Commit 8c8e669b authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Sasha Levin

ecryptfs: don't allow mmap when the lower fs doesn't support it

[ Upstream commit f0fe970d ]

There are legitimate reasons to disallow mmap on certain files, notably
in sysfs or procfs.  We shouldn't emulate mmap support on file systems
that don't offer support natively.

CVE-2016-1583
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Cc: stable@vger.kernel.org
[tyhicks: clean up f_op check by using ecryptfs_file_to_lower()]
Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 050216f6
......@@ -177,6 +177,19 @@ static int read_or_initialize_metadata(struct dentry *dentry)
return rc;
}
static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
{
struct file *lower_file = ecryptfs_file_to_lower(file);
/*
* Don't allow mmap on top of file systems that don't support it
* natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
* allows recursive mounting, this will need to be extended.
*/
if (!lower_file->f_op->mmap)
return -ENODEV;
return generic_file_mmap(file, vma);
}
/**
* ecryptfs_open
* @inode: inode speciying file to open
......@@ -374,7 +387,7 @@ const struct file_operations ecryptfs_main_fops = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ecryptfs_compat_ioctl,
#endif
.mmap = generic_file_mmap,
.mmap = ecryptfs_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
......
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