From dd038b348f51f93550644cfd5183ffe87c99ed57 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 20 Mar 2019 11:39:11 -0700 Subject: [PATCH] fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory 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 Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o --- fs/dcache.c | 2 ++ include/linux/fscrypt.h | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index 2e7e8d85e9b4..4298bb29ff11 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -2787,6 +2788,7 @@ 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); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index aeb87feab683..28c74e0a7231 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -90,6 +90,18 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode) inode->i_sb->s_cop->dummy_context(inode); } +/* + * 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) +{ + dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME; +} + /* crypto.c */ extern void fscrypt_enqueue_decrypt_work(struct work_struct *); extern struct fscrypt_ctx *fscrypt_get_ctx(gfp_t); @@ -247,6 +259,10 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode) return false; } +static inline void fscrypt_handle_d_move(struct dentry *dentry) +{ +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {