From: Vasily Averin <vvs@virtuozzo.com>
Date: Thu, 14 Jan 2016 10:41:14 +0000 (+0300)
Subject: cifs_dbg() outputs an uninitialized buffer in cifs_readdir()
X-Git-Tag: v4.5-rc1~6^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=01b9b0b28626db4a47d7f48744d70abca9914ef1;p=karo-tx-linux.git

cifs_dbg() outputs an uninitialized buffer in cifs_readdir()

In some cases tmp_bug can be not filled in cifs_filldir and stay uninitialized,
therefore its printk with "%s" modifier can leak content of kernelspace memory.
If old content of this buffer does not contain '\0' access bejond end of
allocated object can crash the host.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Steve French <sfrench@localhost.localdomain>
CC: Stable <stable@vger.kernel.org>
---

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 0557c45e9c33..b30a4a6d98a0 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -847,6 +847,7 @@ int cifs_readdir(struct file *file, struct dir_context *ctx)
 		 * if buggy server returns . and .. late do we want to
 		 * check for that here?
 		 */
+		*tmp_buf = 0;
 		rc = cifs_filldir(current_entry, file, ctx,
 				  tmp_buf, max_len);
 		if (rc) {