nfc: virtual_ncidev: Add variable to check if ndev is running

syzbot reported an memory leak that happens when an skb is add to
send_buff after virtual nci closed.
This patch adds a variable to track if the ndev is running before
handling new skb in send function.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Reported-by: syzbot+6eb09d75211863f15e3e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/00000000000075472b06007df4fb@google.com
Reviewed-by: Bongsu Jeon
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: virtual_ncidev: Use module_misc_device macro to simplify the code

Use the module_misc_device macro to simplify the code, which is the
same as declaring with module_init() and module_exit().

Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

NFC: nci: Allow to create multiple virtual nci devices

The current virtual nci driver is great for testing and fuzzing.
But it allows to create at most one "global" device which does not allow
to run parallel tests and harms fuzzing isolation and reproducibility.
Restructure the driver to allow creation of multiple independent devices.
This should be backwards compatible for existing tests.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Cc: Bongsu Jeon <bongsu.jeon@samsung.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20221115100017.787929-1-dvyukov@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

nfc: virtual_ncidev: Fix memory leak in virtual_nci_send()

skb should be free in virtual_nci_send(), otherwise kmemleak will report
memleak.

Steps for reproduction (simulated in qemu):
cd tools/testing/selftests/nci
make
./nci_dev

BUG: memory leak
unreferenced object 0xffff888107588000 (size 208):
comm "nci_dev", pid 206, jiffies 4294945376 (age 368.248s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000008d94c8fd>] __alloc_skb+0x1da/0x290
[<00000000278bc7f8>] nci_send_cmd+0xa3/0x350
[<0000000081256a22>] nci_reset_req+0x6b/0xa0
[<000000009e721112>] __nci_request+0x90/0x250
[<000000005d556e59>] nci_dev_up+0x217/0x5b0
[<00000000e618ce62>] nfc_dev_up+0x114/0x220
[<00000000981e226b>] nfc_genl_dev_up+0x94/0xe0
[<000000009bb03517>] genl_family_rcv_msg_doit.isra.14+0x228/0x2d0
[<00000000b7f8c101>] genl_rcv_msg+0x35c/0x640
[<00000000c94075ff>] netlink_rcv_skb+0x11e/0x350
[<00000000440cfb1e>] genl_rcv+0x24/0x40
[<0000000062593b40>] netlink_unicast+0x43f/0x640
[<000000001d0b13cc>] netlink_sendmsg+0x73a/0xbf0
[<000000003272487f>] __sys_sendto+0x324/0x370
[<00000000ef9f1747>] __x64_sys_sendto+0xdd/0x1b0
[<000000001e437841>] do_syscall_64+0x3f/0x90

Fixes: e624e6c3e777 ("nfc: Add a virtual nci device driver")
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221020030505.15572-1-shangxiaojing@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

nfc: virtual_ncidev: change default device permissions

Device permissions is S_IALLUGO, with many unnecessary bits. Remove them
and also remove read and write permissions from group and others.

Before the change:
crwsrwsrwt 1 0 0 10, 125 Nov 25 13:59 /dev/virtual_nci

After the change:
crw------- 1 0 0 10, 125 Nov 25 14:05 /dev/virtual_nci

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Link: https://lore.kernel.org/r/20211125141457.716921-1-cascardo@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

nfc: virtual_ncidev: Use wait queue instead of polling

In previous version, the user level virtual device application that used
this driver should have the polling scheme to read a NCI frame.
To remove this polling scheme, use Wait Queue.

Signed-off-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: virtual_ncidev: constify pointer to nfc_dev

virtual_ncidev_ioctl() does not modify struct nfc_dev, so local variable
can be a pointer to const.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: constify nci_ops

The struct nci_ops is modified by NFC core in only one case:
nci_allocate_device() receives too many proprietary commands (prop_ops)
to configure. This is a build time known constrain, so a graceful
handling of such case is not necessary.

Instead, fail the nci_allocate_device() and add BUILD_BUG_ON() to places
which set these.

This allows to constify the struct nci_ops (consisting of function
pointers) for correctness and safety.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: Add a virtual nci device driver

NCI virtual device simulates a NCI device to the user. It can be used to
validate the NCI module and applications. This driver supports
communication between the virtual NCI device and NCI module.

Signed-off-by: Bongsu Jeon <bongsu.jeon@samsung.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>