kernel/linux.git/net/ipv6/addrconf.c, branch v6.1.179

ipv6: fix error handling in disable_policy sysctl

2026-07-24T13:54:53+00:00

[ Upstream commit 3e0e51c0ee1d08cc9d48dc17f3248d5b31cf8066 ] When writing to the disable_policy sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is resetting the position argument even if an error occurred during proc_dointvec() and not only during sysctl restart. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: df789fe75206 ("ipv6: Provide ipv6 version of "disable_policy" sysctl") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-5-fmancera@suse.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: fix error handling in forwarding sysctl

2026-07-24T13:54:53+00:00

[ Upstream commit 058b9b19f9639fe1e1225a17c540f61b65bee6ad ] When writing to the forwarding sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. In addition, adjust return code of addrconf_fixup_forwarding() for successful operation. Fixes: b325fddb7f86 ("ipv6: Fix sysctl unregistration deadlock") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-4-fmancera@suse.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: fix error handling in ignore_routes_with_linkdown sysctl

2026-07-24T13:54:52+00:00

[ Upstream commit cf4f2b14401f29ccac56393ca9e4b42a2505f540 ] When writing to the ignore_routes_with_linkdown sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: 35103d11173b ("net: ipv6 sysctl option to ignore routes when nexthop link is down") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-3-fmancera@suse.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: fix error handling in disable_ipv6 sysctl

2026-07-24T13:54:52+00:00

[ Upstream commit c779441e5070e2268bdfe77f6e2e0de926c431e3 ] When writing to the disable_ipv6 sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: 56d417b12e57 ("IPv6: Add 'autoconf' and 'disable_ipv6' module parameters") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-2-fmancera@suse.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD

2026-07-24T13:54:34+00:00

[ Upstream commit 627ac78f2741e2ebd2225e2e953b6964a8a9182f ] addrconf_dad_failure() transitions ifp->state from DAD to POSTDAD via addrconf_dad_end(), which drops ifp->lock on return. The lock is re-acquired after net_info_ratelimited(). A concurrent ipv6_del_addr() can take the lock in that window, set ifp->state to DEAD and run list_del_rcu(&ifp->if_list). addrconf_dad_failure() then overwrites DEAD with ERRDAD at errdad: and schedules a new dad_work. The work calls ipv6_del_addr() again, hitting the already-poisoned list entry: general protection fault: 0000 [#1] SMP NOPTI CPU: 4 PID: 217 Comm: kworker/4:1 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:ipv6_del_addr+0xe9/0x280 RAX: dead000000000122 Call Trace: addrconf_dad_stop+0x113/0x140 addrconf_dad_work+0x28c/0x430 process_one_work+0x1eb/0x3b0 worker_thread+0x4d/0x400 kthread+0x104/0x140 ret_from_fork+0x35/0x40 Fold the addrconf_dad_end() logic into addrconf_dad_failure() under a single ifp->lock critical section. The STABLE_PRIVACY branch temporarily drops ifp->lock around address regeneration, so at lock_errdad: verify the state is still POSTDAD before transitioning to ERRDAD; bail out otherwise to avoid overwriting a state set by another path while the lock was released. Fixes: c15b1ccadb32 ("ipv6: move DAD and addrconf_verify processing to workqueue") Signed-off-by: Linmao Li Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260513025509.3776405-1-lilinmao@kylinos.cn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: prevent possible UaF in addrconf_permanent_addr()

2026-04-11T12:16:20+00:00

[ Upstream commit fd63f185979b047fb22a0dfc6bd94d0cab6a6a70 ] The mentioned helper try to warn the user about an exceptional condition, but the message is delivered too late, accessing the ipv6 after its possible deletion. Reorder the statement to avoid the possible UaF; while at it, place the warning outside the idev->lock as it needs no protection. Reported-by: Jakub Kicinski Closes: https://sashiko.dev/#/patchset/8c8bfe2e1a324e501f0e15fef404a77443fd8caf.1774365668.git.pabeni%40redhat.com Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Signed-off-by: Paolo Abeni Link: https://patch.msgid.link/ef973c3a8cb4f8f1787ed469f3e5391b9fe95aa0.1774601542.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: Fix use-after-free in inet6_addr_del().

2026-02-06T15:43:56+00:00

[ Upstream commit ddf96c393a33aef4887e2e406c76c2f8cda1419c ] syzbot reported use-after-free of inet6_ifaddr in inet6_addr_del(). [0] The cited commit accidentally moved ipv6_del_addr() for mngtmpaddr before reading its ifp->flags for temporary addresses in inet6_addr_del(). Let's move ipv6_del_addr() down to fix the UAF. [0]: BUG: KASAN: slab-use-after-free in inet6_addr_del.constprop.0+0x67a/0x6b0 net/ipv6/addrconf.c:3117 Read of size 4 at addr ffff88807b89c86c by task syz.3.1618/9593 CPU: 0 UID: 0 PID: 9593 Comm: syz.3.1618 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 inet6_addr_del.constprop.0+0x67a/0x6b0 net/ipv6/addrconf.c:3117 addrconf_del_ifaddr+0x11e/0x190 net/ipv6/addrconf.c:3181 inet6_ioctl+0x1e5/0x2b0 net/ipv6/af_inet6.c:582 sock_do_ioctl+0x118/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f164cf8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f164de64038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f164d1e5fa0 RCX: 00007f164cf8f749 RDX: 0000200000000000 RSI: 0000000000008936 RDI: 0000000000000003 RBP: 00007f164d013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f164d1e6038 R14: 00007f164d1e5fa0 R15: 00007ffde15c8288 Allocated by task 9593: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ipv6_add_addr+0x4e3/0x2010 net/ipv6/addrconf.c:1120 inet6_addr_add+0x256/0x9b0 net/ipv6/addrconf.c:3050 addrconf_add_ifaddr+0x1fc/0x450 net/ipv6/addrconf.c:3160 inet6_ioctl+0x103/0x2b0 net/ipv6/af_inet6.c:580 sock_do_ioctl+0x118/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6099: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free_freelist_hook mm/slub.c:2569 [inline] slab_free_bulk mm/slub.c:6696 [inline] kmem_cache_free_bulk mm/slub.c:7383 [inline] kmem_cache_free_bulk+0x2bf/0x680 mm/slub.c:7362 kfree_bulk include/linux/slab.h:830 [inline] kvfree_rcu_bulk+0x1b7/0x1e0 mm/slab_common.c:1523 kvfree_rcu_drain_ready mm/slab_common.c:1728 [inline] kfree_rcu_monitor+0x1d0/0x2f0 mm/slab_common.c:1801 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Fixes: 00b5b7aab9e42 ("net/ipv6: delete temporary address if mngtmpaddr is removed or unmanaged") Reported-by: syzbot+72e610f4f1a930ca9d8a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/696598e9.050a0220.3be5c5.0009.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima Reviewed-by: Hangbin Liu Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260113010538.2019411-1-kuniyu@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: Add sanity checks on ipv6_devconf.rpl_seg_enabled

2025-12-06T21:12:21+00:00

[ Upstream commit 3d95261eeb74958cd496e1875684827dc5d028cc ] In ipv6_rpl_srh_rcv() we use min(net->ipv6.devconf_all->rpl_seg_enabled, idev->cnf.rpl_seg_enabled) is intended to return 0 when either value is zero, but if one of the values is negative it will in fact return non-zero. Signed-off-by: Yue Haibing Link: https://patch.msgid.link/20250901123726.1972881-3-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ipv6: mcast: Check inet6_dev->dead under idev->mc_lock in __ipv6_dev_mc_inc().

2025-08-28T14:25:56+00:00

[ Upstream commit dbd40f318cf2f59759bd170c401adc20ba360a3e ] Since commit 63ed8de4be81 ("mld: add mc_lock for protecting per-interface mld data"), every multicast resource is protected by inet6_dev->mc_lock. RTNL is unnecessary in terms of protection but still needed for synchronisation between addrconf_ifdown() and __ipv6_dev_mc_inc(). Once we removed RTNL, there would be a race below, where we could add a multicast address to a dead inet6_dev. CPU1 CPU2 ==== ==== addrconf_ifdown() __ipv6_dev_mc_inc() if (idev->dead) <-- false dead = true return -ENODEV; ipv6_mc_destroy_dev() / ipv6_mc_down() mutex_lock(&idev->mc_lock) ... mutex_unlock(&idev->mc_lock) mutex_lock(&idev->mc_lock) ... mutex_unlock(&idev->mc_lock) The race window can be easily closed by checking inet6_dev->dead under inet6_dev->mc_lock in __ipv6_dev_mc_inc() as addrconf_ifdown() will acquire it after marking inet6_dev dead. Let's check inet6_dev->dead under mc_lock in __ipv6_dev_mc_inc(). Note that now __ipv6_dev_mc_inc() no longer depends on RTNL and we can remove ASSERT_RTNL() there and the RTNL comment above addrconf_join_solict(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250702230210.3115355-4-kuni1840@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

gre: Fix IPv6 multicast route creation.

2025-07-17T16:32:07+00:00

commit 4e914ef063de40397e25a025c70d9737a9e45a8c upstream. Use addrconf_add_dev() instead of ipv6_find_idev() in addrconf_gre_config() so that we don't just get the inet6_dev, but also install the default ff00::/8 multicast route. Before commit 3e6a0243ff00 ("gre: Fix again IPv6 link-local address generation."), the multicast route was created at the end of the function by addrconf_add_mroute(). But this code path is now only taken in one particular case (gre devices not bound to a local IP address and in EUI64 mode). For all other cases, the function exits early and addrconf_add_mroute() is not called anymore. Using addrconf_add_dev() instead of ipv6_find_idev() in addrconf_gre_config(), fixes the problem as it will create the default multicast route for all gre devices. This also brings addrconf_gre_config() a bit closer to the normal netdevice IPv6 configuration code (addrconf_dev_config()). Cc: stable@vger.kernel.org Fixes: 3e6a0243ff00 ("gre: Fix again IPv6 link-local address generation.") Reported-by: Aiden Yang Closes: https://lore.kernel.org/netdev/CANR=AhRM7YHHXVxJ4DmrTNMeuEOY87K2mLmo9KMed1JMr20p6g@mail.gmail.com/ Reviewed-by: Gary Guo Tested-by: Gary Guo Signed-off-by: Guillaume Nault Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/027a923dcb550ad115e6d93ee8bb7d310378bd01.1752070620.git.gnault@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman