linux-stable.git/drivers/net/wan, branch v5.4.71 Linux kernel stable tree drivers/net/wan/hdlc: Set skb->protocol before transmitting 2020-10-07T06:01:26+00:00 Xie He xie.he.0141@gmail.com 2020-09-16T21:25:07+00:00 126e6099b8c11e160a8a38943e68aaa3782dfab4 [ Upstream commit 9fb030a70431a2a2a1b292dbf0b2f399cc072c16 ] This patch sets skb->protocol before transmitting frames on the HDLC device, so that a user listening on the HDLC device with an AF_PACKET socket will see outgoing frames' sll_protocol field correctly set and consistent with that of incoming frames. 1. Control frames in hdlc_cisco and hdlc_ppp When these drivers send control frames, skb->protocol is not set. This value should be set to htons(ETH_P_HDLC), because when receiving control frames, their skb->protocol is set to htons(ETH_P_HDLC). When receiving, hdlc_type_trans in hdlc.h is called, which then calls cisco_type_trans or ppp_type_trans. The skb->protocol of control frames is set to htons(ETH_P_HDLC) so that the control frames can be received by hdlc_rcv in hdlc.c, which calls cisco_rx or ppp_rx to process the control frames. 2. hdlc_fr When this driver sends control frames, skb->protocol is set to internal values used in this driver. When this driver sends data frames (from upper stacked PVC devices), skb->protocol is the same as that of the user data packet being sent on the upper PVC device (for normal PVC devices), or is htons(ETH_P_802_3) (for Ethernet-emulating PVC devices). However, skb->protocol for both control frames and data frames should be set to htons(ETH_P_HDLC), because when receiving, all frames received on the HDLC device will have their skb->protocol set to htons(ETH_P_HDLC). When receiving, hdlc_type_trans in hdlc.h is called, and because this driver doesn't provide a type_trans function in struct hdlc_proto, all frames will have their skb->protocol set to htons(ETH_P_HDLC). The frames are then received by hdlc_rcv in hdlc.c, which calls fr_rx to process the frames (control frames are consumed and data frames are re-received on upper PVC devices). Cc: Krzysztof Halasa <khc@pm.waw.pl> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9fb030a70431a2a2a1b292dbf0b2f399cc072c16 ]

This patch sets skb->protocol before transmitting frames on the HDLC
device, so that a user listening on the HDLC device with an AF_PACKET
socket will see outgoing frames' sll_protocol field correctly set and
consistent with that of incoming frames.

1. Control frames in hdlc_cisco and hdlc_ppp

When these drivers send control frames, skb->protocol is not set.

This value should be set to htons(ETH_P_HDLC), because when receiving
control frames, their skb->protocol is set to htons(ETH_P_HDLC).

When receiving, hdlc_type_trans in hdlc.h is called, which then calls
cisco_type_trans or ppp_type_trans. The skb->protocol of control frames
is set to htons(ETH_P_HDLC) so that the control frames can be received
by hdlc_rcv in hdlc.c, which calls cisco_rx or ppp_rx to process the
control frames.

2. hdlc_fr

When this driver sends control frames, skb->protocol is set to internal
values used in this driver.

When this driver sends data frames (from upper stacked PVC devices),
skb->protocol is the same as that of the user data packet being sent on
the upper PVC device (for normal PVC devices), or is htons(ETH_P_802_3)
(for Ethernet-emulating PVC devices).

However, skb->protocol for both control frames and data frames should be
set to htons(ETH_P_HDLC), because when receiving, all frames received on
the HDLC device will have their skb->protocol set to htons(ETH_P_HDLC).

When receiving, hdlc_type_trans in hdlc.h is called, and because this
driver doesn't provide a type_trans function in struct hdlc_proto,
all frames will have their skb->protocol set to htons(ETH_P_HDLC).
The frames are then received by hdlc_rcv in hdlc.c, which calls fr_rx
to process the frames (control frames are consumed and data frames
are re-received on upper PVC devices).

Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/wan/lapbether: Make skb->protocol consistent with the header 2020-10-07T06:01:26+00:00 Xie He xie.he.0141@gmail.com 2020-09-16T16:49:18+00:00 3ba3fc3e7ea6175423ac8eb53d6e90ed1258ed94 [ Upstream commit 83f9a9c8c1edc222846dc1bde6e3479703e8e5a3 ] This driver is a virtual driver stacked on top of Ethernet interfaces. When this driver transmits data on the Ethernet device, the skb->protocol setting is inconsistent with the Ethernet header prepended to the skb. This causes a user listening on the Ethernet interface with an AF_PACKET socket, to see different sll_protocol values for incoming and outgoing frames, because incoming frames would have this value set by parsing the Ethernet header. This patch changes the skb->protocol value for outgoing Ethernet frames, making it consistent with the Ethernet header prepended. This makes a user listening on the Ethernet device with an AF_PACKET socket, to see the same sll_protocol value for incoming and outgoing frames. Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 83f9a9c8c1edc222846dc1bde6e3479703e8e5a3 ]

This driver is a virtual driver stacked on top of Ethernet interfaces.

When this driver transmits data on the Ethernet device, the skb->protocol
setting is inconsistent with the Ethernet header prepended to the skb.

This causes a user listening on the Ethernet interface with an AF_PACKET
socket, to see different sll_protocol values for incoming and outgoing
frames, because incoming frames would have this value set by parsing the
Ethernet header.

This patch changes the skb->protocol value for outgoing Ethernet frames,
making it consistent with the Ethernet header prepended. This makes a
user listening on the Ethernet device with an AF_PACKET socket, to see
the same sll_protocol value for incoming and outgoing frames.

Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/wan/hdlc_fr: Add needed_headroom for PVC devices 2020-10-07T06:01:25+00:00 Xie He xie.he.0141@gmail.com 2020-09-03T00:06:58+00:00 985a56c58c4f5fbea988c3b127780fd89fdf72be [ Upstream commit 44a049c42681de71c783d75cd6e56b4e339488b0 ] PVC devices are virtual devices in this driver stacked on top of the actual HDLC device. They are the devices normal users would use. PVC devices have two types: normal PVC devices and Ethernet-emulating PVC devices. When transmitting data with PVC devices, the ndo_start_xmit function will prepend a header of 4 or 10 bytes. Currently this driver requests this headroom to be reserved for normal PVC devices by setting their hard_header_len to 10. However, this does not work when these devices are used with AF_PACKET/RAW sockets. Also, this driver does not request this headroom for Ethernet-emulating PVC devices (but deals with this problem by reallocating the skb when needed, which is not optimal). This patch replaces hard_header_len with needed_headroom, and set needed_headroom for Ethernet-emulating PVC devices, too. This makes the driver to request headroom for all PVC devices in all cases. Cc: Krzysztof Halasa <khc@pm.waw.pl> Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 44a049c42681de71c783d75cd6e56b4e339488b0 ]

PVC devices are virtual devices in this driver stacked on top of the
actual HDLC device. They are the devices normal users would use.
PVC devices have two types: normal PVC devices and Ethernet-emulating
PVC devices.

When transmitting data with PVC devices, the ndo_start_xmit function
will prepend a header of 4 or 10 bytes. Currently this driver requests
this headroom to be reserved for normal PVC devices by setting their
hard_header_len to 10. However, this does not work when these devices
are used with AF_PACKET/RAW sockets. Also, this driver does not request
this headroom for Ethernet-emulating PVC devices (but deals with this
problem by reallocating the skb when needed, which is not optimal).

This patch replaces hard_header_len with needed_headroom, and set
needed_headroom for Ethernet-emulating PVC devices, too. This makes
the driver to request headroom for all PVC devices in all cases.

Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
hdlc_ppp: add range checks in ppp_cp_parse_cr() 2020-09-26T16:03:12+00:00 Dan Carpenter dan.carpenter@oracle.com 2020-09-09T09:46:48+00:00 c3de9daa662617132744731f1b4eb7b5cd1270a8 [ Upstream commit 66d42ed8b25b64eb63111a2b8582c5afc8bf1105 ] There are a couple bugs here: 1) If opt[1] is zero then this results in a forever loop. If the value is less than 2 then it is invalid. 2) It assumes that "len" is more than sizeof(valid_accm) or 6 which can result in memory corruption. In the case of LCP_OPTION_ACCM, then we should check "opt[1]" instead of "len" because, if "opt[1]" is less than sizeof(valid_accm) then "nak_len" gets out of sync and it can lead to memory corruption in the next iterations through the loop. In case of LCP_OPTION_MAGIC, the only valid value for opt[1] is 6, but the code is trying to log invalid data so we should only discard the data when "len" is less than 6 because that leads to a read overflow. Reported-by: ChenNan Of Chaitin Security Research Lab <whutchennan@gmail.com> Fixes: e022c2f07ae5 ("WAN: new synchronous PPP implementation for generic HDLC.") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 66d42ed8b25b64eb63111a2b8582c5afc8bf1105 ]

There are a couple bugs here:
1) If opt[1] is zero then this results in a forever loop.  If the value
   is less than 2 then it is invalid.
2) It assumes that "len" is more than sizeof(valid_accm) or 6 which can
   result in memory corruption.

In the case of LCP_OPTION_ACCM, then  we should check "opt[1]" instead
of "len" because, if "opt[1]" is less than sizeof(valid_accm) then
"nak_len" gets out of sync and it can lead to memory corruption in the
next iterations through the loop.  In case of LCP_OPTION_MAGIC, the
only valid value for opt[1] is 6, but the code is trying to log invalid
data so we should only discard the data when "len" is less than 6
because that leads to a read overflow.

Reported-by: ChenNan Of Chaitin Security Research Lab  <whutchennan@gmail.com>
Fixes: e022c2f07ae5 ("WAN: new synchronous PPP implementation for generic HDLC.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/wan/hdlc_cisco: Add hard_header_len 2020-09-17T11:47:48+00:00 Xie He xie.he.0141@gmail.com 2020-08-28T07:07:52+00:00 bc818ce2d51ec9bc04a7a4bb8a07cd0893e85cfb [ Upstream commit 1a545ebe380bf4c1433e3c136e35a77764fda5ad ] This driver didn't set hard_header_len. This patch sets hard_header_len for it according to its header_ops->create function. This driver's header_ops->create function (cisco_hard_header) creates a header of (struct hdlc_header), so hard_header_len should be set to sizeof(struct hdlc_header). Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Acked-by: Krzysztof Halasa <khc@pm.waw.pl> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1a545ebe380bf4c1433e3c136e35a77764fda5ad ]

This driver didn't set hard_header_len. This patch sets hard_header_len
for it according to its header_ops->create function.

This driver's header_ops->create function (cisco_hard_header) creates
a header of (struct hdlc_header), so hard_header_len should be set to
sizeof(struct hdlc_header).

Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/wan/lapbether: Set network_header before transmitting 2020-09-17T11:47:46+00:00 Xie He xie.he.0141@gmail.com 2020-08-26T03:03:53+00:00 0aa356dde967cc78586008bfad23a34b94e666a7 [ Upstream commit 91244d108441013b7367b3b4dcc6869998676473 ] Set the skb's network_header before it is passed to the underlying Ethernet device for transmission. This patch fixes the following issue: When we use this driver with AF_PACKET sockets, there would be error messages of: protocol 0805 is buggy, dev (Ethernet interface name) printed in the system "dmesg" log. This is because skbs passed down to the Ethernet device for transmission don't have their network_header properly set, and the dev_queue_xmit_nit function in net/core/dev.c complains about this. Reason of setting the network_header to this place (at the end of the Ethernet header, and at the beginning of the Ethernet payload): Because when this driver receives an skb from the Ethernet device, the network_header is also set at this place. Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 91244d108441013b7367b3b4dcc6869998676473 ]

Set the skb's network_header before it is passed to the underlying
Ethernet device for transmission.

This patch fixes the following issue:

When we use this driver with AF_PACKET sockets, there would be error
messages of:
   protocol 0805 is buggy, dev (Ethernet interface name)
printed in the system "dmesg" log.

This is because skbs passed down to the Ethernet device for transmission
don't have their network_header properly set, and the dev_queue_xmit_nit
function in net/core/dev.c complains about this.

Reason of setting the network_header to this place (at the end of the
Ethernet header, and at the beginning of the Ethernet payload):

Because when this driver receives an skb from the Ethernet device, the
network_header is also set at this place.

Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/wan/lapbether: Added needed_tailroom 2020-09-17T11:47:45+00:00 Xie He xie.he.0141@gmail.com 2020-08-21T21:26:59+00:00 0faee7f8c2366b3536fa32643f70ebe74c52bde2 [ Upstream commit 1ee39c1448c4e0d480c5b390e2db1987561fb5c2 ] The underlying Ethernet device may request necessary tailroom to be allocated by setting needed_tailroom. This driver should also set needed_tailroom to request the tailroom needed by the underlying Ethernet device to be allocated. Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1ee39c1448c4e0d480c5b390e2db1987561fb5c2 ]

The underlying Ethernet device may request necessary tailroom to be
allocated by setting needed_tailroom. This driver should also set
needed_tailroom to request the tailroom needed by the underlying
Ethernet device to be allocated.

Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net: wan: wanxl: use $(M68KCC) instead of $(M68KAS) for rebuilding firmware 2020-08-26T08:40:46+00:00 Masahiro Yamada masahiroy@kernel.org 2020-03-26T05:57:16+00:00 c173511a12e442caa6647d891f8f4cdeeba8dec4 commit 734f3719d3438f9cc181d674c33ca9762e9148a1 upstream. The firmware source, wanxlfw.S, is currently compiled by the combo of $(CPP) and $(M68KAS). This is not what we usually do for compiling *.S files. In fact, this Makefile is the only user of $(AS) in the kernel build. Instead of combining $(CPP) and (AS) from different tool sets, using $(M68KCC) as an assembler driver is simpler, and saner. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 734f3719d3438f9cc181d674c33ca9762e9148a1 upstream.

The firmware source, wanxlfw.S, is currently compiled by the combo of
$(CPP) and $(M68KAS). This is not what we usually do for compiling *.S
files. In fact, this Makefile is the only user of $(AS) in the kernel
build.

Instead of combining $(CPP) and (AS) from different tool sets, using
$(M68KCC) as an assembler driver is simpler, and saner.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware 2020-08-26T08:40:46+00:00 Masahiro Yamada masahiroy@kernel.org 2020-03-26T05:57:15+00:00 c7c239c947be1bc9da8cc4a79dfb7951788632b8 commit 63b903dfebdea92aa92ad337d8451a6fbfeabf9d upstream. As far as I understood from the Kconfig help text, this build rule is used to rebuild the driver firmware, which runs on an old m68k-based chip. So, you need m68k tools for the firmware rebuild. wanxl.c is a PCI driver, but CONFIG_M68K does not select CONFIG_HAVE_PCI. So, you cannot enable CONFIG_WANXL_BUILD_FIRMWARE for ARCH=m68k. In other words, ifeq ($(ARCH),m68k) is false here. I am keeping the dead code for now, but rebuilding the firmware requires 'as68k' and 'ld68k', which I do not have in hand. Instead, the kernel.org m68k GCC [1] successfully built it. Allowing a user to pass in CROSS_COMPILE_M68K= is handier. [1] https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/9.2.0/x86_64-gcc-9.2.0-nolibc-m68k-linux.tar.xz Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 63b903dfebdea92aa92ad337d8451a6fbfeabf9d upstream.

As far as I understood from the Kconfig help text, this build rule is
used to rebuild the driver firmware, which runs on an old m68k-based
chip. So, you need m68k tools for the firmware rebuild.

wanxl.c is a PCI driver, but CONFIG_M68K does not select CONFIG_HAVE_PCI.
So, you cannot enable CONFIG_WANXL_BUILD_FIRMWARE for ARCH=m68k. In other
words, ifeq ($(ARCH),m68k) is false here.

I am keeping the dead code for now, but rebuilding the firmware requires
'as68k' and 'ld68k', which I do not have in hand.

Instead, the kernel.org m68k GCC [1] successfully built it.

Allowing a user to pass in CROSS_COMPILE_M68K= is handier.

[1] https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/9.2.0/x86_64-gcc-9.2.0-nolibc-m68k-linux.tar.xz

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/wan/lapbether: Added needed_headroom and a skb->len check 2020-08-19T06:16:22+00:00 Xie He xie.he.0141@gmail.com 2020-08-06T01:50:40+00:00 f6c5d9f3361af1e28cd1337e8b94c8e0adee05dc [ Upstream commit c7ca03c216acb14466a713fedf1b9f2c24994ef2 ] 1. Added a skb->len check This driver expects upper layers to include a pseudo header of 1 byte when passing down a skb for transmission. This driver will read this 1-byte header. This patch added a skb->len check before reading the header to make sure the header exists. 2. Changed to use needed_headroom instead of hard_header_len to request necessary headroom to be allocated In net/packet/af_packet.c, the function packet_snd first reserves a headroom of length (dev->hard_header_len + dev->needed_headroom). Then if the socket is a SOCK_DGRAM socket, it calls dev_hard_header, which calls dev->header_ops->create, to create the link layer header. If the socket is a SOCK_RAW socket, it "un-reserves" a headroom of length (dev->hard_header_len), and assumes the user to provide the appropriate link layer header. So according to the logic of af_packet.c, dev->hard_header_len should be the length of the header that would be created by dev->header_ops->create. However, this driver doesn't provide dev->header_ops, so logically dev->hard_header_len should be 0. So we should use dev->needed_headroom instead of dev->hard_header_len to request necessary headroom to be allocated. This change fixes kernel panic when this driver is used with AF_PACKET SOCK_RAW sockets. Call stack when panic: [ 168.399197] skbuff: skb_under_panic: text:ffffffff819d95fb len:20 put:14 head:ffff8882704c0a00 data:ffff8882704c09fd tail:0x11 end:0xc0 dev:veth0 ... [ 168.399255] Call Trace: [ 168.399259] skb_push.cold+0x14/0x24 [ 168.399262] eth_header+0x2b/0xc0 [ 168.399267] lapbeth_data_transmit+0x9a/0xb0 [lapbether] [ 168.399275] lapb_data_transmit+0x22/0x2c [lapb] [ 168.399277] lapb_transmit_buffer+0x71/0xb0 [lapb] [ 168.399279] lapb_kick+0xe3/0x1c0 [lapb] [ 168.399281] lapb_data_request+0x76/0xc0 [lapb] [ 168.399283] lapbeth_xmit+0x56/0x90 [lapbether] [ 168.399286] dev_hard_start_xmit+0x91/0x1f0 [ 168.399289] ? irq_init_percpu_irqstack+0xc0/0x100 [ 168.399291] __dev_queue_xmit+0x721/0x8e0 [ 168.399295] ? packet_parse_headers.isra.0+0xd2/0x110 [ 168.399297] dev_queue_xmit+0x10/0x20 [ 168.399298] packet_sendmsg+0xbf0/0x19b0 ...... Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Martin Schiller <ms@dev.tdt.de> Cc: Brian Norris <briannorris@chromium.org> Signed-off-by: Xie He <xie.he.0141@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit c7ca03c216acb14466a713fedf1b9f2c24994ef2 ]

1. Added a skb->len check

This driver expects upper layers to include a pseudo header of 1 byte
when passing down a skb for transmission. This driver will read this
1-byte header. This patch added a skb->len check before reading the
header to make sure the header exists.

2. Changed to use needed_headroom instead of hard_header_len to request
necessary headroom to be allocated

In net/packet/af_packet.c, the function packet_snd first reserves a
headroom of length (dev->hard_header_len + dev->needed_headroom).
Then if the socket is a SOCK_DGRAM socket, it calls dev_hard_header,
which calls dev->header_ops->create, to create the link layer header.
If the socket is a SOCK_RAW socket, it "un-reserves" a headroom of
length (dev->hard_header_len), and assumes the user to provide the
appropriate link layer header.

So according to the logic of af_packet.c, dev->hard_header_len should
be the length of the header that would be created by
dev->header_ops->create.

However, this driver doesn't provide dev->header_ops, so logically
dev->hard_header_len should be 0.

So we should use dev->needed_headroom instead of dev->hard_header_len
to request necessary headroom to be allocated.

This change fixes kernel panic when this driver is used with AF_PACKET
SOCK_RAW sockets.

Call stack when panic:

[  168.399197] skbuff: skb_under_panic: text:ffffffff819d95fb len:20
put:14 head:ffff8882704c0a00 data:ffff8882704c09fd tail:0x11 end:0xc0
dev:veth0
...
[  168.399255] Call Trace:
[  168.399259]  skb_push.cold+0x14/0x24
[  168.399262]  eth_header+0x2b/0xc0
[  168.399267]  lapbeth_data_transmit+0x9a/0xb0 [lapbether]
[  168.399275]  lapb_data_transmit+0x22/0x2c [lapb]
[  168.399277]  lapb_transmit_buffer+0x71/0xb0 [lapb]
[  168.399279]  lapb_kick+0xe3/0x1c0 [lapb]
[  168.399281]  lapb_data_request+0x76/0xc0 [lapb]
[  168.399283]  lapbeth_xmit+0x56/0x90 [lapbether]
[  168.399286]  dev_hard_start_xmit+0x91/0x1f0
[  168.399289]  ? irq_init_percpu_irqstack+0xc0/0x100
[  168.399291]  __dev_queue_xmit+0x721/0x8e0
[  168.399295]  ? packet_parse_headers.isra.0+0xd2/0x110
[  168.399297]  dev_queue_xmit+0x10/0x20
[  168.399298]  packet_sendmsg+0xbf0/0x19b0
......

Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Cc: Brian Norris <briannorris@chromium.org>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>