kernel/linux.git/drivers/net/macvlan.c, branch v6.6.142

macvlan: fix macvlan_get_size() not reserving space for IFLA_MACVLAN_BC_CUTOFF

2026-05-23T11:03:23+00:00

[ Upstream commit fa92a77b0ed4d5f11a71665a232ac5a54a4b055d ] macvlan_get_size() does not account for IFLA_MACVLAN_BC_CUTOFF, but macvlan_fill_info() conditionally includes it when port->bc_cutoff != 1. This causes nla_put_s32() to fail with -EMSGSIZE when the netlink skb runs out of space, triggering a WARN_ON in rtnetlink and preventing the interface from being dumped. The bug can be reproduced with: ip link add macvlan0 link eth0 type macvlan mode bridge ip link set macvlan0 type macvlan bc_cutoff 0 ip -d link show macvlan0 # fails with -EMSGSIZE The bc_cutoff feature was added in commit 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff"), which added the nla_put_s32() call in macvlan_fill_info() but missed adding the corresponding nla_total_size(4) in macvlan_get_size(). A follow-up commit 55cef78c244d ("macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF") fixed the missing nla_policy entry but still did not fix the size calculation. Fixes: 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff") Signed-off-by: Dudu Lu Reviewed-by: Vadim Fedorenko Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260413085349.73977-1-phx0fer@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

macvlan: annotate data-races around port->bc_queue_len_used

2026-05-23T11:03:07+00:00

[ Upstream commit 1ef5789d9906df3771c99b7f413caaf2bf473ca5 ] port->bc_queue_len_used is read and written locklessly, add READ_ONCE()/WRITE_ONCE() annotations. While WRITE_ONCE() in macvlan_fill_info() is not yet needed, it is a prereq for future RTNL avoidance. Fixes: d4bff72c8401 ("macvlan: Support for high multicast packet rate") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260401103809.3038139-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: observe an RCU grace period in macvlan_common_newlink() error path

2026-03-04T12:20:21+00:00

[ Upstream commit e3f000f0dee1bfab52e2e61ca6a3835d9e187e35 ] valis reported that a race condition still happens after my prior patch. macvlan_common_newlink() might have made @dev visible before detecting an error, and its caller will directly call free_netdev(dev). We must respect an RCU period, either in macvlan or the core networking stack. After adding a temporary mdelay(1000) in macvlan_forward_source_one() to open the race window, valis repro was: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source (ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 &) ; sleep 0.5 ; ping -c1 -I p1 1.2.3.4 PING 1.2.3.4 (1.2.3.4): 56 data bytes RTNETLINK answers: Invalid argument BUG: KASAN: slab-use-after-free in macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) Read of size 8 at addr ffff888016bb89c0 by task e/175 CPU: 1 UID: 1000 PID: 175 Comm: e Not tainted 6.19.0-rc8+ #33 NONE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) kasan_report (mm/kasan/report.c:597) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) ? tasklet_init (kernel/softirq.c:983) macvlan_handle_frame (drivers/net/macvlan.c:501) Allocated by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) __kasan_kmalloc (mm/kasan/common.c:419) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5657 mm/slub.c:7140) alloc_netdev_mqs (net/core/dev.c:12012) rtnl_create_link (net/core/rtnetlink.c:3648) rtnl_newlink (net/core/rtnetlink.c:3830 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131) Freed by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) kasan_save_free_info (mm/kasan/generic.c:587) __kasan_slab_free (mm/kasan/common.c:287) kfree (mm/slub.c:6674 mm/slub.c:6882) rtnl_newlink (net/core/rtnetlink.c:3845 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131) Fixes: f8db6475a836 ("macvlan: fix error recovery in macvlan_common_newlink()") Signed-off-by: Eric Dumazet Reported-by: valis Link: https://patch.msgid.link/20260213142557.3059043-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: fix error recovery in macvlan_common_newlink()

2026-02-11T12:39:14+00:00

[ Upstream commit f8db6475a83649689c087a8f52486fcc53e627e9 ] valis provided a nice repro to crash the kernel: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 ping -c1 -I p1 1.2.3.4 He also gave a very detailed analysis: The issue is triggered when a new macvlan link is created with MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan port and register_netdevice() called from macvlan_common_newlink() fails (e.g. because of the invalid link name). In this case macvlan_hash_add_source is called from macvlan_change_sources() / macvlan_common_newlink(): This adds a reference to vlan to the port's vlan_source_hash using macvlan_source_entry. vlan is a pointer to the priv data of the link that is being created. When register_netdevice() fails, the error is returned from macvlan_newlink() to rtnl_newlink_create(): if (ops->newlink) err = ops->newlink(dev, ¶ms, extack); else err = register_netdevice(dev); if (err < 0) { free_netdev(dev); goto out; } and free_netdev() is called, causing a kvfree() on the struct net_device that is still referenced in the source entry attached to the lower device's macvlan port. Now all packets sent on the macvlan port with a matching source mac address will trigger a use-after-free in macvlan_forward_source(). With all that, my fix is to make sure we call macvlan_flush_sources() regardless of @create value whenever "goto destroy_macvlan_port;" path is taken. Many thanks to valis for following up on this issue. Fixes: aa5fd0fb7748 ("driver: macvlan: Destroy new macvlan port if macvlan_common_newlink failed.") Signed-off-by: Eric Dumazet Reported-by: valis Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com Closes: https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u Cc: Boudewijn van der Heide Link: https://patch.msgid.link/20260129204359.632556-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: fix possible UAF in macvlan_forward_source()

2026-01-30T09:27:24+00:00

[ Upstream commit 7470a7a63dc162f07c26dbf960e41ee1e248d80e ] Add RCU protection on (struct macvlan_source_entry)->vlan. Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts. This allows macvlan_forward_source() to skip over entries queued for freeing. Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)). Fixes: 79cf79abce71 ("macvlan: add source mode") Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260108133651.1130486-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: Don't propagate promisc change to lower dev in passthru

2023-11-28T17:19:54+00:00

[ Upstream commit 7e1caeace0418381f36b3aa8403dfd82fc57fc53 ] Macvlan device in passthru mode sets its lower device promiscuous mode according to its MACVLAN_FLAG_NOPROMISC flag instead of synchronizing it to its own promiscuity setting. However, macvlan_change_rx_flags() function doesn't check the mode before propagating such changes to the lower device which can cause net_device->promiscuity counter overflow as illustrated by reproduction example [0] and resulting dmesg log [1]. Fix the issue by first verifying the mode in macvlan_change_rx_flags() function before propagating promiscuous mode change to the lower device. [0]: ip link add macvlan1 link enp8s0f0 type macvlan mode passthru ip link set macvlan1 promisc on ip l set dev macvlan1 up ip link set macvlan1 promisc off ip l set dev macvlan1 down ip l set dev macvlan1 up [1]: [ 5156.281724] macvlan1: entered promiscuous mode [ 5156.285467] mlx5_core 0000:08:00.0 enp8s0f0: entered promiscuous mode [ 5156.287639] macvlan1: left promiscuous mode [ 5156.288339] mlx5_core 0000:08:00.0 enp8s0f0: left promiscuous mode [ 5156.290907] mlx5_core 0000:08:00.0 enp8s0f0: entered promiscuous mode [ 5156.317197] mlx5_core 0000:08:00.0 enp8s0f0: promiscuity touches roof, set promiscuity failed. promiscuity feature of device might be broken. Fixes: efdbd2b30caa ("macvlan: Propagate promiscuity setting to lower devices.") Reviewed-by: Gal Pressman Signed-off-by: Vlad Buslov Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20231114175915.1649154-1-vladbu@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: macvlan: convert to ndo_hwtstamp_get() / ndo_hwtstamp_set()

2023-08-03T02:11:06+00:00

macvlan is one of the stackable net devices which pass the hardware timestamping ops to the real device through ndo_eth_ioctl(). This prevents converting any device driver to the new hwtimestamping API without regressions. Remove that limitation in macvlan by using the newly introduced helpers for timestamping through lower devices, that handle both the new and the old driver API. macvlan only implements ndo_eth_ioctl() for these 2 operations, so delete that method. Signed-off-by: Maxim Georgiev Signed-off-by: Vladimir Oltean Reviewed-by: Jacob Keller Link: https://lore.kernel.org/r/20230801142824.1772134-5-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski

macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF

2023-07-26T02:48:50+00:00

The previous commit 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff") added one additional attribute named IFLA_MACVLAN_BC_CUTOFF to allow broadcast cutfoff. However, it forgot to describe the nla_policy at macvlan_policy (drivers/net/macvlan.c). Hence, this suppose NLA_S32 (4 bytes) integer can be faked as empty (0 bytes) by a malicious user, which could leads to OOB in heap just like CVE-2023-3773. To fix it, this commit just completes the nla_policy description for IFLA_MACVLAN_BC_CUTOFF. This enforces the length check and avoids the potential OOB read. Fixes: 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff") Signed-off-by: Lin Ma Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230723080205.3715164-1-linma@zju.edu.cn Signed-off-by: Jakub Kicinski

macvlan: Fix mc_filter calculation

2023-03-31T07:56:42+00:00

On Wed, Mar 29, 2023 at 08:10:26AM +0000, patchwork-bot+netdevbpf@kernel.org wrote: > > Here is the summary with links: > - [1/2] macvlan: Skip broadcast queue if multicast with single receiver > https://git.kernel.org/netdev/net-next/c/d45276e75e90 > - [2/2] macvlan: Add netlink attribute for broadcast cutoff > https://git.kernel.org/netdev/net-next/c/954d1fa1ac93 Sorry, I made an error and posted my patches from an earlier revision so a follow-up fix was missing: ---8<--- The bc_cutoff patch broke the calculation of mc_filter causing some multicast packets to not make it through to the targeted device. Fix this by checking whether vlan is set instead of cutoff >= 0. Also move the cutoff < 0 logic into macvlan_recompute_bc_filter so that it doesn't change the mc_filter at all. Fixes: d45276e75e90 ("macvlan: Skip broadcast queue if multicast with single receiver") Signed-off-by: Herbert Xu Signed-off-by: David S. Miller

macvlan: Add netlink attribute for broadcast cutoff

2023-03-29T08:03:32+00:00

Make the broadcast cutoff configurable through netlink. Note that macvlan is weird because there is no central device for us to configure (the lowerdev could be anything). So all the options are duplicated over what could be thousands of child devices. IFLA_MACVLAN_BC_QUEUE_LEN took the approach of taking the maximum of all child device settings. This is unnecessary as we could simply store the option in the port device and take the last child device that gets updated as the value to use. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller