Commit 02aef422 authored by Eric Biggers's avatar Eric Biggers
Browse files

fscrypt: pass super_block to fscrypt_put_master_key_activeref() 

As this code confused Linus [1], pass the super_block as an argument to
fscrypt_put_master_key_activeref().  This removes the need to have the
back-pointer ->mk_sb, so remove that.

[1] https://lore.kernel.org/linux-fscrypt/CAHk-=wgud4Bc_um+htgfagYpZAnOoCb3NUoW67hc9LhOKsMtJg@mail.gmail.com



Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221110082942.351615-1-ebiggers@kernel.org
parent f0c4d9fc

fs/crypto/fscrypt_private.h

+4 −9
Original line number Diff line number Diff line
@@ -439,13 +439,7 @@ struct fscrypt_master_key_secret { 
struct fscrypt_master_key {



	/*

	 * Back-pointer to the super_block of the filesystem to which this

	 * master key has been added.  Only valid if ->mk_active_refs > 0.

	 */

	struct super_block			*mk_sb;



	/*

	 * Link in ->mk_sb->s_master_keys->key_hashtable.

	 * Link in ->s_master_keys->key_hashtable.

	 * Only valid if ->mk_active_refs > 0.

	 */

	struct hlist_node			mk_node;
@@ -456,7 +450,7 @@ struct fscrypt_master_key { 
	/*

	 * Active and structural reference counts.  An active ref guarantees

	 * that the struct continues to exist, continues to be in the keyring

	 * ->mk_sb->s_master_keys, and that any embedded subkeys (e.g.

	 * ->s_master_keys, and that any embedded subkeys (e.g.

	 * ->mk_direct_keys) that have been prepared continue to exist.

	 * A structural ref only guarantees that the struct continues to exist.

	 *
@@ -569,7 +563,8 @@ static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec) 


void fscrypt_put_master_key(struct fscrypt_master_key *mk);



void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk);

void fscrypt_put_master_key_activeref(struct super_block *sb,

				      struct fscrypt_master_key *mk);



struct fscrypt_master_key *

fscrypt_find_master_key(struct super_block *sb,

fs/crypto/keyring.c

+6 −8
Original line number Diff line number Diff line
@@ -79,10 +79,9 @@ void fscrypt_put_master_key(struct fscrypt_master_key *mk) 
	call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);

}



void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk)

void fscrypt_put_master_key_activeref(struct super_block *sb,

				      struct fscrypt_master_key *mk)

{

	struct super_block *sb = mk->mk_sb;

	struct fscrypt_keyring *keyring = sb->s_master_keys;

	size_t i;



	if (!refcount_dec_and_test(&mk->mk_active_refs))
@@ -93,9 +92,9 @@ void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk) 
	 * destroying any subkeys embedded in it.

	 */



	spin_lock(&keyring->lock);

	spin_lock(&sb->s_master_keys->lock);

	hlist_del_rcu(&mk->mk_node);

	spin_unlock(&keyring->lock);

	spin_unlock(&sb->s_master_keys->lock);



	/*

	 * ->mk_active_refs == 0 implies that ->mk_secret is not present and
@@ -243,7 +242,7 @@ void fscrypt_destroy_keyring(struct super_block *sb) 
			WARN_ON(refcount_read(&mk->mk_struct_refs) != 1);

			WARN_ON(!is_master_key_secret_present(&mk->mk_secret));

			wipe_master_key_secret(&mk->mk_secret);

			fscrypt_put_master_key_activeref(mk);

			fscrypt_put_master_key_activeref(sb, mk);

		}

	}

	kfree_sensitive(keyring);
@@ -424,7 +423,6 @@ static int add_new_master_key(struct super_block *sb, 
	if (!mk)

		return -ENOMEM;



	mk->mk_sb = sb;

	init_rwsem(&mk->mk_sem);

	refcount_set(&mk->mk_struct_refs, 1);

	mk->mk_spec = *mk_spec;
@@ -1068,7 +1066,7 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users) 
	err = -ENOKEY;

	if (is_master_key_secret_present(&mk->mk_secret)) {

		wipe_master_key_secret(&mk->mk_secret);

		fscrypt_put_master_key_activeref(mk);

		fscrypt_put_master_key_activeref(sb, mk);

		err = 0;

	}

	inodes_remain = refcount_read(&mk->mk_active_refs) > 0;

fs/crypto/keysetup.c

+1 −1
Original line number Diff line number Diff line
@@ -509,7 +509,7 @@ static void put_crypt_info(struct fscrypt_info *ci) 
		spin_lock(&mk->mk_decrypted_inodes_lock);

		list_del(&ci->ci_master_key_link);

		spin_unlock(&mk->mk_decrypted_inodes_lock);

		fscrypt_put_master_key_activeref(mk);

		fscrypt_put_master_key_activeref(ci->ci_inode->i_sb, mk);

	}

	memzero_explicit(ci, sizeof(*ci));

	kmem_cache_free(fscrypt_info_cachep, ci);