From: Eric Biggers ebiggers@google.com
stable inclusion from linux-4.19.155 commit 906242d10b0b9279e5fda9691c13500d5b1fb543
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commit 0bf3d5c1604ecbbd4e49e9f5b3c79152b87adb0d upstream.
Make __d_move() clear DCACHE_ENCRYPTED_NAME on the source dentry. This is needed for when d_splice_alias() moves a directory's encrypted alias to its decrypted alias as a result of the encryption key being added.
Otherwise, the decrypted alias will incorrectly be invalidated on the next lookup, causing problems such as unmounting a mount the user just mount()ed there.
Note that we don't have to support arbitrary moves of this flag because fscrypt doesn't allow dentries with DCACHE_ENCRYPTED_NAME to be the source or target of a rename().
Fixes: 28b4c263961c ("ext4 crypto: revalidate dentry after adding or removing the key") Reported-by: Sarthak Kukreti sarthakkukreti@chromium.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/dcache.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/fs/dcache.c b/fs/dcache.c index a0793f96a9e8..333106c83edd 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2758,6 +2758,20 @@ static void copy_name(struct dentry *dentry, struct dentry *target) kfree_rcu(old_name, u.head); }
+/* + * When d_splice_alias() moves a directory's encrypted alias to its decrypted + * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME + * must be cleared. Note that we don't have to support arbitrary moves of this + * flag because fscrypt doesn't allow encrypted aliases to be the source or + * target of a rename(). + */ +static inline void fscrypt_handle_d_move(struct dentry *dentry) +{ +#if IS_ENABLED(CONFIG_FS_ENCRYPTION) + dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME; +#endif +} + /* * __d_move - move a dentry * @dentry: entry to move @@ -2833,6 +2847,7 @@ static void __d_move(struct dentry *dentry, struct dentry *target, list_move(&dentry->d_child, &dentry->d_parent->d_subdirs); __d_rehash(dentry); fsnotify_update_flags(dentry); + fscrypt_handle_d_move(dentry);
write_seqcount_end(&target->d_seq); write_seqcount_end(&dentry->d_seq);