CVE-2021-47237

In the Linux kernel, the following vulnerability has been resolved: net:
hamradio: fix memory leak in mkiss_close My local syzbot instance hit
memory leak in mkiss_open()[1]. The problem was in missing free_netdev() in
mkiss_close(). In mkiss_open() netdevice is allocated and then registered,
but in mkiss_close() netdevice was only unregistered, but not freed. Fail
log: BUG: memory leak unreferenced object 0xffff8880281ba000 (size 4096):
comm “syz-executor.1”, pid 11443, jiffies 4295046091 (age 17.660s) hex dump
(first 32 bytes): 61 78 30 00 00 00 00 00 00 00 00 00 00 00 00 00
ax0… 00 27 fa 2a 80 88 ff ff 00 00 00 00 00 00 00 00
.'.*… backtrace: [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0
[<ffffffff8706e7e8>] alloc_netdev_mqs+0x98/0xe80 [<ffffffff84e64192>]
mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110
[<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>]
tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200
[<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>]
entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced
object 0xffff8880141a9a00 (size 96): comm “syz-executor.1”, pid 11443,
jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): e8 a2 1b 28 80
88 ff ff e8 a2 1b 28 80 88 ff ff …(…(… 98 92 9c aa b0 40 02 00
00 00 00 00 00 00 00 00 …@… backtrace: [<ffffffff8709f68b>]
__hw_addr_create_ex+0x5b/0x310 [<ffffffff8709fb38>]
__hw_addr_add_ex+0x1f8/0x2b0 [<ffffffff870a0c7b>] dev_addr_init+0x10b/0x1f0
[<ffffffff8706e88b>] alloc_netdev_mqs+0x13b/0xe80 [<ffffffff84e64192>]
mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110
[<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>]
tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200
[<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>]
entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced
object 0xffff8880219bfc00 (size 512): comm “syz-executor.1”, pid 11443,
jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): 00 a0 1b 28 80
88 ff ff 80 8f b1 8d ff ff ff ff …(… 80 8f b1 8d ff ff ff ff
00 00 00 00 00 00 00 00 … backtrace: [<ffffffff81a27201>]
kvmalloc_node+0x61/0xf0 [<ffffffff8706eec7>] alloc_netdev_mqs+0x777/0xe80
[<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>]
tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670
[<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>]
__x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0
[<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory
leak unreferenced object 0xffff888029b2b200 (size 256): comm
“syz-executor.1”, pid 11443, jiffies 4295046091 (age 17.660s) 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: [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0
[<ffffffff8706f062>] alloc_netdev_mqs+0x912/0xe80 [<ffffffff84e64192>]
mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110
[<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>]
tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200
[<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>]
entry_SYSCALL_64_after_hwframe+0x44/0xae