<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/net/ipv6/addrconf.c, branch v6.12.80</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.80</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.80'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-04-02T11:09:35+00:00</updated>
<entry>
<title>ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist.</title>
<updated>2026-04-02T11:09:35+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@google.com</email>
</author>
<published>2026-03-20T07:23:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c58c705939c75eb6979cccc0fcc7159e5e09ad22'/>
<id>urn:sha1:c58c705939c75eb6979cccc0fcc7159e5e09ad22</id>
<content type='text'>
[ Upstream commit 4be7b99c253f0c85a255cc1db7127ba3232dfa30 ]

The cited commit mechanically put fib6_remove_gc_list()
just after every fib6_clean_expires() call.

When a temporary route is promoted to a permanent route,
there may already be exception routes tied to it.

If fib6_remove_gc_list() removes the route from tb6_gc_hlist,
such exception routes will no longer be aged.

Let's replace fib6_remove_gc_list() with a new helper
fib6_may_remove_gc_list() and use fib6_age_exceptions() there.

Note that net-&gt;ipv6 is only compiled when CONFIG_IPV6 is
enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded.

Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: Fix use-after-free in inet6_addr_del().</title>
<updated>2026-01-23T10:18:39+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@google.com</email>
</author>
<published>2026-01-13T01:05:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=2684610a9c9c53f262fd864fa5c407e79f304804'/>
<id>urn:sha1:2684610a9c9c53f262fd864fa5c407e79f304804</id>
<content type='text'>
[ 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-&gt;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:
 &lt;TASK&gt;
 __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 &lt;48&gt; 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
 &lt;/TASK&gt;

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 &lt;kuniyu@google.com&gt;
Reviewed-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://patch.msgid.link/20260113010538.2019411-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: Add sanity checks on ipv6_devconf.rpl_seg_enabled</title>
<updated>2025-11-13T20:34:18+00:00</updated>
<author>
<name>Yue Haibing</name>
<email>yuehaibing@huawei.com</email>
</author>
<published>2025-09-01T12:37:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=483303d94c2d4452a5eac12ed97263c5c486ac5a'/>
<id>urn:sha1:483303d94c2d4452a5eac12ed97263c5c486ac5a</id>
<content type='text'>
[ Upstream commit 3d95261eeb74958cd496e1875684827dc5d028cc ]

In ipv6_rpl_srh_rcv() we use min(net-&gt;ipv6.devconf_all-&gt;rpl_seg_enabled,
idev-&gt;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 &lt;yuehaibing@huawei.com&gt;
Link: https://patch.msgid.link/20250901123726.1972881-3-yuehaibing@huawei.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: mcast: Check inet6_dev-&gt;dead under idev-&gt;mc_lock in __ipv6_dev_mc_inc().</title>
<updated>2025-08-20T16:30:33+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@google.com</email>
</author>
<published>2025-07-02T23:01:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=347b94ee253e7268ec4079d5fafba8f29981f7e7'/>
<id>urn:sha1:347b94ee253e7268ec4079d5fafba8f29981f7e7</id>
<content type='text'>
[ Upstream commit dbd40f318cf2f59759bd170c401adc20ba360a3e ]

Since commit 63ed8de4be81 ("mld: add mc_lock for protecting
per-interface mld data"), every multicast resource is protected
by inet6_dev-&gt;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-&gt;dead) &lt;-- false
    dead = true                       return -ENODEV;
    ipv6_mc_destroy_dev() / ipv6_mc_down()
      mutex_lock(&amp;idev-&gt;mc_lock)
      ...
      mutex_unlock(&amp;idev-&gt;mc_lock)
                                    mutex_lock(&amp;idev-&gt;mc_lock)
                                    ...
                                    mutex_unlock(&amp;idev-&gt;mc_lock)

The race window can be easily closed by checking inet6_dev-&gt;dead
under inet6_dev-&gt;mc_lock in __ipv6_dev_mc_inc() as addrconf_ifdown()
will acquire it after marking inet6_dev dead.

Let's check inet6_dev-&gt;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 &lt;kuniyu@google.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://patch.msgid.link/20250702230210.3115355-4-kuni1840@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>gre: Fix IPv6 multicast route creation.</title>
<updated>2025-07-17T16:37:09+00:00</updated>
<author>
<name>Guillaume Nault</name>
<email>gnault@redhat.com</email>
</author>
<published>2025-07-09T14:30:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8f65277317a8ef1fbe392763755908314c9675a9'/>
<id>urn:sha1:8f65277317a8ef1fbe392763755908314c9675a9</id>
<content type='text'>
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 &lt;ling@moedove.com&gt;
Closes: https://lore.kernel.org/netdev/CANR=AhRM7YHHXVxJ4DmrTNMeuEOY87K2mLmo9KMed1JMr20p6g@mail.gmail.com/
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Tested-by: Gary Guo &lt;gary@garyguo.net&gt;
Signed-off-by: Guillaume Nault &lt;gnault@redhat.com&gt;
Reviewed-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Link: https://patch.msgid.link/027a923dcb550ad115e6d93ee8bb7d310378bd01.1752070620.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>gre: Fix again IPv6 link-local address generation.</title>
<updated>2025-05-18T06:24:48+00:00</updated>
<author>
<name>Guillaume Nault</name>
<email>gnault@redhat.com</email>
</author>
<published>2025-05-02T22:57:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=35be4c0cdf46a8ecf16733ec78c920213c7442b1'/>
<id>urn:sha1:35be4c0cdf46a8ecf16733ec78c920213c7442b1</id>
<content type='text'>
[ Upstream commit 3e6a0243ff002ddbd7ee18a8974ae61d2e6ed00d ]

Use addrconf_addr_gen() to generate IPv6 link-local addresses on GRE
devices in most cases and fall back to using add_v4_addrs() only in
case the GRE configuration is incompatible with addrconf_addr_gen().

GRE used to use addrconf_addr_gen() until commit e5dd729460ca ("ip/ip6_gre:
use the same logic as SIT interfaces when computing v6LL address")
restricted this use to gretap and ip6gretap devices, and created
add_v4_addrs() (borrowed from SIT) for non-Ethernet GRE ones.

The original problem came when commit 9af28511be10 ("addrconf: refuse
isatap eui64 for INADDR_ANY") made __ipv6_isatap_ifid() fail when its
addr parameter was 0. The commit says that this would create an invalid
address, however, I couldn't find any RFC saying that the generated
interface identifier would be wrong. Anyway, since gre over IPv4
devices pass their local tunnel address to __ipv6_isatap_ifid(), that
commit broke their IPv6 link-local address generation when the local
address was unspecified.

Then commit e5dd729460ca ("ip/ip6_gre: use the same logic as SIT
interfaces when computing v6LL address") tried to fix that case by
defining add_v4_addrs() and calling it to generate the IPv6 link-local
address instead of using addrconf_addr_gen() (apart for gretap and
ip6gretap devices, which would still use the regular
addrconf_addr_gen(), since they have a MAC address).

That broke several use cases because add_v4_addrs() isn't properly
integrated into the rest of IPv6 Neighbor Discovery code. Several of
these shortcomings have been fixed over time, but add_v4_addrs()
remains broken on several aspects. In particular, it doesn't send any
Router Sollicitations, so the SLAAC process doesn't start until the
interface receives a Router Advertisement. Also, add_v4_addrs() mostly
ignores the address generation mode of the interface
(/proc/sys/net/ipv6/conf/*/addr_gen_mode), thus breaking the
IN6_ADDR_GEN_MODE_RANDOM and IN6_ADDR_GEN_MODE_STABLE_PRIVACY cases.

Fix the situation by using add_v4_addrs() only in the specific scenario
where the normal method would fail. That is, for interfaces that have
all of the following characteristics:

  * run over IPv4,
  * transport IP packets directly, not Ethernet (that is, not gretap
    interfaces),
  * tunnel endpoint is INADDR_ANY (that is, 0),
  * device address generation mode is EUI64.

In all other cases, revert back to the regular addrconf_addr_gen().

Also, remove the special case for ip6gre interfaces in add_v4_addrs(),
since ip6gre devices now always use addrconf_addr_gen() instead.

Note:
  This patch was originally applied as commit 183185a18ff9 ("gre: Fix
  IPv6 link-local address generation."). However, it was then reverted
  by commit fc486c2d060f ("Revert "gre: Fix IPv6 link-local address
  generation."") because it uncovered another bug that ended up
  breaking net/forwarding/ip6gre_custom_multipath_hash.sh. That other
  bug has now been fixed by commit 4d0ab3a6885e ("ipv6: Start path
  selection from the first nexthop"). Therefore we can now revive this
  GRE patch (no changes since original commit 183185a18ff9 ("gre: Fix
  IPv6 link-local address generation.").

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Guillaume Nault &lt;gnault@redhat.com&gt;
Reviewed-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Link: https://patch.msgid.link/a88cc5c4811af36007645d610c95102dccb360a6.1746225214.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: fix omitted netlink attributes when using RTEXT_FILTER_SKIP_STATS</title>
<updated>2025-04-10T12:39:34+00:00</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>ffmancera@riseup.net</email>
</author>
<published>2025-04-02T12:17:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=de579015d132e742af32611900b038ffbe5a0850'/>
<id>urn:sha1:de579015d132e742af32611900b038ffbe5a0850</id>
<content type='text'>
[ Upstream commit 7ac6ea4a3e0898db76aecccd68fb2c403eb7d24e ]

Using RTEXT_FILTER_SKIP_STATS is incorrectly skipping non-stats IPv6
netlink attributes on link dump. This causes issues on userspace tools,
e.g iproute2 is not rendering address generation mode as it should due
to missing netlink attribute.

Move the filling of IFLA_INET6_STATS and IFLA_INET6_ICMP6STATS to a
helper function guarded by a flag check to avoid hitting the same
situation in the future.

Fixes: d5566fd72ec1 ("rtnetlink: RTEXT_FILTER_SKIP_STATS support to avoid dumping inet/inet6 stats")
Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250402121751.3108-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>Revert "gre: Fix IPv6 link-local address generation."</title>
<updated>2025-03-28T21:03:28+00:00</updated>
<author>
<name>Guillaume Nault</name>
<email>gnault@redhat.com</email>
</author>
<published>2025-03-19T21:26:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a3ff812d68f64c48c082e37d46a8098769f77504'/>
<id>urn:sha1:a3ff812d68f64c48c082e37d46a8098769f77504</id>
<content type='text'>
[ Upstream commit fc486c2d060f67d672ddad81724f7c8a4d329570 ]

This reverts commit 183185a18ff96751db52a46ccf93fff3a1f42815.

This patch broke net/forwarding/ip6gre_custom_multipath_hash.sh in some
circumstances (https://lore.kernel.org/netdev/Z9RIyKZDNoka53EO@mini-arch/).
Let's revert it while the problem is being investigated.

Fixes: 183185a18ff9 ("gre: Fix IPv6 link-local address generation.")
Signed-off-by: Guillaume Nault &lt;gnault@redhat.com&gt;
Link: https://patch.msgid.link/8b1ce738eb15dd841aab9ef888640cab4f6ccfea.1742418408.git.gnault@redhat.com
Acked-by: Stanislav Fomichev &lt;sdf@fomichev.me&gt;
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>gre: Fix IPv6 link-local address generation.</title>
<updated>2025-03-22T19:54:13+00:00</updated>
<author>
<name>Guillaume Nault</name>
<email>gnault@redhat.com</email>
</author>
<published>2025-03-07T19:28:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a4d42b59011509dc1c40ab291ed5e47d94b1d452'/>
<id>urn:sha1:a4d42b59011509dc1c40ab291ed5e47d94b1d452</id>
<content type='text'>
[ Upstream commit 183185a18ff96751db52a46ccf93fff3a1f42815 ]

Use addrconf_addr_gen() to generate IPv6 link-local addresses on GRE
devices in most cases and fall back to using add_v4_addrs() only in
case the GRE configuration is incompatible with addrconf_addr_gen().

GRE used to use addrconf_addr_gen() until commit e5dd729460ca
("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL
address") restricted this use to gretap and ip6gretap devices, and
created add_v4_addrs() (borrowed from SIT) for non-Ethernet GRE ones.

The original problem came when commit 9af28511be10 ("addrconf: refuse
isatap eui64 for INADDR_ANY") made __ipv6_isatap_ifid() fail when its
addr parameter was 0. The commit says that this would create an invalid
address, however, I couldn't find any RFC saying that the generated
interface identifier would be wrong. Anyway, since gre over IPv4
devices pass their local tunnel address to __ipv6_isatap_ifid(), that
commit broke their IPv6 link-local address generation when the local
address was unspecified.

Then commit e5dd729460ca ("ip/ip6_gre: use the same logic as SIT
interfaces when computing v6LL address") tried to fix that case by
defining add_v4_addrs() and calling it to generate the IPv6 link-local
address instead of using addrconf_addr_gen() (apart for gretap and
ip6gretap devices, which would still use the regular
addrconf_addr_gen(), since they have a MAC address).

That broke several use cases because add_v4_addrs() isn't properly
integrated into the rest of IPv6 Neighbor Discovery code. Several of
these shortcomings have been fixed over time, but add_v4_addrs()
remains broken on several aspects. In particular, it doesn't send any
Router Sollicitations, so the SLAAC process doesn't start until the
interface receives a Router Advertisement. Also, add_v4_addrs() mostly
ignores the address generation mode of the interface
(/proc/sys/net/ipv6/conf/*/addr_gen_mode), thus breaking the
IN6_ADDR_GEN_MODE_RANDOM and IN6_ADDR_GEN_MODE_STABLE_PRIVACY cases.

Fix the situation by using add_v4_addrs() only in the specific scenario
where the normal method would fail. That is, for interfaces that have
all of the following characteristics:

  * run over IPv4,
  * transport IP packets directly, not Ethernet (that is, not gretap
    interfaces),
  * tunnel endpoint is INADDR_ANY (that is, 0),
  * device address generation mode is EUI64.

In all other cases, revert back to the regular addrconf_addr_gen().

Also, remove the special case for ip6gre interfaces in add_v4_addrs(),
since ip6gre devices now always use addrconf_addr_gen() instead.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Guillaume Nault &lt;gnault@redhat.com&gt;
Reviewed-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Link: https://patch.msgid.link/559c32ce5c9976b269e6337ac9abb6a96abe5096.1741375285.git.gnault@redhat.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: avoid possible NULL deref in modify_prefix_route()</title>
<updated>2024-12-14T19:03:04+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-11-26T19:28:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=01f95357e47219a9c4b29e177b717edbfab721b4'/>
<id>urn:sha1:01f95357e47219a9c4b29e177b717edbfab721b4</id>
<content type='text'>
[ Upstream commit a747e02430dfb3657141f99aa6b09331283fa493 ]

syzbot found a NULL deref [1] in modify_prefix_route(), caused by one
fib6_info without a fib6_table pointer set.

This can happen for net-&gt;ipv6.fib6_null_entry

[1]
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 UID: 0 PID: 5837 Comm: syz-executor888 Not tainted 6.12.0-syzkaller-09567-g7eef7e306d3c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
 RIP: 0010:__lock_acquire+0xe4/0x3c40 kernel/locking/lockdep.c:5089
Code: 08 84 d2 0f 85 15 14 00 00 44 8b 0d ca 98 f5 0e 45 85 c9 0f 84 b4 0e 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 &lt;80&gt; 3c 02 00 0f 85 96 2c 00 00 49 8b 04 24 48 3d a0 07 7f 93 0f 84
RSP: 0018:ffffc900035d7268 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000006 RSI: 1ffff920006bae5f RDI: 0000000000000030
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90608e17 R11: 0000000000000001 R12: 0000000000000030
R13: ffff888036334880 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555579e90380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc59cc4278 CR3: 0000000072b54000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 &lt;TASK&gt;
  lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
  _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
  spin_lock_bh include/linux/spinlock.h:356 [inline]
  modify_prefix_route+0x30b/0x8b0 net/ipv6/addrconf.c:4831
  inet6_addr_modify net/ipv6/addrconf.c:4923 [inline]
  inet6_rtm_newaddr+0x12c7/0x1ab0 net/ipv6/addrconf.c:5055
  rtnetlink_rcv_msg+0x3c7/0xea0 net/core/rtnetlink.c:6920
  netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2541
  netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
  netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1347
  netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891
  sock_sendmsg_nosec net/socket.c:711 [inline]
  __sock_sendmsg net/socket.c:726 [inline]
  ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583
  ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637
  __sys_sendmsg+0x16e/0x220 net/socket.c:2669
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd1dcef8b79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc59cc4378 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd1dcef8b79
RDX: 0000000000040040 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00000000000113fd R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 00007ffc59cc438c
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 &lt;/TASK&gt;

Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.")
Reported-by: syzbot+1de74b0794c40c8eb300@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/67461f7f.050a0220.1286eb.0021.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
CC: Kui-Feng Lee &lt;thinker.li@gmail.com&gt;
Cc: David Ahern &lt;dsahern@kernel.org&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
</feed>
