This is a note to let you know that I've just added the patch titled
nbd: fix possible overflow on 'first_minor' in nbd_dev_add()
to the 5.10-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:
nbd-fix-possible-overflow-on-first_minor-in-nbd_dev_add.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 858f1bf65d3d9c00b5e2d8ca87dc79ed88267c98 Mon Sep 17 00:00:00 2001
From: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx>
Date: Sat, 21 May 2022 15:37:48 +0800
Subject: nbd: fix possible overflow on 'first_minor' in nbd_dev_add()
From: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx>
commit 858f1bf65d3d9c00b5e2d8ca87dc79ed88267c98 upstream.
When 'index' is a big numbers, it may become negative which forced
to 'int'. then 'index << part_shift' might overflow to a positive
value that is not greater than '0xfffff', then sysfs might complains
about duplicate creation. Because of this, move the 'index' judgment
to the front will fix it and be better.
Fixes: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices")
Fixes: 940c264984fd ("nbd: fix possible overflow for 'first_minor' in nbd_dev_add()")
Signed-off-by: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220521073749.3146892-6-yukuai3@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Wen Yang <wenyang.linux@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/nbd.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1771,17 +1771,7 @@ static int nbd_dev_add(int index)
refcount_set(&nbd->refs, 1);
INIT_LIST_HEAD(&nbd->list);
disk->major = NBD_MAJOR;
-
- /* Too big first_minor can cause duplicate creation of
- * sysfs files/links, since index << part_shift might overflow, or
- * MKDEV() expect that the max bits of first_minor is 20.
- */
disk->first_minor = index << part_shift;
- if (disk->first_minor < index || disk->first_minor > MINORMASK) {
- err = -EINVAL;
- goto out_free_idr;
- }
-
disk->fops = &nbd_fops;
disk->private_data = nbd;
sprintf(disk->disk_name, "nbd%d", index);
@@ -1875,8 +1865,19 @@ static int nbd_genl_connect(struct sk_bu
if (!netlink_capable(skb, CAP_SYS_ADMIN))
return -EPERM;
- if (info->attrs[NBD_ATTR_INDEX])
+ if (info->attrs[NBD_ATTR_INDEX]) {
index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
+
+ /*
+ * Too big first_minor can cause duplicate creation of
+ * sysfs files/links, since index << part_shift might overflow, or
+ * MKDEV() expect that the max bits of first_minor is 20.
+ */
+ if (index < 0 || index > MINORMASK >> part_shift) {
+ printk(KERN_ERR "nbd: illegal input index %d\n", index);
+ return -EINVAL;
+ }
+ }
if (!info->attrs[NBD_ATTR_SOCKETS]) {
printk(KERN_ERR "nbd: must specify at least one socket\n");
return -EINVAL;
Patches currently in stable-queue which might be from zhangwensheng5@xxxxxxxxxx are
queue-5.10/nbd-fix-possible-overflow-on-first_minor-in-nbd_dev_add.patch
