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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-08-31 10:01:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-08-31 10:01:14 -0700 |
| commit | cd358208d703fca446b52f3cf8f23c18f9e7705e (patch) | |
| tree | c3a7930959a5a28fac428d09adfe5912bc2a7e51 /Documentation/filesystems | |
| parent | 87045e6546078dae215d1bd3b2bc82b3ada3ca77 (diff) | |
| parent | 38ef66b05cfa3560323344a0b3e09e583f1eb974 (diff) | |
Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt
Pull fscrypt updates from Eric Biggers:
"Some small fixes and cleanups for fs/crypto/:
- Fix ->getattr() for ext4, f2fs, and ubifs to report the correct
st_size for encrypted symlinks
- Use base64url instead of a custom Base64 variant
- Document struct fscrypt_operations"
* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
fscrypt: document struct fscrypt_operations
fscrypt: align Base64 encoding with RFC 4648 base64url
fscrypt: remove mention of symlink st_size quirk from documentation
ubifs: report correct st_size for encrypted symlinks
f2fs: report correct st_size for encrypted symlinks
ext4: report correct st_size for encrypted symlinks
fscrypt: add fscrypt_symlink_getattr() for computing st_size
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 15 |
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 |