Patch "ubifs: Don't leak kernel memory to the MTD" has been added to the 4.12-stable tree

Patch "ubifs: Don't leak kernel memory to the MTD" has been added to the 4.12-stable tree

[gregkh]

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

    ubifs: Don't leak kernel memory to the MTD

to the 4.12-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:
     ubifs-don-t-leak-kernel-memory-to-the-mtd.patch
and it can be found in the queue-4.12 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 4acadda74ff8b949c448c0282765ae747e088c87 Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Fri, 16 Jun 2017 16:21:44 +0200
Subject: ubifs: Don't leak kernel memory to the MTD

From: Richard Weinberger <richard@nod.at>

commit 4acadda74ff8b949c448c0282765ae747e088c87 upstream.

When UBIFS prepares data structures which will be written to the MTD it
ensues that their lengths are multiple of 8. Since it uses kmalloc() the
padded bytes are left uninitialized and we leak a few bytes of kernel
memory to the MTD.
To make sure that all bytes are initialized, let's switch to kzalloc().
Kzalloc() is fine in this case because the buffers are not huge and in
the IO path the performance bottleneck is anyway the MTD.

Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ubifs/journal.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -574,7 +574,7 @@ int ubifs_jnl_update(struct ubifs_info *
 	/* Make sure to also account for extended attributes */
 	len += host_ui->data_len;
 
-	dent = kmalloc(len, GFP_NOFS);
+	dent = kzalloc(len, GFP_NOFS);
 	if (!dent)
 		return -ENOMEM;
 
@@ -967,7 +967,7 @@ int ubifs_jnl_xrename(struct ubifs_info
 	if (twoparents)
 		len += plen;
 
-	dent1 = kmalloc(len, GFP_NOFS);
+	dent1 = kzalloc(len, GFP_NOFS);
 	if (!dent1)
 		return -ENOMEM;
 
@@ -1117,7 +1117,7 @@ int ubifs_jnl_rename(struct ubifs_info *
 	len = aligned_dlen1 + aligned_dlen2 + ALIGN(ilen, 8) + ALIGN(plen, 8);
 	if (move)
 		len += plen;
-	dent = kmalloc(len, GFP_NOFS);
+	dent = kzalloc(len, GFP_NOFS);
 	if (!dent)
 		return -ENOMEM;
 
@@ -1500,7 +1500,7 @@ int ubifs_jnl_delete_xattr(struct ubifs_
 	hlen = host_ui->data_len + UBIFS_INO_NODE_SZ;
 	len = aligned_xlen + UBIFS_INO_NODE_SZ + ALIGN(hlen, 8);
 
-	xent = kmalloc(len, GFP_NOFS);
+	xent = kzalloc(len, GFP_NOFS);
 	if (!xent)
 		return -ENOMEM;
 
@@ -1607,7 +1607,7 @@ int ubifs_jnl_change_xattr(struct ubifs_
 	aligned_len1 = ALIGN(len1, 8);
 	aligned_len = aligned_len1 + ALIGN(len2, 8);
 
-	ino = kmalloc(aligned_len, GFP_NOFS);
+	ino = kzalloc(aligned_len, GFP_NOFS);
 	if (!ino)
 		return -ENOMEM;
 


Patches currently in stable-queue which might be from richard@nod.at are

queue-4.12/ubifs-don-t-leak-kernel-memory-to-the-mtd.patch
queue-4.12/ubifs-don-t-encrypt-special-files-on-creation.patch
queue-4.12/ubifs-correctly-evict-xattr-inodes.patch
queue-4.12/ubifs-set-double-hash-cookie-also-for-rename_exchange.patch