Fix artifact v4 upload above 8MB (#31664)

Multiple chunks are uploaded with type "block" without using
"appendBlock" and eventually out of order for bigger uploads.
8MB seems to be the chunk size

This change parses the blockList uploaded after all blocks to get the
final artifact size and order them correctly before calculating the
sha256 checksum over all blocks

Fixes #31354

tests/integration/api_actions_artifact_v4_test.go

@@ -7,12 +7,14 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"encoding/hex"
+	"encoding/xml"
 	"io"
 	"net/http"
 	"strings"
 	"testing"
 	"time"
 
+	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/routers/api/actions"
 	actions_service "code.gitea.io/gitea/services/actions"
 	"code.gitea.io/gitea/tests"
@@ -170,6 +172,134 @@ func TestActionsArtifactV4UploadSingleFileWithRetentionDays(t *testing.T) {
 	assert.True(t, finalizeResp.Ok)
 }
 
+func TestActionsArtifactV4UploadSingleFileWithPotentialHarmfulBlockID(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	token, err := actions_service.CreateAuthorizationToken(48, 792, 193)
+	assert.NoError(t, err)
+
+	// acquire artifact upload url
+	req := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/CreateArtifact", toProtoJSON(&actions.CreateArtifactRequest{
+		Version:                 4,
+		Name:                    "artifactWithPotentialHarmfulBlockID",
+		WorkflowRunBackendId:    "792",
+		WorkflowJobRunBackendId: "193",
+	})).AddTokenAuth(token)
+	resp := MakeRequest(t, req, http.StatusOK)
+	var uploadResp actions.CreateArtifactResponse
+	protojson.Unmarshal(resp.Body.Bytes(), &uploadResp)
+	assert.True(t, uploadResp.Ok)
+	assert.Contains(t, uploadResp.SignedUploadUrl, "/twirp/github.actions.results.api.v1.ArtifactService/UploadArtifact")
+
+	// get upload urls
+	idx := strings.Index(uploadResp.SignedUploadUrl, "/twirp/")
+	url := uploadResp.SignedUploadUrl[idx:] + "&comp=block&blockid=%2f..%2fmyfile"
+	blockListURL := uploadResp.SignedUploadUrl[idx:] + "&comp=blocklist"
+
+	// upload artifact chunk
+	body := strings.Repeat("A", 1024)
+	req = NewRequestWithBody(t, "PUT", url, strings.NewReader(body))
+	MakeRequest(t, req, http.StatusCreated)
+
+	// verify that the exploit didn't work
+	_, err = storage.Actions.Stat("myfile")
+	assert.Error(t, err)
+
+	// upload artifact blockList
+	blockList := &actions.BlockList{
+		Latest: []string{
+			"/../myfile",
+		},
+	}
+	rawBlockList, err := xml.Marshal(blockList)
+	assert.NoError(t, err)
+	req = NewRequestWithBody(t, "PUT", blockListURL, bytes.NewReader(rawBlockList))
+	MakeRequest(t, req, http.StatusCreated)
+
+	t.Logf("Create artifact confirm")
+
+	sha := sha256.Sum256([]byte(body))
+
+	// confirm artifact upload
+	req = NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/FinalizeArtifact", toProtoJSON(&actions.FinalizeArtifactRequest{
+		Name:                    "artifactWithPotentialHarmfulBlockID",
+		Size:                    1024,
+		Hash:                    wrapperspb.String("sha256:" + hex.EncodeToString(sha[:])),
+		WorkflowRunBackendId:    "792",
+		WorkflowJobRunBackendId: "193",
+	})).
+		AddTokenAuth(token)
+	resp = MakeRequest(t, req, http.StatusOK)
+	var finalizeResp actions.FinalizeArtifactResponse
+	protojson.Unmarshal(resp.Body.Bytes(), &finalizeResp)
+	assert.True(t, finalizeResp.Ok)
+}
+
+func TestActionsArtifactV4UploadSingleFileWithChunksOutOfOrder(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	token, err := actions_service.CreateAuthorizationToken(48, 792, 193)
+	assert.NoError(t, err)
+
+	// acquire artifact upload url
+	req := NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/CreateArtifact", toProtoJSON(&actions.CreateArtifactRequest{
+		Version:                 4,
+		Name:                    "artifactWithChunksOutOfOrder",
+		WorkflowRunBackendId:    "792",
+		WorkflowJobRunBackendId: "193",
+	})).AddTokenAuth(token)
+	resp := MakeRequest(t, req, http.StatusOK)
+	var uploadResp actions.CreateArtifactResponse
+	protojson.Unmarshal(resp.Body.Bytes(), &uploadResp)
+	assert.True(t, uploadResp.Ok)
+	assert.Contains(t, uploadResp.SignedUploadUrl, "/twirp/github.actions.results.api.v1.ArtifactService/UploadArtifact")
+
+	// get upload urls
+	idx := strings.Index(uploadResp.SignedUploadUrl, "/twirp/")
+	block1URL := uploadResp.SignedUploadUrl[idx:] + "&comp=block&blockid=block1"
+	block2URL := uploadResp.SignedUploadUrl[idx:] + "&comp=block&blockid=block2"
+	blockListURL := uploadResp.SignedUploadUrl[idx:] + "&comp=blocklist"
+
+	// upload artifact chunks
+	bodyb := strings.Repeat("B", 1024)
+	req = NewRequestWithBody(t, "PUT", block2URL, strings.NewReader(bodyb))
+	MakeRequest(t, req, http.StatusCreated)
+
+	bodya := strings.Repeat("A", 1024)
+	req = NewRequestWithBody(t, "PUT", block1URL, strings.NewReader(bodya))
+	MakeRequest(t, req, http.StatusCreated)
+
+	// upload artifact blockList
+	blockList := &actions.BlockList{
+		Latest: []string{
+			"block1",
+			"block2",
+		},
+	}
+	rawBlockList, err := xml.Marshal(blockList)
+	assert.NoError(t, err)
+	req = NewRequestWithBody(t, "PUT", blockListURL, bytes.NewReader(rawBlockList))
+	MakeRequest(t, req, http.StatusCreated)
+
+	t.Logf("Create artifact confirm")
+
+	sha := sha256.Sum256([]byte(bodya + bodyb))
+
+	// confirm artifact upload
+	req = NewRequestWithBody(t, "POST", "/twirp/github.actions.results.api.v1.ArtifactService/FinalizeArtifact", toProtoJSON(&actions.FinalizeArtifactRequest{
+		Name:                    "artifactWithChunksOutOfOrder",
+		Size:                    2048,
+		Hash:                    wrapperspb.String("sha256:" + hex.EncodeToString(sha[:])),
+		WorkflowRunBackendId:    "792",
+		WorkflowJobRunBackendId: "193",
+	})).
+		AddTokenAuth(token)
+	resp = MakeRequest(t, req, http.StatusOK)
+	var finalizeResp actions.FinalizeArtifactResponse
+	protojson.Unmarshal(resp.Body.Bytes(), &finalizeResp)
+	assert.True(t, finalizeResp.Ok)
+}
+
 func TestActionsArtifactV4DownloadSingle(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()