Commit f0fe970d authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Tyler Hicks

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

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>
parent 78c4e172
......@@ -169,6 +169,19 @@ out:
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 specifying file to open
......@@ -403,7 +416,7 @@ 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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