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Diffstat (limited to 'lib/nlattr.c')
-rw-r--r--lib/nlattr.c200
1 files changed, 116 insertions, 84 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c
index d26de6156b97..cace9b307781 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -69,7 +69,8 @@ static int validate_nla_bitfield32(const struct nlattr *nla,
static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
const struct nla_policy *policy,
- struct netlink_ext_ack *extack)
+ struct netlink_ext_ack *extack,
+ unsigned int validate)
{
const struct nlattr *entry;
int rem;
@@ -86,8 +87,8 @@ static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
return -ERANGE;
}
- ret = nla_validate(nla_data(entry), nla_len(entry),
- maxtype, policy, extack);
+ ret = __nla_validate(nla_data(entry), nla_len(entry),
+ maxtype, policy, validate, extack);
if (ret < 0)
return ret;
}
@@ -154,13 +155,17 @@ static int nla_validate_int_range(const struct nla_policy *pt,
}
static int validate_nla(const struct nlattr *nla, int maxtype,
- const struct nla_policy *policy,
+ const struct nla_policy *policy, unsigned int validate,
struct netlink_ext_ack *extack)
{
+ u16 strict_start_type = policy[0].strict_start_type;
const struct nla_policy *pt;
int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
int err = -ERANGE;
+ if (strict_start_type && type >= strict_start_type)
+ validate |= NL_VALIDATE_STRICT;
+
if (type <= 0 || type > maxtype)
return 0;
@@ -172,6 +177,26 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
(pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
current->comm, type);
+ if (validate & NL_VALIDATE_STRICT_ATTRS) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "invalid attribute length");
+ return -EINVAL;
+ }
+ }
+
+ if (validate & NL_VALIDATE_NESTED) {
+ if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&
+ !(nla->nla_type & NLA_F_NESTED)) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "NLA_F_NESTED is missing");
+ return -EINVAL;
+ }
+ if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&
+ pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "NLA_F_NESTED not expected");
+ return -EINVAL;
+ }
}
switch (pt->type) {
@@ -244,8 +269,9 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
if (attrlen < NLA_HDRLEN)
goto out_err;
if (pt->validation_data) {
- err = nla_validate(nla_data(nla), nla_len(nla), pt->len,
- pt->validation_data, extack);
+ err = __nla_validate(nla_data(nla), nla_len(nla), pt->len,
+ pt->validation_data, validate,
+ extack);
if (err < 0) {
/*
* return directly to preserve the inner
@@ -268,7 +294,7 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
err = nla_validate_array(nla_data(nla), nla_len(nla),
pt->len, pt->validation_data,
- extack);
+ extack, validate);
if (err < 0) {
/*
* return directly to preserve the inner
@@ -278,10 +304,23 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
}
}
break;
+
+ case NLA_UNSPEC:
+ if (validate & NL_VALIDATE_UNSPEC) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "Unsupported attribute");
+ return -EINVAL;
+ }
+ /* fall through */
+ case NLA_MIN_LEN:
+ if (attrlen < pt->len)
+ goto out_err;
+ break;
+
default:
if (pt->len)
minlen = pt->len;
- else if (pt->type != NLA_UNSPEC)
+ else
minlen = nla_attr_minlen[pt->type];
if (attrlen < minlen)
@@ -315,37 +354,76 @@ out_err:
return err;
}
+static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
+ const struct nla_policy *policy,
+ unsigned int validate,
+ struct netlink_ext_ack *extack,
+ struct nlattr **tb)
+{
+ const struct nlattr *nla;
+ int rem;
+
+ if (tb)
+ memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
+
+ nla_for_each_attr(nla, head, len, rem) {
+ u16 type = nla_type(nla);
+
+ if (type == 0 || type > maxtype) {
+ if (validate & NL_VALIDATE_MAXTYPE) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "Unknown attribute type");
+ return -EINVAL;
+ }
+ continue;
+ }
+ if (policy) {
+ int err = validate_nla(nla, maxtype, policy,
+ validate, extack);
+
+ if (err < 0)
+ return err;
+ }
+
+ if (tb)
+ tb[type] = (struct nlattr *)nla;
+ }
+
+ 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 (validate & NL_VALIDATE_TRAILING)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/**
- * nla_validate - Validate a stream of attributes
+ * __nla_validate - Validate a stream of attributes
* @head: head of attribute stream
* @len: length of attribute stream
* @maxtype: maximum attribute type to be expected
* @policy: validation policy
+ * @validate: validation strictness
* @extack: extended ACK report struct
*
* Validates all attributes in the specified attribute stream against the
- * specified policy. Attributes with a type exceeding maxtype will be
- * ignored. See documenation of struct nla_policy for more details.
+ * specified policy. Validation depends on the validate flags passed, see
+ * &enum netlink_validation for more details on that.
+ * See documenation of struct nla_policy for more details.
*
* Returns 0 on success or a negative error code.
*/
-int nla_validate(const struct nlattr *head, int len, int maxtype,
- const struct nla_policy *policy,
- struct netlink_ext_ack *extack)
+int __nla_validate(const struct nlattr *head, int len, int maxtype,
+ const struct nla_policy *policy, unsigned int validate,
+ struct netlink_ext_ack *extack)
{
- const struct nlattr *nla;
- int rem;
-
- nla_for_each_attr(nla, head, len, rem) {
- int err = validate_nla(nla, maxtype, policy, extack);
-
- if (err < 0)
- return err;
- }
-
- return 0;
+ return __nla_validate_parse(head, len, maxtype, policy, validate,
+ extack, NULL);
}
-EXPORT_SYMBOL(nla_validate);
+EXPORT_SYMBOL(__nla_validate);
/**
* nla_policy_len - Determin the max. length of a policy
@@ -377,76 +455,30 @@ nla_policy_len(const struct nla_policy *p, int n)
EXPORT_SYMBOL(nla_policy_len);
/**
- * nla_parse - Parse a stream of attributes into a tb buffer
+ * __nla_parse - Parse a stream of attributes into a tb buffer
* @tb: destination array with maxtype+1 elements
* @maxtype: maximum attribute type to be expected
* @head: head of attribute stream
* @len: length of attribute stream
* @policy: validation policy
+ * @validate: validation strictness
+ * @extack: extended ACK pointer
*
* Parses a stream of attributes and stores a pointer to each attribute in
- * the tb array accessible via the attribute type. Attributes with a type
- * exceeding maxtype will be silently ignored for backwards compatibility
- * reasons. policy may be set to NULL if no validation is required.
+ * the tb array accessible via the attribute type.
+ * Validation is controlled by the @validate parameter.
*
* Returns 0 on success or a negative error code.
*/
-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;
-
- memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
-
- nla_for_each_attr(nla, head, len, rem) {
- u16 type = nla_type(nla);
-
- 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);
-
- if (err < 0)
- return err;
- }
-
- tb[type] = (struct nlattr *)nla;
- }
-
- 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)
+int __nla_parse(struct nlattr **tb, int maxtype,
+ const struct nlattr *head, int len,
+ const struct nla_policy *policy, unsigned int validate,
+ struct netlink_ext_ack *extack)
{
- return __nla_parse(tb, maxtype, head, len, true, policy, extack);
+ return __nla_validate_parse(head, len, maxtype, policy, validate,
+ extack, tb);
}
-EXPORT_SYMBOL(nla_parse_strict);
+EXPORT_SYMBOL(__nla_parse);
/**
* nla_find - Find a specific attribute in a stream of attributes