From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 16 Apr 2015 05:56:00 +0000 (-0400)
Subject: ext4 crypto: enable encryption feature flag
X-Git-Tag: omap-for-v4.1/fixes-rc1~89^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6ddb2447846a8ece111e316a2863c2355023682d;p=pandora-kernel.git

ext4 crypto: enable encryption feature flag

Also add the test dummy encryption mode flag so we can more easily
test the encryption patches using xfstests.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index 572bd97f58dd..c8392af8abbb 100644
--- a/fs/ext4/crypto_key.c
+++ b/fs/ext4/crypto_key.c
@@ -98,6 +98,7 @@ int ext4_generate_encryption_key(struct inode *inode)
 	struct ext4_encryption_key *master_key;
 	struct ext4_encryption_context ctx;
 	struct user_key_payload *ukp;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	int res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
 				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
 				 &ctx, sizeof(ctx));
@@ -109,6 +110,20 @@ int ext4_generate_encryption_key(struct inode *inode)
 	}
 	res = 0;
 
+	if (S_ISREG(inode->i_mode))
+		crypt_key->mode = ctx.contents_encryption_mode;
+	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+		crypt_key->mode = ctx.filenames_encryption_mode;
+	else {
+		printk(KERN_ERR "ext4 crypto: Unsupported inode type.\n");
+		BUG();
+	}
+	crypt_key->size = ext4_encryption_key_size(crypt_key->mode);
+	BUG_ON(!crypt_key->size);
+	if (DUMMY_ENCRYPTION_ENABLED(sbi)) {
+		memset(crypt_key->raw, 0x42, EXT4_AES_256_XTS_KEY_SIZE);
+		goto out;
+	}
 	memcpy(full_key_descriptor, EXT4_KEY_DESC_PREFIX,
 	       EXT4_KEY_DESC_PREFIX_SIZE);
 	sprintf(full_key_descriptor + EXT4_KEY_DESC_PREFIX_SIZE,
@@ -129,21 +144,9 @@ int ext4_generate_encryption_key(struct inode *inode)
 		goto out;
 	}
 	master_key = (struct ext4_encryption_key *)ukp->data;
-
-	if (S_ISREG(inode->i_mode))
-		crypt_key->mode = ctx.contents_encryption_mode;
-	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
-		crypt_key->mode = ctx.filenames_encryption_mode;
-	else {
-		printk(KERN_ERR "ext4 crypto: Unsupported inode type.\n");
-		BUG();
-	}
-	crypt_key->size = ext4_encryption_key_size(crypt_key->mode);
-	BUG_ON(!crypt_key->size);
 	BUILD_BUG_ON(EXT4_AES_128_ECB_KEY_SIZE !=
 		     EXT4_KEY_DERIVATION_NONCE_SIZE);
 	BUG_ON(master_key->size != EXT4_AES_256_XTS_KEY_SIZE);
-	BUG_ON(crypt_key->size < EXT4_AES_256_CBC_KEY_SIZE);
 	res = ext4_derive_key_aes(ctx.nonce, master_key->raw, crypt_key->raw);
 out:
 	if (keyring_key)
diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
index 749ed6e91e50..30eaf9e9864a 100644
--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -169,13 +169,25 @@ int ext4_inherit_context(struct inode *parent, struct inode *child)
 				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
 				 &ctx, sizeof(ctx));
 
-	if (res != sizeof(ctx))
-		return -ENOENT;
-
+	if (res != sizeof(ctx)) {
+		if (DUMMY_ENCRYPTION_ENABLED(EXT4_SB(parent->i_sb))) {
+			ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1;
+			ctx.contents_encryption_mode =
+				EXT4_ENCRYPTION_MODE_AES_256_XTS;
+			ctx.filenames_encryption_mode =
+				EXT4_ENCRYPTION_MODE_AES_256_CTS;
+			memset(ctx.master_key_descriptor, 0x42,
+			       EXT4_KEY_DESCRIPTOR_SIZE);
+			res = 0;
+		} else {
+			goto out;
+		}
+	}
 	get_random_bytes(ctx.nonce, EXT4_KEY_DERIVATION_NONCE_SIZE);
 	res = ext4_xattr_set(child, EXT4_XATTR_INDEX_ENCRYPTION,
 			     EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
 			     sizeof(ctx), 0);
+out:
 	if (!res)
 		ext4_set_inode_flag(child, EXT4_INODE_ENCRYPT);
 	return res;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 86d15706d27a..0179654faf79 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1200,8 +1200,16 @@ struct ext4_super_block {
 /*
  * run-time mount flags
  */
-#define EXT4_MF_MNTDIR_SAMPLED	0x0001
-#define EXT4_MF_FS_ABORTED	0x0002	/* Fatal error detected */
+#define EXT4_MF_MNTDIR_SAMPLED		0x0001
+#define EXT4_MF_FS_ABORTED		0x0002	/* Fatal error detected */
+#define EXT4_MF_TEST_DUMMY_ENCRYPTION	0x0004
+
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+#define DUMMY_ENCRYPTION_ENABLED(sbi) (unlikely((sbi)->s_mount_flags & \
+						EXT4_MF_TEST_DUMMY_ENCRYPTION))
+#else
+#define DUMMY_ENCRYPTION_ENABLED(sbi) (0)
+#endif
 
 /* Number of quota types we support */
 #define EXT4_MAXQUOTAS 2
@@ -1613,8 +1621,9 @@ static inline int ext4_encrypted_inode(struct inode *inode)
 					 EXT4_FEATURE_INCOMPAT_EXTENTS| \
 					 EXT4_FEATURE_INCOMPAT_64BIT| \
 					 EXT4_FEATURE_INCOMPAT_FLEX_BG| \
-					 EXT4_FEATURE_INCOMPAT_MMP |	\
-					 EXT4_FEATURE_INCOMPAT_INLINE_DATA)
+					 EXT4_FEATURE_INCOMPAT_MMP | \
+					 EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
+					 EXT4_FEATURE_INCOMPAT_ENCRYPT)
 #define EXT4_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
 					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
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