| Message ID | 20190220065249.32099-5-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fscrypt: key management improvements | expand |
On Wed, Feb 20, 2019 at 7:55 AM Eric Biggers <ebiggers@kernel.org> wrote: > > From: Eric Biggers <ebiggers@google.com> > > Add an ->s_master_keys keyring to 'struct super_block'. New fscrypt > ioctls will allow adding and removing encryption keys from this keyring. > This will enable solving multiple interrelated problems with how fscrypt > keys are provided and managed currently, including: > > - Making the key status (which is currently per-process) match the > filesystem-level status of which encrypted files are "unlocked". > > - Supporting a proper API to remove encryption keys, "locking" the > corresponding encrypted files. > > - Caching an HMAC transform for each master key, allowing the use of > HKDF while still retaining good performance. > > - Preventing denial of service via keyctl_invalidate(). > > Similar to the existing ->s_cop, the keyring is added to the VFS-level > superblock struct rather than separately to the ext4, f2fs, and ubifs > superblock structs so that it can be used by the shared code in > fs/crypto/. To minimize overhead, the keyring will only be allocated if > userspace actually adds a key; otherwise will stay NULL. > > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > fs/super.c | 3 +++ > include/linux/fs.h | 1 + > 2 files changed, 4 insertions(+) > > diff --git a/fs/super.c b/fs/super.c > index 48e25eba8465..7ca05dda905c 100644 > --- a/fs/super.c > +++ b/fs/super.c > @@ -291,6 +291,9 @@ static void __put_super(struct super_block *s) > security_sb_free(s); > put_user_ns(s->s_user_ns); > kfree(s->s_subtype); > +#ifdef CONFIG_FS_ENCRYPTION > + key_put(s->s_master_keys); > +#endif Please wrap this in a static inline function such that you can get rid of the ifdef here. Just like put_user_ns() does.
diff --git a/fs/super.c b/fs/super.c index 48e25eba8465..7ca05dda905c 100644 --- a/fs/super.c +++ b/fs/super.c @@ -291,6 +291,9 @@ static void __put_super(struct super_block *s) security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); +#ifdef CONFIG_FS_ENCRYPTION + key_put(s->s_master_keys); +#endif call_rcu(&s->rcu, destroy_super_rcu); } } diff --git a/include/linux/fs.h b/include/linux/fs.h index ba7889bb9ef6..70d929ac89f9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1405,6 +1405,7 @@ struct super_block { const struct xattr_handler **s_xattr; #ifdef CONFIG_FS_ENCRYPTION const struct fscrypt_operations *s_cop; + struct key *s_master_keys; /* master crypto keys in use */ #endif struct hlist_bl_head s_roots; /* alternate root dentries for NFS */ struct list_head s_mounts; /* list of mounts; _not_ for fs use */