Commit c29f1845 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

netlink: move extack setting into validate_nla() 



This unifies the code between nla_parse() which sets the bad
attribute pointer and an error message, and nla_validate()
which only sets the bad attribute pointer.

It also cleans up the code for NLA_REJECT and paves the way
for nested policy validation, as it will allow us to easily
skip setting the "generic" message without any extra args
like the **error_msg now, just passing the extack through is
now enough.

While at it, remove the unnecessary label in nla_parse().

Suggested-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 48fde90a

lib/nlattr.c

+36 −32
Original line number Diff line number Diff line
@@ -69,10 +69,11 @@ static int validate_nla_bitfield32(const struct nlattr *nla, 


static int validate_nla(const struct nlattr *nla, int maxtype,

			const struct nla_policy *policy,

			const char **error_msg)

			struct netlink_ext_ack *extack)

{

	const struct nla_policy *pt;

	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);

	int err = -ERANGE;



	if (type <= 0 || type > maxtype)

		return 0;
@@ -90,24 +91,31 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
	switch (pt->type) {

	case NLA_EXACT_LEN:

		if (attrlen != pt->len)

			return -ERANGE;

			goto out_err;

		break;



	case NLA_REJECT:

		if (pt->validation_data && error_msg)

			*error_msg = pt->validation_data;

		if (extack && pt->validation_data) {

			NL_SET_BAD_ATTR(extack, nla);

			extack->_msg = pt->validation_data;

			return -EINVAL;

		}

		err = -EINVAL;

		goto out_err;



	case NLA_FLAG:

		if (attrlen > 0)

			return -ERANGE;

			goto out_err;

		break;



	case NLA_BITFIELD32:

		if (attrlen != sizeof(struct nla_bitfield32))

			return -ERANGE;

			goto out_err;



		return validate_nla_bitfield32(nla, pt->validation_data);

		err = validate_nla_bitfield32(nla, pt->validation_data);

		if (err)

			goto out_err;

		break;



	case NLA_NUL_STRING:

		if (pt->len)
@@ -115,13 +123,15 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
		else

			minlen = attrlen;



		if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)

			return -EINVAL;

		if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {

			err = -EINVAL;

			goto out_err;

		}

		/* fall through */



	case NLA_STRING:

		if (attrlen < 1)

			return -ERANGE;

			goto out_err;



		if (pt->len) {

			char *buf = nla_data(nla);
@@ -130,13 +140,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
				attrlen--;



			if (attrlen > pt->len)

				return -ERANGE;

				goto out_err;

		}

		break;



	case NLA_BINARY:

		if (pt->len && attrlen > pt->len)

			return -ERANGE;

			goto out_err;

		break;



	case NLA_NESTED:
@@ -152,10 +162,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
			minlen = nla_attr_minlen[pt->type];



		if (attrlen < minlen)

			return -ERANGE;

			goto out_err;

	}



	return 0;

out_err:

	NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation");

	return err;

}



/**
@@ -180,13 +193,11 @@ int nla_validate(const struct nlattr *head, int len, int maxtype, 
	int rem;



	nla_for_each_attr(nla, head, len, rem) {

		int err = validate_nla(nla, maxtype, policy, NULL);

		int err = validate_nla(nla, maxtype, policy, extack);



		if (err < 0) {

			NL_SET_BAD_ATTR(extack, nla);

		if (err < 0)

			return err;

	}

	}



	return 0;

}
@@ -241,7 +252,7 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head, 
	      struct netlink_ext_ack *extack)

{

	const struct nlattr *nla;

	int rem, err;

	int rem;



	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
@@ -249,17 +260,12 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head, 
		u16 type = nla_type(nla);



		if (type > 0 && type <= maxtype) {

			static const char _msg[] = "Attribute failed policy validation";

			const char *msg = _msg;



			if (policy) {

				err = validate_nla(nla, maxtype, policy, &msg);

				if (err < 0) {

					NL_SET_BAD_ATTR(extack, nla);

					if (extack)

						extack->_msg = msg;

					goto errout;

				}

				int err = validate_nla(nla, maxtype, policy,

						       extack);



				if (err < 0)

					return err;

			}



			tb[type] = (struct nlattr *)nla;
@@ -270,9 +276,7 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head, 
		pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",

				    rem, current->comm);



	err = 0;

errout:

	return err;

	return 0;

}

EXPORT_SYMBOL(nla_parse);

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