diff options
| -rw-r--r-- | io/tst-lchmod.c | 83 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/fchmodat.c | 28 |
2 files changed, 49 insertions, 62 deletions
diff --git a/io/tst-lchmod.c b/io/tst-lchmod.c index 73e45549af..59873f130d 100644 --- a/io/tst-lchmod.c +++ b/io/tst-lchmod.c @@ -102,68 +102,44 @@ test_1 (bool do_relative_path, int (*chmod_func) (int fd, const char *, mode_t, TEST_VERIFY ((st.st_mode & 0777) != 2); mode_t original_symlink_mode = st.st_mode; - /* Set to true if AT_SYMLINK_NOFOLLOW is supported. */ - bool nofollow; - /* We should be able to change the mode of a file, including through the symbolic link to-file. */ const char *arg = select_path (do_relative_path, path_file, "file"); TEST_COMPARE (chmod_func (fd, arg, 1, 0), 0); xstat (path_file, &st); TEST_COMPARE (st.st_mode & 0777, 1); - int ret = chmod_func (fd, path_file, 2, AT_SYMLINK_NOFOLLOW); - if (ret == 0) - { - printf ("info: AT_SYMLINK_NOFOLLOW support in %s\n", tempdir); - nofollow = true; - } - else - { - printf ("info: no AT_SYMLINK_NOFOLLOW support in %s\n", tempdir); - nofollow = false; - - /* Set up things for the code below. */ - TEST_COMPARE (chmod_func (fd, path_file, 2, 0), 0); - } + arg = select_path (do_relative_path, path_to_file, "to-file"); + TEST_COMPARE (chmod_func (fd, path_to_file, 2, 0), 0); xstat (path_file, &st); TEST_COMPARE (st.st_mode & 0777, 2); - arg = select_path (do_relative_path, path_to_file, "to-file"); - TEST_COMPARE (chmod_func (fd, path_to_file, 1, 0), 0); + xlstat (path_to_file, &st); + TEST_COMPARE (original_symlink_mode, st.st_mode); + arg = select_path (do_relative_path, path_file, "file"); + TEST_COMPARE (chmod_func (fd, arg, 1, 0), 0); xstat (path_file, &st); TEST_COMPARE (st.st_mode & 0777, 1); xlstat (path_to_file, &st); TEST_COMPARE (original_symlink_mode, st.st_mode); - /* Changing the mode of a symbolic link may fail. */ + /* Changing the mode of a symbolic link should fail fail. */ arg = select_path (do_relative_path, path_to_file, "to-file"); - ret = chmod_func (fd, arg, 2, AT_SYMLINK_NOFOLLOW); - if (nofollow) - { - TEST_COMPARE (ret, 0); - - /* The mode of the link changed. */ - xlstat (path_to_file, &st); - TEST_COMPARE (st.st_mode & 0777, 2); - - /* But the mode of the file is unchanged. */ - xstat (path_file, &st); - TEST_COMPARE (st.st_mode & 0777, 1); + int ret = chmod_func (fd, arg, 2, AT_SYMLINK_NOFOLLOW); + TEST_COMPARE (ret, -1); + TEST_COMPARE (errno, EOPNOTSUPP); - } - else - { - TEST_COMPARE (ret, -1); - TEST_COMPARE (errno, EOPNOTSUPP); + /* The modes should remain unchanged. */ + xstat (path_file, &st); + TEST_COMPARE (st.st_mode & 0777, 1); + xlstat (path_to_file, &st); + TEST_COMPARE (original_symlink_mode, st.st_mode); - /* The modes should remain unchanged. */ - xstat (path_file, &st); - TEST_COMPARE (st.st_mode & 0777, 1); - xlstat (path_to_file, &st); - TEST_COMPARE (original_symlink_mode, st.st_mode); - } + arg = select_path (do_relative_path, path_to_file, "to-file"); + ret = chmod_func (fd, arg, 2, AT_SYMLINK_NOFOLLOW); + TEST_COMPARE (ret, -1); + TEST_COMPARE (errno, EOPNOTSUPP); - /* If we have NOFOLLOW support, we should be able to change the mode - of a dangling symbolic link or a symbolic link loop. */ + /* Likewise, changing dangling and looping symbolic links must + fail. */ const char *paths[] = { path_dangling, path_loop }; for (size_t i = 0; i < array_length (paths); ++i) { @@ -178,19 +154,10 @@ test_1 (bool do_relative_path, int (*chmod_func) (int fd, const char *, mode_t, original_symlink_mode = st.st_mode; arg = select_path (do_relative_path, path, filename); ret = chmod_func (fd, arg, new_mode, AT_SYMLINK_NOFOLLOW); - if (nofollow) - { - TEST_COMPARE (ret, 0); - xlstat (path, &st); - TEST_COMPARE (st.st_mode & 0777, new_mode); - } - else /* !nofollow. */ - { - TEST_COMPARE (ret, -1); - TEST_COMPARE (errno, EOPNOTSUPP); - xlstat (path, &st); - TEST_COMPARE (st.st_mode, original_symlink_mode); - } + TEST_COMPARE (ret, -1); + TEST_COMPARE (errno, EOPNOTSUPP); + xlstat (path, &st); + TEST_COMPARE (st.st_mode, original_symlink_mode); } /* A missing file should always result in ENOENT. The presence of diff --git a/sysdeps/unix/sysv/linux/fchmodat.c b/sysdeps/unix/sysv/linux/fchmodat.c index 719053b333..17eca54051 100644 --- a/sysdeps/unix/sysv/linux/fchmodat.c +++ b/sysdeps/unix/sysv/linux/fchmodat.c @@ -45,6 +45,30 @@ fchmodat (int fd, const char *file, mode_t mode, int flag) caller can treat them as temporary if necessary. */ return pathfd; + /* Use fstatat because fstat does not work on O_PATH descriptors + before Linux 3.6. */ + struct stat64 st; + if (fstatat64 (pathfd, "", &st, AT_EMPTY_PATH) != 0) + { + __close_nocancel (pathfd); + return -1; + } + + /* Some Linux versions with some file systems can actually + change symbolic link permissions via /proc, but this is not + intentional, and it gives inconsistent results (e.g., error + return despite mode change). The expected behavior is that + symbolic link modes cannot be changed at all, and this check + enforces that. */ + if (S_ISLNK (st.st_mode)) + { + __close_nocancel (pathfd); + __set_errno (EOPNOTSUPP); + return -1; + } + + /* For most file systems, fchmod does not operate on O_PATH + descriptors, so go through /proc. */ char buf[32]; if (__snprintf (buf, sizeof (buf), "/proc/self/fd/%d", pathfd) < 0) { @@ -54,10 +78,6 @@ fchmodat (int fd, const char *file, mode_t mode, int flag) return -1; } - /* This operates directly on the symbolic link if it is one. - /proc/self/fd files look like symbolic links, but they are - not. (fchmod and fchmodat do not work on O_PATH descriptors, - similar to fstat before Linux 3.6.) */ int ret = __chmod (buf, mode); if (ret != 0) { |