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Message-Id: <1428894996-7852-13-git-send-email-tytso@mit.edu>
Date: Sun, 12 Apr 2015 23:16:28 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: mhalcrow@...gle.com, Ildar Muslukhov <ildarm@...gle.com>,
Theodore Ts'o <tytso@....edu>
Subject: [PATCH-v2 12/20] ext4 crypto: implement the ext4 decryption read path
From: Michael Halcrow <mhalcrow@...gle.com>
Change-Id: Ie9c043a132a01da60d1617662cd30307639f5599
Signed-off-by: Michael Halcrow <mhalcrow@...gle.com>
Signed-off-by: Ildar Muslukhov <ildarm@...gle.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
fs/ext4/file.c | 19 ++++++++++++++--
fs/ext4/inode.c | 8 +++++++
fs/ext4/readpage.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 90 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 8131be8..756d10f 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -28,6 +28,7 @@
#include <linux/pagevec.h>
#include "ext4.h"
#include "ext4_jbd2.h"
+#include "ext4_crypto.h"
#include "xattr.h"
#include "acl.h"
@@ -200,6 +201,13 @@ 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);
vma->vm_ops = &ext4_file_vm_ops;
return 0;
@@ -212,6 +220,7 @@ 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))) {
@@ -250,11 +259,17 @@ 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 dcc836c..5b6b7b6 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -39,6 +39,7 @@
#include <linux/ratelimit.h>
#include <linux/aio.h>
#include <linux/bitops.h>
+#include <linux/prefetch.h>
#include "ext4_jbd2.h"
#include "ext4_crypto.h"
@@ -3363,6 +3364,13 @@ 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 fff9fe6..171b9ac 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -47,6 +47,46 @@
#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.
*
* The mpage code never puts partial pages into a BIO (except for end-of-file).
@@ -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;
--
2.3.0
--
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