From 05d7f547bea1872e711ee97bd46aace6cf61c42b Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Thu, 2 May 2019 16:15:10 +0200 Subject: [PATCH] genetlink: do not validate dump requests if there is no policy Unlike do requests, dump genetlink requests now perform strict validation by default even if the genetlink family does not set policy and maxtype because it does validation and parsing on its own (e.g. because it wants to allow different message format for different commands). While the null policy will be ignored, maxtype (which would be zero) is still checked so that any attribute will fail validation. The solution is to only call __nla_validate() from genl_family_rcv_msg() if family->maxtype is set. Fixes: ef6243acb478 ("genetlink: optionally validate strictly/dumps") Signed-off-by: Michal Kubecek Reviewed-by: Johannes Berg Signed-off-by: David S. Miller --- net/netlink/genetlink.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 79cfa031dc7d..efccd1ac9a66 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -537,21 +537,25 @@ static int genl_family_rcv_msg(const struct genl_family *family, return -EOPNOTSUPP; if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) { - unsigned int validate = NL_VALIDATE_STRICT; int hdrlen = GENL_HDRLEN + family->hdrsize; - if (ops->validate & GENL_DONT_VALIDATE_DUMP_STRICT) - validate = NL_VALIDATE_LIBERAL; - if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) return -EINVAL; - rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen), - nlmsg_attrlen(nlh, hdrlen), - family->maxattr, family->policy, - validate, extack); - if (rc) - return rc; + if (family->maxattr) { + unsigned int validate = NL_VALIDATE_STRICT; + + if (ops->validate & + GENL_DONT_VALIDATE_DUMP_STRICT) + validate = NL_VALIDATE_LIBERAL; + rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen), + nlmsg_attrlen(nlh, hdrlen), + family->maxattr, + family->policy, + validate, extack); + if (rc) + return rc; + } } if (!family->parallel_ops) {