Messages in this thread | | | Date | Fri, 11 Mar 2022 10:43:10 +0800 | Subject | Re: [PATCH -next] nbd: fix possible overflow on 'first_minor' in nbd_dev_add() | From | "zhangwensheng (E)" <> |
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friendly ping...
在 2022/3/10 17:32, Zhang Wensheng 写道: > 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@huawei.com> > --- > drivers/block/nbd.c | 24 ++++++++++++------------ > 1 file changed, 12 insertions(+), 12 deletions(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 5a1f98494ddd..b3cdfc0ffb98 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -1800,17 +1800,6 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs) > refcount_set(&nbd->refs, 0); > 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_work; > - } > - > disk->minors = 1 << part_shift; > disk->fops = &nbd_fops; > disk->private_data = nbd; > @@ -1915,8 +1904,19 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) > 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;
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