Re: [syzbot] [wireless?] memory leak in hwsim_new_radio_nl

[shaozhengchao <shaozhengchao@huawei.com>]

On 2023/5/13 4:34, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    105131df9c3b Merge tag 'dt-fixes-6.4' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1193dc92280000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=fa9562c0bfb72fa2
> dashboard link: https://syzkaller.appspot.com/bug?extid=904ce6fbb38532d9795c
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10b4577c280000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14a9e29e280000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/029c9c553eb9/disk-105131df.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/c807843227d1/vmlinux-105131df.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/dfce3441d47b/bzImage-105131df.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+904ce6fbb38532d9795c@syzkaller.appspotmail.com
> 
> Warning: Permanently added '10.128.1.177' (ECDSA) to the list of known hosts.
> executing program
> executing program
> BUG: memory leak
> unreferenced object 0xffff88810e2ac920 (size 32):
>    comm "syz-executor238", pid 4983, jiffies 4294944120 (age 14.000s)
>    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:
>      [<ffffffff815458a4>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1057
>      [<ffffffff830fc4fb>] kmalloc include/linux/slab.h:559 [inline]
>      [<ffffffff830fc4fb>] hwsim_new_radio_nl+0x43b/0x660 drivers/net/wireless/virtual/mac80211_hwsim.c:5962
>      [<ffffffff83f4aa6e>] genl_family_rcv_msg_doit.isra.0+0xee/0x150 net/netlink/genetlink.c:968
>      [<ffffffff83f4ada7>] genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>      [<ffffffff83f4ada7>] genl_rcv_msg+0x2d7/0x430 net/netlink/genetlink.c:1065
>      [<ffffffff83f49111>] netlink_rcv_skb+0x91/0x1e0 net/netlink/af_netlink.c:2546
>      [<ffffffff83f4a118>] genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076
>      [<ffffffff83f4805b>] netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
>      [<ffffffff83f4805b>] netlink_unicast+0x39b/0x4d0 net/netlink/af_netlink.c:1365
>      [<ffffffff83f4852a>] netlink_sendmsg+0x39a/0x720 net/netlink/af_netlink.c:1913
>      [<ffffffff83db5258>] sock_sendmsg_nosec net/socket.c:724 [inline]
>      [<ffffffff83db5258>] sock_sendmsg+0x58/0xb0 net/socket.c:747
>      [<ffffffff83db5817>] ____sys_sendmsg+0x397/0x430 net/socket.c:2503
>      [<ffffffff83db9e08>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2557
>      [<ffffffff83db9fac>] __sys_sendmsg+0x8c/0x100 net/socket.c:2586
>      [<ffffffff84a127b9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>      [<ffffffff84a127b9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>      [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> BUG: memory leak
> unreferenced object 0xffff88810e2ac800 (size 32):
>    comm "syz-executor238", pid 4984, jiffies 4294944700 (age 8.200s)
>    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:
>      [<ffffffff815458a4>] kmalloc_trace+0x24/0x90 mm/slab_common.c:1057
>      [<ffffffff830fc4fb>] kmalloc include/linux/slab.h:559 [inline]
>      [<ffffffff830fc4fb>] hwsim_new_radio_nl+0x43b/0x660 drivers/net/wireless/virtual/mac80211_hwsim.c:5962
>      [<ffffffff83f4aa6e>] genl_family_rcv_msg_doit.isra.0+0xee/0x150 net/netlink/genetlink.c:968
>      [<ffffffff83f4ada7>] genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>      [<ffffffff83f4ada7>] genl_rcv_msg+0x2d7/0x430 net/netlink/genetlink.c:1065
>      [<ffffffff83f49111>] netlink_rcv_skb+0x91/0x1e0 net/netlink/af_netlink.c:2546
>      [<ffffffff83f4a118>] genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076
>      [<ffffffff83f4805b>] netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
>      [<ffffffff83f4805b>] netlink_unicast+0x39b/0x4d0 net/netlink/af_netlink.c:1365
>      [<ffffffff83f4852a>] netlink_sendmsg+0x39a/0x720 net/netlink/af_netlink.c:1913
>      [<ffffffff83db5258>] sock_sendmsg_nosec net/socket.c:724 [inline]
>      [<ffffffff83db5258>] sock_sendmsg+0x58/0xb0 net/socket.c:747
>      [<ffffffff83db5817>] ____sys_sendmsg+0x397/0x430 net/socket.c:2503
>      [<ffffffff83db9e08>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2557
>      [<ffffffff83db9fac>] __sys_sendmsg+0x8c/0x100 net/socket.c:2586
>      [<ffffffff84a127b9>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>      [<ffffffff84a127b9>] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>      [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> 
> 
> ---
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> 

This issue is introduced by 92d13386ec55 ("mac80211_hwsim: add PMSR
capability support")
When parse_pmsr_capa failed in hwsim_new_radio_nl, the memory resources
applied for by pmsr_capa are not released. It should replace
param.pmsr_capa with pmsr_capa to release memory.

I will fix it today.

Zhengchao Shao