netdev - [PATCH bpf-next v5 5/8] xdp: Provide extack messages when prog attachment failed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190201001954.4130-6-maciej.fijalkowski@intel.com>
Date:   Fri,  1 Feb 2019 01:19:51 +0100
From:   Maciej Fijalkowski <maciejromanfijalkowski@...il.com>
To:     daniel@...earbox.net, ast@...nel.org
Cc:     netdev@...r.kernel.org, jakub.kicinski@...ronome.com,
        brouer@...hat.com, john.fastabend@...il.com
Subject: [PATCH bpf-next v5 5/8] xdp: Provide extack messages when prog attachment failed

In order to provide more meaningful messages to user when the process of
loading xdp program onto network interface failed, let's add extack
messages within dev_change_xdp_fd.

Suggested-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
---
 net/core/dev.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 8e276e0192a1..bfa4be42afff 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7983,8 +7983,10 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
 	query = flags & XDP_FLAGS_HW_MODE ? XDP_QUERY_PROG_HW : XDP_QUERY_PROG;
 
 	bpf_op = bpf_chk = ops->ndo_bpf;
-	if (!bpf_op && (flags & (XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE)))
+	if (!bpf_op && (flags & (XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE))) {
+		NL_SET_ERR_MSG(extack, "underlying driver does not support XDP in native mode");
 		return -EOPNOTSUPP;
+	}
 	if (!bpf_op || (flags & XDP_FLAGS_SKB_MODE))
 		bpf_op = generic_xdp_install;
 	if (bpf_op == bpf_chk)
@@ -7992,11 +7994,15 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
 
 	if (fd >= 0) {
 		if (__dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG) ||
-		    __dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG_HW))
+		    __dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG_HW)) {
+			NL_SET_ERR_MSG(extack, "native and generic XDP can't be active at the same time");
 			return -EEXIST;
+		}
 		if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) &&
-		    __dev_xdp_query(dev, bpf_op, query))
+		    __dev_xdp_query(dev, bpf_op, query)) {
+			NL_SET_ERR_MSG(extack, "XDP program already attached");
 			return -EBUSY;
+		}
 
 		prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP,
 					     bpf_op == ops->ndo_bpf);
-- 
2.16.1