mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-29 20:30:35 +00:00
![Jack Qiu](/assets/img/avatar_default.png)
Because fsverity_descriptor_location.version is constant, so use macro for better reading. Signed-off-by: Jack Qiu <jack.qiu@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
261 lines
6.9 KiB
C
261 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* fs/f2fs/verity.c: fs-verity support for f2fs
|
|
*
|
|
* Copyright 2019 Google LLC
|
|
*/
|
|
|
|
/*
|
|
* Implementation of fsverity_operations for f2fs.
|
|
*
|
|
* Like ext4, f2fs stores the verity metadata (Merkle tree and
|
|
* fsverity_descriptor) past the end of the file, starting at the first 64K
|
|
* boundary beyond i_size. This approach works because (a) verity files are
|
|
* readonly, and (b) pages fully beyond i_size aren't visible to userspace but
|
|
* can be read/written internally by f2fs with only some relatively small
|
|
* changes to f2fs. Extended attributes cannot be used because (a) f2fs limits
|
|
* the total size of an inode's xattr entries to 4096 bytes, which wouldn't be
|
|
* enough for even a single Merkle tree block, and (b) f2fs encryption doesn't
|
|
* encrypt xattrs, yet the verity metadata *must* be encrypted when the file is
|
|
* because it contains hashes of the plaintext data.
|
|
*
|
|
* Using a 64K boundary rather than a 4K one keeps things ready for
|
|
* architectures with 64K pages, and it doesn't necessarily waste space on-disk
|
|
* since there can be a hole between i_size and the start of the Merkle tree.
|
|
*/
|
|
|
|
#include <linux/f2fs_fs.h>
|
|
|
|
#include "f2fs.h"
|
|
#include "xattr.h"
|
|
|
|
#define F2FS_VERIFY_VER (1)
|
|
|
|
static inline loff_t f2fs_verity_metadata_pos(const struct inode *inode)
|
|
{
|
|
return round_up(inode->i_size, 65536);
|
|
}
|
|
|
|
/*
|
|
* Read some verity metadata from the inode. __vfs_read() can't be used because
|
|
* we need to read beyond i_size.
|
|
*/
|
|
static int pagecache_read(struct inode *inode, void *buf, size_t count,
|
|
loff_t pos)
|
|
{
|
|
while (count) {
|
|
size_t n = min_t(size_t, count,
|
|
PAGE_SIZE - offset_in_page(pos));
|
|
struct page *page;
|
|
void *addr;
|
|
|
|
page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT,
|
|
NULL);
|
|
if (IS_ERR(page))
|
|
return PTR_ERR(page);
|
|
|
|
addr = kmap_atomic(page);
|
|
memcpy(buf, addr + offset_in_page(pos), n);
|
|
kunmap_atomic(addr);
|
|
|
|
put_page(page);
|
|
|
|
buf += n;
|
|
pos += n;
|
|
count -= n;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Write some verity metadata to the inode for FS_IOC_ENABLE_VERITY.
|
|
* kernel_write() can't be used because the file descriptor is readonly.
|
|
*/
|
|
static int pagecache_write(struct inode *inode, const void *buf, size_t count,
|
|
loff_t pos)
|
|
{
|
|
if (pos + count > inode->i_sb->s_maxbytes)
|
|
return -EFBIG;
|
|
|
|
while (count) {
|
|
size_t n = min_t(size_t, count,
|
|
PAGE_SIZE - offset_in_page(pos));
|
|
struct page *page;
|
|
void *fsdata;
|
|
void *addr;
|
|
int res;
|
|
|
|
res = pagecache_write_begin(NULL, inode->i_mapping, pos, n, 0,
|
|
&page, &fsdata);
|
|
if (res)
|
|
return res;
|
|
|
|
addr = kmap_atomic(page);
|
|
memcpy(addr + offset_in_page(pos), buf, n);
|
|
kunmap_atomic(addr);
|
|
|
|
res = pagecache_write_end(NULL, inode->i_mapping, pos, n, n,
|
|
page, fsdata);
|
|
if (res < 0)
|
|
return res;
|
|
if (res != n)
|
|
return -EIO;
|
|
|
|
buf += n;
|
|
pos += n;
|
|
count -= n;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Format of f2fs verity xattr. This points to the location of the verity
|
|
* descriptor within the file data rather than containing it directly because
|
|
* the verity descriptor *must* be encrypted when f2fs encryption is used. But,
|
|
* f2fs encryption does not encrypt xattrs.
|
|
*/
|
|
struct fsverity_descriptor_location {
|
|
__le32 version;
|
|
__le32 size;
|
|
__le64 pos;
|
|
};
|
|
|
|
static int f2fs_begin_enable_verity(struct file *filp)
|
|
{
|
|
struct inode *inode = file_inode(filp);
|
|
int err;
|
|
|
|
if (f2fs_verity_in_progress(inode))
|
|
return -EBUSY;
|
|
|
|
if (f2fs_is_atomic_file(inode) || f2fs_is_volatile_file(inode))
|
|
return -EOPNOTSUPP;
|
|
|
|
/*
|
|
* Since the file was opened readonly, we have to initialize the quotas
|
|
* here and not rely on ->open() doing it. This must be done before
|
|
* evicting the inline data.
|
|
*/
|
|
err = dquot_initialize(inode);
|
|
if (err)
|
|
return err;
|
|
|
|
err = f2fs_convert_inline_inode(inode);
|
|
if (err)
|
|
return err;
|
|
|
|
set_inode_flag(inode, FI_VERITY_IN_PROGRESS);
|
|
return 0;
|
|
}
|
|
|
|
static int f2fs_end_enable_verity(struct file *filp, const void *desc,
|
|
size_t desc_size, u64 merkle_tree_size)
|
|
{
|
|
struct inode *inode = file_inode(filp);
|
|
u64 desc_pos = f2fs_verity_metadata_pos(inode) + merkle_tree_size;
|
|
struct fsverity_descriptor_location dloc = {
|
|
.version = cpu_to_le32(F2FS_VERIFY_VER),
|
|
.size = cpu_to_le32(desc_size),
|
|
.pos = cpu_to_le64(desc_pos),
|
|
};
|
|
int err = 0;
|
|
|
|
if (desc != NULL) {
|
|
/* Succeeded; write the verity descriptor. */
|
|
err = pagecache_write(inode, desc, desc_size, desc_pos);
|
|
|
|
/* Write all pages before clearing FI_VERITY_IN_PROGRESS. */
|
|
if (!err)
|
|
err = filemap_write_and_wait(inode->i_mapping);
|
|
}
|
|
|
|
/* If we failed, truncate anything we wrote past i_size. */
|
|
if (desc == NULL || err)
|
|
f2fs_truncate(inode);
|
|
|
|
clear_inode_flag(inode, FI_VERITY_IN_PROGRESS);
|
|
|
|
if (desc != NULL && !err) {
|
|
err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_VERITY,
|
|
F2FS_XATTR_NAME_VERITY, &dloc, sizeof(dloc),
|
|
NULL, XATTR_CREATE);
|
|
if (!err) {
|
|
file_set_verity(inode);
|
|
f2fs_set_inode_flags(inode);
|
|
f2fs_mark_inode_dirty_sync(inode, true);
|
|
}
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int f2fs_get_verity_descriptor(struct inode *inode, void *buf,
|
|
size_t buf_size)
|
|
{
|
|
struct fsverity_descriptor_location dloc;
|
|
int res;
|
|
u32 size;
|
|
u64 pos;
|
|
|
|
/* Get the descriptor location */
|
|
res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_VERITY,
|
|
F2FS_XATTR_NAME_VERITY, &dloc, sizeof(dloc), NULL);
|
|
if (res < 0 && res != -ERANGE)
|
|
return res;
|
|
if (res != sizeof(dloc) || dloc.version != cpu_to_le32(F2FS_VERIFY_VER)) {
|
|
f2fs_warn(F2FS_I_SB(inode), "unknown verity xattr format");
|
|
return -EINVAL;
|
|
}
|
|
size = le32_to_cpu(dloc.size);
|
|
pos = le64_to_cpu(dloc.pos);
|
|
|
|
/* Get the descriptor */
|
|
if (pos + size < pos || pos + size > inode->i_sb->s_maxbytes ||
|
|
pos < f2fs_verity_metadata_pos(inode) || size > INT_MAX) {
|
|
f2fs_warn(F2FS_I_SB(inode), "invalid verity xattr");
|
|
return -EFSCORRUPTED;
|
|
}
|
|
if (buf_size) {
|
|
if (size > buf_size)
|
|
return -ERANGE;
|
|
res = pagecache_read(inode, buf, size, pos);
|
|
if (res)
|
|
return res;
|
|
}
|
|
return size;
|
|
}
|
|
|
|
static struct page *f2fs_read_merkle_tree_page(struct inode *inode,
|
|
pgoff_t index,
|
|
unsigned long num_ra_pages)
|
|
{
|
|
struct page *page;
|
|
|
|
index += f2fs_verity_metadata_pos(inode) >> PAGE_SHIFT;
|
|
|
|
page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED);
|
|
if (!page || !PageUptodate(page)) {
|
|
if (page)
|
|
put_page(page);
|
|
else if (num_ra_pages > 1)
|
|
page_cache_readahead_unbounded(inode->i_mapping, NULL,
|
|
index, num_ra_pages, 0);
|
|
page = read_mapping_page(inode->i_mapping, index, NULL);
|
|
}
|
|
return page;
|
|
}
|
|
|
|
static int f2fs_write_merkle_tree_block(struct inode *inode, const void *buf,
|
|
u64 index, int log_blocksize)
|
|
{
|
|
loff_t pos = f2fs_verity_metadata_pos(inode) + (index << log_blocksize);
|
|
|
|
return pagecache_write(inode, buf, 1 << log_blocksize, pos);
|
|
}
|
|
|
|
const struct fsverity_operations f2fs_verityops = {
|
|
.begin_enable_verity = f2fs_begin_enable_verity,
|
|
.end_enable_verity = f2fs_end_enable_verity,
|
|
.get_verity_descriptor = f2fs_get_verity_descriptor,
|
|
.read_merkle_tree_page = f2fs_read_merkle_tree_page,
|
|
.write_merkle_tree_block = f2fs_write_merkle_tree_block,
|
|
};
|