<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/include/linux/netdevice.h, branch v4.19.259</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.259</id>
<link rel='self' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.19.259'/>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/'/>
<updated>2022-04-15T12:14:36Z</updated>
<entry>
<title>netdevice: add the case if dev is NULL</title>
<updated>2022-04-15T12:14:36Z</updated>
<author>
<name>Yajun Deng</name>
<email>yajun.deng@linux.dev</email>
</author>
<published>2021-08-05T11:54:34Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=574a12b4445076a04499962ce8b8ae15f75a7955'/>
<id>urn:sha1:574a12b4445076a04499962ce8b8ae15f75a7955</id>
<content type='text'>
commit b37a466837393af72fe8bcb8f1436410f3f173f3 upstream.

Add the case if dev is NULL in dev_{put, hold}, so the caller doesn't
need to care whether dev is NULL or not.

Signed-off-by: Yajun Deng &lt;yajun.deng@linux.dev&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Pavel Machek &lt;pavel@denx.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: fix information leakage in /proc/net/ptype</title>
<updated>2022-02-08T17:23:08Z</updated>
<author>
<name>Congyu Liu</name>
<email>liu3101@purdue.edu</email>
</author>
<published>2022-01-18T19:20:13Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=b67ad6170c0ea87391bb253f35d1f78857736e54'/>
<id>urn:sha1:b67ad6170c0ea87391bb253f35d1f78857736e54</id>
<content type='text'>
commit 47934e06b65637c88a762d9c98329ae6e3238888 upstream.

In one net namespace, after creating a packet socket without binding
it to a device, users in other net namespaces can observe the new
`packet_type` added by this packet socket by reading `/proc/net/ptype`
file. This is minor information leakage as packet socket is
namespace aware.

Add a net pointer in `packet_type` to keep the net namespace of
of corresponding packet socket. In `ptype_seq_show`, this net pointer
must be checked when it is not NULL.

Fixes: 2feb27dbe00c ("[NETNS]: Minor information leak via /proc/net/ptype file.")
Signed-off-by: Congyu Liu &lt;liu3101@purdue.edu&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: annotate data-races on txq-&gt;xmit_lock_owner</title>
<updated>2021-12-08T07:50:14Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2021-11-30T17:01:55Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=2fd949365fe6628fb22f9224782592cb1fff600c'/>
<id>urn:sha1:2fd949365fe6628fb22f9224782592cb1fff600c</id>
<content type='text'>
commit 7a10d8c810cfad3e79372d7d1c77899d86cd6662 upstream.

syzbot found that __dev_queue_xmit() is reading txq-&gt;xmit_lock_owner
without annotations.

No serious issue there, let's document what is happening there.

BUG: KCSAN: data-race in __dev_queue_xmit / __dev_queue_xmit

write to 0xffff888139d09484 of 4 bytes by interrupt on cpu 0:
 __netif_tx_unlock include/linux/netdevice.h:4437 [inline]
 __dev_queue_xmit+0x948/0xf70 net/core/dev.c:4229
 dev_queue_xmit_accel+0x19/0x20 net/core/dev.c:4265
 macvlan_queue_xmit drivers/net/macvlan.c:543 [inline]
 macvlan_start_xmit+0x2b3/0x3d0 drivers/net/macvlan.c:567
 __netdev_start_xmit include/linux/netdevice.h:4987 [inline]
 netdev_start_xmit include/linux/netdevice.h:5001 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 sch_direct_xmit+0x1b2/0x7c0 net/sched/sch_generic.c:342
 __dev_xmit_skb+0x83d/0x1370 net/core/dev.c:3817
 __dev_queue_xmit+0x590/0xf70 net/core/dev.c:4194
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
 neigh_hh_output include/net/neighbour.h:511 [inline]
 neigh_output include/net/neighbour.h:525 [inline]
 ip6_finish_output2+0x995/0xbb0 net/ipv6/ip6_output.c:126
 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
 ip6_finish_output+0x444/0x4c0 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ndisc_send_skb+0x486/0x610 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x3b0/0x3e0 net/ipv6/ndisc.c:702
 addrconf_rs_timer+0x370/0x540 net/ipv6/addrconf.c:3898
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
 expire_timers+0x116/0x240 kernel/time/timer.c:1466
 __run_timers+0x368/0x410 kernel/time/timer.c:1734
 run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1747
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 __irq_exit_rcu kernel/softirq.c:636 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x3e/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20

read to 0xffff888139d09484 of 4 bytes by interrupt on cpu 1:
 __dev_queue_xmit+0x5e3/0xf70 net/core/dev.c:4213
 dev_queue_xmit_accel+0x19/0x20 net/core/dev.c:4265
 macvlan_queue_xmit drivers/net/macvlan.c:543 [inline]
 macvlan_start_xmit+0x2b3/0x3d0 drivers/net/macvlan.c:567
 __netdev_start_xmit include/linux/netdevice.h:4987 [inline]
 netdev_start_xmit include/linux/netdevice.h:5001 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 sch_direct_xmit+0x1b2/0x7c0 net/sched/sch_generic.c:342
 __dev_xmit_skb+0x83d/0x1370 net/core/dev.c:3817
 __dev_queue_xmit+0x590/0xf70 net/core/dev.c:4194
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
 neigh_resolve_output+0x3db/0x410 net/core/neighbour.c:1523
 neigh_output include/net/neighbour.h:527 [inline]
 ip6_finish_output2+0x9be/0xbb0 net/ipv6/ip6_output.c:126
 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
 ip6_finish_output+0x444/0x4c0 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ndisc_send_skb+0x486/0x610 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x3b0/0x3e0 net/ipv6/ndisc.c:702
 addrconf_rs_timer+0x370/0x540 net/ipv6/addrconf.c:3898
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
 expire_timers+0x116/0x240 kernel/time/timer.c:1466
 __run_timers+0x368/0x410 kernel/time/timer.c:1734
 run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1747
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 __irq_exit_rcu kernel/softirq.c:636 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x8d/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 kcsan_setup_watchpoint+0x94/0x420 kernel/kcsan/core.c:443
 folio_test_anon include/linux/page-flags.h:581 [inline]
 PageAnon include/linux/page-flags.h:586 [inline]
 zap_pte_range+0x5ac/0x10e0 mm/memory.c:1347
 zap_pmd_range mm/memory.c:1467 [inline]
 zap_pud_range mm/memory.c:1496 [inline]
 zap_p4d_range mm/memory.c:1517 [inline]
 unmap_page_range+0x2dc/0x3d0 mm/memory.c:1538
 unmap_single_vma+0x157/0x210 mm/memory.c:1583
 unmap_vmas+0xd0/0x180 mm/memory.c:1615
 exit_mmap+0x23d/0x470 mm/mmap.c:3170
 __mmput+0x27/0x1b0 kernel/fork.c:1113
 mmput+0x3d/0x50 kernel/fork.c:1134
 exit_mm+0xdb/0x170 kernel/exit.c:507
 do_exit+0x608/0x17a0 kernel/exit.c:819
 do_group_exit+0xce/0x180 kernel/exit.c:929
 get_signal+0xfc3/0x1550 kernel/signal.c:2852
 arch_do_signal_or_restart+0x8c/0x2e0 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x113/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -&gt; 0xffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28712 Comm: syz-executor.0 Tainted: G        W         5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Link: https://lore.kernel.org/r/20211130170155.2331929-1-eric.dumazet@gmail.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>net: don't unconditionally copy_from_user a struct ifreq for socket ioctls</title>
<updated>2021-09-03T07:58:03Z</updated>
<author>
<name>Peter Collingbourne</name>
<email>pcc@google.com</email>
</author>
<published>2021-08-26T19:46:01Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=e9544276b3e60800a150f27fe5d031d133c77eea'/>
<id>urn:sha1:e9544276b3e60800a150f27fe5d031d133c77eea</id>
<content type='text'>
commit d0efb16294d145d157432feda83877ae9d7cdf37 upstream.

A common implementation of isatty(3) involves calling a ioctl passing
a dummy struct argument and checking whether the syscall failed --
bionic and glibc use TCGETS (passing a struct termios), and musl uses
TIOCGWINSZ (passing a struct winsize). If the FD is a socket, we will
copy sizeof(struct ifreq) bytes of data from the argument and return
-EFAULT if that fails. The result is that the isatty implementations
may return a non-POSIX-compliant value in errno in the case where part
of the dummy struct argument is inaccessible, as both struct termios
and struct winsize are smaller than struct ifreq (at least on arm64).

Although there is usually enough stack space following the argument
on the stack that this did not present a practical problem up to now,
with MTE stack instrumentation it's more likely for the copy to fail,
as the memory following the struct may have a different tag.

Fix the problem by adding an early check for whether the ioctl is a
valid socket ioctl, and return -ENOTTY if it isn't.

Fixes: 44c02a2c3dc5 ("dev_ioctl(): move copyin/copyout to callers")
Link: https://linux-review.googlesource.com/id/I869da6cf6daabc3e4b7b82ac979683ba05e27d4d
Signed-off-by: Peter Collingbourne &lt;pcc@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 4.19
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: Introduce parse_protocol header_ops callback</title>
<updated>2021-03-17T15:43:42Z</updated>
<author>
<name>Maxim Mikityanskiy</name>
<email>maximmi@mellanox.com</email>
</author>
<published>2019-02-21T12:39:58Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=6eef125294f50a3bd68de12263073a1abba7ab70'/>
<id>urn:sha1:6eef125294f50a3bd68de12263073a1abba7ab70</id>
<content type='text'>
commit e78b2915517e8fcadb1bc130ad6aeac7099e510c upstream.

Introduce a new optional header_ops callback called parse_protocol and a
wrapper function dev_parse_header_protocol, similar to dev_parse_header.

The new callback's purpose is to extract the protocol number from the L2
header, the format of which is known to the driver, but not to the upper
layers of the stack.

Signed-off-by: Maxim Mikityanskiy &lt;maximmi@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: watchdog: hold device global xmit lock during tx disable</title>
<updated>2021-02-23T14:00:58Z</updated>
<author>
<name>Edwin Peer</name>
<email>edwin.peer@broadcom.com</email>
</author>
<published>2021-02-06T01:37:32Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=bb7addea77224d0c6e471f6b7290f5b609416319'/>
<id>urn:sha1:bb7addea77224d0c6e471f6b7290f5b609416319</id>
<content type='text'>
commit 3aa6bce9af0e25b735c9c1263739a5639a336ae8 upstream.

Prevent netif_tx_disable() running concurrently with dev_watchdog() by
taking the device global xmit lock. Otherwise, the recommended:

	netif_carrier_off(dev);
	netif_tx_disable(dev);

driver shutdown sequence can happen after the watchdog has already
checked carrier, resulting in possible false alarms. This is because
netif_tx_lock() only sets the frozen bit without maintaining the locks
on the individual queues.

Fixes: c3f26a269c24 ("netdev: Fix lockdep warnings in multiqueue configurations.")
Signed-off-by: Edwin Peer &lt;edwin.peer@broadcom.com&gt;
Reviewed-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: core: reduce recursion limit value</title>
<updated>2020-07-01T03:17:07Z</updated>
<author>
<name>Taehee Yoo</name>
<email>ap420073@gmail.com</email>
</author>
<published>2020-06-16T15:52:05Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=b11d1c71912b1f3e4474e1b231a2d21d2b9e3a27'/>
<id>urn:sha1:b11d1c71912b1f3e4474e1b231a2d21d2b9e3a27</id>
<content type='text'>
[ Upstream commit fb7861d14c8d7edac65b2fcb6e8031cb138457b2 ]

In the current code, -&gt;ndo_start_xmit() can be executed recursively only
10 times because of stack memory.
But, in the case of the vxlan, 10 recursion limit value results in
a stack overflow.
In the current code, the nested interface is limited by 8 depth.
There is no critical reason that the recursion limitation value should
be 10.
So, it would be good to be the same value with the limitation value of
nesting interface depth.

Test commands:
    ip link add vxlan10 type vxlan vni 10 dstport 4789 srcport 4789 4789
    ip link set vxlan10 up
    ip a a 192.168.10.1/24 dev vxlan10
    ip n a 192.168.10.2 dev vxlan10 lladdr fc:22:33:44:55:66 nud permanent

    for i in {9..0}
    do
        let A=$i+1
	ip link add vxlan$i type vxlan vni $i dstport 4789 srcport 4789 4789
	ip link set vxlan$i up
	ip a a 192.168.$i.1/24 dev vxlan$i
	ip n a 192.168.$i.2 dev vxlan$i lladdr fc:22:33:44:55:66 nud permanent
	bridge fdb add fc:22:33:44:55:66 dev vxlan$A dst 192.168.$i.2 self
    done
    hping3 192.168.10.2 -2 -d 60000

Splat looks like:
[  103.814237][ T1127] =============================================================================
[  103.871955][ T1127] BUG kmalloc-2k (Tainted: G    B            ): Padding overwritten. 0x00000000897a2e4f-0x000
[  103.873187][ T1127] -----------------------------------------------------------------------------
[  103.873187][ T1127]
[  103.874252][ T1127] INFO: Slab 0x000000005cccc724 objects=5 used=5 fp=0x0000000000000000 flags=0x10000000001020
[  103.881323][ T1127] CPU: 3 PID: 1127 Comm: hping3 Tainted: G    B             5.7.0+ #575
[  103.882131][ T1127] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[  103.883006][ T1127] Call Trace:
[  103.883324][ T1127]  dump_stack+0x96/0xdb
[  103.883716][ T1127]  slab_err+0xad/0xd0
[  103.884106][ T1127]  ? _raw_spin_unlock+0x1f/0x30
[  103.884620][ T1127]  ? get_partial_node.isra.78+0x140/0x360
[  103.885214][ T1127]  slab_pad_check.part.53+0xf7/0x160
[  103.885769][ T1127]  ? pskb_expand_head+0x110/0xe10
[  103.886316][ T1127]  check_slab+0x97/0xb0
[  103.886763][ T1127]  alloc_debug_processing+0x84/0x1a0
[  103.887308][ T1127]  ___slab_alloc+0x5a5/0x630
[  103.887765][ T1127]  ? pskb_expand_head+0x110/0xe10
[  103.888265][ T1127]  ? lock_downgrade+0x730/0x730
[  103.888762][ T1127]  ? pskb_expand_head+0x110/0xe10
[  103.889244][ T1127]  ? __slab_alloc+0x3e/0x80
[  103.889675][ T1127]  __slab_alloc+0x3e/0x80
[  103.890108][ T1127]  __kmalloc_node_track_caller+0xc7/0x420
[ ... ]

Fixes: 11a766ce915f ("net: Increase xmit RECURSION_LIMIT to 10.")
Signed-off-by: Taehee Yoo &lt;ap420073@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: use correct this_cpu primitive in dev_recursion_level</title>
<updated>2020-07-01T03:17:04Z</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-04-03T06:28:35Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=3a708efa69237c687ee1bd6a7014b2130db90776'/>
<id>urn:sha1:3a708efa69237c687ee1bd6a7014b2130db90776</id>
<content type='text'>
commit 28b05b92886871bdd8e6a9df73e3a15845fe8ef4 upstream.

syzbot reports:
BUG: using __this_cpu_read() in preemptible code:
caller is dev_recursion_level include/linux/netdevice.h:3052 [inline]
 __this_cpu_preempt_check+0x246/0x270 lib/smp_processor_id.c:47
 dev_recursion_level include/linux/netdevice.h:3052 [inline]
 ip6_skb_dst_mtu include/net/ip6_route.h:245 [inline]

I erronously downgraded a this_cpu_read to __this_cpu_read when
moving dev_recursion_level() around.

Reported-by: syzbot+51471b4aae195285a4a3@syzkaller.appspotmail.com
Fixes: 97cdcf37b57e ("net: place xmit recursion in softnet data")
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>net: place xmit recursion in softnet data</title>
<updated>2020-07-01T03:17:04Z</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-04-01T14:42:13Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=edbe653223915b1deee0c4df909d5da924650cec'/>
<id>urn:sha1:edbe653223915b1deee0c4df909d5da924650cec</id>
<content type='text'>
commit 97cdcf37b57e3f204be3000b9eab9686f38b4356 upstream.

This fills a hole in softnet data, so no change in structure size.

Also prepares for xmit_more placement in the same spot;
skb-&gt;xmit_more will be removed in followup patch.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>net: rtnetlink: validate IFLA_MTU attribute in rtnl_create_link()</title>
<updated>2020-01-29T15:43:16Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-22T06:47:29Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=be1a2be7a7b0ed5a758fd8decc39386ba3b5d556'/>
<id>urn:sha1:be1a2be7a7b0ed5a758fd8decc39386ba3b5d556</id>
<content type='text'>
[ Upstream commit d836f5c69d87473ff65c06a6123e5b2cf5e56f5b ]

rtnl_create_link() needs to apply dev-&gt;min_mtu and dev-&gt;max_mtu
checks that we apply in do_setlink()

Otherwise malicious users can crash the kernel, for example after
an integer overflow :

BUG: KASAN: use-after-free in memset include/linux/string.h:365 [inline]
BUG: KASAN: use-after-free in __alloc_skb+0x37b/0x5e0 net/core/skbuff.c:238
Write of size 32 at addr ffff88819f20b9c0 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 &lt;IRQ&gt;
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 memset+0x24/0x40 mm/kasan/common.c:108
 memset include/linux/string.h:365 [inline]
 __alloc_skb+0x37b/0x5e0 net/core/skbuff.c:238
 alloc_skb include/linux/skbuff.h:1049 [inline]
 alloc_skb_with_frags+0x93/0x590 net/core/skbuff.c:5664
 sock_alloc_send_pskb+0x7ad/0x920 net/core/sock.c:2242
 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2259
 mld_newpack+0x1d7/0x7f0 net/ipv6/mcast.c:1609
 add_grhead.isra.0+0x299/0x370 net/ipv6/mcast.c:1713
 add_grec+0x7db/0x10b0 net/ipv6/mcast.c:1844
 mld_send_cr net/ipv6/mcast.c:1970 [inline]
 mld_ifc_timer_expire+0x3d3/0x950 net/ipv6/mcast.c:2477
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 &lt;/IRQ&gt;
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 98 6b ea f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 44 1c 60 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 34 1c 60 00 fb f4 &lt;c3&gt; cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 4e 5d 9a f9 e8 79
RSP: 0018:ffffffff89807ce8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13266ae RBX: ffffffff8987a1c0 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff8987aa54
RBP: ffffffff89807d18 R08: ffffffff8987a1c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff8a799980 R14: 0000000000000000 R15: 0000000000000000
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690
 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361
 rest_init+0x23b/0x371 init/main.c:451
 arch_call_rest_init+0xe/0x1b
 start_kernel+0x904/0x943 init/main.c:784
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490
 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

The buggy address belongs to the page:
page:ffffea00067c82c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
raw: 057ffe0000000000 ffffea00067c82c8 ffffea00067c82c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88819f20b880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819f20b900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
&gt;ffff88819f20b980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88819f20ba00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819f20ba80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

Fixes: 61e84623ace3 ("net: centralize net_device min/max MTU checking")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
