Revert "UPSTREAM: mm/memfd: make F_SEAL_FUTURE_WRITE seal more robust" (3a49374a) · Commits · e / devices / android_kernel_oneplus_sm7250

fs/hugetlbfs/inode.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -530,7 +530,7 @@ static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
		inode_lock(inode);

		/* protected by i_mutex */
		if (info->seals & (F_SEAL_WRITE \| F_SEAL_FUTURE_WRITE)) {
		if (info->seals & F_SEAL_WRITE) {
		inode_unlock(inode);
		return -EPERM;
		}

mm/memfd.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -220,6 +220,25 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
		}
		}

		if ((seals & F_SEAL_FUTURE_WRITE) &&
		!(*file_seals & F_SEAL_FUTURE_WRITE)) {
		/*
		* The FUTURE_WRITE seal also prevents growing and shrinking
		* so we need them to be already set, or requested now.
		*/
		int test_seals = (seals \| *file_seals) &
		(F_SEAL_GROW \| F_SEAL_SHRINK);

		if (test_seals != (F_SEAL_GROW \| F_SEAL_SHRINK)) {
		error = -EINVAL;
		goto unlock;
		}

		spin_lock(&file->f_lock);
		file->f_mode &= ~(FMODE_WRITE \| FMODE_PWRITE);
		spin_unlock(&file->f_lock);
		}

		*file_seals \|= seals;
		error = 0;

mm/shmem.c

+3 −21

Original line number	Diff line number	Diff line
		@@ -2169,23 +2169,6 @@ int shmem_lock(struct file file, int lock, struct user_struct user)

		static int shmem_mmap(struct file file, struct vm_area_struct vma)
		{
		struct shmem_inode_info *info = SHMEM_I(file_inode(file));

		/*
		* New PROT_READ and MAP_SHARED mmaps are not allowed when "future
		* write" seal active.
		*/
		if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE) &&
		(info->seals & F_SEAL_FUTURE_WRITE))
		return -EPERM;

		/*
		* Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED read-only
		* mapping, take care to not allow mprotect to revert protections.
		*/
		if (info->seals & F_SEAL_FUTURE_WRITE)
		vma->vm_flags &= ~(VM_MAYWRITE);

		file_accessed(file);
		vma->vm_ops = &shmem_vm_ops;
		if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
		@@ -2439,9 +2422,8 @@ shmem_write_begin(struct file file, struct address_space mapping,
		pgoff_t index = pos >> PAGE_SHIFT;

		/* i_mutex is held by caller */
		if (unlikely(info->seals & (F_SEAL_GROW \|
		F_SEAL_WRITE \| F_SEAL_FUTURE_WRITE))) {
		if (info->seals & (F_SEAL_WRITE \| F_SEAL_FUTURE_WRITE))
		if (unlikely(info->seals & (F_SEAL_WRITE \| F_SEAL_GROW))) {
		if (info->seals & F_SEAL_WRITE)
		return -EPERM;
		if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size)
		return -EPERM;
		@@ -2704,7 +2686,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq);

		/* protected by i_mutex */
		if (info->seals & (F_SEAL_WRITE \| F_SEAL_FUTURE_WRITE)) {
		if (info->seals & F_SEAL_WRITE) {
		error = -EPERM;
		goto out;
		}