From: Johannes Berg <johannes.b...@intel.com>
Use a validation type instead, so we can later expose
the NLA_* values to userspace for policy descriptions.
Signed-off-by: Johannes Berg <johannes.b...@intel.com>
---
include/net/netlink.h | 15 ++++++++-------
lib/nlattr.c | 16 ++++++++++------
2 files changed, 18 insertions(+), 13 deletions(-)
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 6c79a1d0e30f..8104d935a827 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -182,7 +182,6 @@ enum {
NLA_BITFIELD32,
NLA_REJECT,
NLA_EXACT_LEN,
- NLA_EXACT_LEN_WARN,
NLA_MIN_LEN,
__NLA_TYPE_MAX,
};
@@ -204,6 +203,7 @@ enum nla_policy_validation {
NLA_VALIDATE_MAX,
NLA_VALIDATE_RANGE_PTR,
NLA_VALIDATE_FUNCTION,
+ NLA_VALIDATE_WARN_TOO_LONG,
};
/**
@@ -237,10 +237,10 @@ enum nla_policy_validation {
* just like "All other"
* NLA_BITFIELD32 Unused
* NLA_REJECT Unused
- * NLA_EXACT_LEN Attribute must have exactly this length, otherwise
- * it is rejected.
- * NLA_EXACT_LEN_WARN Attribute should have exactly this length, a warning
- * is logged if it is longer, shorter is rejected.
+ * NLA_EXACT_LEN Attribute should have exactly this length, otherwise
+ * it is rejected or warned about, the latter happening
+ * if and only if the `validation_type' is set to
+ * NLA_VALIDATE_WARN_TOO_LONG.
* NLA_MIN_LEN Minimum length of attribute payload
* All other Minimum length of attribute payload
*
@@ -353,8 +353,9 @@ struct nla_policy {
};
#define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len }
-#define NLA_POLICY_EXACT_LEN_WARN(_len) { .type = NLA_EXACT_LEN_WARN, \
- .len = _len }
+#define NLA_POLICY_EXACT_LEN_WARN(_len) \
+ { .type = NLA_EXACT_LEN, .len = _len, \
+ .validation_type = NLA_VALIDATE_WARN_TOO_LONG, }
#define NLA_POLICY_MIN_LEN(_len) { .type = NLA_MIN_LEN, .len = _len }
#define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN)
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 2e6e6e29efda..5fe1e7baf371 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -245,7 +245,9 @@ static int validate_nla(const struct nlattr *nla, int
maxtype,
BUG_ON(pt->type > NLA_TYPE_MAX);
if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) ||
- (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
+ (pt->type == NLA_EXACT_LEN &&
+ pt->validation_type == NLA_VALIDATE_WARN_TOO_LONG &&
+ 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) {
@@ -256,11 +258,6 @@ static int validate_nla(const struct nlattr *nla, int
maxtype,
}
switch (pt->type) {
- case NLA_EXACT_LEN:
- if (attrlen != pt->len)
- goto out_err;
- break;
-
case NLA_REJECT:
if (extack && pt->reject_message) {
NL_SET_BAD_ATTR(extack, nla);
@@ -373,6 +370,13 @@ static int validate_nla(const struct nlattr *nla, int
maxtype,
goto out_err;
break;
+ case NLA_EXACT_LEN:
+ if (pt->validation_type != NLA_VALIDATE_WARN_TOO_LONG) {
+ if (attrlen != pt->len)
+ goto out_err;
+ break;
+ }
+ /* fall through */
default:
if (pt->len)
minlen = pt->len;
--
2.17.2
