ext4 crypto: implement the ext4 decryption read path (c9c7429c) · Commits · EulixOS / Software / Kernel

fs/ext4/file.c

+16 −2

Original line number	Diff line number	Diff line
		@@ -218,6 +218,13 @@ static const struct vm_operations_struct ext4_file_vm_ops = {

		static int ext4_file_mmap(struct file file, struct vm_area_struct vma)
		{
		struct inode *inode = file->f_mapping->host;

		if (ext4_encrypted_inode(inode)) {
		int err = ext4_generate_encryption_key(inode);
		if (err)
		return 0;
		}
		file_accessed(file);
		if (IS_DAX(file_inode(file))) {
		vma->vm_ops = &ext4_dax_vm_ops;
		@@ -235,6 +242,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
		struct vfsmount *mnt = filp->f_path.mnt;
		struct path path;
		char buf[64], *cp;
		int ret;

		if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
		!(sb->s_flags & MS_RDONLY))) {
		@@ -273,11 +281,17 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
		* writing and the journal is present
		*/
		if (filp->f_mode & FMODE_WRITE) {
		int ret = ext4_inode_attach_jinode(inode);
		ret = ext4_inode_attach_jinode(inode);
		if (ret < 0)
		return ret;
		}
		return dquot_file_open(inode, filp);
		ret = dquot_file_open(inode, filp);
		if (!ret && ext4_encrypted_inode(inode)) {
		ret = ext4_generate_encryption_key(inode);
		if (ret)
		ret = -EACCES;
		}
		return ret;
		}

		/*

fs/ext4/inode.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -3370,6 +3370,13 @@ static int __ext4_block_zero_page_range(handle_t *handle,
		/* Uhhuh. Read error. Complain and punt. */
		if (!buffer_uptodate(bh))
		goto unlock;
		if (S_ISREG(inode->i_mode) &&
		ext4_encrypted_inode(inode)) {
		/* We expect the key to be set. */
		BUG_ON(!ext4_has_encryption_key(inode));
		BUG_ON(blocksize != PAGE_CACHE_SIZE);
		WARN_ON_ONCE(ext4_decrypt_one(inode, page));
		}
		}
		if (ext4_should_journal_data(inode)) {
		BUFFER_TRACE(bh, "get write access");

fs/ext4/readpage.c

+65 −1

Original line number	Diff line number	Diff line
		@@ -46,6 +46,46 @@

		#include "ext4.h"

		/*
		* Call ext4_decrypt on every single page, reusing the encryption
		* context.
		*/
		static void completion_pages(struct work_struct *work)
		{
		#ifdef CONFIG_EXT4_FS_ENCRYPTION
		struct ext4_crypto_ctx *ctx =
		container_of(work, struct ext4_crypto_ctx, work);
		struct bio *bio = ctx->bio;
		struct bio_vec *bv;
		int i;

		bio_for_each_segment_all(bv, bio, i) {
		struct page *page = bv->bv_page;

		int ret = ext4_decrypt(ctx, page);
		if (ret) {
		WARN_ON_ONCE(1);
		SetPageError(page);
		} else
		SetPageUptodate(page);
		unlock_page(page);
		}
		ext4_release_crypto_ctx(ctx);
		bio_put(bio);
		#else
		BUG();
		#endif
		}

		static inline bool ext4_bio_encrypted(struct bio *bio)
		{
		#ifdef CONFIG_EXT4_FS_ENCRYPTION
		return unlikely(bio->bi_private != NULL);
		#else
		return false;
		#endif
		}

		/*
		* I/O completion handler for multipage BIOs.
		*
		@@ -63,6 +103,18 @@ static void mpage_end_io(struct bio *bio, int err)
		struct bio_vec *bv;
		int i;

		if (ext4_bio_encrypted(bio)) {
		struct ext4_crypto_ctx *ctx = bio->bi_private;

		if (err) {
		ext4_release_crypto_ctx(ctx);
		} else {
		INIT_WORK(&ctx->work, completion_pages);
		ctx->bio = bio;
		queue_work(ext4_read_workqueue, &ctx->work);
		return;
		}
		}
		bio_for_each_segment_all(bv, bio, i) {
		struct page *page = bv->bv_page;

		@@ -223,13 +275,25 @@ int ext4_mpage_readpages(struct address_space *mapping,
		bio = NULL;
		}
		if (bio == NULL) {
		struct ext4_crypto_ctx *ctx = NULL;

		if (ext4_encrypted_inode(inode) &&
		S_ISREG(inode->i_mode)) {
		ctx = ext4_get_crypto_ctx(inode);
		if (IS_ERR(ctx))
		goto set_error_page;
		}
		bio = bio_alloc(GFP_KERNEL,
		min_t(int, nr_pages, bio_get_nr_vecs(bdev)));
		if (!bio)
		if (!bio) {
		if (ctx)
		ext4_release_crypto_ctx(ctx);
		goto set_error_page;
		}
		bio->bi_bdev = bdev;
		bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
		bio->bi_end_io = mpage_end_io;
		bio->bi_private = ctx;
		}

		length = first_hole << blkbits;