fscrypt: factor out fscrypt_policy_to_key_spec()

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 <ebiggers@google.com>
Link: https://lore.kernel.org/r/20220501050857.538984-4-ebiggers@kernel.org

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 33f08f1b1974ed158a191b0d3808e32af5ddd510..7c93325161b07eb429961bf755445e0c0be6d1f3 100644 (file)
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -623,6 +623,8 @@ 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 6b509af13e0da87d2ae35137c43ab191a6c1b188..c35711896bd4fb3b37b617946dd34a1565c3fe10 100644 (file)
--- 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 ed3d623724cddbc0cef5b06948db83726f87b574..2a11276913a985174bba33589ffd625e829af2f2 100644 (file)
--- 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)
 {