The patch titled
Subject: hugetlb: implement memfd sealing
has been added to the -mm tree. Its filename is
hugetlb-implement-memfd-sealing.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/hugetlb-implement-memfd-sealing.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/hugetlb-implement-memfd-sealing.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
Subject: hugetlb: implement memfd sealing
Implements memfd sealing, similar to shmem:
- WRITE: deny fallocate(PUNCH_HOLE). mmap() write is denied in
memfd_add_seals(). write() doesn't exist for hugetlbfs.
- SHRINK: added similar check as shmem_setattr()
- GROW: added similar check as shmem_setattr() & shmem_fallocate()
Except write() operation that doesn't exist with hugetlbfs, that
should make sealing as close as it can be to shmem support.
Link: http://lkml.kernel.org/r/20171107122800.25517-5-marcandre.lureau@xxxxxxxxxx
Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: David Herrmann <dh.herrmann@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 29 +++++++++++++++++++++++++++--
include/linux/hugetlb.h | 1 +
2 files changed, 28 insertions(+), 2 deletions(-)
diff -puN fs/hugetlbfs/inode.c~hugetlb-implement-memfd-sealing fs/hugetlbfs/inode.c
--- a/fs/hugetlbfs/inode.c~hugetlb-implement-memfd-sealing
+++ a/fs/hugetlbfs/inode.c
@@ -510,8 +510,16 @@ static long hugetlbfs_punch_hole(struct
if (hole_end > hole_start) {
struct address_space *mapping = inode->i_mapping;
+ struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
inode_lock(inode);
+
+ /* protected by i_mutex */
+ if (info->seals & F_SEAL_WRITE) {
+ inode_unlock(inode);
+ return -EPERM;
+ }
+
i_mmap_lock_write(mapping);
if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
hugetlb_vmdelete_list(&mapping->i_mmap,
@@ -529,6 +537,7 @@ static long hugetlbfs_fallocate(struct f
loff_t len)
{
struct inode *inode = file_inode(file);
+ struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
struct address_space *mapping = inode->i_mapping;
struct hstate *h = hstate_inode(inode);
struct vm_area_struct pseudo_vma;
@@ -560,6 +569,11 @@ static long hugetlbfs_fallocate(struct f
if (error)
goto out;
+ if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
+ error = -EPERM;
+ goto out;
+ }
+
/*
* Initialize a pseudo vma as this is required by the huge page
* allocation routines. If NUMA is configured, use page index
@@ -650,6 +664,7 @@ static int hugetlbfs_setattr(struct dent
struct hstate *h = hstate_inode(inode);
int error;
unsigned int ia_valid = attr->ia_valid;
+ struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
BUG_ON(!inode);
@@ -658,9 +673,16 @@ static int hugetlbfs_setattr(struct dent
return error;
if (ia_valid & ATTR_SIZE) {
- if (attr->ia_size & ~huge_page_mask(h))
+ loff_t oldsize = inode->i_size;
+ loff_t newsize = attr->ia_size;
+
+ if (newsize & ~huge_page_mask(h))
return -EINVAL;
- error = hugetlb_vmtruncate(inode, attr->ia_size);
+ /* protected by i_mutex */
+ if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
+ (newsize > oldsize && (info->seals & F_SEAL_GROW)))
+ return -EPERM;
+ error = hugetlb_vmtruncate(inode, newsize);
if (error)
return error;
}
@@ -712,6 +734,8 @@ static struct inode *hugetlbfs_get_inode
inode = new_inode(sb);
if (inode) {
+ struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
+
inode->i_ino = get_next_ino();
inode_init_owner(inode, dir, mode);
lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
@@ -719,6 +743,7 @@ static struct inode *hugetlbfs_get_inode
inode->i_mapping->a_ops = &hugetlbfs_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
inode->i_mapping->private_data = resv_map;
+ info->seals = F_SEAL_SEAL;
switch (mode & S_IFMT) {
default:
init_special_inode(inode, mode, dev);
diff -puN include/linux/hugetlb.h~hugetlb-implement-memfd-sealing include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~hugetlb-implement-memfd-sealing
+++ a/include/linux/hugetlb.h
@@ -273,6 +273,7 @@ static inline struct hugetlbfs_sb_info *
struct hugetlbfs_inode_info {
struct shared_policy policy;
struct inode vfs_inode;
+ unsigned int seals;
};
static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
_
Patches currently in -mm which might be from marcandre.lureau@xxxxxxxxxx are
shmem-unexport-shmem_add_seals-shmem_get_seals.patch
shmem-rename-functions-that-are-memfd-related.patch
hugetlb-expose-hugetlbfs_inode_info-in-header.patch
hugetlb-implement-memfd-sealing.patch
shmem-add-sealing-support-to-hugetlb-backed-memfd.patch
memfd-test-test-hugetlbfs-sealing.patch
memfd-test-add-memfd-hugetlb-prefix-when-testing-hugetlbfs.patch
memfd-test-move-common-code-to-a-shared-unit.patch
memfd-test-run-fuse-test-on-hugetlb-backend-memory.patch
mm-page_owner-align-with-pageblock_nr_pages.patch
--
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