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authorDaniel Rosenberg <drosen@google.com>2020-01-20 14:31:56 -0800
committerEric Biggers <ebiggers@google.com>2020-01-22 14:47:15 -0800
commit6e1918cfb263acacd3fc9239127732b69de64695 (patch)
treef568fcd5fbed7df8ff441c664f18be933593ebd7 /include/linux/fscrypt.h
parent1b3b827ee5230a73c8ed1b2cd8d53b4bd001268b (diff)
fscrypt: don't allow v1 policies with casefolding
Casefolded encrypted directories will use a new dirhash method that requires a secret key. If the directory uses a v2 encryption policy, it's easy to derive this key from the master key using HKDF. However, v1 encryption policies don't provide a way to derive additional keys. Therefore, don't allow casefolding on directories that use a v1 policy. Specifically, make it so that trying to enable casefolding on a directory that has a v1 policy fails, trying to set a v1 policy on a casefolded directory fails, and trying to open a casefolded directory that has a v1 policy (if one somehow exists on-disk) fails. Signed-off-by: Daniel Rosenberg <drosen@google.com> [EB: improved commit message, updated fscrypt.rst, and other cleanups] Link: https://lore.kernel.org/r/20200120223201.241390-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'include/linux/fscrypt.h')
-rw-r--r--include/linux/fscrypt.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 6fe8d0f96a4a..3984eadd7023 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -263,6 +263,8 @@ extern int __fscrypt_prepare_rename(struct inode *old_dir,
unsigned int flags);
extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct fscrypt_name *fname);
+extern int fscrypt_prepare_setflags(struct inode *inode,
+ unsigned int oldflags, unsigned int flags);
extern int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link);
@@ -519,6 +521,13 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir,
return -EOPNOTSUPP;
}
+static inline int fscrypt_prepare_setflags(struct inode *inode,
+ unsigned int oldflags,
+ unsigned int flags)
+{
+ return 0;
+}
+
static inline int __fscrypt_prepare_symlink(struct inode *dir,
unsigned int len,
unsigned int max_len,