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Revert "nbd: fix possible overflow on 'first_minor' in nbd_dev_add()"
commit7198bfc201
upstream. This reverts commit6d35d04a9e
. 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 <somlo@cmu.edu> Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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1 changed files with 12 additions and 12 deletions
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@ -1800,6 +1800,17 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
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refcount_set(&nbd->refs, 0);
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INIT_LIST_HEAD(&nbd->list);
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disk->major = NBD_MAJOR;
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/* Too big first_minor can cause duplicate creation of
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* sysfs files/links, since index << part_shift might overflow, or
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* MKDEV() expect that the max bits of first_minor is 20.
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*/
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disk->first_minor = index << part_shift;
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if (disk->first_minor < index || disk->first_minor > MINORMASK) {
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err = -EINVAL;
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goto out_free_work;
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}
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disk->minors = 1 << part_shift;
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disk->fops = &nbd_fops;
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disk->private_data = nbd;
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@ -1904,19 +1915,8 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
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if (!netlink_capable(skb, CAP_SYS_ADMIN))
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return -EPERM;
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if (info->attrs[NBD_ATTR_INDEX]) {
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if (info->attrs[NBD_ATTR_INDEX])
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index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
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/*
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* Too big first_minor can cause duplicate creation of
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* sysfs files/links, since index << part_shift might overflow, or
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* MKDEV() expect that the max bits of first_minor is 20.
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*/
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if (index < 0 || index > MINORMASK >> part_shift) {
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printk(KERN_ERR "nbd: illegal input index %d\n", index);
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return -EINVAL;
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}
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}
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if (!info->attrs[NBD_ATTR_SOCKETS]) {
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printk(KERN_ERR "nbd: must specify at least one socket\n");
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return -EINVAL;
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