2022-05-01 19:27:28

by Eric Biggers

[permalink] [raw]
Subject: [PATCH v2 3/7] fscrypt: factor out fscrypt_policy_to_key_spec()

From: Eric Biggers <[email protected]>

Factor out a function that builds the fscrypt_key_specifier for an
fscrypt_policy. Before this was only needed when finding the key for a
file, but now it will also be needed for test_dummy_encryption support.

Signed-off-by: Eric Biggers <[email protected]>
---
fs/crypto/fscrypt_private.h | 2 ++
fs/crypto/keysetup.c | 20 +++-----------------
fs/crypto/policy.c | 20 ++++++++++++++++++++
3 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 5b0a9e6478b5d..f32d0ee91e70e 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -621,6 +621,8 @@ int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci);

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);
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 eede186b04ce3..571d220d6e226 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -425,23 +425,9 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
if (err)
return err;

- switch (ci->ci_policy.version) {
- case FSCRYPT_POLICY_V1:
- mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
- memcpy(mk_spec.u.descriptor,
- ci->ci_policy.v1.master_key_descriptor,
- FSCRYPT_KEY_DESCRIPTOR_SIZE);
- break;
- case FSCRYPT_POLICY_V2:
- mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
- memcpy(mk_spec.u.identifier,
- ci->ci_policy.v2.master_key_identifier,
- FSCRYPT_KEY_IDENTIFIER_SIZE);
- break;
- default:
- WARN_ON(1);
- return -EINVAL;
- }
+ err = fscrypt_policy_to_key_spec(&ci->ci_policy, &mk_spec);
+ if (err)
+ return err;

key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
if (IS_ERR(key)) {
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index ed3d623724cdd..2a11276913a98 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -32,6 +32,26 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
}

+int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy,
+ struct fscrypt_key_specifier *key_spec)
+{
+ switch (policy->version) {
+ case FSCRYPT_POLICY_V1:
+ key_spec->type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
+ memcpy(key_spec->u.descriptor, policy->v1.master_key_descriptor,
+ FSCRYPT_KEY_DESCRIPTOR_SIZE);
+ return 0;
+ case FSCRYPT_POLICY_V2:
+ key_spec->type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
+ memcpy(key_spec->u.identifier, policy->v2.master_key_identifier,
+ FSCRYPT_KEY_IDENTIFIER_SIZE);
+ return 0;
+ default:
+ WARN_ON(1);
+ return -EINVAL;
+ }
+}
+
static const union fscrypt_policy *
fscrypt_get_dummy_policy(struct super_block *sb)
{
--
2.36.0