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From: Eric Biggers <ebiggers@kernel.org>
To: linux-fscrypt@vger.kernel.org
Cc: Daniel Rosenberg <drosen@google.com>
Subject: [PATCH 1/4] fscrypt: split up fscrypt_supported_policy() by policy version
Date: Mon,  9 Dec 2019 13:18:26 -0800	[thread overview]
Message-ID: <20191209211829.239800-2-ebiggers@kernel.org> (raw)
In-Reply-To: <20191209211829.239800-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Make fscrypt_supported_policy() call new functions
fscrypt_supported_v1_policy() and fscrypt_supported_v2_policy(), to
reduce the indentation level and make the code easier to read.

Also adjust the function comment to mention that whether the encryption
policy is supported can also depend on the inode.

No change in behavior.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/crypto/policy.c | 116 +++++++++++++++++++++++----------------------
 1 file changed, 59 insertions(+), 57 deletions(-)

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 96f528071bed3..fdb13ce69cd28 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -63,13 +63,65 @@ static bool supported_iv_ino_lblk_64_policy(
 	return true;
 }
 
+static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy,
+					const struct inode *inode)
+{
+	if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+				     policy->filenames_encryption_mode)) {
+		fscrypt_warn(inode,
+			     "Unsupported encryption modes (contents %d, filenames %d)",
+			     policy->contents_encryption_mode,
+			     policy->filenames_encryption_mode);
+		return false;
+	}
+
+	if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
+			      FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
+		fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
+			     policy->flags);
+		return false;
+	}
+
+	return true;
+}
+
+static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
+					const struct inode *inode)
+{
+	if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
+				     policy->filenames_encryption_mode)) {
+		fscrypt_warn(inode,
+			     "Unsupported encryption modes (contents %d, filenames %d)",
+			     policy->contents_encryption_mode,
+			     policy->filenames_encryption_mode);
+		return false;
+	}
+
+	if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+		fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
+			     policy->flags);
+		return false;
+	}
+
+	if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
+	    !supported_iv_ino_lblk_64_policy(policy, inode))
+		return false;
+
+	if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {
+		fscrypt_warn(inode, "Reserved bits set in encryption policy");
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * fscrypt_supported_policy - check whether an encryption policy is supported
  *
  * Given an encryption policy, check whether all its encryption modes and other
- * settings are supported by this kernel.  (But we don't currently don't check
- * for crypto API support here, so attempting to use an algorithm not configured
- * into the crypto API will still fail later.)
+ * settings are supported by this kernel on the given inode.  (But we don't
+ * currently don't check for crypto API support here, so attempting to use an
+ * algorithm not configured into the crypto API will still fail later.)
  *
  * Return: %true if supported, else %false
  */
@@ -77,60 +129,10 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
 			      const struct inode *inode)
 {
 	switch (policy_u->version) {
-	case FSCRYPT_POLICY_V1: {
-		const struct fscrypt_policy_v1 *policy = &policy_u->v1;
-
-		if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
-					     policy->filenames_encryption_mode)) {
-			fscrypt_warn(inode,
-				     "Unsupported encryption modes (contents %d, filenames %d)",
-				     policy->contents_encryption_mode,
-				     policy->filenames_encryption_mode);
-			return false;
-		}
-
-		if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
-				      FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
-			fscrypt_warn(inode,
-				     "Unsupported encryption flags (0x%02x)",
-				     policy->flags);
-			return false;
-		}
-
-		return true;
-	}
-	case FSCRYPT_POLICY_V2: {
-		const struct fscrypt_policy_v2 *policy = &policy_u->v2;
-
-		if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
-					     policy->filenames_encryption_mode)) {
-			fscrypt_warn(inode,
-				     "Unsupported encryption modes (contents %d, filenames %d)",
-				     policy->contents_encryption_mode,
-				     policy->filenames_encryption_mode);
-			return false;
-		}
-
-		if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
-			fscrypt_warn(inode,
-				     "Unsupported encryption flags (0x%02x)",
-				     policy->flags);
-			return false;
-		}
-
-		if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
-		    !supported_iv_ino_lblk_64_policy(policy, inode))
-			return false;
-
-		if (memchr_inv(policy->__reserved, 0,
-			       sizeof(policy->__reserved))) {
-			fscrypt_warn(inode,
-				     "Reserved bits set in encryption policy");
-			return false;
-		}
-
-		return true;
-	}
+	case FSCRYPT_POLICY_V1:
+		return fscrypt_supported_v1_policy(&policy_u->v1, inode);
+	case FSCRYPT_POLICY_V2:
+		return fscrypt_supported_v2_policy(&policy_u->v2, inode);
 	}
 	return false;
 }
-- 
2.24.0.393.g34dc348eaf-goog


  reply	other threads:[~2019-12-09 21:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 21:18 [PATCH 0/4] fscrypt: fscrypt_supported_policy() fixes and cleanups Eric Biggers
2019-12-09 21:18 ` Eric Biggers [this message]
2019-12-09 21:18 ` [PATCH 2/4] fscrypt: check for appropriate use of DIRECT_KEY flag earlier Eric Biggers
2019-12-09 21:18 ` [PATCH 3/4] fscrypt: move fscrypt_valid_enc_modes() to policy.c Eric Biggers
2019-12-09 21:18 ` [PATCH 4/4] fscrypt: remove fscrypt_is_direct_key_policy() Eric Biggers
2020-01-03 17:00 ` [PATCH 0/4] fscrypt: fscrypt_supported_policy() fixes and cleanups Eric Biggers

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