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authorMichal Kubecek <mkubecek@suse.cz>2019-05-02 16:15:10 +0200
committerDavid S. Miller <davem@davemloft.net>2019-05-04 01:27:11 -0400
commitb424e432e770d6dd572765459d5b6a96a19c5286 (patch)
treef2aad0917c7a2e619bca6eefa82eb6b3355fb537 /lib
parentd54a16b20157ce300298eb4a1169bf9acfda3d08 (diff)
downloadlinux-b424e432e770d6dd572765459d5b6a96a19c5286.tar.gz
netlink: add validation of NLA_F_NESTED flag
Add new validation flag NL_VALIDATE_NESTED which adds three consistency
checks of NLA_F_NESTED_FLAG:

  - the flag is set on attributes with NLA_NESTED{,_ARRAY} policy
  - the flag is not set on attributes with other policies except NLA_UNSPEC
  - the flag is set on attribute passed to nla_parse_nested()

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

v2: change error messages to mention NLA_F_NESTED explicitly
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib')
-rw-r--r--lib/nlattr.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c
index adc919b32bf9..cace9b307781 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -184,6 +184,21 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
 		}
 	}
 
+	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) {
 	case NLA_EXACT_LEN:
 		if (attrlen != pt->len)