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Message-ID: <e6b7d789-bbac-a414-b6dc-f55b53b6cd5f@huawei.com>
Date: Mon, 20 Jul 2020 09:02:43 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Daeho Jeong <daeho43@...il.com>, <linux-kernel@...r.kernel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>, <kernel-team@...roid.com>
CC: Daeho Jeong <daehojeong@...gle.com>,
Jaegeuk Kim <jaegeuk@...nel.org>
Subject: Re: [PATCH v2] f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl
On 2020/7/18 14:15, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@...gle.com>
>
> Added a new ioctl to send discard commands or/and zero out
> to selected data area of a regular file for security reason.
>
> The way of handling range.len of F2FS_IOC_SEC_TRIM_FILE:
> 1. Added -1 value support for range.len to secure trim the whole blocks
> starting from range.start regardless of i_size.
> 2. If the end of the range passes over the end of file, it means until
> the end of file (i_size).
> 3. ignored the case of that range.len is zero to prevent the function
> from making end_addr zero and triggering different behaviour of
> the function.
>
> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> Reviewed-by: Chao Yu <yuchao0@...wei.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
> Changes in v2:
v6...though it's trivial...
> - Support zeroout for encrypted files
> ---
> fs/f2fs/f2fs.h | 15 ++++
> fs/f2fs/file.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 210 insertions(+)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f29eb1f94f57..bdfb331b6519 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -434,6 +434,8 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
> _IOR(F2FS_IOCTL_MAGIC, 18, __u64)
> #define F2FS_IOC_RESERVE_COMPRESS_BLOCKS \
> _IOR(F2FS_IOCTL_MAGIC, 19, __u64)
> +#define F2FS_IOC_SEC_TRIM_FILE _IOW(F2FS_IOCTL_MAGIC, 20, \
> + struct f2fs_sectrim_range)
>
> #define F2FS_IOC_GET_VOLUME_NAME FS_IOC_GETFSLABEL
> #define F2FS_IOC_SET_VOLUME_NAME FS_IOC_SETFSLABEL
> @@ -453,6 +455,13 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
> #define F2FS_GOING_DOWN_METAFLUSH 0x3 /* going down with meta flush */
> #define F2FS_GOING_DOWN_NEED_FSCK 0x4 /* going down to trigger fsck */
>
> +/*
> + * Flags used by F2FS_IOC_SEC_TRIM_FILE
> + */
> +#define F2FS_TRIM_FILE_DISCARD 0x1 /* send discard command */
> +#define F2FS_TRIM_FILE_ZEROOUT 0x2 /* zero out */
> +#define F2FS_TRIM_FILE_MASK 0x3
> +
> #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
> /*
> * ioctl commands in 32 bit emulation
> @@ -488,6 +497,12 @@ struct f2fs_flush_device {
> u32 segments; /* # of segments to flush */
> };
>
> +struct f2fs_sectrim_range {
> + u64 start;
> + u64 len;
> + u64 flags;
> +};
> +
> /* for inline stuff */
> #define DEF_INLINE_RESERVED_SIZE 1
> static inline int get_extra_isize(struct inode *inode);
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 1af37f3b3309..e0a4a95fbad7 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -21,6 +21,7 @@
> #include <linux/uuid.h>
> #include <linux/file.h>
> #include <linux/nls.h>
> +#include <linux/sched/signal.h>
>
> #include "f2fs.h"
> #include "node.h"
> @@ -3759,6 +3760,197 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
> return ret;
> }
>
> +static int f2fs_secure_erase(struct block_device *bdev, struct inode *inode,
> + pgoff_t off, block_t block, block_t len, u32 flags)
> +{
> + struct request_queue *q = bdev_get_queue(bdev);
> + sector_t sector = SECTOR_FROM_BLOCK(block);
> + sector_t nr_sects = SECTOR_FROM_BLOCK(len);
> + int ret = 0;
> +
> + if (!q)
> + return -ENXIO;
> +
> + if (flags & F2FS_TRIM_FILE_DISCARD)
> + ret = blkdev_issue_discard(bdev, sector, nr_sects, GFP_NOFS,
> + blk_queue_secure_erase(q) ?
> + BLKDEV_DISCARD_SECURE : 0);
> +
> + if (!ret && (flags & F2FS_TRIM_FILE_ZEROOUT)) {
> + if (IS_ENCRYPTED(inode))
> + ret = fscrypt_zeroout_range(inode, off, block, len);
> + else
> + ret = blkdev_issue_zeroout(bdev, sector, nr_sects,
> + GFP_NOFS, 0);
> + }
> +
> + return ret;
> +}
> +
> +static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
> +{
> + struct inode *inode = file_inode(filp);
> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> + struct address_space *mapping = inode->i_mapping;
> + struct block_device *prev_bdev = NULL;
> + struct f2fs_sectrim_range range;
> + pgoff_t index, pg_end, prev_index = 0;
> + block_t prev_block = 0, len = 0;
> + loff_t end_addr;
> + bool to_end = false;
> + int ret = 0;
> +
> + if (!(filp->f_mode & FMODE_WRITE))
> + return -EBADF;
> +
> + if (copy_from_user(&range, (struct f2fs_sectrim_range __user *)arg,
> + sizeof(range)))
> + return -EFAULT;
> +
> + if (range.flags == 0 || (range.flags & ~F2FS_TRIM_FILE_MASK) ||
> + !S_ISREG(inode->i_mode))
> + return -EINVAL;
> +
> + if ((range.flags & F2FS_TRIM_FILE_DISCARD) &&
> + !f2fs_hw_support_discard(sbi))
> + return -EOPNOTSUPP;
Why not checking condition here? encryption and multidevice status is stable.
> +
> + file_start_write(filp);
> + inode_lock(inode);
> +
> + if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
> + range.start >= inode->i_size) {
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + if ((range.flags & F2FS_TRIM_FILE_ZEROOUT) &&
> + IS_ENCRYPTED(inode) && f2fs_is_multi_device(sbi)) {
> + ret = -EOPNOTSUPP;
> + goto err;
> + }
> +
> + if (range.len == 0)
> + goto err;
> +
> + if (inode->i_size - range.start > range.len) {
> + end_addr = range.start + range.len;
> + } else {
> + end_addr = range.len == (u64)-1 ?
> + sbi->sb->s_maxbytes : inode->i_size;
> + to_end = true;
> + }
> +
> + if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
> + (!to_end && !IS_ALIGNED(end_addr, F2FS_BLKSIZE))) {
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + index = F2FS_BYTES_TO_BLK(range.start);
> + pg_end = DIV_ROUND_UP(end_addr, F2FS_BLKSIZE);
> +
> + ret = f2fs_convert_inline_inode(inode);
> + if (ret)
> + goto err;
> +
> + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> + down_write(&F2FS_I(inode)->i_mmap_sem);
> +
> + ret = filemap_write_and_wait_range(mapping, range.start,
> + to_end ? LLONG_MAX : end_addr - 1);
> + if (ret)
> + goto out;
> +
> + truncate_inode_pages_range(mapping, range.start,
> + to_end ? -1 : end_addr - 1);
> +
> + while (index < pg_end) {
> + struct dnode_of_data dn;
> + pgoff_t end_offset, count;
> + int i;
> +
> + set_new_dnode(&dn, inode, NULL, NULL, 0);
> + ret = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
> + if (ret) {
> + if (ret == -ENOENT) {
> + index = f2fs_get_next_page_offset(&dn, index);
> + continue;
> + }
> + goto out;
> + }
> +
> + end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
> + count = min(end_offset - dn.ofs_in_node, pg_end - index);
> + for (i = 0; i < count; i++, index++, dn.ofs_in_node++) {
> + struct block_device *cur_bdev;
> + block_t blkaddr = f2fs_data_blkaddr(&dn);
> +
> + if (!__is_valid_data_blkaddr(blkaddr))
> + continue;
> +
> + if (!f2fs_is_valid_blkaddr(sbi, blkaddr,
> + DATA_GENERIC_ENHANCE)) {
> + ret = -EFSCORRUPTED;
> + f2fs_put_dnode(&dn);
> + goto out;
> + }
> +
> + cur_bdev = f2fs_target_device(sbi, blkaddr, NULL);
> + if (f2fs_is_multi_device(sbi)) {
> + int di = f2fs_target_device_index(sbi, blkaddr);
> +
> + blkaddr -= FDEV(di).start_blk;
> + }
> +
> + if (len) {
> + if (prev_bdev == cur_bdev &&
> + index == prev_index + len &&
> + blkaddr == prev_block + len) {
> + len++;
> + } else {
> + ret = f2fs_secure_erase(prev_bdev,
> + inode, prev_index, prev_block,
> + len, range.flags);
> + if (ret) {
> + f2fs_put_dnode(&dn);
> + goto out;
> + }
> +
> + len = 0;
> + }
> + }
> +
> + if (!len) {
> + prev_bdev = cur_bdev;
> + prev_index = index;
> + prev_block = blkaddr;
> + len = 1;
> + }
> + }
> +
> + f2fs_put_dnode(&dn);
> +
> + if (fatal_signal_pending(current)) {
> + ret = -EINTR;
> + goto out;
> + }
> + cond_resched();
> + }
> +
> + if (len)
> + ret = f2fs_secure_erase(prev_bdev, inode, prev_index,
> + prev_block, len, range.flags);
> +out:
> + up_write(&F2FS_I(inode)->i_mmap_sem);
> + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> +err:
> + inode_unlock(inode);
> + file_end_write(filp);
> +
> + return ret;
> +}
> +
> long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
> @@ -3845,6 +4037,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> return f2fs_release_compress_blocks(filp, arg);
> case F2FS_IOC_RESERVE_COMPRESS_BLOCKS:
> return f2fs_reserve_compress_blocks(filp, arg);
> + case F2FS_IOC_SEC_TRIM_FILE:
> + return f2fs_sec_trim_file(filp, arg);
> default:
> return -ENOTTY;
> }
> @@ -4014,6 +4208,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> case F2FS_IOC_GET_COMPRESS_BLOCKS:
> case F2FS_IOC_RELEASE_COMPRESS_BLOCKS:
> case F2FS_IOC_RESERVE_COMPRESS_BLOCKS:
> + case F2FS_IOC_SEC_TRIM_FILE:
> break;
> default:
> return -ENOIOCTLCMD;
>
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