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>

6 files changed, 79 insertions, 24 deletions

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| \
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 850267c89407..2cf18a2d5c72 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -998,7 +998,8 @@ got:
 
         /* If the directory encrypted, then we should encrypt the inode. */
         if ((S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) &&
-            ext4_encrypted_inode(dir))
+            (ext4_encrypted_inode(dir) ||
+             DUMMY_ENCRYPTION_ENABLED(sbi)))
                 ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
 
         ext4_set_inode_flags(inode);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d201426b8d39..4f87127f781f 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2582,7 +2582,8 @@ retry:
                 ext4_set_aops(inode);
                 err = 0;
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-                if (!err && ext4_encrypted_inode(dir)) {
+                if (!err && (ext4_encrypted_inode(dir) ||
+                             DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)))) {
                         err = ext4_inherit_context(dir, inode);
                         if (err) {
                                 clear_nlink(inode);
@@ -2777,7 +2778,8 @@ retry:
         if (err)
                 goto out_clear_inode;
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-        if (ext4_encrypted_inode(dir)) {
+        if (ext4_encrypted_inode(dir) ||
+            DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb))) {
                 err = ext4_inherit_context(dir, inode);
                 if (err)
                         goto out_clear_inode;
@@ -3202,7 +3204,8 @@ static int ext4_symlink(struct inode *dir,
         disk_link.len = len + 1;
         disk_link.name = (char *) symname;
 
-        encryption_required = ext4_encrypted_inode(dir);
+        encryption_required = (ext4_encrypted_inode(dir) ||
+                               DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
         if (encryption_required)
                 disk_link.len = encrypted_symlink_data_len(len) + 1;
         if (disk_link.len > dir->i_sb->s_blocksize)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1008ca258de4..f9ebd58f40dd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1106,7 +1106,7 @@ enum {
         Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
         Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
         Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
-        Opt_data_err_abort, Opt_data_err_ignore,
+        Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
         Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
         Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
         Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
@@ -1197,6 +1197,7 @@ static const match_table_t tokens = {
         {Opt_init_itable, "init_itable"},
         {Opt_noinit_itable, "noinit_itable"},
         {Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
+        {Opt_test_dummy_encryption, "test_dummy_encryption"},
         {Opt_removed, "check=none"},    /* mount option from ext2/3 */
         {Opt_removed, "nocheck"},       /* mount option from ext2/3 */
         {Opt_removed, "reservation"},   /* mount option from ext2/3 */
@@ -1398,6 +1399,7 @@ static const struct mount_opts {
         {Opt_jqfmt_vfsv0, QFMT_VFS_V0, MOPT_QFMT},
         {Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
         {Opt_max_dir_size_kb, 0, MOPT_GTE0},
+        {Opt_test_dummy_encryption, 0, MOPT_GTE0},
         {Opt_err, 0, 0}
 };
 
@@ -1574,6 +1576,15 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
                 }
                 *journal_ioprio =
                         IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, arg);
+        } else if (token == Opt_test_dummy_encryption) {
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+                sbi->s_mount_flags |= EXT4_MF_TEST_DUMMY_ENCRYPTION;
+                ext4_msg(sb, KERN_WARNING,
+                         "Test dummy encryption mode enabled");
+#else
+                ext4_msg(sb, KERN_WARNING,
+                         "Test dummy encryption mount option ignored");
+#endif
         } else if (m->flags & MOPT_DATAJ) {
                 if (is_remount) {
                         if (!sbi->s_journal)
@@ -2671,11 +2682,13 @@ static struct attribute *ext4_attrs[] = {
 EXT4_INFO_ATTR(lazy_itable_init);
 EXT4_INFO_ATTR(batched_discard);
 EXT4_INFO_ATTR(meta_bg_resize);
+EXT4_INFO_ATTR(encryption);
 
 static struct attribute *ext4_feat_attrs[] = {
         ATTR_LIST(lazy_itable_init),
         ATTR_LIST(batched_discard),
         ATTR_LIST(meta_bg_resize),
+        ATTR_LIST(encryption),
         NULL,
 };
 
@@ -3683,6 +3696,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                 }
         }
 
+        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_ENCRYPT) &&
+            es->s_encryption_level) {
+                ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
+                         es->s_encryption_level);
+                goto failed_mount;
+        }
+
         if (sb->s_blocksize != blocksize) {
                 /* Validate the filesystem blocksize */
                 if (!sb_set_blocksize(sb, blocksize)) {
@@ -4045,6 +4065,13 @@ no_journal:
                 }
         }
 
+        if (unlikely(sbi->s_mount_flags & EXT4_MF_TEST_DUMMY_ENCRYPTION) &&
+            !(sb->s_flags & MS_RDONLY) &&
+            !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_ENCRYPT)) {
+                EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_ENCRYPT);
+                ext4_commit_super(sb, 1);
+        }
+
         /*
          * Get the # of file system overhead blocks from the
          * superblock if present.