<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/core, branch v5.4.70</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>bpf: Fix clobbering of r2 in bpf_gen_ld_abs</title>
<updated>2020-10-01T11:18:17+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2020-09-07T22:04:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5e77009e33a16f8c5987f6ced2fc322c7b89fd60'/>
<id>5e77009e33a16f8c5987f6ced2fc322c7b89fd60</id>
<content type='text'>
[ Upstream commit e6a18d36118bea3bf497c9df4d9988b6df120689 ]

Bryce reported that he saw the following with:

  0:  r6 = r1
  1:  r1 = 12
  2:  r0 = *(u16 *)skb[r1]

The xlated sequence was incorrectly clobbering r2 with pointer
value of r6 ...

  0: (bf) r6 = r1
  1: (b7) r1 = 12
  2: (bf) r1 = r6
  3: (bf) r2 = r1
  4: (85) call bpf_skb_load_helper_16_no_cache#7692160

... and hence call to the load helper never succeeded given the
offset was too high. Fix it by reordering the load of r6 to r1.

Other than that the insn has similar calling convention than BPF
helpers, that is, r0 - r5 are scratch regs, so nothing else
affected after the insn.

Fixes: e0cea7ce988c ("bpf: implement ld_abs/ld_ind in native bpf")
Reported-by: Bryce Kahle &lt;bryce.kahle@datadoghq.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/cace836e4d07bb63b1a53e49c5dfb238a040c298.1599512096.git.daniel@iogearbox.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e6a18d36118bea3bf497c9df4d9988b6df120689 ]

Bryce reported that he saw the following with:

  0:  r6 = r1
  1:  r1 = 12
  2:  r0 = *(u16 *)skb[r1]

The xlated sequence was incorrectly clobbering r2 with pointer
value of r6 ...

  0: (bf) r6 = r1
  1: (b7) r1 = 12
  2: (bf) r1 = r6
  3: (bf) r2 = r1
  4: (85) call bpf_skb_load_helper_16_no_cache#7692160

... and hence call to the load helper never succeeded given the
offset was too high. Fix it by reordering the load of r6 to r1.

Other than that the insn has similar calling convention than BPF
helpers, that is, r0 - r5 are scratch regs, so nothing else
affected after the insn.

Fixes: e0cea7ce988c ("bpf: implement ld_abs/ld_ind in native bpf")
Reported-by: Bryce Kahle &lt;bryce.kahle@datadoghq.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/cace836e4d07bb63b1a53e49c5dfb238a040c298.1599512096.git.daniel@iogearbox.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>devlink: Fix reporter's recovery condition</title>
<updated>2020-10-01T11:17:58+00:00</updated>
<author>
<name>Aya Levin</name>
<email>ayal@mellanox.com</email>
</author>
<published>2020-05-04T08:27:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9325e9e5abf6eb4f5136f642ad7d5fa4a7a8572d'/>
<id>9325e9e5abf6eb4f5136f642ad7d5fa4a7a8572d</id>
<content type='text'>
[ Upstream commit bea0c5c942d3b4e9fb6ed45f6a7de74c6b112437 ]

Devlink health core conditions the reporter's recovery with the
expiration of the grace period. This is not relevant for the first
recovery. Explicitly demand that the grace period will only apply to
recoveries other than the first.

Fixes: c8e1da0bf923 ("devlink: Add health report functionality")
Signed-off-by: Aya Levin &lt;ayal@mellanox.com&gt;
Reviewed-by: Moshe Shemesh &lt;moshe@mellanox.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bea0c5c942d3b4e9fb6ed45f6a7de74c6b112437 ]

Devlink health core conditions the reporter's recovery with the
expiration of the grace period. This is not relevant for the first
recovery. Explicitly demand that the grace period will only apply to
recoveries other than the first.

Fixes: c8e1da0bf923 ("devlink: Add health report functionality")
Signed-off-by: Aya Levin &lt;ayal@mellanox.com&gt;
Reviewed-by: Moshe Shemesh &lt;moshe@mellanox.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>neigh_stat_seq_next() should increase position index</title>
<updated>2020-10-01T11:17:24+00:00</updated>
<author>
<name>Vasily Averin</name>
<email>vvs@virtuozzo.com</email>
</author>
<published>2020-01-23T07:11:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2ba309f086b822d89a7d8528d1516e5eebf49791'/>
<id>2ba309f086b822d89a7d8528d1516e5eebf49791</id>
<content type='text'>
[ Upstream commit 1e3f9f073c47bee7c23e77316b07bc12338c5bba ]

if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin &lt;vvs@virtuozzo.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 1e3f9f073c47bee7c23e77316b07bc12338c5bba ]

if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin &lt;vvs@virtuozzo.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Fix bridge enslavement failure</title>
<updated>2020-09-26T16:03:13+00:00</updated>
<author>
<name>Ido Schimmel</name>
<email>idosch@nvidia.com</email>
</author>
<published>2020-09-10T11:01:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d3c2188ee6e644c5159422cbdc892a21653ad38d'/>
<id>d3c2188ee6e644c5159422cbdc892a21653ad38d</id>
<content type='text'>
[ Upstream commit e1b9efe6baebe79019a2183176686a0e709388ae ]

When a netdev is enslaved to a bridge, its parent identifier is queried.
This is done so that packets that were already forwarded in hardware
will not be forwarded again by the bridge device between netdevs
belonging to the same hardware instance.

The operation fails when the netdev is an upper of netdevs with
different parent identifiers.

Instead of failing the enslavement, have dev_get_port_parent_id() return
'-EOPNOTSUPP' which will signal the bridge to skip the query operation.
Other callers of the function are not affected by this change.

Fixes: 7e1146e8c10c ("net: devlink: introduce devlink_compat_switch_id_get() helper")
Signed-off-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reported-by: Vasundhara Volam &lt;vasundhara-v.volam@broadcom.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@nvidia.com&gt;
Reviewed-by: Nikolay Aleksandrov &lt;nikolay@nvidia.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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e1b9efe6baebe79019a2183176686a0e709388ae ]

When a netdev is enslaved to a bridge, its parent identifier is queried.
This is done so that packets that were already forwarded in hardware
will not be forwarded again by the bridge device between netdevs
belonging to the same hardware instance.

The operation fails when the netdev is an upper of netdevs with
different parent identifiers.

Instead of failing the enslavement, have dev_get_port_parent_id() return
'-EOPNOTSUPP' which will signal the bridge to skip the query operation.
Other callers of the function are not affected by this change.

Fixes: 7e1146e8c10c ("net: devlink: introduce devlink_compat_switch_id_get() helper")
Signed-off-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reported-by: Vasundhara Volam &lt;vasundhara-v.volam@broadcom.com&gt;
Reviewed-by: Jiri Pirko &lt;jiri@nvidia.com&gt;
Reviewed-by: Nikolay Aleksandrov &lt;nikolay@nvidia.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ipv4: Initialize flowi4_multipath_hash in data path</title>
<updated>2020-09-26T16:03:12+00:00</updated>
<author>
<name>David Ahern</name>
<email>dsahern@gmail.com</email>
</author>
<published>2020-09-13T18:43:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=583ff79349f905de7fe893a7d7e0331cde8645c0'/>
<id>583ff79349f905de7fe893a7d7e0331cde8645c0</id>
<content type='text'>
[ Upstream commit 1869e226a7b3ef75b4f70ede2f1b7229f7157fa4 ]

flowi4_multipath_hash was added by the commit referenced below for
tunnels. Unfortunately, the patch did not initialize the new field
for several fast path lookups that do not initialize the entire flow
struct to 0. Fix those locations. Currently, flowi4_multipath_hash
is random garbage and affects the hash value computed by
fib_multipath_hash for multipath selection.

Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: David Ahern &lt;dsahern@gmail.com&gt;
Cc: wenxu &lt;wenxu@ucloud.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 1869e226a7b3ef75b4f70ede2f1b7229f7157fa4 ]

flowi4_multipath_hash was added by the commit referenced below for
tunnels. Unfortunately, the patch did not initialize the new field
for several fast path lookups that do not initialize the entire flow
struct to 0. Fix those locations. Currently, flowi4_multipath_hash
is random garbage and affects the hash value computed by
fib_multipath_hash for multipath selection.

Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: David Ahern &lt;dsahern@gmail.com&gt;
Cc: wenxu &lt;wenxu@ucloud.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: handle the return value of pskb_carve_frag_list() correctly</title>
<updated>2020-09-23T10:40:34+00:00</updated>
<author>
<name>Miaohe Lin</name>
<email>linmiaohe@huawei.com</email>
</author>
<published>2020-08-15T08:46:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=78607d494c92641b38323b59b25cdc750d1ec7bf'/>
<id>78607d494c92641b38323b59b25cdc750d1ec7bf</id>
<content type='text'>
commit eabe861881a733fc84f286f4d5a1ffaddd4f526f upstream.

pskb_carve_frag_list() may return -ENOMEM in pskb_carve_inside_nonlinear().
we should handle this correctly or we would get wrong sk_buff.

Fixes: 6fa01ccd8830 ("skbuff: Add pskb_extract() helper function")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit eabe861881a733fc84f286f4d5a1ffaddd4f526f upstream.

pskb_carve_frag_list() may return -ENOMEM in pskb_carve_inside_nonlinear().
we should handle this correctly or we would get wrong sk_buff.

Fixes: 6fa01ccd8830 ("skbuff: Add pskb_extract() helper function")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: disable netpoll on fresh napis</title>
<updated>2020-09-12T12:18:55+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2020-08-26T19:40:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ddb279d64b724b197dec829c016b5d386314b970'/>
<id>ddb279d64b724b197dec829c016b5d386314b970</id>
<content type='text'>
[ Upstream commit 96e97bc07e90f175a8980a22827faf702ca4cb30 ]

napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.

This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().

To ensure memory ordering is correct we need to use RCU accessors.

Reported-by: Rob Sherwood &lt;rsher@fb.com&gt;
Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 96e97bc07e90f175a8980a22827faf702ca4cb30 ]

napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.

This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().

To ensure memory ordering is correct we need to use RCU accessors.

Reported-by: Rob Sherwood &lt;rsher@fb.com&gt;
Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-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;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: core: use listified Rx for GRO_NORMAL in napi_gro_receive()</title>
<updated>2020-09-09T17:12:31+00:00</updated>
<author>
<name>Alexander Lobakin</name>
<email>alobakin@dlink.ru</email>
</author>
<published>2019-10-14T08:00:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=de53545e8d4c145773da033b331581b7cbcc15da'/>
<id>de53545e8d4c145773da033b331581b7cbcc15da</id>
<content type='text'>
commit 6570bc79c0dfff0f228b7afd2de720fb4e84d61d upstream.

Commit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL
skbs") made use of listified skb processing for the users of
napi_gro_frags().
The same technique can be used in a way more common napi_gro_receive()
to speed up non-merged (GRO_NORMAL) skbs for a wide range of drivers
including gro_cells and mac80211 users.
This slightly changes the return value in cases where skb is being
dropped by the core stack, but it seems to have no impact on related
drivers' functionality.
gro_normal_batch is left untouched as it's very individual for every
single system configuration and might be tuned in manual order to
achieve an optimal performance.

Signed-off-by: Alexander Lobakin &lt;alobakin@dlink.ru&gt;
Acked-by: Edward Cree &lt;ecree@solarflare.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Hyunsoon Kim &lt;h10.kim@samsung.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6570bc79c0dfff0f228b7afd2de720fb4e84d61d upstream.

Commit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL
skbs") made use of listified skb processing for the users of
napi_gro_frags().
The same technique can be used in a way more common napi_gro_receive()
to speed up non-merged (GRO_NORMAL) skbs for a wide range of drivers
including gro_cells and mac80211 users.
This slightly changes the return value in cases where skb is being
dropped by the core stack, but it seems to have no impact on related
drivers' functionality.
gro_normal_batch is left untouched as it's very individual for every
single system configuration and might be tuned in manual order to
achieve an optimal performance.

Signed-off-by: Alexander Lobakin &lt;alobakin@dlink.ru&gt;
Acked-by: Edward Cree &lt;ecree@solarflare.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Hyunsoon Kim &lt;h10.kim@samsung.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: Fix potential wrong skb-&gt;protocol in skb_vlan_untag()</title>
<updated>2020-09-03T09:26:39+00:00</updated>
<author>
<name>Miaohe Lin</name>
<email>linmiaohe@huawei.com</email>
</author>
<published>2020-08-15T08:44:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6ed89176755c6157cd61215592f9be8ff0b543ce'/>
<id>6ed89176755c6157cd61215592f9be8ff0b543ce</id>
<content type='text'>
[ Upstream commit 55eff0eb7460c3d50716ed9eccf22257b046ca92 ]

We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). So
we should pull VLAN_HLEN + sizeof(unsigned short) in skb_vlan_untag() or
we may access the wrong data.

Fixes: 0d5501c1c828 ("net: Always untag vlan-tagged traffic on input.")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.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>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 55eff0eb7460c3d50716ed9eccf22257b046ca92 ]

We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). So
we should pull VLAN_HLEN + sizeof(unsigned short) in skb_vlan_untag() or
we may access the wrong data.

Fixes: 0d5501c1c828 ("net: Always untag vlan-tagged traffic on input.")
Signed-off-by: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: sock_ops sk access may stomp registers when dst_reg = src_reg</title>
<updated>2020-08-26T08:40:59+00:00</updated>
<author>
<name>John Fastabend</name>
<email>john.fastabend@gmail.com</email>
</author>
<published>2020-08-11T22:04:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6e0bc946cbeec538322820786b5fb5200a2216ab'/>
<id>6e0bc946cbeec538322820786b5fb5200a2216ab</id>
<content type='text'>
[ Upstream commit 84f44df664e9f0e261157e16ee1acd77cc1bb78d ]

Similar to patch ("bpf: sock_ops ctx access may stomp registers") if the
src_reg = dst_reg when reading the sk field of a sock_ops struct we
generate xlated code,

  53: (61) r9 = *(u32 *)(r9 +28)
  54: (15) if r9 == 0x0 goto pc+3
  56: (79) r9 = *(u64 *)(r9 +0)

This stomps on the r9 reg to do the sk_fullsock check and then when
reading the skops-&gt;sk field instead of the sk pointer we get the
sk_fullsock. To fix use similar pattern noted in the previous fix
and use the temp field to save/restore a register used to do
sk_fullsock check.

After the fix the generated xlated code reads,

  52: (7b) *(u64 *)(r9 +32) = r8
  53: (61) r8 = *(u32 *)(r9 +28)
  54: (15) if r9 == 0x0 goto pc+3
  55: (79) r8 = *(u64 *)(r9 +32)
  56: (79) r9 = *(u64 *)(r9 +0)
  57: (05) goto pc+1
  58: (79) r8 = *(u64 *)(r9 +32)

Here r9 register was in-use so r8 is chosen as the temporary register.
In line 52 r8 is saved in temp variable and at line 54 restored in case
fullsock != 0. Finally we handle fullsock == 0 case by restoring at
line 58.

This adds a new macro SOCK_OPS_GET_SK it is almost possible to merge
this with SOCK_OPS_GET_FIELD, but I found the extra branch logic a
bit more confusing than just adding a new macro despite a bit of
duplicating code.

Fixes: 1314ef561102e ("bpf: export bpf_sock for BPF_PROG_TYPE_SOCK_OPS prog type")
Signed-off-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Song Liu &lt;songliubraving@fb.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/159718349653.4728.6559437186853473612.stgit@john-Precision-5820-Tower
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 84f44df664e9f0e261157e16ee1acd77cc1bb78d ]

Similar to patch ("bpf: sock_ops ctx access may stomp registers") if the
src_reg = dst_reg when reading the sk field of a sock_ops struct we
generate xlated code,

  53: (61) r9 = *(u32 *)(r9 +28)
  54: (15) if r9 == 0x0 goto pc+3
  56: (79) r9 = *(u64 *)(r9 +0)

This stomps on the r9 reg to do the sk_fullsock check and then when
reading the skops-&gt;sk field instead of the sk pointer we get the
sk_fullsock. To fix use similar pattern noted in the previous fix
and use the temp field to save/restore a register used to do
sk_fullsock check.

After the fix the generated xlated code reads,

  52: (7b) *(u64 *)(r9 +32) = r8
  53: (61) r8 = *(u32 *)(r9 +28)
  54: (15) if r9 == 0x0 goto pc+3
  55: (79) r8 = *(u64 *)(r9 +32)
  56: (79) r9 = *(u64 *)(r9 +0)
  57: (05) goto pc+1
  58: (79) r8 = *(u64 *)(r9 +32)

Here r9 register was in-use so r8 is chosen as the temporary register.
In line 52 r8 is saved in temp variable and at line 54 restored in case
fullsock != 0. Finally we handle fullsock == 0 case by restoring at
line 58.

This adds a new macro SOCK_OPS_GET_SK it is almost possible to merge
this with SOCK_OPS_GET_FIELD, but I found the extra branch logic a
bit more confusing than just adding a new macro despite a bit of
duplicating code.

Fixes: 1314ef561102e ("bpf: export bpf_sock for BPF_PROG_TYPE_SOCK_OPS prog type")
Signed-off-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Song Liu &lt;songliubraving@fb.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/159718349653.4728.6559437186853473612.stgit@john-Precision-5820-Tower
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
