From c9c7429c2e486f375bddd0c338cc3ad366123717 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Sun, 12 Apr 2015 00:56:10 -0400 Subject: [PATCH] ext4 crypto: implement the ext4 decryption read path Signed-off-by: Michael Halcrow Signed-off-by: Ildar Muslukhov Signed-off-by: Theodore Ts'o --- fs/ext4/file.c | 18 +++++++++++-- fs/ext4/inode.c | 7 +++++ fs/ext4/readpage.c | 66 +++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 88 insertions(+), 3 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index fcc6c1349186..b132a3c6b6fb 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -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; } /* diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 7c4527e10ae4..8b4fe626919a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -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"); diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c index fff9fe6aacf8..171b9ac4b45e 100644 --- a/fs/ext4/readpage.c +++ b/fs/ext4/readpage.c @@ -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; -- 2.20.1