1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <linux/kernel.h>
3*4882a593Smuzhiyun #include <net/netlink.h>
4*4882a593Smuzhiyun #include <linux/drbd_genl_api.h>
5*4882a593Smuzhiyun #include "drbd_nla.h"
6*4882a593Smuzhiyun
drbd_nla_check_mandatory(int maxtype,struct nlattr * nla)7*4882a593Smuzhiyun static int drbd_nla_check_mandatory(int maxtype, struct nlattr *nla)
8*4882a593Smuzhiyun {
9*4882a593Smuzhiyun struct nlattr *head = nla_data(nla);
10*4882a593Smuzhiyun int len = nla_len(nla);
11*4882a593Smuzhiyun int rem;
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun /*
14*4882a593Smuzhiyun * validate_nla (called from nla_parse_nested) ignores attributes
15*4882a593Smuzhiyun * beyond maxtype, and does not understand the DRBD_GENLA_F_MANDATORY flag.
16*4882a593Smuzhiyun * In order to have it validate attributes with the DRBD_GENLA_F_MANDATORY
17*4882a593Smuzhiyun * flag set also, check and remove that flag before calling
18*4882a593Smuzhiyun * nla_parse_nested.
19*4882a593Smuzhiyun */
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun nla_for_each_attr(nla, head, len, rem) {
22*4882a593Smuzhiyun if (nla->nla_type & DRBD_GENLA_F_MANDATORY) {
23*4882a593Smuzhiyun nla->nla_type &= ~DRBD_GENLA_F_MANDATORY;
24*4882a593Smuzhiyun if (nla_type(nla) > maxtype)
25*4882a593Smuzhiyun return -EOPNOTSUPP;
26*4882a593Smuzhiyun }
27*4882a593Smuzhiyun }
28*4882a593Smuzhiyun return 0;
29*4882a593Smuzhiyun }
30*4882a593Smuzhiyun
drbd_nla_parse_nested(struct nlattr * tb[],int maxtype,struct nlattr * nla,const struct nla_policy * policy)31*4882a593Smuzhiyun int drbd_nla_parse_nested(struct nlattr *tb[], int maxtype, struct nlattr *nla,
32*4882a593Smuzhiyun const struct nla_policy *policy)
33*4882a593Smuzhiyun {
34*4882a593Smuzhiyun int err;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun err = drbd_nla_check_mandatory(maxtype, nla);
37*4882a593Smuzhiyun if (!err)
38*4882a593Smuzhiyun err = nla_parse_nested_deprecated(tb, maxtype, nla, policy,
39*4882a593Smuzhiyun NULL);
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun return err;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
drbd_nla_find_nested(int maxtype,struct nlattr * nla,int attrtype)44*4882a593Smuzhiyun struct nlattr *drbd_nla_find_nested(int maxtype, struct nlattr *nla, int attrtype)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun int err;
47*4882a593Smuzhiyun /*
48*4882a593Smuzhiyun * If any nested attribute has the DRBD_GENLA_F_MANDATORY flag set and
49*4882a593Smuzhiyun * we don't know about that attribute, reject all the nested
50*4882a593Smuzhiyun * attributes.
51*4882a593Smuzhiyun */
52*4882a593Smuzhiyun err = drbd_nla_check_mandatory(maxtype, nla);
53*4882a593Smuzhiyun if (err)
54*4882a593Smuzhiyun return ERR_PTR(err);
55*4882a593Smuzhiyun return nla_find_nested(nla, attrtype);
56*4882a593Smuzhiyun }
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