugs, along
with tests and reproducers to catch future regressions.

Fixes celestiaorg#3727
Fixes celestiaorg#3728
Fixes celestiaorg#3729
Fixes celestiaorg#3730
Fixes celestiaorg#3731

blob/blob.go

@@ -168,6 +168,10 @@ func (b *Blob) UnmarshalJSON(data []byte) error {
 		return err
 	}
 
+	if len(jsonBlob.Namespace) == 0 {
+		return errors.New("expected a non-empty namespace")
+	}
+
 	b.Blob = &blob.Blob{}
 	b.Blob.NamespaceVersion = uint32(jsonBlob.Namespace.Version())
 	b.Blob.NamespaceId = jsonBlob.Namespace.ID()

blob/blob_fuzz_test.go

@@ -0,0 +1,92 @@
+package blob
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/celestiaorg/celestia-node/blob/blobtest"
+)
+
+func FuzzProofEqual(f *testing.F) {
+	if testing.Short() {
+		f.Skip("in -short mode")
+	}
+
+	// 1. Generate the corpus.
+	squareBlobs, err := blobtest.GenerateV0Blobs([]int{16}, false)
+	if err != nil {
+		f.Fatal(err)
+	}
+
+	blobs, err := convertBlobs(squareBlobs...)
+	if err != nil {
+		f.Fatal(err)
+	}
+
+	for _, blob := range blobs {
+		jsonBlob, err := blob.MarshalJSON()
+		if err != nil {
+			f.Fatal(err)
+		}
+		f.Add(jsonBlob)
+	}
+
+	// 2. Run the fuzzer.
+	f.Fuzz(func(t *testing.T, jsonBlob []byte) {
+		blob := new(Blob)
+		_ = blob.UnmarshalJSON(jsonBlob)
+	})
+}
+
+type verifyCorpus struct {
+	CP         *CommitmentProof `json:"commitment_proof"`
+	Root       []byte           `json:"root"`
+	SThreshold int              `json:"sub_threshold"`
+}
+
+func FuzzCommitmentProofVerify(f *testing.F) {
+	if testing.Short() {
+		f.Skip("in -short mode")
+	}
+
+	path := filepath.Join("testdata", "fuzz-corpus", "verify-*.json")
+	paths, err := filepath.Glob(path)
+	if err != nil {
+		f.Fatal(err)
+	}
+
+	// Add the corpra.
+	for _, path := range paths {
+		blob, err := os.ReadFile(path)
+		if err != nil {
+			f.Fatal(err)
+		}
+
+		var values []*verifyCorpus
+		if err := json.Unmarshal(blob, &values); err != nil {
+			f.Fatal(err)
+		}
+
+		for _, value := range values {
+			blob, err := json.Marshal(value)
+			if err != nil {
+				f.Fatal(err)
+			}
+			f.Add(blob)
+		}
+	}
+
+	f.Fuzz(func(t *testing.T, valueJSON []byte) {
+		val := new(verifyCorpus)
+		if err := json.Unmarshal(valueJSON, val); err != nil {
+			return
+		}
+		commitProof := val.CP
+		if commitProof == nil {
+			return
+		}
+		_, _ = commitProof.Verify(val.Root, val.SThreshold)
+	})
+}

blob/commitment_proof.go

@@ -2,6 +2,7 @@ package blob
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 
 	"github.com/celestiaorg/celestia-app/v2/pkg/appconsts"
@@ -85,6 +86,15 @@ func (commitmentProof *CommitmentProof) Validate() error {
 // Expects the commitment proof to be properly formulated and validated
 // using the Validate() function.
 func (commitmentProof *CommitmentProof) Verify(root []byte, subtreeRootThreshold int) (bool, error) {
+	if len(root) == 0 {
+		return false, errors.New("root must be non-empty")
+	}
+
+	rp := commitmentProof.RowProof
+	if err := rp.Validate(root); err != nil {
+		return false, err
+	}
+
 	nmtHasher := nmt.NewNmtHasher(appconsts.NewBaseHashFunc(), share.NamespaceSize, true)
 
 	// computes the total number of shares proven.
@@ -93,6 +103,10 @@ func (commitmentProof *CommitmentProof) Verify(root []byte, subtreeRootThreshold
 		numberOfShares += proof.End() - proof.Start()
 	}
 
+	if subtreeRootThreshold <= 0 {
+		return false, errors.New("subtreeRootThreshould must be > 0")
+	}
+
 	// use the computed total number of shares to calculate the subtree roots
 	// width.
 	// the subtree roots width is defined in ADR-013:
@@ -108,6 +122,15 @@ func (commitmentProof *CommitmentProof) Verify(root []byte, subtreeRootThreshold
 		if err != nil {
 			return false, err
 		}
+
+		if len(commitmentProof.SubtreeRoots) < subtreeRootsCursor {
+			return false, fmt.Errorf("len(commitmentProof.SubtreeRoots)=%d < subtreeRootsCursor=%d",
+				len(commitmentProof.SubtreeRoots), subtreeRootsCursor)
+		}
+		if len(commitmentProof.SubtreeRoots) < subtreeRootsCursor+len(ranges) {
+			return false, fmt.Errorf("len(commitmentProof.SubtreeRoots)=%d < subtreeRootsCursor+len(ranges)=%d",
+				len(commitmentProof.SubtreeRoots), subtreeRootsCursor+len(ranges))
+		}
 		valid, err := subtreeRootProof.VerifySubtreeRootInclusion(
 			nmtHasher,
 			commitmentProof.SubtreeRoots[subtreeRootsCursor:subtreeRootsCursor+len(ranges)],

blob/repro_test.go

@@ -0,0 +1,64 @@
+package blob_test
+
+import (
+	"testing"
+
+	"github.com/celestiaorg/celestia-app/v2/pkg/proof"
+	"github.com/celestiaorg/celestia-node/blob"
+	"github.com/celestiaorg/nmt"
+	"github.com/celestiaorg/nmt/pb"
+)
+
+// Reported at https://github.com/celestiaorg/celestia-node/issues/3731.
+func TestCommitmentProofRowProofVerifyWithEmptyRoot(t *testing.T) {
+	cp := &blob.CommitmentProof{
+		RowProof: proof.RowProof{
+			Proofs: []*proof.Proof{{}},
+		},
+	}
+	root := []byte{0xd3, 0x4d, 0x34}
+	if _, err := cp.Verify(root, 1); err == nil {
+		t.Fatal("expected a non-nil error")
+	}
+}
+
+// Reported at https://github.com/celestiaorg/celestia-node/issues/3730.
+func TestCommitmentProofRowProofVerify(t *testing.T) {
+	cp := &blob.CommitmentProof{
+		RowProof: proof.RowProof{
+			Proofs: []*proof.Proof{{}},
+		},
+	}
+	if _, err := cp.Verify(nil, 1); err == nil {
+		t.Fatal("expected a non-nil error")
+	}
+}
+
+// Reported at https://github.com/celestiaorg/celestia-node/issues/3729.
+func TestCommitmentProofVerifySliceBound(t *testing.T) {
+	proof := nmt.ProtoToProof(pb.Proof{End: 1})
+	cp := &blob.CommitmentProof{
+		SubtreeRootProofs: []*nmt.Proof{
+			&proof,
+		},
+	}
+	if _, err := cp.Verify(nil, 1); err == nil {
+		t.Fatal("expected a non-nil error")
+	}
+}
+
+// Reported at https://github.com/celestiaorg/celestia-node/issues/3728.
+func TestCommitmentProofVerifyZeroSubThreshold(t *testing.T) {
+	cp := new(blob.CommitmentProof)
+	if _, err := cp.Verify(nil, 0); err == nil {
+		t.Fatal("expected a non-nil error")
+	}
+}
+
+// Reported at https://github.com/celestiaorg/celestia-node/issues/3727.
+func TestBlobUnmarshalRepro(t *testing.T) {
+	blob := new(blob.Blob)
+	if err := blob.UnmarshalJSON([]byte("{}")); err == nil {
+		t.Fatal("expected a non-nil error")
+	}
+}

blob/testdata/fuzz/FuzzCommitmentProofVerify/582528ddfad69eb5

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("0")

blob/testdata/fuzz/FuzzCommitmentProofVerify/6a2b4b982dc67bf9

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{\"Commitment_proof\":{\"suBtree_root_proofs\":[{\"end\":1}]},\"suB_threshold\":1}")

blob/testdata/fuzz/FuzzCommitmentProofVerify/8093511184ad3e25

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{}")

blob/testdata/fuzz/FuzzCommitmentProofVerify/c23296029c66526c

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{\"Commitment_proof\":{\"row_proof\":{\"proofs\":[{}]}},\"root\":\"0000\",\"suB_threshold\":1}")

blob/testdata/fuzz/FuzzCommitmentProofVerify/ea1afcc1fa86d415

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{\"Commitment_proof\":{\"row_proof\":{\"proofs\":[{}]}},\"suB_threshold\":1}")

blob/testdata/fuzz/FuzzCommitmentProofVerify/fa5be9420bbacd9a

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{\"Commitment_proof\":{}}")

blob/testdata/fuzz/FuzzProofEqual/8093511184ad3e25

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("{}")