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-rw-r--r--fs/ext4/crypto.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
new file mode 100644
index 000000000..453d4da5d
--- /dev/null
+++ b/fs/ext4/crypto.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/quotaops.h>
+#include <linux/uuid.h>
+
+#include "ext4.h"
+#include "xattr.h"
+#include "ext4_jbd2.h"
+
+static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
+ const struct fscrypt_name *src)
+{
+ memset(dst, 0, sizeof(*dst));
+
+ dst->usr_fname = src->usr_fname;
+ dst->disk_name = src->disk_name;
+ dst->hinfo.hash = src->hash;
+ dst->hinfo.minor_hash = src->minor_hash;
+ dst->crypto_buf = src->crypto_buf;
+}
+
+int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
+ int lookup, struct ext4_filename *fname)
+{
+ struct fscrypt_name name;
+ int err;
+
+ err = fscrypt_setup_filename(dir, iname, lookup, &name);
+ if (err)
+ return err;
+
+ ext4_fname_from_fscrypt_name(fname, &name);
+
+#if IS_ENABLED(CONFIG_UNICODE)
+ err = ext4_fname_setup_ci_filename(dir, iname, fname);
+ if (err)
+ ext4_fname_free_filename(fname);
+#endif
+ return err;
+}
+
+int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
+ struct ext4_filename *fname)
+{
+ struct fscrypt_name name;
+ int err;
+
+ err = fscrypt_prepare_lookup(dir, dentry, &name);
+ if (err)
+ return err;
+
+ ext4_fname_from_fscrypt_name(fname, &name);
+
+#if IS_ENABLED(CONFIG_UNICODE)
+ err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
+ if (err)
+ ext4_fname_free_filename(fname);
+#endif
+ return err;
+}
+
+void ext4_fname_free_filename(struct ext4_filename *fname)
+{
+ struct fscrypt_name name;
+
+ name.crypto_buf = fname->crypto_buf;
+ fscrypt_free_filename(&name);
+
+ fname->crypto_buf.name = NULL;
+ fname->usr_fname = NULL;
+ fname->disk_name.name = NULL;
+
+#if IS_ENABLED(CONFIG_UNICODE)
+ kfree(fname->cf_name.name);
+ fname->cf_name.name = NULL;
+#endif
+}
+
+static bool uuid_is_zero(__u8 u[16])
+{
+ int i;
+
+ for (i = 0; i < 16; i++)
+ if (u[i])
+ return false;
+ return true;
+}
+
+int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg)
+{
+ struct super_block *sb = file_inode(filp)->i_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int err, err2;
+ handle_t *handle;
+
+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
+
+ if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
+ err = mnt_want_write_file(filp);
+ if (err)
+ return err;
+ handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ goto pwsalt_err_exit;
+ }
+ err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto pwsalt_err_journal;
+ lock_buffer(sbi->s_sbh);
+ generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(sbi->s_sbh);
+ err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
+pwsalt_err_journal:
+ err2 = ext4_journal_stop(handle);
+ if (err2 && !err)
+ err = err2;
+pwsalt_err_exit:
+ mnt_drop_write_file(filp);
+ if (err)
+ return err;
+ }
+
+ if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16))
+ return -EFAULT;
+ return 0;
+}
+
+static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
+{
+ return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+ EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
+}
+
+static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
+ void *fs_data)
+{
+ handle_t *handle = fs_data;
+ int res, res2, credits, retries = 0;
+
+ /*
+ * Encrypting the root directory is not allowed because e2fsck expects
+ * lost+found to exist and be unencrypted, and encrypting the root
+ * directory would imply encrypting the lost+found directory as well as
+ * the filename "lost+found" itself.
+ */
+ if (inode->i_ino == EXT4_ROOT_INO)
+ return -EPERM;
+
+ if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
+ return -EINVAL;
+
+ if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+ return -EOPNOTSUPP;
+
+ res = ext4_convert_inline_data(inode);
+ if (res)
+ return res;
+
+ /*
+ * If a journal handle was specified, then the encryption context is
+ * being set on a new inode via inheritance and is part of a larger
+ * transaction to create the inode. Otherwise the encryption context is
+ * being set on an existing inode in its own transaction. Only in the
+ * latter case should the "retry on ENOSPC" logic be used.
+ */
+
+ if (handle) {
+ res = ext4_xattr_set_handle(handle, inode,
+ EXT4_XATTR_INDEX_ENCRYPTION,
+ EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+ ctx, len, 0);
+ if (!res) {
+ ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+ ext4_clear_inode_state(inode,
+ EXT4_STATE_MAY_INLINE_DATA);
+ /*
+ * Update inode->i_flags - S_ENCRYPTED will be enabled,
+ * S_DAX may be disabled
+ */
+ ext4_set_inode_flags(inode, false);
+ }
+ return res;
+ }
+
+ res = dquot_initialize(inode);
+ if (res)
+ return res;
+retry:
+ res = ext4_xattr_set_credits(inode, len, false /* is_create */,
+ &credits);
+ if (res)
+ return res;
+
+ handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
+ EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+ ctx, len, 0);
+ if (!res) {
+ ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+ /*
+ * Update inode->i_flags - S_ENCRYPTED will be enabled,
+ * S_DAX may be disabled
+ */
+ ext4_set_inode_flags(inode, false);
+ res = ext4_mark_inode_dirty(handle, inode);
+ if (res)
+ EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
+ }
+ res2 = ext4_journal_stop(handle);
+
+ if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+ if (!res)
+ res = res2;
+ return res;
+}
+
+static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
+{
+ return EXT4_SB(sb)->s_dummy_enc_policy.policy;
+}
+
+static bool ext4_has_stable_inodes(struct super_block *sb)
+{
+ return ext4_has_feature_stable_inodes(sb);
+}
+
+static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
+ int *ino_bits_ret, int *lblk_bits_ret)
+{
+ *ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
+ *lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
+}
+
+const struct fscrypt_operations ext4_cryptops = {
+ .key_prefix = "ext4:",
+ .get_context = ext4_get_context,
+ .set_context = ext4_set_context,
+ .get_dummy_policy = ext4_get_dummy_policy,
+ .empty_dir = ext4_empty_dir,
+ .has_stable_inodes = ext4_has_stable_inodes,
+ .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits,
+};