linux-stable.git/net/ipv4, branch v5.4.7 Linux kernel stable tree gre: refetch erspan header from skb->data after pskb_may_pull() 2019-12-18T15:08:51+00:00 Cong Wang xiyou.wangcong@gmail.com 2019-12-06T03:39:02+00:00 23fbdd5d1e826454a1ce199e716e2015033212c4 [ Upstream commit 0e4940928c26527ce8f97237fef4c8a91cd34207 ] After pskb_may_pull() we should always refetch the header pointers from the skb->data in case it got reallocated. In gre_parse_header(), the erspan header is still fetched from the 'options' pointer which is fetched before pskb_may_pull(). Found this during code review of a KMSAN bug report. Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup") Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Acked-by: William Tu <u9012063@gmail.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 0e4940928c26527ce8f97237fef4c8a91cd34207 ]

After pskb_may_pull() we should always refetch the header
pointers from the skb->data in case it got reallocated.

In gre_parse_header(), the erspan header is still fetched
from the 'options' pointer which is fetched before
pskb_may_pull().

Found this during code review of a KMSAN bug report.

Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup")
Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Acked-by: William Tu <u9012063@gmail.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcp: md5: fix potential overestimation of TCP option space 2019-12-18T15:08:35+00:00 Eric Dumazet edumazet@google.com 2019-12-05T18:10:15+00:00 2fc7d173ea6121349165f49c8bd91f82c79a9da1 [ Upstream commit 9424e2e7ad93ffffa88f882c9bc5023570904b55 ] Back in 2008, Adam Langley fixed the corner case of packets for flows having all of the following options : MD5 TS SACK Since MD5 needs 20 bytes, and TS needs 12 bytes, no sack block can be cooked from the remaining 8 bytes. tcp_established_options() correctly sets opts->num_sack_blocks to zero, but returns 36 instead of 32. This means TCP cooks packets with 4 extra bytes at the end of options, containing unitialized bytes. Fixes: 33ad798c924b ("tcp: options clean up") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 9424e2e7ad93ffffa88f882c9bc5023570904b55 ]

Back in 2008, Adam Langley fixed the corner case of packets for flows
having all of the following options : MD5 TS SACK

Since MD5 needs 20 bytes, and TS needs 12 bytes, no sack block
can be cooked from the remaining 8 bytes.

tcp_established_options() correctly sets opts->num_sack_blocks
to zero, but returns 36 instead of 32.

This means TCP cooks packets with 4 extra bytes at the end
of options, containing unitialized bytes.

Fixes: 33ad798c924b ("tcp: options clean up")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
inet: protect against too small mtu values. 2019-12-18T15:08:17+00:00 Eric Dumazet edumazet@google.com 2019-12-06T04:43:46+00:00 20f72aae9b21577e5c325c53817ce4ea00eb1133 [ Upstream commit 501a90c945103e8627406763dac418f20f3837b2 ] syzbot was once again able to crash a host by setting a very small mtu on loopback device. Let's make inetdev_valid_mtu() available in include/net/ip.h, and use it in ip_setup_cork(), so that we protect both ip_append_page() and __ip_append_data() Also add a READ_ONCE() when the device mtu is read. Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(), even if other code paths might write over this field. Add a big comment in include/linux/netdevice.h about dev->mtu needing READ_ONCE()/WRITE_ONCE() annotations. Hopefully we will add the missing ones in followup patches. [1] refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89 RSP: 0018:ffff88809689f550 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1 R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001 R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40 refcount_add include/linux/refcount.h:193 [inline] skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821 kernel_sendpage+0x92/0xf0 net/socket.c:3794 sock_sendpage+0x8b/0xc0 net/socket.c:936 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636 splice_from_pipe+0x108/0x170 fs/splice.c:671 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842 do_splice_from fs/splice.c:861 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1035 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441409 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180 R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 501a90c945103e8627406763dac418f20f3837b2 ]

syzbot was once again able to crash a host by setting a very small mtu
on loopback device.

Let's make inetdev_valid_mtu() available in include/net/ip.h,
and use it in ip_setup_cork(), so that we protect both ip_append_page()
and __ip_append_data()

Also add a READ_ONCE() when the device mtu is read.

Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(),
even if other code paths might write over this field.

Add a big comment in include/linux/netdevice.h about dev->mtu
needing READ_ONCE()/WRITE_ONCE() annotations.

Hopefully we will add the missing ones in followup patches.

[1]

refcount_t: saturated; leaking memory.
WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22
Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89
RSP: 0018:ffff88809689f550 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c
RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1
R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001
R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40
 refcount_add include/linux/refcount.h:193 [inline]
 skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999
 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096
 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383
 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276
 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821
 kernel_sendpage+0x92/0xf0 net/socket.c:3794
 sock_sendpage+0x8b/0xc0 net/socket.c:936
 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458
 splice_from_pipe_feed fs/splice.c:512 [inline]
 __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636
 splice_from_pipe+0x108/0x170 fs/splice.c:671
 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842
 do_splice_from fs/splice.c:861 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1035
 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078
 do_sendfile+0x597/0xd00 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441409
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010
R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180
R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: skmsg: fix TLS 1.3 crash with full sk_msg 2019-12-04T21:31:01+00:00 Jakub Kicinski jakub.kicinski@netronome.com 2019-11-27T20:16:41+00:00 3cef7ef9c42562212574c32b98fbb1617a2ff515 [ Upstream commit 031097d9e079e40dce401031d1012e83d80eaf01 ] TLS 1.3 started using the entry at the end of the SG array for chaining-in the single byte content type entry. This mostly works: [ E E E E E E . . ] ^ ^ start end E < content type / [ E E E E E E C . ] ^ ^ start end (Where E denotes a populated SG entry; C denotes a chaining entry.) If the array is full, however, the end will point to the start: [ E E E E E E E E ] ^ start end And we end up overwriting the start: E < content type / [ C E E E E E E E ] ^ start end The sg array is supposed to be a circular buffer with start and end markers pointing anywhere. In case where start > end (i.e. the circular buffer has "wrapped") there is an extra entry reserved at the end to chain the two halves together. [ E E E E E E . . l ] (Where l is the reserved entry for "looping" back to front. As suggested by John, let's reserve another entry for chaining SG entries after the main circular buffer. Note that this entry has to be pointed to by the end entry so its position is not fixed. Examples of full messages: [ E E E E E E E E . l ] ^ ^ start end <---------------. [ E E . E E E E E E l ] ^ ^ end start Now the end will always point to an unused entry, so TLS 1.3 can always use it. Fixes: 130b392c6cd6 ("net: tls: Add tls 1.3 support") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 031097d9e079e40dce401031d1012e83d80eaf01 ]

TLS 1.3 started using the entry at the end of the SG array
for chaining-in the single byte content type entry. This mostly
works:

[ E E E E E E . . ]
  ^           ^
   start       end

                 E < content type
               /
[ E E E E E E C . ]
  ^           ^
   start       end

(Where E denotes a populated SG entry; C denotes a chaining entry.)

If the array is full, however, the end will point to the start:

[ E E E E E E E E ]
  ^
   start
   end

And we end up overwriting the start:

    E < content type
   /
[ C E E E E E E E ]
  ^
   start
   end

The sg array is supposed to be a circular buffer with start and
end markers pointing anywhere. In case where start > end
(i.e. the circular buffer has "wrapped") there is an extra entry
reserved at the end to chain the two halves together.

[ E E E E E E . . l ]

(Where l is the reserved entry for "looping" back to front.

As suggested by John, let's reserve another entry for chaining
SG entries after the main circular buffer. Note that this entry
has to be pointed to by the end entry so its position is not fixed.

Examples of full messages:

[ E E E E E E E E . l ]
  ^               ^
   start           end

   <---------------.
[ E E . E E E E E E l ]
      ^ ^
   end   start

Now the end will always point to an unused entry, so TLS 1.3
can always use it.

Fixes: 130b392c6cd6 ("net: tls: Add tls 1.3 support")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udp: drop skb extensions before marking skb stateless 2019-11-22T17:28:46+00:00 Florian Westphal fw@strlen.de 2019-11-21T05:56:23+00:00 677bf08cfdf9ee411c2084157f15d85edb09a81a Once udp stack has set the UDP_SKB_IS_STATELESS flag, later skb free assumes all skb head state has been dropped already. This will leak the extension memory in case the skb has extensions other than the ipsec secpath, e.g. bridge nf data. To fix this, set the UDP_SKB_IS_STATELESS flag only if we don't have extensions or if the extension space can be free'd. Fixes: 895b5c9f206eb7d25dc1360a ("netfilter: drop bridge nf reset from nf_reset") Cc: Paolo Abeni <pabeni@redhat.com> Reported-by: Byron Stanoszek <gandalf@winds.org> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Once udp stack has set the UDP_SKB_IS_STATELESS flag, later skb free
assumes all skb head state has been dropped already.

This will leak the extension memory in case the skb has extensions other
than the ipsec secpath, e.g. bridge nf data.

To fix this, set the UDP_SKB_IS_STATELESS flag only if we don't have
extensions or if the extension space can be free'd.

Fixes: 895b5c9f206eb7d25dc1360a ("netfilter: drop bridge nf reset from nf_reset")
Cc: Paolo Abeni <pabeni@redhat.com>
Reported-by: Byron Stanoszek <gandalf@winds.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4: fix sysctl max for fib_multipath_hash_policy 2019-11-19T01:25:36+00:00 Marcelo Ricardo Leitner marcelo.leitner@gmail.com 2019-11-18T12:46:09+00:00 ca749bbb108c24a876014c804f9777c545be4d59 Commit eec4844fae7c ("proc/sysctl: add shared variables for range check") did: - .extra2 = &two, + .extra2 = SYSCTL_ONE, here, which doesn't seem to be intentional, given the changelog. This patch restores it to the previous, as the value of 2 still makes sense (used in fib_multipath_hash()). Fixes: eec4844fae7c ("proc/sysctl: add shared variables for range check") Cc: Matteo Croce <mcroce@redhat.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Commit eec4844fae7c ("proc/sysctl: add shared variables for range
check") did:
-               .extra2         = &two,
+               .extra2         = SYSCTL_ONE,
here, which doesn't seem to be intentional, given the changelog.
This patch restores it to the previous, as the value of 2 still makes
sense (used in fib_multipath_hash()).

Fixes: eec4844fae7c ("proc/sysctl: add shared variables for range check")
Cc: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipmr: Fix skb headroom in ipmr_get_route(). 2019-11-16T21:06:54+00:00 Guillaume Nault gnault@redhat.com 2019-11-15T17:29:52+00:00 7901cd97963d6cbde88fa25a4a446db3554c16c6 In route.c, inet_rtm_getroute_build_skb() creates an skb with no headroom. This skb is then used by inet_rtm_getroute() which may pass it to rt_fill_info() and, from there, to ipmr_get_route(). The later might try to reuse this skb by cloning it and prepending an IPv4 header. But since the original skb has no headroom, skb_push() triggers skb_under_panic(): skbuff: skb_under_panic: text:00000000ca46ad8a len:80 put:20 head:00000000cd28494e data:000000009366fd6b tail:0x3c end:0xec0 dev:veth0 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:108! invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 6 PID: 587 Comm: ip Not tainted 5.4.0-rc6+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014 RIP: 0010:skb_panic+0xbf/0xd0 Code: 41 a2 ff 8b 4b 70 4c 8b 4d d0 48 c7 c7 20 76 f5 8b 44 8b 45 bc 48 8b 55 c0 48 8b 75 c8 41 54 41 57 41 56 41 55 e8 75 dc 7a ff <0f> 0b 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RSP: 0018:ffff888059ddf0b0 EFLAGS: 00010286 RAX: 0000000000000086 RBX: ffff888060a315c0 RCX: ffffffff8abe4822 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88806c9a79cc RBP: ffff888059ddf118 R08: ffffed100d9361b1 R09: ffffed100d9361b0 R10: ffff88805c68aee3 R11: ffffed100d9361b1 R12: ffff88805d218000 R13: ffff88805c689fec R14: 000000000000003c R15: 0000000000000ec0 FS: 00007f6af184b700(0000) GS:ffff88806c980000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc8204a000 CR3: 0000000057b40006 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_push+0x7e/0x80 ipmr_get_route+0x459/0x6fa rt_fill_info+0x692/0x9f0 inet_rtm_getroute+0xd26/0xf20 rtnetlink_rcv_msg+0x45d/0x630 netlink_rcv_skb+0x1a5/0x220 rtnetlink_rcv+0x15/0x20 netlink_unicast+0x305/0x3a0 netlink_sendmsg+0x575/0x730 sock_sendmsg+0xb5/0xc0 ___sys_sendmsg+0x497/0x4f0 __sys_sendmsg+0xcb/0x150 __x64_sys_sendmsg+0x48/0x50 do_syscall_64+0xd2/0xac0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Actually the original skb used to have enough headroom, but the reserve_skb() call was lost with the introduction of inet_rtm_getroute_build_skb() by commit 404eb77ea766 ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE"). We could reserve some headroom again in inet_rtm_getroute_build_skb(), but this function shouldn't be responsible for handling the special case of ipmr_get_route(). Let's handle that directly in ipmr_get_route() by calling skb_realloc_headroom() instead of skb_clone(). Fixes: 404eb77ea766 ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE") Signed-off-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
In route.c, inet_rtm_getroute_build_skb() creates an skb with no
headroom. This skb is then used by inet_rtm_getroute() which may pass
it to rt_fill_info() and, from there, to ipmr_get_route(). The later
might try to reuse this skb by cloning it and prepending an IPv4
header. But since the original skb has no headroom, skb_push() triggers
skb_under_panic():

skbuff: skb_under_panic: text:00000000ca46ad8a len:80 put:20 head:00000000cd28494e data:000000009366fd6b tail:0x3c end:0xec0 dev:veth0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:108!
invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 6 PID: 587 Comm: ip Not tainted 5.4.0-rc6+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
RIP: 0010:skb_panic+0xbf/0xd0
Code: 41 a2 ff 8b 4b 70 4c 8b 4d d0 48 c7 c7 20 76 f5 8b 44 8b 45 bc 48 8b 55 c0 48 8b 75 c8 41 54 41 57 41 56 41 55 e8 75 dc 7a ff <0f> 0b 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
RSP: 0018:ffff888059ddf0b0 EFLAGS: 00010286
RAX: 0000000000000086 RBX: ffff888060a315c0 RCX: ffffffff8abe4822
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88806c9a79cc
RBP: ffff888059ddf118 R08: ffffed100d9361b1 R09: ffffed100d9361b0
R10: ffff88805c68aee3 R11: ffffed100d9361b1 R12: ffff88805d218000
R13: ffff88805c689fec R14: 000000000000003c R15: 0000000000000ec0
FS:  00007f6af184b700(0000) GS:ffff88806c980000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8204a000 CR3: 0000000057b40006 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_push+0x7e/0x80
 ipmr_get_route+0x459/0x6fa
 rt_fill_info+0x692/0x9f0
 inet_rtm_getroute+0xd26/0xf20
 rtnetlink_rcv_msg+0x45d/0x630
 netlink_rcv_skb+0x1a5/0x220
 rtnetlink_rcv+0x15/0x20
 netlink_unicast+0x305/0x3a0
 netlink_sendmsg+0x575/0x730
 sock_sendmsg+0xb5/0xc0
 ___sys_sendmsg+0x497/0x4f0
 __sys_sendmsg+0xcb/0x150
 __x64_sys_sendmsg+0x48/0x50
 do_syscall_64+0xd2/0xac0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Actually the original skb used to have enough headroom, but the
reserve_skb() call was lost with the introduction of
inet_rtm_getroute_build_skb() by commit 404eb77ea766 ("ipv4: support
sport, dport and ip_proto in RTM_GETROUTE").

We could reserve some headroom again in inet_rtm_getroute_build_skb(),
but this function shouldn't be responsible for handling the special
case of ipmr_get_route(). Let's handle that directly in
ipmr_get_route() by calling skb_realloc_headroom() instead of
skb_clone().

Fixes: 404eb77ea766 ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv4: Fix table id reference in fib_sync_down_addr 2019-11-08T00:14:36+00:00 David Ahern dsahern@kernel.org 2019-11-07T18:29:52+00:00 e0a312629fefa943534fc46f7bfbe6de3fdaf463 Hendrik reported routes in the main table using source address are not removed when the address is removed. The problem is that fib_sync_down_addr does not account for devices in the default VRF which are associated with the main table. Fix by updating the table id reference. Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs") Reported-by: Hendrik Donner <hd@os-cillation.de> Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Hendrik reported routes in the main table using source address are not
removed when the address is removed. The problem is that fib_sync_down_addr
does not account for devices in the default VRF which are associated
with the main table. Fix by updating the table id reference.

Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs")
Reported-by: Hendrik Donner <hd@os-cillation.de>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet: stop leaking jiffies on the wire 2019-11-01T21:57:52+00:00 Eric Dumazet edumazet@google.com 2019-11-01T17:32:19+00:00 a904a0693c189691eeee64f6c6b188bd7dc244e9 Historically linux tried to stick to RFC 791, 1122, 2003 for IPv4 ID field generation. RFC 6864 made clear that no matter how hard we try, we can not ensure unicity of IP ID within maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. Linux uses a per socket inet generator (inet_id), initialized at connection startup with a XOR of 'jiffies' and other fields that appear clear on the wire. Thiemo Nagel pointed that this strategy is a privacy concern as this provides 16 bits of entropy to fingerprint devices. Let's switch to a random starting point, this is just as good as far as RFC 6864 is concerned and does not leak anything critical. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Thiemo Nagel <tnagel@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Historically linux tried to stick to RFC 791, 1122, 2003
for IPv4 ID field generation.

RFC 6864 made clear that no matter how hard we try,
we can not ensure unicity of IP ID within maximum
lifetime for all datagrams with a given source
address/destination address/protocol tuple.

Linux uses a per socket inet generator (inet_id), initialized
at connection startup with a XOR of 'jiffies' and other
fields that appear clear on the wire.

Thiemo Nagel pointed that this strategy is a privacy
concern as this provides 16 bits of entropy to fingerprint
devices.

Let's switch to a random starting point, this is just as
good as far as RFC 6864 is concerned and does not leak
anything critical.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Thiemo Nagel <tnagel@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp: increase tcp_max_syn_backlog max value 2019-10-31T21:02:01+00:00 Eric Dumazet edumazet@google.com 2019-10-30T17:05:46+00:00 623d0c2db02043e43b698fdd8de1bd398b8e7b37 tcp_max_syn_backlog default value depends on memory size and TCP ehash size. Before this patch, the max value was 2048 [1], which is considered too small nowadays. Increase it to 4096 to match the recent SOMAXCONN change. [1] This is with TCP ehash size being capped to 524288 buckets. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Yue Cao <ycao009@ucr.edu> Signed-off-by: David S. Miller <davem@davemloft.net> 
tcp_max_syn_backlog default value depends on memory size
and TCP ehash size. Before this patch, the max value
was 2048 [1], which is considered too small nowadays.

Increase it to 4096 to match the recent SOMAXCONN change.

[1] This is with TCP ehash size being capped to 524288 buckets.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Yue Cao <ycao009@ucr.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>