Linux-libre 4.2-gnu

1 files changed, 209 insertions, 0 deletions

diff --git a/fs/f2fs/crypto_policy.c b/fs/f2fs/crypto_policy.c
new file mode 100644
index 000000000..d4a96af51
--- /dev/null
+++ b/fs/f2fs/crypto_policy.c
@@ -0,0 +1,209 @@
+/*
+ * copied from linux/fs/ext4/crypto_policy.c
+ *
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility.
+ *
+ * This contains encryption policy functions for f2fs with some modifications
+ * to support f2fs-specific xattr APIs.
+ *
+ * Written by Michael Halcrow, 2015.
+ * Modified by Jaegeuk Kim, 2015.
+ */
+#include <linux/random.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/f2fs_fs.h>
+
+#include "f2fs.h"
+#include "xattr.h"
+
+static int f2fs_inode_has_encryption_context(struct inode *inode)
+{
+	int res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
+			F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, NULL, 0, NULL);
+	return (res > 0);
+}
+
+/*
+ * check whether the policy is consistent with the encryption context
+ * for the inode
+ */
+static int f2fs_is_encryption_context_consistent_with_policy(
+	struct inode *inode, const struct f2fs_encryption_policy *policy)
+{
+	struct f2fs_encryption_context ctx;
+	int res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
+				F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
+				sizeof(ctx), NULL);
+
+	if (res != sizeof(ctx))
+		return 0;
+
+	return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
+				F2FS_KEY_DESCRIPTOR_SIZE) == 0 &&
+			(ctx.flags == policy->flags) &&
+			(ctx.contents_encryption_mode ==
+			 policy->contents_encryption_mode) &&
+			(ctx.filenames_encryption_mode ==
+			 policy->filenames_encryption_mode));
+}
+
+static int f2fs_create_encryption_context_from_policy(
+	struct inode *inode, const struct f2fs_encryption_policy *policy)
+{
+	struct f2fs_encryption_context ctx;
+
+	ctx.format = F2FS_ENCRYPTION_CONTEXT_FORMAT_V1;
+	memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
+			F2FS_KEY_DESCRIPTOR_SIZE);
+
+	if (!f2fs_valid_contents_enc_mode(policy->contents_encryption_mode)) {
+		printk(KERN_WARNING
+		       "%s: Invalid contents encryption mode %d\n", __func__,
+			policy->contents_encryption_mode);
+		return -EINVAL;
+	}
+
+	if (!f2fs_valid_filenames_enc_mode(policy->filenames_encryption_mode)) {
+		printk(KERN_WARNING
+		       "%s: Invalid filenames encryption mode %d\n", __func__,
+			policy->filenames_encryption_mode);
+		return -EINVAL;
+	}
+
+	if (policy->flags & ~F2FS_POLICY_FLAGS_VALID)
+		return -EINVAL;
+
+	ctx.contents_encryption_mode = policy->contents_encryption_mode;
+	ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
+	ctx.flags = policy->flags;
+	BUILD_BUG_ON(sizeof(ctx.nonce) != F2FS_KEY_DERIVATION_NONCE_SIZE);
+	get_random_bytes(ctx.nonce, F2FS_KEY_DERIVATION_NONCE_SIZE);
+
+	return f2fs_setxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
+			F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
+			sizeof(ctx), NULL, XATTR_CREATE);
+}
+
+int f2fs_process_policy(const struct f2fs_encryption_policy *policy,
+			struct inode *inode)
+{
+	if (policy->version != 0)
+		return -EINVAL;
+
+	if (!S_ISDIR(inode->i_mode))
+		return -EINVAL;
+
+	if (!f2fs_inode_has_encryption_context(inode)) {
+		if (!f2fs_empty_dir(inode))
+			return -ENOTEMPTY;
+		return f2fs_create_encryption_context_from_policy(inode,
+								  policy);
+	}
+
+	if (f2fs_is_encryption_context_consistent_with_policy(inode, policy))
+		return 0;
+
+	printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n",
+	       __func__);
+	return -EINVAL;
+}
+
+int f2fs_get_policy(struct inode *inode, struct f2fs_encryption_policy *policy)
+{
+	struct f2fs_encryption_context ctx;
+	int res;
+
+	if (!f2fs_encrypted_inode(inode))
+		return -ENODATA;
+
+	res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
+				F2FS_XATTR_NAME_ENCRYPTION_CONTEXT,
+				&ctx, sizeof(ctx), NULL);
+	if (res != sizeof(ctx))
+		return -ENODATA;
+	if (ctx.format != F2FS_ENCRYPTION_CONTEXT_FORMAT_V1)
+		return -EINVAL;
+
+	policy->version = 0;
+	policy->contents_encryption_mode = ctx.contents_encryption_mode;
+	policy->filenames_encryption_mode = ctx.filenames_encryption_mode;
+	policy->flags = ctx.flags;
+	memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor,
+			F2FS_KEY_DESCRIPTOR_SIZE);
+	return 0;
+}
+
+int f2fs_is_child_context_consistent_with_parent(struct inode *parent,
+						struct inode *child)
+{
+	struct f2fs_crypt_info *parent_ci, *child_ci;
+	int res;
+
+	if ((parent == NULL) || (child == NULL)) {
+		pr_err("parent %p child %p\n", parent, child);
+		BUG_ON(1);
+	}
+
+	/* no restrictions if the parent directory is not encrypted */
+	if (!f2fs_encrypted_inode(parent))
+		return 1;
+	/* if the child directory is not encrypted, this is always a problem */
+	if (!f2fs_encrypted_inode(child))
+		return 0;
+	res = f2fs_get_encryption_info(parent);
+	if (res)
+		return 0;
+	res = f2fs_get_encryption_info(child);
+	if (res)
+		return 0;
+	parent_ci = F2FS_I(parent)->i_crypt_info;
+	child_ci = F2FS_I(child)->i_crypt_info;
+	if (!parent_ci && !child_ci)
+		return 1;
+	if (!parent_ci || !child_ci)
+		return 0;
+
+	return (memcmp(parent_ci->ci_master_key,
+			child_ci->ci_master_key,
+			F2FS_KEY_DESCRIPTOR_SIZE) == 0 &&
+		(parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
+		(parent_ci->ci_filename_mode == child_ci->ci_filename_mode) &&
+		(parent_ci->ci_flags == child_ci->ci_flags));
+}
+
+/**
+ * f2fs_inherit_context() - Sets a child context from its parent
+ * @parent: Parent inode from which the context is inherited.
+ * @child:  Child inode that inherits the context from @parent.
+ *
+ * Return: Zero on success, non-zero otherwise
+ */
+int f2fs_inherit_context(struct inode *parent, struct inode *child,
+						struct page *ipage)
+{
+	struct f2fs_encryption_context ctx;
+	struct f2fs_crypt_info *ci;
+	int res;
+
+	res = f2fs_get_encryption_info(parent);
+	if (res < 0)
+		return res;
+
+	ci = F2FS_I(parent)->i_crypt_info;
+	BUG_ON(ci == NULL);
+
+	ctx.format = F2FS_ENCRYPTION_CONTEXT_FORMAT_V1;
+
+	ctx.contents_encryption_mode = ci->ci_data_mode;
+	ctx.filenames_encryption_mode = ci->ci_filename_mode;
+	ctx.flags = ci->ci_flags;
+	memcpy(ctx.master_key_descriptor, ci->ci_master_key,
+			F2FS_KEY_DESCRIPTOR_SIZE);
+
+	get_random_bytes(ctx.nonce, F2FS_KEY_DERIVATION_NONCE_SIZE);
+	return f2fs_setxattr(child, F2FS_XATTR_INDEX_ENCRYPTION,
+				F2FS_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
+				sizeof(ctx), ipage, XATTR_CREATE);
+}