From: Zhang Wensheng zhangwensheng5@huawei.com
hulk inclusion category: bugfix bugzilla: 186386, https://gitee.com/openeuler/kernel/issues/I520OX CVE: NA backport: openEuler-22.03-LTS
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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") Signed-off-by: Zhang Wensheng zhangwensheng5@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/block/nbd.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 1bb9f45f2e3d..0ab548c78f24 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1760,14 +1760,6 @@ static int nbd_dev_add(int index) int err = -ENOMEM; int first_minor = index << part_shift;
- /* - * Too big index can cause duplicate creation of sysfs files/links, - * because MKDEV() expect that the max first minor is MINORMASK, or - * index << part_shift can overflow. - */ - if (first_minor < index || first_minor > MINORMASK) - return -EINVAL; - nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL); if (!nbd) goto out; @@ -1924,8 +1916,20 @@ 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;