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Commit 198aac25 authored by Joel Fernandes's avatar Joel Fernandes
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Revert "UPSTREAM: mm: Add an F_SEAL_FUTURE_WRITE seal to memfd" 

This reverts commit 1dc8ca44.

Change-Id: I513034073c278e2ae58a53352cc2553a256a7ee0
parent 3a49374a

include/uapi/linux/fcntl.h

+0 −1
Original line number Diff line number Diff line
@@ -41,7 +41,6 @@ 
#define F_SEAL_SHRINK	0x0002	/* prevent file from shrinking */

#define F_SEAL_GROW	0x0004	/* prevent file from growing */

#define F_SEAL_WRITE	0x0008	/* prevent writes */

#define F_SEAL_FUTURE_WRITE	0x0010  /* prevent future writes while mapped */

/* (1U << 31) is reserved for signed error codes */



/*

mm/memfd.c

+1 −21
Original line number Diff line number Diff line
@@ -150,8 +150,7 @@ static unsigned int *memfd_file_seals_ptr(struct file *file) 
#define F_ALL_SEALS (F_SEAL_SEAL | \

		     F_SEAL_SHRINK | \

		     F_SEAL_GROW | \

		     F_SEAL_WRITE | \

		     F_SEAL_FUTURE_WRITE)

		     F_SEAL_WRITE)



static int memfd_add_seals(struct file *file, unsigned int seals)

{
@@ -220,25 +219,6 @@ 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;