diff --git a/.github/workflows/git.yml b/.github/workflows/git.yml index 95398087c..d46cd3b0e 100644 --- a/.github/workflows/git.yml +++ b/.github/workflows/git.yml @@ -16,14 +16,14 @@ jobs: GIT_DIST_PATH: .git-dist/${{ matrix.git[0] }} steps: + - name: Checkout code + uses: actions/checkout@v4 + - name: Install Go uses: actions/setup-go@v4 with: go-version: 1.21.x - - name: Checkout code - uses: actions/checkout@v4 - - name: Install build dependencies run: sudo apt-get update && sudo apt-get install gettext libcurl4-openssl-dev diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml index 875dda7be..378000871 100644 --- a/.github/workflows/test.yml +++ b/.github/workflows/test.yml @@ -13,13 +13,13 @@ jobs: runs-on: ${{ matrix.platform }} steps: + - name: Checkout code + uses: actions/checkout@v4 + - name: Install Go uses: actions/setup-go@v4 with: go-version: ${{ matrix.go-version }} - - - name: Checkout code - uses: actions/checkout@v4 - name: Configure known hosts if: matrix.platform != 'ubuntu-latest' diff --git a/worktree.go b/worktree.go index 66cb3d29c..ad525c1a4 100644 --- a/worktree.go +++ b/worktree.go @@ -7,6 +7,7 @@ import ( "io" "os" "path/filepath" + "runtime" "strings" "github.com/go-git/go-billy/v5" @@ -394,6 +395,9 @@ func (w *Worktree) resetWorktree(t *object.Tree) error { b := newIndexBuilder(idx) for _, ch := range changes { + if err := w.validChange(ch); err != nil { + return err + } if err := w.checkoutChange(ch, t, b); err != nil { return err } @@ -403,6 +407,104 @@ func (w *Worktree) resetWorktree(t *object.Tree) error { return w.r.Storer.SetIndex(idx) } +// worktreeDeny is a list of paths that are not allowed +// to be used when resetting the worktree. +var worktreeDeny = map[string]struct{}{ + // .git + GitDirName: {}, + + // For other historical reasons, file names that do not conform to the 8.3 + // format (up to eight characters for the basename, three for the file + // extension, certain characters not allowed such as `+`, etc) are associated + // with a so-called "short name", at least on the `C:` drive by default. + // Which means that `git~1/` is a valid way to refer to `.git/`. + "git~1": {}, +} + +// validPath checks whether paths are valid. +// The rules around invalid paths could differ from upstream based on how +// filesystems are managed within go-git, but they are largely the same. +// +// For upstream rules: +// https://github.com/git/git/blob/564d0252ca632e0264ed670534a51d18a689ef5d/read-cache.c#L946 +// https://github.com/git/git/blob/564d0252ca632e0264ed670534a51d18a689ef5d/path.c#L1383 +func validPath(paths ...string) error { + for _, p := range paths { + parts := strings.FieldsFunc(p, func(r rune) bool { return (r == '\\' || r == '/') }) + if _, denied := worktreeDeny[strings.ToLower(parts[0])]; denied { + return fmt.Errorf("invalid path prefix: %q", p) + } + + if runtime.GOOS == "windows" { + // Volume names are not supported, in both formats: \\ and :. + if vol := filepath.VolumeName(p); vol != "" { + return fmt.Errorf("invalid path: %q", p) + } + + if !windowsValidPath(parts[0]) { + return fmt.Errorf("invalid path: %q", p) + } + } + + for _, part := range parts { + if part == ".." { + return fmt.Errorf("invalid path %q: cannot use '..'", p) + } + } + } + return nil +} + +// windowsPathReplacer defines the chars that need to be replaced +// as part of windowsValidPath. +var windowsPathReplacer *strings.Replacer + +func init() { + windowsPathReplacer = strings.NewReplacer(" ", "", ".", "") +} + +func windowsValidPath(part string) bool { + if len(part) > 3 && strings.EqualFold(part[:4], GitDirName) { + // For historical reasons, file names that end in spaces or periods are + // automatically trimmed. Therefore, `.git . . ./` is a valid way to refer + // to `.git/`. + if windowsPathReplacer.Replace(part[4:]) == "" { + return false + } + + // For yet other historical reasons, NTFS supports so-called "Alternate Data + // Streams", i.e. metadata associated with a given file, referred to via + // `::`. There exists a default stream + // type for directories, allowing `.git/` to be accessed via + // `.git::$INDEX_ALLOCATION/`. + // + // For performance reasons, _all_ Alternate Data Streams of `.git/` are + // forbidden, not just `::$INDEX_ALLOCATION`. + if len(part) > 4 && part[4:5] == ":" { + return false + } + } + return true +} + +func (w *Worktree) validChange(ch merkletrie.Change) error { + action, err := ch.Action() + if err != nil { + return nil + } + + switch action { + case merkletrie.Delete: + return validPath(ch.From.String()) + case merkletrie.Insert: + return validPath(ch.To.String()) + case merkletrie.Modify: + return validPath(ch.From.String(), ch.To.String()) + } + + return nil +} + func (w *Worktree) checkoutChange(ch merkletrie.Change, t *object.Tree, idx *indexBuilder) error { a, err := ch.Action() if err != nil { @@ -575,6 +677,11 @@ func (w *Worktree) checkoutFile(f *object.File) (err error) { } func (w *Worktree) checkoutFileSymlink(f *object.File) (err error) { + // https://github.com/git/git/commit/10ecfa76491e4923988337b2e2243b05376b40de + if strings.EqualFold(f.Name, gitmodulesFile) { + return ErrGitModulesSymlink + } + from, err := f.Reader() if err != nil { return diff --git a/worktree_test.go b/worktree_test.go index 3e057a79d..50ff189fa 100644 --- a/worktree_test.go +++ b/worktree_test.go @@ -4,6 +4,7 @@ import ( "bytes" "context" "errors" + "fmt" "io" "os" "path/filepath" @@ -2747,3 +2748,77 @@ func (s *WorktreeSuite) TestLinkedWorktree(c *C) { c.Assert(err, Equals, ErrRepositoryIncomplete) } } + +func TestValidPath(t *testing.T) { + type testcase struct { + path string + wantErr bool + } + + tests := []testcase{ + {".git", true}, + {".git/b", true}, + {".git\\b", true}, + {"git~1", true}, + {"a/../b", true}, + {"a\\..\\b", true}, + {".gitmodules", false}, + {".gitignore", false}, + {"a..b", false}, + {".", false}, + {"a/.git", false}, + {"a\\.git", false}, + {"a/.git/b", false}, + {"a\\.git\\b", false}, + } + + if runtime.GOOS == "windows" { + tests = append(tests, []testcase{ + {"\\\\a\\b", true}, + {"C:\\a\\b", true}, + {".git . . .", true}, + {".git . . ", true}, + {".git ", true}, + {".git.", true}, + {".git::$INDEX_ALLOCATION", true}, + }...) + } + + for _, tc := range tests { + t.Run(fmt.Sprintf("%s", tc.path), func(t *testing.T) { + err := validPath(tc.path) + if tc.wantErr { + assert.Error(t, err) + } else { + assert.NoError(t, err) + } + }) + } +} + +func TestWindowsValidPath(t *testing.T) { + tests := []struct { + path string + want bool + }{ + {".git", false}, + {".git . . .", false}, + {".git ", false}, + {".git ", false}, + {".git . .", false}, + {".git . .", false}, + {".git::$INDEX_ALLOCATION", false}, + {".git:", false}, + {"a", true}, + {"a\\b", true}, + {"a/b", true}, + {".gitm", true}, + } + + for _, tc := range tests { + t.Run(fmt.Sprintf("%s", tc.path), func(t *testing.T) { + got := windowsValidPath(tc.path) + assert.Equal(t, tc.want, got) + }) + } +}