ecryptfs: don't allow mmap when the lower fs doesn't support it (f0fe970d) · Commits · 戴 / test

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:

Jeff Mahoney <jeffm@suse.com> Cc: stable@vger.kernel.org [tyhicks: clean up f_op check by using ecryptfs_file_to_lower()] Signed-off-by:

Tyler Hicks <tyhicks@canonical.com>

fs/ecryptfs/file.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -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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