From 03bf604fc08abc9bb2d75bde21c96c9df4894a3b Mon Sep 17 00:00:00 2001 From: Jakob Unterwurzacher Date: Tue, 5 Dec 2017 23:31:07 +0100 Subject: [PATCH] syscallcompat: OpenNofollow: use O_DIRECTORY flag ...when opening intermedia directories to give us an extra layer of safety. From the FreeBSD man page: This flag can be used to prevent applications with elevated privileges from opening files which are even unsafe to open with O_RDONLY, such as device nodes. --- internal/syscallcompat/open_nofollow.go | 6 +++--- internal/syscallcompat/open_nofollow_test.go | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/internal/syscallcompat/open_nofollow.go b/internal/syscallcompat/open_nofollow.go index 1afa54c..4f75bd6 100644 --- a/internal/syscallcompat/open_nofollow.go +++ b/internal/syscallcompat/open_nofollow.go @@ -22,8 +22,8 @@ func OpenNofollow(baseDir string, relPath string, flags int, mode uint32) (fd in tlog.Warn.Printf("BUG: OpenNofollow called with absolute relPath=%q", relPath) return -1, syscall.EINVAL } - // Open the base dir - dirfd, err := syscall.Open(baseDir, syscall.O_RDONLY, 0) + // Open the base dir (following symlinks) + dirfd, err := syscall.Open(baseDir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0) if err != nil { return -1, err } @@ -39,7 +39,7 @@ func OpenNofollow(baseDir string, relPath string, flags int, mode uint32) (fd in // Walk intermediate directories var dirfd2 int for _, name := range dirs { - dirfd2, err = Openat(dirfd, name, syscall.O_RDONLY|syscall.O_NOFOLLOW, 0) + dirfd2, err = Openat(dirfd, name, syscall.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_DIRECTORY, 0) syscall.Close(dirfd) if err != nil { return -1, err diff --git a/internal/syscallcompat/open_nofollow_test.go b/internal/syscallcompat/open_nofollow_test.go index 37ea76b..1f21557 100644 --- a/internal/syscallcompat/open_nofollow_test.go +++ b/internal/syscallcompat/open_nofollow_test.go @@ -31,8 +31,8 @@ func TestOpenNofollow(t *testing.T) { if err == nil { t.Fatalf("should have failed") } - if err != syscall.ELOOP { - t.Errorf("expected ELOOP, got %v", err) + if err != syscall.ELOOP && err != syscall.ENOTDIR { + t.Errorf("expected ELOOP or ENOTDIR, got %v", err) } // Check to see that the base dir can be opened as well fd, err = OpenNofollow(tmpDir, "", syscall.O_RDONLY, 0)