Patch "vfs: ioctl: prevent double-fetch in dedupe ioctl" has been added to the 4.6-stable tree

Patch "vfs: ioctl: prevent double-fetch in dedupe ioctl" has been added to the 4.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    vfs: ioctl: prevent double-fetch in dedupe ioctl

to the 4.6-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:
     vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 10eec60ce79187686e052092e5383c99b4420a20 Mon Sep 17 00:00:00 2001
From: Scott Bauer <sbauer@plzdonthack.me>
Date: Wed, 27 Jul 2016 19:11:29 -0600
Subject: vfs: ioctl: prevent double-fetch in dedupe ioctl

From: Scott Bauer <sbauer@plzdonthack.me>

commit 10eec60ce79187686e052092e5383c99b4420a20 upstream.

This prevents a double-fetch from user space that can lead to to an
undersized allocation and heap overflow.

Fixes: 54dbc1517237 ("vfs: hoist the btrfs deduplication ioctl to the vfs")
Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ioctl.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -590,6 +590,7 @@ static long ioctl_file_dedupe_range(stru
 		goto out;
 	}
 
+	same->dest_count = count;
 	ret = vfs_dedupe_file_range(file, same);
 	if (ret)
 		goto out;


Patches currently in stable-queue which might be from sbauer@plzdonthack.me are

queue-4.6/vfs-ioctl-prevent-double-fetch-in-dedupe-ioctl.patch