mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-13 05:54:23 +08:00
7e2fca52ef
Saves four implicit call to compound_head(). Link: https://lkml.kernel.org/r/20230812062612.3184990-1-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
296 lines
6.4 KiB
C
296 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright IBM Corporation, 2021
|
|
*
|
|
* Author: Mike Rapoport <rppt@linux.ibm.com>
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/memfd.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/printk.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/pseudo_fs.h>
|
|
#include <linux/secretmem.h>
|
|
#include <linux/set_memory.h>
|
|
#include <linux/sched/signal.h>
|
|
|
|
#include <uapi/linux/magic.h>
|
|
|
|
#include <asm/tlbflush.h>
|
|
|
|
#include "internal.h"
|
|
|
|
#undef pr_fmt
|
|
#define pr_fmt(fmt) "secretmem: " fmt
|
|
|
|
/*
|
|
* Define mode and flag masks to allow validation of the system call
|
|
* parameters.
|
|
*/
|
|
#define SECRETMEM_MODE_MASK (0x0)
|
|
#define SECRETMEM_FLAGS_MASK SECRETMEM_MODE_MASK
|
|
|
|
static bool secretmem_enable __ro_after_init = 1;
|
|
module_param_named(enable, secretmem_enable, bool, 0400);
|
|
MODULE_PARM_DESC(secretmem_enable,
|
|
"Enable secretmem and memfd_secret(2) system call");
|
|
|
|
static atomic_t secretmem_users;
|
|
|
|
bool secretmem_active(void)
|
|
{
|
|
return !!atomic_read(&secretmem_users);
|
|
}
|
|
|
|
static vm_fault_t secretmem_fault(struct vm_fault *vmf)
|
|
{
|
|
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
|
|
struct inode *inode = file_inode(vmf->vma->vm_file);
|
|
pgoff_t offset = vmf->pgoff;
|
|
gfp_t gfp = vmf->gfp_mask;
|
|
unsigned long addr;
|
|
struct page *page;
|
|
struct folio *folio;
|
|
vm_fault_t ret;
|
|
int err;
|
|
|
|
if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode))
|
|
return vmf_error(-EINVAL);
|
|
|
|
filemap_invalidate_lock_shared(mapping);
|
|
|
|
retry:
|
|
page = find_lock_page(mapping, offset);
|
|
if (!page) {
|
|
folio = folio_alloc(gfp | __GFP_ZERO, 0);
|
|
if (!folio) {
|
|
ret = VM_FAULT_OOM;
|
|
goto out;
|
|
}
|
|
|
|
page = &folio->page;
|
|
err = set_direct_map_invalid_noflush(page);
|
|
if (err) {
|
|
folio_put(folio);
|
|
ret = vmf_error(err);
|
|
goto out;
|
|
}
|
|
|
|
__folio_mark_uptodate(folio);
|
|
err = filemap_add_folio(mapping, folio, offset, gfp);
|
|
if (unlikely(err)) {
|
|
folio_put(folio);
|
|
/*
|
|
* If a split of large page was required, it
|
|
* already happened when we marked the page invalid
|
|
* which guarantees that this call won't fail
|
|
*/
|
|
set_direct_map_default_noflush(page);
|
|
if (err == -EEXIST)
|
|
goto retry;
|
|
|
|
ret = vmf_error(err);
|
|
goto out;
|
|
}
|
|
|
|
addr = (unsigned long)page_address(page);
|
|
flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
|
|
}
|
|
|
|
vmf->page = page;
|
|
ret = VM_FAULT_LOCKED;
|
|
|
|
out:
|
|
filemap_invalidate_unlock_shared(mapping);
|
|
return ret;
|
|
}
|
|
|
|
static const struct vm_operations_struct secretmem_vm_ops = {
|
|
.fault = secretmem_fault,
|
|
};
|
|
|
|
static int secretmem_release(struct inode *inode, struct file *file)
|
|
{
|
|
atomic_dec(&secretmem_users);
|
|
return 0;
|
|
}
|
|
|
|
static int secretmem_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
unsigned long len = vma->vm_end - vma->vm_start;
|
|
|
|
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
|
|
return -EINVAL;
|
|
|
|
if (!mlock_future_ok(vma->vm_mm, vma->vm_flags | VM_LOCKED, len))
|
|
return -EAGAIN;
|
|
|
|
vm_flags_set(vma, VM_LOCKED | VM_DONTDUMP);
|
|
vma->vm_ops = &secretmem_vm_ops;
|
|
|
|
return 0;
|
|
}
|
|
|
|
bool vma_is_secretmem(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_ops == &secretmem_vm_ops;
|
|
}
|
|
|
|
static const struct file_operations secretmem_fops = {
|
|
.release = secretmem_release,
|
|
.mmap = secretmem_mmap,
|
|
};
|
|
|
|
static int secretmem_migrate_folio(struct address_space *mapping,
|
|
struct folio *dst, struct folio *src, enum migrate_mode mode)
|
|
{
|
|
return -EBUSY;
|
|
}
|
|
|
|
static void secretmem_free_folio(struct folio *folio)
|
|
{
|
|
set_direct_map_default_noflush(&folio->page);
|
|
folio_zero_segment(folio, 0, folio_size(folio));
|
|
}
|
|
|
|
const struct address_space_operations secretmem_aops = {
|
|
.dirty_folio = noop_dirty_folio,
|
|
.free_folio = secretmem_free_folio,
|
|
.migrate_folio = secretmem_migrate_folio,
|
|
};
|
|
|
|
static int secretmem_setattr(struct mnt_idmap *idmap,
|
|
struct dentry *dentry, struct iattr *iattr)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
struct address_space *mapping = inode->i_mapping;
|
|
unsigned int ia_valid = iattr->ia_valid;
|
|
int ret;
|
|
|
|
filemap_invalidate_lock(mapping);
|
|
|
|
if ((ia_valid & ATTR_SIZE) && inode->i_size)
|
|
ret = -EINVAL;
|
|
else
|
|
ret = simple_setattr(idmap, dentry, iattr);
|
|
|
|
filemap_invalidate_unlock(mapping);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct inode_operations secretmem_iops = {
|
|
.setattr = secretmem_setattr,
|
|
};
|
|
|
|
static struct vfsmount *secretmem_mnt;
|
|
|
|
static struct file *secretmem_file_create(unsigned long flags)
|
|
{
|
|
struct file *file;
|
|
struct inode *inode;
|
|
const char *anon_name = "[secretmem]";
|
|
const struct qstr qname = QSTR_INIT(anon_name, strlen(anon_name));
|
|
int err;
|
|
|
|
inode = alloc_anon_inode(secretmem_mnt->mnt_sb);
|
|
if (IS_ERR(inode))
|
|
return ERR_CAST(inode);
|
|
|
|
err = security_inode_init_security_anon(inode, &qname, NULL);
|
|
if (err) {
|
|
file = ERR_PTR(err);
|
|
goto err_free_inode;
|
|
}
|
|
|
|
file = alloc_file_pseudo(inode, secretmem_mnt, "secretmem",
|
|
O_RDWR, &secretmem_fops);
|
|
if (IS_ERR(file))
|
|
goto err_free_inode;
|
|
|
|
mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
|
|
mapping_set_unevictable(inode->i_mapping);
|
|
|
|
inode->i_op = &secretmem_iops;
|
|
inode->i_mapping->a_ops = &secretmem_aops;
|
|
|
|
/* pretend we are a normal file with zero size */
|
|
inode->i_mode |= S_IFREG;
|
|
inode->i_size = 0;
|
|
|
|
return file;
|
|
|
|
err_free_inode:
|
|
iput(inode);
|
|
return file;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(memfd_secret, unsigned int, flags)
|
|
{
|
|
struct file *file;
|
|
int fd, err;
|
|
|
|
/* make sure local flags do not confict with global fcntl.h */
|
|
BUILD_BUG_ON(SECRETMEM_FLAGS_MASK & O_CLOEXEC);
|
|
|
|
if (!secretmem_enable)
|
|
return -ENOSYS;
|
|
|
|
if (flags & ~(SECRETMEM_FLAGS_MASK | O_CLOEXEC))
|
|
return -EINVAL;
|
|
if (atomic_read(&secretmem_users) < 0)
|
|
return -ENFILE;
|
|
|
|
fd = get_unused_fd_flags(flags & O_CLOEXEC);
|
|
if (fd < 0)
|
|
return fd;
|
|
|
|
file = secretmem_file_create(flags);
|
|
if (IS_ERR(file)) {
|
|
err = PTR_ERR(file);
|
|
goto err_put_fd;
|
|
}
|
|
|
|
file->f_flags |= O_LARGEFILE;
|
|
|
|
atomic_inc(&secretmem_users);
|
|
fd_install(fd, file);
|
|
return fd;
|
|
|
|
err_put_fd:
|
|
put_unused_fd(fd);
|
|
return err;
|
|
}
|
|
|
|
static int secretmem_init_fs_context(struct fs_context *fc)
|
|
{
|
|
return init_pseudo(fc, SECRETMEM_MAGIC) ? 0 : -ENOMEM;
|
|
}
|
|
|
|
static struct file_system_type secretmem_fs = {
|
|
.name = "secretmem",
|
|
.init_fs_context = secretmem_init_fs_context,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
|
|
static int __init secretmem_init(void)
|
|
{
|
|
if (!secretmem_enable)
|
|
return 0;
|
|
|
|
secretmem_mnt = kern_mount(&secretmem_fs);
|
|
if (IS_ERR(secretmem_mnt))
|
|
return PTR_ERR(secretmem_mnt);
|
|
|
|
/* prevent secretmem mappings from ever getting PROT_EXEC */
|
|
secretmem_mnt->mnt_flags |= MNT_NOEXEC;
|
|
|
|
return 0;
|
|
}
|
|
fs_initcall(secretmem_init);
|