Messages in this thread | | | Date | Thu, 31 Mar 2022 08:45:27 +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 2022/3/17 21:05, zhangwensheng (E) 写道: > friendly ping... > > 在 2022/3/11 10:43, zhangwensheng (E) 写道: >> 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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