From 0aabd2f75c8af50d4849ee97046214bcb338cec4 Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Fri, 11 Oct 2019 09:40:09 +0200 Subject: [PATCH] genetlink: do not parse attributes for families with zero maxattr Commit 61a1afebc302 ("net: genetlink: push attrbuf allocation and parsing to a separate function") moved attribute buffer allocation and attribute parsing from genl_family_rcv_msg_doit() into a separate function genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls __nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own parsing). The parser error is ignored and does not propagate out of genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute type") is set in extack and if further processing generates no error or warning, it stays there and is interpreted as a warning by userspace. Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses the call of genl_family_rcv_msg_attrs_parse() if family->maxattr is zero. Move this logic inside genl_family_rcv_msg_attrs_parse() so that we don't have to handle it in each caller. v3: put the check inside genl_family_rcv_msg_attrs_parse() v2: adjust also argument of genl_family_rcv_msg_attrs_free() Fixes: 61a1afebc302 ("net: genetlink: push attrbuf allocation and parsing to a separate function") Signed-off-by: Michal Kubecek Acked-by: Jiri Pirko Acked-by: Jakub Kicinski Signed-off-by: David S. Miller --- net/netlink/genetlink.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index ecc2bd3e73e4b..0522b2b1fd958 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -483,6 +483,9 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family, struct nlattr **attrbuf; int err; + if (!family->maxattr) + return NULL; + if (parallel) { attrbuf = kmalloc_array(family->maxattr + 1, sizeof(struct nlattr *), GFP_KERNEL); @@ -582,9 +585,6 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family, if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) return -EINVAL; - if (!family->maxattr) - goto no_attrs; - attrs = genl_family_rcv_msg_attrs_parse(family, nlh, extack, ops, hdrlen, GENL_DONT_VALIDATE_DUMP_STRICT, @@ -649,7 +649,6 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family, attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, ops, hdrlen, GENL_DONT_VALIDATE_STRICT, - family->maxattr && family->parallel_ops); if (IS_ERR(attrbuf)) return PTR_ERR(attrbuf); @@ -676,8 +675,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family, family->post_doit(ops, skb, &info); out: - genl_family_rcv_msg_attrs_free(family, attrbuf, - family->maxattr && family->parallel_ops); + genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops); return err; } -- 2.39.5