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Re: [Linux-ima-devel] [PATCH 3/3] ima: use fs method to read integrity data
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From: Linus T. <tor...@li...> - 2017-09-15 05:50:35
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This is still wrong.
(a) there is no explanation for why we need that exclusive lock in the
first place
Why should a read need exclusive access? You'd think shared is sufficient.
But regardless, it needs *explanation*.
(b) the lockdep test isn't for the exclusive lock that the code comment
says it is
So no, this needs more work.
Linus
On Sep 14, 2017 21:59, "Mimi Zohar" <zo...@li...> wrote:
> From: Christoph Hellwig <hc...@ls...>
>
> Add a new ->integrity_read file operation to read data for integrity
> hash collection. This is defined to be equivalent to ->read_iter,
> except that it will be called with the i_rwsem held exclusively.
>
> (Based on Christoph's original patch.)
>
> Signed-off-by: Christoph Hellwig <hc...@ls...>
> Cc: Matthew Garrett <mj...@sr...>
> Cc: Jan Kara <ja...@su...>
> Cc: "Theodore Ts'o" <ty...@mi...>
> Cc: Andreas Dilger <adi...@di...>
> Cc: Jaegeuk Kim <ja...@ke...>
> Cc: Chao Yu <yu...@hu...>
> Cc: Steven Whitehouse <swh...@re...>
> Cc: Bob Peterson <rpe...@re...>
> Cc: David Woodhouse <dw...@in...>
> Cc: Dave Kleikamp <sh...@ke...>
> Cc: Ryusuke Konishi <kon...@la...>
> Cc: Mark Fasheh <mf...@ve...>
> Cc: Joel Becker <jl...@ev...>
> Cc: Richard Weinberger <ri...@no...>
> Cc: "Darrick J. Wong" <dar...@or...>
> Cc: Hugh Dickins <hu...@go...>
> Cc: Chris Mason <cl...@fb...>
> Signed-off-by: Mimi Zohar <zo...@li...>
> Reviewed-by: Jan Kara <ja...@su...>
> Reviewed-by: Dmitry Kasatkin <dmi...@hu...>
> ---
> fs/btrfs/file.c | 1 +
> fs/efivarfs/file.c | 1 +
> fs/ext2/file.c | 17 +++++++++++++++++
> fs/ext4/file.c | 20 ++++++++++++++++++++
> fs/f2fs/file.c | 1 +
> fs/jffs2/file.c | 1 +
> fs/jfs/file.c | 1 +
> fs/nilfs2/file.c | 1 +
> fs/ramfs/file-mmu.c | 1 +
> fs/ramfs/file-nommu.c | 1 +
> fs/ubifs/file.c | 1 +
> fs/xfs/xfs_file.c | 21 +++++++++++++++++++++
> include/linux/fs.h | 1 +
> mm/shmem.c | 1 +
> security/integrity/iint.c | 20 ++++++++++++++------
> 15 files changed, 83 insertions(+), 6 deletions(-)
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 9e75d8a39aac..2542dc66c85c 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -3125,6 +3125,7 @@ const struct file_operations btrfs_file_operations =
> {
> #endif
> .clone_file_range = btrfs_clone_file_range,
> .dedupe_file_range = btrfs_dedupe_file_range,
> + .integrity_read = generic_file_read_iter,
> };
>
> void btrfs_auto_defrag_exit(void)
> diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
> index 863f1b100165..17955a92a5b3 100644
> --- a/fs/efivarfs/file.c
> +++ b/fs/efivarfs/file.c
> @@ -179,4 +179,5 @@ const struct file_operations efivarfs_file_operations
> = {
> .write = efivarfs_file_write,
> .llseek = no_llseek,
> .unlocked_ioctl = efivarfs_file_ioctl,
> + .integrity_read = efivarfs_file_read_iter,
> };
> diff --git a/fs/ext2/file.c b/fs/ext2/file.c
> index d34d32bdc944..111069de1973 100644
> --- a/fs/ext2/file.c
> +++ b/fs/ext2/file.c
> @@ -192,6 +192,22 @@ static ssize_t ext2_file_read_iter(struct kiocb
> *iocb, struct iov_iter *to)
> return generic_file_read_iter(iocb, to);
> }
>
> +static ssize_t ext2_file_integrity_read_iter(struct kiocb *iocb,
> + struct iov_iter *to)
> +{
> + struct inode *inode = file_inode(iocb->ki_filp);
> +
> + lockdep_assert_held(&inode->i_rwsem);
> +#ifdef CONFIG_FS_DAX
> + if (!iov_iter_count(to))
> + return 0; /* skip atime */
> +
> + if (IS_DAX(iocb->ki_filp->f_mapping->host))
> + return dax_iomap_rw(iocb, to, &ext2_iomap_ops);
> +#endif
> + return generic_file_read_iter(iocb, to);
> +}
> +
> static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter
> *from)
> {
> #ifdef CONFIG_FS_DAX
> @@ -216,6 +232,7 @@ const struct file_operations ext2_file_operations = {
> .get_unmapped_area = thp_get_unmapped_area,
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> + .integrity_read = ext2_file_integrity_read_iter,
> };
>
> const struct inode_operations ext2_file_inode_operations = {
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 58294c9a7e1d..3ab4105c8578 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -74,6 +74,25 @@ static ssize_t ext4_file_read_iter(struct kiocb *iocb,
> struct iov_iter *to)
> return generic_file_read_iter(iocb, to);
> }
>
> +static ssize_t ext4_file_integrity_read_iter(struct kiocb *iocb,
> + struct iov_iter *to)
> +{
> + struct inode *inode = file_inode(iocb->ki_filp);
> +
> + lockdep_assert_held(&inode->i_rwsem);
> + if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
> + return -EIO;
> +
> + if (!iov_iter_count(to))
> + return 0; /* skip atime */
> +
> +#ifdef CONFIG_FS_DAX
> + if (IS_DAX(inode))
> + return dax_iomap_rw(iocb, to, &ext4_iomap_ops);
> +#endif
> + return generic_file_read_iter(iocb, to);
> +}
> +
> /*
> * Called when an inode is released. Note that this is different
> * from ext4_file_open: open gets called at every open, but release
> @@ -747,6 +766,7 @@ const struct file_operations ext4_file_operations = {
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> .fallocate = ext4_fallocate,
> + .integrity_read = ext4_file_integrity_read_iter,
> };
>
> const struct inode_operations ext4_file_inode_operations = {
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 2706130c261b..82ea81da0b2d 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2514,4 +2514,5 @@ const struct file_operations f2fs_file_operations = {
> #endif
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> + .integrity_read = generic_file_read_iter,
> };
> diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
> index c12476e309c6..5a63034cccf5 100644
> --- a/fs/jffs2/file.c
> +++ b/fs/jffs2/file.c
> @@ -57,6 +57,7 @@ const struct file_operations jffs2_file_operations =
> .mmap = generic_file_readonly_mmap,
> .fsync = jffs2_fsync,
> .splice_read = generic_file_splice_read,
> + .integrity_read = generic_file_read_iter,
> };
>
> /* jffs2_file_inode_operations */
> diff --git a/fs/jfs/file.c b/fs/jfs/file.c
> index 739492c7a3fd..423512a810e4 100644
> --- a/fs/jfs/file.c
> +++ b/fs/jfs/file.c
> @@ -162,4 +162,5 @@ const struct file_operations jfs_file_operations = {
> #ifdef CONFIG_COMPAT
> .compat_ioctl = jfs_compat_ioctl,
> #endif
> + .integrity_read = generic_file_read_iter,
> };
> diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
> index c5fa3dee72fc..55e058ac487f 100644
> --- a/fs/nilfs2/file.c
> +++ b/fs/nilfs2/file.c
> @@ -150,6 +150,7 @@ const struct file_operations nilfs_file_operations = {
> /* .release = nilfs_release_file, */
> .fsync = nilfs_sync_file,
> .splice_read = generic_file_splice_read,
> + .integrity_read = generic_file_read_iter,
> };
>
> const struct inode_operations nilfs_file_inode_operations = {
> diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c
> index 12af0490322f..4f24d1b589b1 100644
> --- a/fs/ramfs/file-mmu.c
> +++ b/fs/ramfs/file-mmu.c
> @@ -47,6 +47,7 @@ const struct file_operations ramfs_file_operations = {
> .splice_write = iter_file_splice_write,
> .llseek = generic_file_llseek,
> .get_unmapped_area = ramfs_mmu_get_unmapped_area,
> + .integrity_read = generic_file_read_iter,
> };
>
> const struct inode_operations ramfs_file_inode_operations = {
> diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
> index 2ef7ce75c062..5ee704fa84e0 100644
> --- a/fs/ramfs/file-nommu.c
> +++ b/fs/ramfs/file-nommu.c
> @@ -50,6 +50,7 @@ const struct file_operations ramfs_file_operations = {
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> .llseek = generic_file_llseek,
> + .integrity_read = generic_file_read_iter,
> };
>
> const struct inode_operations ramfs_file_inode_operations = {
> diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
> index 8cad0b19b404..5e52a315e18b 100644
> --- a/fs/ubifs/file.c
> +++ b/fs/ubifs/file.c
> @@ -1747,4 +1747,5 @@ const struct file_operations ubifs_file_operations =
> {
> #ifdef CONFIG_COMPAT
> .compat_ioctl = ubifs_compat_ioctl,
> #endif
> + .integrity_read = generic_file_read_iter,
> };
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index c4893e226fd8..0a6704b563d6 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -292,6 +292,26 @@ xfs_file_read_iter(
> return ret;
> }
>
> +static ssize_t
> +xfs_integrity_read(
> + struct kiocb *iocb,
> + struct iov_iter *to)
> +{
> + struct inode *inode = file_inode(iocb->ki_filp);
> + struct xfs_mount *mp = XFS_I(inode)->i_mount;
> +
> + lockdep_assert_held(&inode->i_rwsem);
> +
> + XFS_STATS_INC(mp, xs_read_calls);
> +
> + if (XFS_FORCED_SHUTDOWN(mp))
> + return -EIO;
> +
> + if (IS_DAX(inode))
> + return dax_iomap_rw(iocb, to, &xfs_iomap_ops);
> + return generic_file_read_iter(iocb, to);
> +}
> +
> /*
> * Zero any on disk space between the current EOF and the new, larger EOF.
> *
> @@ -1175,6 +1195,7 @@ const struct file_operations xfs_file_operations = {
> .fallocate = xfs_file_fallocate,
> .clone_file_range = xfs_file_clone_range,
> .dedupe_file_range = xfs_file_dedupe_range,
> + .integrity_read = xfs_integrity_read,
> };
>
> const struct file_operations xfs_dir_file_operations = {
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index e522d25d0836..f6a01d3efce5 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1699,6 +1699,7 @@ struct file_operations {
> u64);
> ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file
> *,
> u64);
> + ssize_t (*integrity_read)(struct kiocb *, struct iov_iter *);
> } __randomize_layout;
>
> struct inode_operations {
> diff --git a/mm/shmem.c b/mm/shmem.c
> index b0aa6075d164..805d99011ca4 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -3849,6 +3849,7 @@ static const struct file_operations
> shmem_file_operations = {
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> .fallocate = shmem_fallocate,
> + .integrity_read = shmem_file_read_iter,
> #endif
> };
>
> diff --git a/security/integrity/iint.c b/security/integrity/iint.c
> index c84e05866052..c3a07276f745 100644
> --- a/security/integrity/iint.c
> +++ b/security/integrity/iint.c
> @@ -21,6 +21,7 @@
> #include <linux/rbtree.h>
> #include <linux/file.h>
> #include <linux/uaccess.h>
> +#include <linux/uio.h>
> #include "integrity.h"
>
> static struct rb_root integrity_iint_tree = RB_ROOT;
> @@ -184,18 +185,25 @@ security_initcall(integrity_iintcache_init);
> int integrity_kernel_read(struct file *file, loff_t offset,
> void *addr, unsigned long count)
> {
> - mm_segment_t old_fs;
> - char __user *buf = (char __user *)addr;
> + struct inode *inode = file_inode(file);
> + struct kvec iov = { .iov_base = addr, .iov_len = count };
> + struct kiocb kiocb;
> + struct iov_iter iter;
> ssize_t ret;
>
> + lockdep_assert_held(&inode->i_rwsem);
> +
> if (!(file->f_mode & FMODE_READ))
> return -EBADF;
> + if (!file->f_op->integrity_read)
> + return -EBADF;
>
> - old_fs = get_fs();
> - set_fs(get_ds());
> - ret = __vfs_read(file, buf, count, &offset);
> - set_fs(old_fs);
> + init_sync_kiocb(&kiocb, file);
> + kiocb.ki_pos = offset;
> + iov_iter_kvec(&iter, READ | ITER_KVEC, &iov, 1, count);
>
> + ret = file->f_op->integrity_read(&kiocb, &iter);
> + BUG_ON(ret == -EIOCBQUEUED);
> return ret;
> }
>
> --
> 2.7.4
>
>
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