[f2fs-dev] [PATCH 9/9] fs: f2fs: support diskcipher

[f2fs-dev] [PATCH 9/9] fs: f2fs: support diskcipher

[boojin.kim]

F2FS checks the crypto properties of the inode, and if it is a diskcipher,
sets it to BIO before submitting the BIO.
When using diskcipher, F2FS does not encrypt the data before submitting
the bio and decrypt the data on complete of the BIO.

F2FS uses DUN(device unit number) as the IV(initial vector)
for cryptographic operations.
DUN can support the Garbage collection of f2fs.
Even if a data is moved in the storage device by garbage collection,
the data has same DUN, so that the data can be decrypted.
F2FS calculates DUN of data and sets it to BIO.

Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Signed-off-by: Boojin Kim <boojin.kim@samsung.com>
---
 fs/f2fs/data.c | 98
++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/f2fs/f2fs.h |  2 +-
 2 files changed, 97 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3dfefab..c8252bf 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -85,6 +85,52 @@ struct bio_post_read_ctx {
 	unsigned int enabled_steps;
 };
 
+/* device unit number for iv sector */
+#define PG_DUN(i, p)	\
+	((((i)->i_ino & 0xffffffff) << 32) | (p & 0xffffffff))
+
+static inline bool f2fs_may_encrypt_bio(struct inode *inode,
+		struct f2fs_io_info *fio)
+{
+#ifdef CONFIG_CRYPTO_DISKCIPHER
+	if (fio && (fio->type != DATA || fio->encrypted_page))
+		return false;
+
+	return (f2fs_encrypted_file(inode) &&
+			fscrypt_disk_encrypted(inode));
+#else
+	return false;
+#endif
+}
+
+static inline bool f2fs_bio_disk_encrypted(unsigned int bi_opf)
+{
+	if (bi_opf & REQ_CRYPT)
+		return true;
+	else
+		return false;
+}
+
+static bool f2fs_mergeable_bio(struct bio *bio, u64 dun, void *ci,
+				bool bio_encrypted)
+{
+#ifdef CONFIG_CRYPTO_DISKCIPHER
+	if (!bio)
+		return true;
+
+	/* if both of them are not encrypted, no further check is needed */
+	if (!f2fs_bio_disk_encrypted(bio->bi_opf) && !bio_encrypted)
+		return true;
+
+	if (bio->bi_aux_private == ci)
+		return bio_end_dun(bio) == dun;
+	else
+		return false;
+#else
+	return true;
+#endif
+}
+
 static void __read_end_io(struct bio *bio)
 {
 	struct page *page;
@@ -174,6 +220,9 @@ static void f2fs_read_end_io(struct bio *bio)
 		bio->bi_status = BLK_STS_IOERR;
 	}
 
+	if (f2fs_bio_disk_encrypted(bio->bi_opf))
+		goto end_io;
+
 	if (f2fs_bio_post_read_required(bio)) {
 		struct bio_post_read_ctx *ctx = bio->bi_private;
 
@@ -182,6 +231,7 @@ static void f2fs_read_end_io(struct bio *bio)
 		return;
 	}
 
+end_io:
 	__read_end_io(bio);
 }
 
@@ -362,7 +412,10 @@ static void __submit_merged_bio(struct f2fs_bio_info
*io)
 	if (!io->bio)
 		return;
 
-	bio_set_op_attrs(io->bio, fio->op, fio->op_flags);
+	if (f2fs_bio_disk_encrypted(io->bio->bi_opf))
+		bio_set_op_attrs(io->bio, fio->op, fio->op_flags |
REQ_CRYPT);
+	else
+		bio_set_op_attrs(io->bio, fio->op, fio->op_flags);
 
 	if (is_read_io(fio->op))
 		trace_f2fs_prepare_read_bio(io->sbi->sb, fio->type,
io->bio);
@@ -476,6 +529,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 	struct bio *bio;
 	struct page *page = fio->encrypted_page ?
 			fio->encrypted_page : fio->page;
+	struct inode *inode = fio->page->mapping->host;
 
 	if (!f2fs_is_valid_blkaddr(fio->sbi, fio->new_blkaddr,
 			fio->is_por ? META_POR : (__is_meta_io(fio) ?
@@ -502,6 +556,9 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 	inc_page_count(fio->sbi, is_read_io(fio->op) ?
 			__read_io_type(page): WB_DATA_TYPE(fio->page));
 
+	if (f2fs_may_encrypt_bio(inode, fio))
+		fscrypt_set_bio(inode, bio, PG_DUN(inode,
fio->page->index));
+
 	__submit_bio(fio->sbi, bio, fio->type);
 	return 0;
 }
@@ -604,6 +661,9 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
 	struct f2fs_bio_info *io = sbi->write_io[btype] + fio->temp;
 	struct page *bio_page;
+	struct inode *inode;
+	bool bio_encrypted;
+	u64 dun;
 
 	f2fs_bug_on(sbi, is_read_io(fio->op));
 
@@ -624,6 +684,9 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	verify_fio_blkaddr(fio);
 
 	bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;
+	inode = fio->page->mapping->host;
+	dun = PG_DUN(inode, fio->page->index);
+	bio_encrypted = f2fs_may_encrypt_bio(inode, fio);
 
 	/* set submitted = true as a return value */
 	fio->submitted = true;
@@ -633,6 +696,10 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	if (io->bio && !io_is_mergeable(sbi, io->bio, io, fio,
 			io->last_block_in_bio, fio->new_blkaddr))
 		__submit_merged_bio(io);
+
+	if (!f2fs_mergeable_bio(io->bio, dun,
+			fscrypt_get_diskcipher(inode), bio_encrypted))
+		__submit_merged_bio(io);
 alloc_new:
 	if (io->bio == NULL) {
 		if ((fio->type == DATA || fio->type == NODE) &&
@@ -644,6 +711,9 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 		io->bio = __bio_alloc(sbi, fio->new_blkaddr, fio->io_wbc,
 						BIO_MAX_PAGES, false,
 						fio->type, fio->temp);
+		if (bio_encrypted)
+			fscrypt_set_bio(inode, io->bio, dun);
+
 		io->fio = *fio;
 	}
 
@@ -691,7 +761,7 @@ static struct bio *f2fs_grab_read_bio(struct inode
*inode, block_t blkaddr,
 	bio->bi_end_io = f2fs_read_end_io;
 	bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
 
-	if (f2fs_encrypted_file(inode))
+	if (f2fs_encrypted_file(inode) && !fscrypt_disk_encrypted(inode))
 		post_read_steps |= 1 << STEP_DECRYPT;
 
 	if (f2fs_need_verity(inode, first_idx))
@@ -731,6 +801,10 @@ static int f2fs_submit_page_read(struct inode *inode,
struct page *page,
 	}
 	ClearPageError(page);
 	inc_page_count(sbi, F2FS_RD_DATA);
+
+	if (f2fs_may_encrypt_bio(inode, NULL))
+		fscrypt_set_bio(inode, bio, PG_DUN(inode, page->index));
+
 	__submit_bio(sbi, bio, DATA);
 	return 0;
 }
@@ -1665,6 +1739,8 @@ static int f2fs_read_single_page(struct inode *inode,
struct page *page,
 	sector_t last_block_in_file;
 	sector_t block_nr;
 	int ret = 0;
+	bool bio_encrypted;
+	u64 dun;
 
 	block_in_file = (sector_t)page_index(page);
 	last_block = block_in_file + nr_pages;
@@ -1734,6 +1810,15 @@ static int f2fs_read_single_page(struct inode *inode,
struct page *page,
 		__submit_bio(F2FS_I_SB(inode), bio, DATA);
 		bio = NULL;
 	}
+
+	dun = PG_DUN(inode, page->index);
+	bio_encrypted = f2fs_may_encrypt_bio(inode, NULL);
+	if (!f2fs_mergeable_bio(bio, dun, fscrypt_get_diskcipher(inode),
+				bio_encrypted)) {
+		__submit_bio(F2FS_I_SB(inode), bio, DATA);
+		bio = NULL;
+	}
+
 	if (bio == NULL) {
 		bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
 				is_readahead ? REQ_RAHEAD : 0, page->index);
@@ -1742,6 +1827,8 @@ static int f2fs_read_single_page(struct inode *inode,
struct page *page,
 			bio = NULL;
 			goto out;
 		}
+		if (f2fs_may_encrypt_bio(inode, NULL))
+			fscrypt_set_bio(inode, bio, dun);
 	}
 
 	/*
@@ -1870,6 +1957,9 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
 	f2fs_wait_on_block_writeback(inode, fio->old_blkaddr);
 
 retry_encrypt:
+	if (fscrypt_disk_encrypted(inode))
+		return 0;
+
 	fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(fio->page,
 							       PAGE_SIZE, 0,
 							       gfp_flags);
@@ -2804,6 +2894,10 @@ static void f2fs_dio_submit_bio(struct bio *bio,
struct inode *inode,
 	if (!dio)
 		goto out;
 
+	if (dio->inode && fscrypt_has_encryption_key(dio->inode))
+		fscrypt_set_bio(inode, bio, PG_DUN(inode,
+				file_offset >> PAGE_SHIFT));
+
 	dio->inode = inode;
 	dio->orig_end_io = bio->bi_end_io;
 	dio->orig_private = bio->bi_private;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0cbf1d4..8447542 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3706,7 +3706,7 @@ static inline bool f2fs_force_buffered_io(struct inode
*inode,
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	int rw = iov_iter_rw(iter);
 
-	if (f2fs_post_read_required(inode))
+	if (f2fs_post_read_required(inode) &&
!fscrypt_disk_encrypted(inode))
 		return true;
 	if (f2fs_is_multi_device(sbi))
 		return true;
-- 
2.7.4



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