diff mbox series

[v25,21/30] mm: Re-introduce vm_flags to do_mmap()

Message ID 20210415221419.31835-22-yu-cheng.yu@intel.com (mailing list archive)
State New
Headers show
Series Control-flow Enforcement: Shadow Stack | expand

Commit Message

Yu, Yu-cheng April 15, 2021, 10:14 p.m. UTC
There was no more caller passing vm_flags to do_mmap(), and vm_flags was
removed from the function's input by:

    commit 45e55300f114 ("mm: remove unnecessary wrapper function do_mmap_pgoff()").

There is a new user now.  Shadow stack allocation passes VM_SHADOW_STACK to
do_mmap().  Thus, re-introduce vm_flags to do_mmap().

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org
---
v24:
- Change VM_SHSTK to VM_SHADOW_STACK.
- Update commit log.

 fs/aio.c           |  2 +-
 include/linux/mm.h |  3 ++-
 ipc/shm.c          |  2 +-
 mm/mmap.c          | 10 +++++-----
 mm/nommu.c         |  4 ++--
 mm/util.c          |  2 +-
 6 files changed, 12 insertions(+), 11 deletions(-)

Comments

Kirill A. Shutemov April 23, 2021, 10:31 a.m. UTC | #1
On Thu, Apr 15, 2021 at 03:14:10PM -0700, Yu-cheng Yu wrote:
> There was no more caller passing vm_flags to do_mmap(), and vm_flags was
> removed from the function's input by:
> 
>     commit 45e55300f114 ("mm: remove unnecessary wrapper function do_mmap_pgoff()").
> 
> There is a new user now.  Shadow stack allocation passes VM_SHADOW_STACK to
> do_mmap().  Thus, re-introduce vm_flags to do_mmap().
> 
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> Reviewed-by: Peter Collingbourne <pcc@google.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: linux-mm@kvack.org

Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Yu, Yu-cheng April 23, 2021, 3:59 p.m. UTC | #2
On 4/23/2021 3:31 AM, Kirill A. Shutemov wrote:
> On Thu, Apr 15, 2021 at 03:14:10PM -0700, Yu-cheng Yu wrote:
>> There was no more caller passing vm_flags to do_mmap(), and vm_flags was
>> removed from the function's input by:
>>
>>      commit 45e55300f114 ("mm: remove unnecessary wrapper function do_mmap_pgoff()").
>>
>> There is a new user now.  Shadow stack allocation passes VM_SHADOW_STACK to
>> do_mmap().  Thus, re-introduce vm_flags to do_mmap().
>>
>> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
>> Reviewed-by: Peter Collingbourne <pcc@google.com>
>> Reviewed-by: Kees Cook <keescook@chromium.org>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Oleg Nesterov <oleg@redhat.com>
>> Cc: linux-mm@kvack.org
> 
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> 

Thanks for reviewing.

Yu-cheng
diff mbox series

Patch

diff --git a/fs/aio.c b/fs/aio.c
index 1f32da13d39e..b5d0586209a7 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -529,7 +529,7 @@  static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
 
 	ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
 				 PROT_READ | PROT_WRITE,
-				 MAP_SHARED, 0, &unused, NULL);
+				 MAP_SHARED, 0, 0, &unused, NULL);
 	mmap_write_unlock(mm);
 	if (IS_ERR((void *)ctx->mmap_base)) {
 		ctx->mmap_size = 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3e9c84f21ef6..1ccec5cc399b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2576,7 +2576,8 @@  extern unsigned long mmap_region(struct file *file, unsigned long addr,
 	struct list_head *uf);
 extern unsigned long do_mmap(struct file *file, unsigned long addr,
 	unsigned long len, unsigned long prot, unsigned long flags,
-	unsigned long pgoff, unsigned long *populate, struct list_head *uf);
+	vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
+	struct list_head *uf);
 extern int __do_munmap(struct mm_struct *, unsigned long, size_t,
 		       struct list_head *uf, bool downgrade);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t,
diff --git a/ipc/shm.c b/ipc/shm.c
index febd88daba8c..b6370eb1eaab 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1556,7 +1556,7 @@  long do_shmat(int shmid, char __user *shmaddr, int shmflg,
 			goto invalid;
 	}
 
-	addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
+	addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
 	*raddr = addr;
 	err = 0;
 	if (IS_ERR_VALUE(addr))
diff --git a/mm/mmap.c b/mm/mmap.c
index d77fb39b6ab5..7b2992ef8ee0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1401,11 +1401,11 @@  static inline bool file_mmap_ok(struct file *file, struct inode *inode,
  */
 unsigned long do_mmap(struct file *file, unsigned long addr,
 			unsigned long len, unsigned long prot,
-			unsigned long flags, unsigned long pgoff,
-			unsigned long *populate, struct list_head *uf)
+			unsigned long flags, vm_flags_t vm_flags,
+			unsigned long pgoff, unsigned long *populate,
+			struct list_head *uf)
 {
 	struct mm_struct *mm = current->mm;
-	vm_flags_t vm_flags;
 	int pkey = 0;
 
 	*populate = 0;
@@ -1467,7 +1467,7 @@  unsigned long do_mmap(struct file *file, unsigned long addr,
 	 * to. we assume access permissions have been handled by the open
 	 * of the memory object, so we don't do any here.
 	 */
-	vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
+	vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
 			mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
 	if (flags & MAP_LOCKED)
@@ -3047,7 +3047,7 @@  SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 
 	file = get_file(vma->vm_file);
 	ret = do_mmap(vma->vm_file, start, size,
-			prot, flags, pgoff, &populate, NULL);
+			prot, flags, 0, pgoff, &populate, NULL);
 	fput(file);
 out:
 	mmap_write_unlock(mm);
diff --git a/mm/nommu.c b/mm/nommu.c
index 5c9ab799c0e6..9b6f7a1895c2 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1071,6 +1071,7 @@  unsigned long do_mmap(struct file *file,
 			unsigned long len,
 			unsigned long prot,
 			unsigned long flags,
+			vm_flags_t vm_flags,
 			unsigned long pgoff,
 			unsigned long *populate,
 			struct list_head *uf)
@@ -1078,7 +1079,6 @@  unsigned long do_mmap(struct file *file,
 	struct vm_area_struct *vma;
 	struct vm_region *region;
 	struct rb_node *rb;
-	vm_flags_t vm_flags;
 	unsigned long capabilities, result;
 	int ret;
 
@@ -1097,7 +1097,7 @@  unsigned long do_mmap(struct file *file,
 
 	/* we've determined that we can make the mapping, now translate what we
 	 * now know into VMA flags */
-	vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+	vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
 
 	/* we're going to need to record the mapping */
 	region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
diff --git a/mm/util.c b/mm/util.c
index 54870226cea6..49cbd4400d13 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -516,7 +516,7 @@  unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
 	if (!ret) {
 		if (mmap_write_lock_killable(mm))
 			return -EINTR;
-		ret = do_mmap(file, addr, len, prot, flag, pgoff, &populate,
+		ret = do_mmap(file, addr, len, prot, flag, 0, pgoff, &populate,
 			      &uf);
 		mmap_write_unlock(mm);
 		userfaultfd_unmap_complete(mm, &uf);