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Commit 1da2a42d authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Dmitry Shmidt
Browse files

UPSTREAM: Revert "ecryptfs: forbid opening files without mmap handler" 



(cherry picked from commit 78c4e172412de5d0456dc00d2b34050aa0b683b5)

This reverts upstream commit 2f36db71009304b3f0b95afacd8eba1f9f046b87.

It fixed a local root exploit but also introduced a dependency on
the lower file system implementing an mmap operation just to open a file,
which is a bit of a heavy hammer.  The right fix is to have mmap depend
on the existence of the mmap handler instead.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>

Fixes: Change-Id I0be77c7f8bd3046bc34cd87ef577529792d479bc
       ("UPSTREAM: ecryptfs: forbid opening files without mmap handler")
Change-Id: Ib9bc87099f7f89e4e12dbc1a79e884dcadb1befb
Signed-off-by: default avatarAmit Pundir <amit.pundir@linaro.org>
parent 0b848391

fs/ecryptfs/kthread.c

+2 −11
Original line number Diff line number Diff line
@@ -25,7 +25,6 @@ 
#include <linux/slab.h>

#include <linux/wait.h>

#include <linux/mount.h>

#include <linux/file.h>

#include "ecryptfs_kernel.h"



struct ecryptfs_open_req {
@@ -148,7 +147,7 @@ int ecryptfs_privileged_open(struct file **lower_file, 
	flags |= IS_RDONLY(d_inode(lower_dentry)) ? O_RDONLY : O_RDWR;

	(*lower_file) = dentry_open(&req.path, flags, cred);

	if (!IS_ERR(*lower_file))

		goto have_file;

		goto out;

	if ((flags & O_ACCMODE) == O_RDONLY) {

		rc = PTR_ERR((*lower_file));

		goto out;
@@ -166,16 +165,8 @@ int ecryptfs_privileged_open(struct file **lower_file, 
	mutex_unlock(&ecryptfs_kthread_ctl.mux);

	wake_up(&ecryptfs_kthread_ctl.wait);

	wait_for_completion(&req.done);

	if (IS_ERR(*lower_file)) {

	if (IS_ERR(*lower_file))

		rc = PTR_ERR(*lower_file);

		goto out;

	}

have_file:

	if ((*lower_file)->f_op->mmap == NULL) {

		fput(*lower_file);

		*lower_file = NULL;

		rc = -EMEDIUMTYPE;

	}

out:

	return rc;

}