diff options
| author | Eric Biggers <ebiggers@google.com> | 2023-02-07 22:21:03 -0800 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2023-02-07 22:30:30 -0800 |
| commit | 60e463f0be9874692a56a7d419a6e39029b6290d (patch) | |
| tree | 0c8a86275f6b293eee0ad9081158311a07fe48ed /fs/crypto | |
| parent | 6d796c50f84ca79f1722bb131799e5a5710c4700 (diff) | |
fscrypt: add the test dummy encryption key on-demand
When the key for an inode is not found but the inode is using the
test_dummy_encryption policy, automatically add the
test_dummy_encryption key to the filesystem keyring. This eliminates
the need for all the individual filesystems to do this at mount time,
which is a bit tricky to clean up from on failure.
Note: this covers the call to fscrypt_find_master_key() from inode key
setup, but not from the fscrypt ioctls. So, this isn't *exactly* the
same as the key being present from the very beginning. I think we can
tolerate that, though, since the inode key setup caller is the only one
that actually matters in the context of test_dummy_encryption.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230208062107.199831-2-ebiggers@kernel.org
Diffstat (limited to 'fs/crypto')
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 1 | ||||
| -rw-r--r-- | fs/crypto/keysetup.c | 25 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 3 |
3 files changed, 25 insertions, 4 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 316a778cec0f..17dd33d9a522 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -651,6 +651,7 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1, const union fscrypt_policy *policy2); int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, struct fscrypt_key_specifier *key_spec); +const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb); bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, const struct inode *inode); int fscrypt_policy_from_context(union fscrypt_policy *policy_u, diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 94757ccd3056..20323c0ba4c5 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -438,6 +438,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, bool need_dirhash_key, struct fscrypt_master_key **mk_ret) { + struct super_block *sb = ci->ci_inode->i_sb; struct fscrypt_key_specifier mk_spec; struct fscrypt_master_key *mk; int err; @@ -450,8 +451,28 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, if (err) return err; - mk = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec); - if (!mk) { + mk = fscrypt_find_master_key(sb, &mk_spec); + if (unlikely(!mk)) { + const union fscrypt_policy *dummy_policy = + fscrypt_get_dummy_policy(sb); + + /* + * Add the test_dummy_encryption key on-demand. In principle, + * it should be added at mount time. Do it here instead so that + * the individual filesystems don't need to worry about adding + * this key at mount time and cleaning up on mount failure. + */ + if (dummy_policy && + fscrypt_policies_equal(dummy_policy, &ci->ci_policy)) { + struct fscrypt_dummy_policy tmp = { dummy_policy }; + + err = fscrypt_add_test_dummy_key(sb, &tmp); + if (err) + return err; + mk = fscrypt_find_master_key(sb, &mk_spec); + } + } + if (unlikely(!mk)) { if (ci->ci_policy.version != FSCRYPT_POLICY_V1) return -ENOKEY; diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 893661b52376..69dca4ff5f48 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -53,8 +53,7 @@ int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, } } -static const union fscrypt_policy * -fscrypt_get_dummy_policy(struct super_block *sb) +const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb) { if (!sb->s_cop->get_dummy_policy) return NULL; |