diff options
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/filesystem.go | 11 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/tmpfs/filesystem.go | 2 | ||||
| -rw-r--r-- | test/syscalls/linux/open.cc | 32 |
3 files changed, 44 insertions, 1 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go index eaef2594d..40fec890a 100644 --- a/pkg/sentry/fsimpl/gofer/filesystem.go +++ b/pkg/sentry/fsimpl/gofer/filesystem.go @@ -844,6 +844,13 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf } } if rp.Done() { + // Reject attempts to open mount root directory with O_CREAT. + if mayCreate && rp.MustBeDir() { + return nil, syserror.EISDIR + } + if mustCreate { + return nil, syserror.EEXIST + } return start.openLocked(ctx, rp, &opts) } @@ -856,6 +863,10 @@ afterTrailingSymlink: if err := parent.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil { return nil, err } + // Reject attempts to open directories with O_CREAT. + if mayCreate && rp.MustBeDir() { + return nil, syserror.EISDIR + } // Determine whether or not we need to create a file. parent.dirMu.Lock() child, err := fs.stepLocked(ctx, rp, parent, false /* mayFollowSymlinks */, &ds) diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go index 065812065..a4864df53 100644 --- a/pkg/sentry/fsimpl/tmpfs/filesystem.go +++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go @@ -320,7 +320,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf fs.mu.Lock() defer fs.mu.Unlock() if rp.Done() { - // Reject attempts to open directories with O_CREAT. + // Reject attempts to open mount root directory with O_CREAT. if rp.MustBeDir() { return nil, syserror.EISDIR } diff --git a/test/syscalls/linux/open.cc b/test/syscalls/linux/open.cc index bf350946b..c7147c20b 100644 --- a/test/syscalls/linux/open.cc +++ b/test/syscalls/linux/open.cc @@ -95,6 +95,38 @@ TEST_F(OpenTest, OTruncAndReadOnlyFile) { Open(dirpath.c_str(), O_TRUNC | O_RDONLY, 0666)); } +TEST_F(OpenTest, OCreateDirectory) { + SKIP_IF(IsRunningWithVFS1()); + auto dirpath = GetAbsoluteTestTmpdir(); + + // Normal case: existing directory. + ASSERT_THAT(open(dirpath.c_str(), O_RDWR | O_CREAT, 0666), + SyscallFailsWithErrno(EISDIR)); + // Trailing separator on existing directory. + ASSERT_THAT(open(dirpath.append("/").c_str(), O_RDWR | O_CREAT, 0666), + SyscallFailsWithErrno(EISDIR)); + // Trailing separator on non-existing directory. + ASSERT_THAT(open(JoinPath(dirpath, "non-existent").append("/").c_str(), + O_RDWR | O_CREAT, 0666), + SyscallFailsWithErrno(EISDIR)); + // "." special case. + ASSERT_THAT(open(JoinPath(dirpath, ".").c_str(), O_RDWR | O_CREAT, 0666), + SyscallFailsWithErrno(EISDIR)); +} + +TEST_F(OpenTest, MustCreateExisting) { + auto dirPath = GetAbsoluteTestTmpdir(); + + // Existing directory. + ASSERT_THAT(open(dirPath.c_str(), O_RDWR | O_CREAT | O_EXCL, 0666), + SyscallFailsWithErrno(EEXIST)); + + // Existing file. + auto newFile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dirPath)); + ASSERT_THAT(open(newFile.path().c_str(), O_RDWR | O_CREAT | O_EXCL, 0666), + SyscallFailsWithErrno(EEXIST)); +} + TEST_F(OpenTest, ReadOnly) { char buf; const FileDescriptor ro_file = |