This is a note to let you know that I've just added the patch titled
ecryptfs: forbid opening files without mmap handler
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ecryptfs-forbid-opening-files-without-mmap-handler.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2f36db71009304b3f0b95afacd8eba1f9f046b87 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh@xxxxxxxxxx>
Date: Wed, 1 Jun 2016 11:55:06 +0200
Subject: ecryptfs: forbid opening files without mmap handler
From: Jann Horn <jannh@xxxxxxxxxx>
commit 2f36db71009304b3f0b95afacd8eba1f9f046b87 upstream.
This prevents users from triggering a stack overflow through a recursive
invocation of pagefault handling that involves mapping procfs files into
virtual memory.
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
Acked-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ecryptfs/kthread.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
--- a/fs/ecryptfs/kthread.c
+++ b/fs/ecryptfs/kthread.c
@@ -25,6 +25,7 @@
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/mount.h>
+#include <linux/file.h>
#include "ecryptfs_kernel.h"
struct ecryptfs_open_req {
@@ -147,7 +148,7 @@ int ecryptfs_privileged_open(struct file
flags |= IS_RDONLY(lower_dentry->d_inode) ? O_RDONLY : O_RDWR;
(*lower_file) = dentry_open(&req.path, flags, cred);
if (!IS_ERR(*lower_file))
- goto out;
+ goto have_file;
if ((flags & O_ACCMODE) == O_RDONLY) {
rc = PTR_ERR((*lower_file));
goto out;
@@ -165,8 +166,16 @@ int ecryptfs_privileged_open(struct 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;
}
Patches currently in stable-queue which might be from jannh@xxxxxxxxxx are
queue-3.14/ecryptfs-forbid-opening-files-without-mmap-handler.patch
queue-3.14/proc-prevent-stacking-filesystems-on-top.patch
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