From mboxrd@z Thu Jan 1 00:00:00 1970 From: Haseeb Malik Date: Fri, 11 Sep 2026 19:57:21 -0400 Subject: [PATCH net] macsec: initialize SecY before registering the netdevice MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260911-fix-macsec-net-v1-1-c82aa58ae741@gmail.com> X-B4-Tracking: v=1; b=H4sIAGCVpGoC/x2MQQrCQAxFr1KyNnSmYku9irjIxIzNolEmIkLp3 Y0u3+P9v4FLU3E4dxs0eavrwwLyoQNeyO6CeguGIQ1jmnPGqh9ciV0YTV5Y67HwSSYqiSBGzyZ R/A8vEAFcQxZywdLIePl9he5XUoN9/wIHzjdwgAAAAA== To: Sabrina Dubroca Cc: Andrew Lunn , Simon Horman , Hangbin Liu , Felix Walter , netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, Jakub Kicinski , syzbot+f2f6312ad1b5a0bfe316@syzkaller.appspotmail.com, "David S. Miller" , Paolo Abeni , Eric Dumazet , linux-kernel@vger.kernel.org X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1789171045; l=5581; i=haseebulhaq55@gmail.com; s=default; h=from:subject:message-id; bh=KSA/709t2+4DBX9OBd6ktaJ9IHFKNEyjhqrtYtrgPRk=; b=FrLFoZNkqAVAf7jQS/0uFbGMIu17BznN0PwdWaGq1SToCd23aRuB6hYGqH+mVpXpzbVxTabmS enUsZOBgTJtBKiIxLN+NmoXcMhIT5LsIaTkofNp4wm66wc4EjNhz+9M X-Developer-Key: i=haseebulhaq55@gmail.com; a=ed25519; pk=U/yCVc6cTsqDqxWLzvoONZ7DUA3EfRU+rfO9Xxo4p2w= X-Endpoint-Received: by B4 Relay for haseebulhaq55@gmail.com/default with auth_id=1026 List-Id: B4 Relay Submissions Creating a MACsec device with MAC offload over an LRO-capable lower device triggers a warning in rtmsg_ifinfo_build_skb() when IPv4 forwarding is enabled by default. register_netdevice() invokes inetdev_init(), which disables LRO and emits a NETDEV_FEAT_CHANGE notification. This reaches macsec_fill_info() before macsec_add_dev() initializes the SecY. key_len is still zero, so macsec_fill_info() returns -EMSGSIZE and trips the WARN_ON in rtmsg_ifinfo_build_skb(), even though the skb has enough space. Initialize the SecY and apply the new-link attributes before registration. Move the per-CPU statistics and metadata destination allocation into ndo_init(), and release partial allocations on failure. Keep SCI assignment after registration because ndo_init() may inherit the lower device's MAC address. Fixes: ccfdec908922 ("macsec: Add support for GCM-AES-256 cipher suite") Reported-by: syzbot+f2f6312ad1b5a0bfe316@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f2f6312ad1b5a0bfe316 Suggested-by: Sabrina Dubroca Link: https://lists.openwall.net/linux-kernel/2026/08/19/552 Assisted-by: LLM Signed-off-by: Haseeb Malik --- Tests: - arm64 KASAN/lockdep kernel build - original syzbot reproducer and reduced reproducer - 16 cipher/offload/forwarding combinations - link notifications, configuration error paths, and encrypted veth traffic - W=1 MACsec object builds with allmodconfig and allyesconfig --- drivers/net/macsec.c | 66 ++++++++++++++++++++++++++++------------------------ 1 file changed, 35 insertions(+), 31 deletions(-) diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 6f9f3aceffaa..11207d671fb6 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -3539,6 +3539,20 @@ static int macsec_dev_init(struct net_device *dev) if (err) return err; + err = -ENOMEM; + macsec->stats = netdev_alloc_pcpu_stats(struct pcpu_secy_stats); + if (!macsec->stats) + goto destroy_gro_cells; + + macsec->secy.tx_sc.stats = netdev_alloc_pcpu_stats(struct pcpu_tx_sc_stats); + if (!macsec->secy.tx_sc.stats) + goto free_secy_stats; + + macsec->secy.tx_sc.md_dst = metadata_dst_alloc(0, METADATA_MACSEC, + GFP_KERNEL); + if (!macsec->secy.tx_sc.md_dst) + goto free_tx_sc_stats; + macsec_inherit_tso_max(dev); dev->hw_features = real_dev->hw_features & MACSEC_OFFLOAD_FEATURES; @@ -3560,6 +3574,14 @@ static int macsec_dev_init(struct net_device *dev) netdev_hold(real_dev, &macsec->dev_tracker, GFP_KERNEL); return 0; + +free_tx_sc_stats: + free_percpu(macsec->secy.tx_sc.stats); +free_secy_stats: + free_percpu(macsec->stats); +destroy_gro_cells: + gro_cells_destroy(&macsec->gro_cells); + return err; } static void macsec_dev_uninit(struct net_device *dev) @@ -4116,29 +4138,11 @@ static sci_t dev_to_sci(struct net_device *dev, __be16 port) return make_sci(dev->dev_addr, port); } -static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len) +static void macsec_init_secy(struct net_device *dev, u8 icv_len) { struct macsec_dev *macsec = macsec_priv(dev); struct macsec_secy *secy = &macsec->secy; - macsec->stats = netdev_alloc_pcpu_stats(struct pcpu_secy_stats); - if (!macsec->stats) - return -ENOMEM; - - secy->tx_sc.stats = netdev_alloc_pcpu_stats(struct pcpu_tx_sc_stats); - if (!secy->tx_sc.stats) - return -ENOMEM; - - secy->tx_sc.md_dst = metadata_dst_alloc(0, METADATA_MACSEC, GFP_KERNEL); - if (!secy->tx_sc.md_dst) - /* macsec and secy percpu stats will be freed when unregistering - * net_device in macsec_free_netdev() - */ - return -ENOMEM; - - if (sci == MACSEC_UNDEF_SCI) - sci = dev_to_sci(dev, MACSEC_PORT_ES); - secy->netdev = dev; secy->operational = true; secy->key_len = DEFAULT_SAK_LEN; @@ -4148,16 +4152,12 @@ static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len) secy->replay_protect = false; secy->xpn = DEFAULT_XPN; - secy->sci = sci; - secy->tx_sc.md_dst->u.macsec_info.sci = sci; secy->tx_sc.active = true; secy->tx_sc.encoding_sa = DEFAULT_ENCODING_SA; secy->tx_sc.encrypt = DEFAULT_ENCRYPT; secy->tx_sc.send_sci = DEFAULT_SEND_SCI; secy->tx_sc.end_station = false; secy->tx_sc.scb = false; - - return 0; } static struct lock_class_key macsec_netdev_addr_lock_key; @@ -4220,6 +4220,14 @@ static int macsec_newlink(struct net_device *dev, if (rx_handler && rx_handler != macsec_handle_frame) return -EBUSY; + /* Registration can notify listeners before returning. */ + macsec_init_secy(dev, icv_len); + if (data) { + err = macsec_changelink_common(dev, data); + if (err) + return err; + } + err = register_netdevice(dev); if (err < 0) return err; @@ -4247,15 +4255,11 @@ static int macsec_newlink(struct net_device *dev, goto unlink; } - err = macsec_add_dev(dev, sci, icv_len); - if (err) - goto unlink; + if (sci == MACSEC_UNDEF_SCI) + sci = dev_to_sci(dev, MACSEC_PORT_ES); - if (data) { - err = macsec_changelink_common(dev, data); - if (err) - goto del_dev; - } + macsec->secy.sci = sci; + macsec->secy.tx_sc.md_dst->u.macsec_info.sci = sci; /* If h/w offloading is available, propagate to the device */ if (macsec_is_offloaded(macsec)) { --- base-commit: 78445023439506ebd83b86d40b1e428a3b309d4a change-id: 20260911-fix-macsec-net-ff3bc5e7ab0a Best regards, -- Haseeb Malik