summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJeff Mahoney <jeffm@suse.com>2016-07-05 17:32:30 -0400
committerSasha Levin <alexander.levin@verizon.com>2016-07-19 15:49:46 -0400
commitbda373bb186b027786681f930959deb56f4de01b (patch)
tree0b6cabd37d261406b6a149cb197cd88f165e801a
parentdb86fac6fe0f05f02be9fbc5fcfa236f3209076c (diff)
ecryptfs: don't allow mmap when the lower fs doesn't support it
[ Upstream commit f0fe970df3838c202ef6c07a4c2b36838ef0a88b ] 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> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--fs/ecryptfs/file.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 72afcc629d7b..f56a4216d081 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -170,6 +170,19 @@ 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 speciying file to open
@@ -365,7 +378,7 @@ 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,