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-rw-r--r--Documentation/filesystems/fscrypt.rst15
1 files changed, 5 insertions, 10 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 44b67ebd6e40..0eb799d9d05a 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -1063,11 +1063,6 @@ astute users may notice some differences in behavior:
- DAX (Direct Access) is not supported on encrypted files.
-- The st_size of an encrypted symlink will not necessarily give the
- length of the symlink target as required by POSIX. It will actually
- give the length of the ciphertext, which will be slightly longer
- than the plaintext due to NUL-padding and an extra 2-byte overhead.
-
- The maximum length of an encrypted symlink is 2 bytes shorter than
the maximum length of an unencrypted symlink. For example, on an
EXT4 filesystem with a 4K block size, unencrypted symlinks can be up
@@ -1235,12 +1230,12 @@ the user-supplied name to get the ciphertext.
Lookups without the key are more complicated. The raw ciphertext may
contain the ``\0`` and ``/`` characters, which are illegal in
-filenames. Therefore, readdir() must base64-encode the ciphertext for
-presentation. For most filenames, this works fine; on ->lookup(), the
-filesystem just base64-decodes the user-supplied name to get back to
-the raw ciphertext.
+filenames. Therefore, readdir() must base64url-encode the ciphertext
+for presentation. For most filenames, this works fine; on ->lookup(),
+the filesystem just base64url-decodes the user-supplied name to get
+back to the raw ciphertext.
-However, for very long filenames, base64 encoding would cause the
+However, for very long filenames, base64url encoding would cause the
filename length to exceed NAME_MAX. To prevent this, readdir()
actually presents long filenames in an abbreviated form which encodes
a strong "hash" of the ciphertext filename, along with the optional