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From 33afeac21b9cb79ad8fc5caf239af89c79e25e1e Mon Sep 17 00:00:00 2001
From: Benjamin Randazzo <benjamin@randazzo.fr>
Date: Sat, 25 Jul 2015 16:36:50 +0200
Subject: md: use kzalloc() when bitmap is disabled
commit b6878d9e03043695dbf3fa1caa6dfc09db225b16 upstream.
In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a
mdu_bitmap_file_t called "file".
5769 file = kmalloc(sizeof(*file), GFP_NOIO);
5770 if (!file)
5771 return -ENOMEM;
This structure is copied to user space at the end of the function.
5786 if (err == 0 &&
5787 copy_to_user(arg, file, sizeof(*file)))
5788 err = -EFAULT
But if bitmap is disabled only the first byte of "file" is initialized
with zero, so it's possible to read some bytes (up to 4095) of kernel
space memory from user space. This is an information leak.
5775 /* bitmap disabled, zero the first byte and copy out */
5776 if (!mddev->bitmap_info.file)
5777 file->pathname[0] = '\0';
Fixes CVE-2015-5697.
Upstream-Status: Backport
Signed-off-by: Benjamin Randazzo <benjamin@randazzo.fr>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
---
drivers/md/md.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index b920028..e462151 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5740,7 +5740,7 @@ static int get_bitmap_file(struct mddev *mddev, void __user * arg)
char *ptr;
int err;
- file = kmalloc(sizeof(*file), GFP_NOIO);
+ file = kzalloc(sizeof(*file), GFP_NOIO);
if (!file)
return -ENOMEM;
--
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