From ef10d49a490f83627f87e0ddf0cd5b5e7b286373 Mon Sep 17 00:00:00 2001
From: Matthew Suozzo <msuozzo@google.com>
Date: Sun, 22 Sep 2024 09:27:38 -0400
Subject: [PATCH] Add cargo registryscan PoC

---
 tools/registryscan/main.go | 162 +++++++++++++++++++++++++++++++++++++
 1 file changed, 162 insertions(+)
 create mode 100644 tools/registryscan/main.go

diff --git a/tools/registryscan/main.go b/tools/registryscan/main.go
new file mode 100644
index 0000000..4fbb273
--- /dev/null
+++ b/tools/registryscan/main.go
@@ -0,0 +1,162 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/object"
+)
+
+type Package struct {
+	Name    string
+	Version string
+	Path    string
+}
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Println("Usage: go run main.go <path_to_lock_file> <path_to_git_repo>")
+		os.Exit(1)
+	}
+
+	lockFilePath := os.Args[1]
+	repoPath := os.Args[2]
+
+	packages, err := parseCargoLock(lockFilePath)
+	if err != nil {
+		fmt.Printf("Error parsing Cargo.lock: %v\n", err)
+		os.Exit(1)
+	}
+
+	repo, err := git.PlainOpen(repoPath)
+	if err != nil {
+		fmt.Printf("Error opening git repository: %v\n", err)
+		os.Exit(1)
+	}
+
+	// XXX: Needs to be manually adjusted to account for published date.
+	published := time.Now()
+	commit, err := findCommitWithVersions(repo, packages, published)
+	if err != nil {
+		fmt.Printf("Error finding commit: %v\n", err)
+		os.Exit(1)
+	}
+
+	if commit != nil {
+		fmt.Printf("Found commit: %s\n", commit.Hash)
+	} else {
+		fmt.Println("No commit found containing all package versions")
+	}
+}
+
+func parseCargoLock(filePath string) ([]Package, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var packages []Package
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "name = ") {
+			name := strings.Trim(strings.TrimPrefix(line, "name = "), "\"")
+			if scanner.Scan() {
+				versionLine := scanner.Text()
+				if strings.HasPrefix(versionLine, "version = ") {
+					version := strings.Trim(strings.TrimPrefix(versionLine, "version = "), "\"")
+					packages = append(packages, Package{Name: name, Version: version, Path: getPackageFilePath(name)})
+				}
+			}
+		}
+	}
+	fmt.Println(packages)
+
+	return packages, scanner.Err()
+}
+
+func getPackageFilePath(packageName string) string {
+	packageName = strings.ToLower(packageName)
+	switch len(packageName) {
+	case 1:
+		return filepath.Join("1", packageName)
+	case 2:
+		return filepath.Join("2", packageName)
+	case 3:
+		return filepath.Join("3", string(packageName[0]), packageName)
+	default:
+		return filepath.Join(packageName[:2], packageName[2:4], packageName)
+	}
+}
+
+func findCommitWithVersions(repo *git.Repository, packages []Package, published time.Time) (*object.Commit, error) {
+	fmt.Println("Calculating commits...")
+	commitIter, err := repo.Log(&git.LogOptions{Until: &published, Order: git.LogOrderCommitterTime})
+	if err != nil {
+		return nil, err
+	}
+
+	fmt.Println("Starting search...")
+	var c *object.Commit
+	var maxFound int
+	blobHashes := make(map[string]plumbing.Hash)
+	present := make(map[string]bool)
+	// TODO: detect yanking
+	err = commitIter.ForEach(func(commit *object.Commit) error {
+		fmt.Printf("Analyzing %s [time: %s]... ", commit.Hash.String(), commit.Committer.When)
+		tree, err := commit.Tree()
+		if err != nil {
+			return err
+		}
+		var found int
+		for _, pkg := range packages {
+			entry, err := tree.FindEntry(pkg.Path)
+			if err != nil {
+				continue
+			}
+			if entry.Hash != blobHashes[pkg.Path] {
+				blob, err := repo.BlobObject(entry.Hash)
+				if err != nil {
+					panic(err)
+				}
+				reader, err := blob.Reader()
+				if err != nil {
+					panic(err)
+				}
+				defer reader.Close()
+				content, err := io.ReadAll(reader)
+				if err != nil {
+					panic(err)
+				}
+				blobHashes[pkg.Path] = entry.Hash
+				present[pkg.Path] = bytes.Contains(content, []byte(`"vers":"`+pkg.Version+`"`))
+			}
+
+			if present[pkg.Path] {
+				found++
+			}
+		}
+		fmt.Printf("Found %02d\n", found)
+
+		if found >= maxFound {
+			maxFound = found
+			c = commit
+			return nil
+		} else {
+			return io.EOF
+		}
+	})
+	if err != nil && err != io.EOF {
+		return nil, err
+	}
+	return c, nil
+}