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-rw-r--r--include/net/netlink.h17
-rw-r--r--lib/nlattr.c48
2 files changed, 53 insertions, 12 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 9522a0bf1f3a..f1db8e594847 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -373,6 +373,9 @@ int nla_validate(const struct nlattr *head, int len, int maxtype,
int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
int len, const struct nla_policy *policy,
struct netlink_ext_ack *extack);
+int nla_parse_strict(struct nlattr **tb, int maxtype, const struct nlattr *head,
+ int len, const struct nla_policy *policy,
+ struct netlink_ext_ack *extack);
int nla_policy_len(const struct nla_policy *, int);
struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
@@ -525,6 +528,20 @@ static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
nlmsg_attrlen(nlh, hdrlen), policy, extack);
}
+static inline int nlmsg_parse_strict(const struct nlmsghdr *nlh, int hdrlen,
+ struct nlattr *tb[], int maxtype,
+ const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
+ NL_SET_ERR_MSG(extack, "Invalid header length");
+ return -EINVAL;
+ }
+
+ return nla_parse_strict(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
+ nlmsg_attrlen(nlh, hdrlen), policy, extack);
+}
+
/**
* nlmsg_find_attr - find a specific attribute in a netlink message
* @nlh: netlink message header
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 1e900bb414ef..d26de6156b97 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -391,9 +391,10 @@ EXPORT_SYMBOL(nla_policy_len);
*
* Returns 0 on success or a negative error code.
*/
-int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
- int len, const struct nla_policy *policy,
- struct netlink_ext_ack *extack)
+static int __nla_parse(struct nlattr **tb, int maxtype,
+ const struct nlattr *head, int len,
+ bool strict, const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
{
const struct nlattr *nla;
int rem;
@@ -403,27 +404,50 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
nla_for_each_attr(nla, head, len, rem) {
u16 type = nla_type(nla);
- if (type > 0 && type <= maxtype) {
- if (policy) {
- int err = validate_nla(nla, maxtype, policy,
- extack);
-
- if (err < 0)
- return err;
+ if (type == 0 || type > maxtype) {
+ if (strict) {
+ NL_SET_ERR_MSG(extack, "Unknown attribute type");
+ return -EINVAL;
}
+ continue;
+ }
+ if (policy) {
+ int err = validate_nla(nla, maxtype, policy, extack);
- tb[type] = (struct nlattr *)nla;
+ if (err < 0)
+ return err;
}
+
+ tb[type] = (struct nlattr *)nla;
}
- if (unlikely(rem > 0))
+ if (unlikely(rem > 0)) {
pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
rem, current->comm);
+ NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes");
+ if (strict)
+ return -EINVAL;
+ }
return 0;
}
+
+int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
+ int len, const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ return __nla_parse(tb, maxtype, head, len, false, policy, extack);
+}
EXPORT_SYMBOL(nla_parse);
+int nla_parse_strict(struct nlattr **tb, int maxtype, const struct nlattr *head,
+ int len, const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ return __nla_parse(tb, maxtype, head, len, true, policy, extack);
+}
+EXPORT_SYMBOL(nla_parse_strict);
+
/**
* nla_find - Find a specific attribute in a stream of attributes
* @head: head of attribute stream