From 7198bfc2017644c6b92d2ecef9b8b8e0363bb5fd Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 2 Apr 2022 11:40:23 -0600 Subject: Revert "nbd: fix possible overflow on 'first_minor' in nbd_dev_add()" This reverts commit 6d35d04a9e18990040e87d2bbf72689252669d54. Both Gabriel and Borislav report that this commit casues a regression with nbd: sysfs: cannot create duplicate filename '/dev/block/43:0' Revert it before 5.18-rc1 and we'll investigage this separately in due time. Link: https://lore.kernel.org/all/YkiJTnFOt9bTv6A2@zn.tnic/ Reported-by: Gabriel L. Somlo Reported-by: Borislav Petkov Signed-off-by: Jens Axboe --- 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 b3cdfc0ffb98..5a1f98494ddd 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1800,6 +1800,17 @@ 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; @@ -1904,19 +1915,8 @@ 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; -- cgit