Re: [PATCH v2] net: qrtr: fix null-ptr-deref in qrtr_ns_remove

[David Miller]

From: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
Date: Tue, 5 Jan 2021 13:57:54 +0800

> A null-ptr-deref bug is reported by Hulk Robot like this:
> --------------
> KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]
> Call Trace:
> qrtr_ns_remove+0x22/0x40 [ns]
> qrtr_proto_fini+0xa/0x31 [qrtr]
> __x64_sys_delete_module+0x337/0x4e0
> do_syscall_64+0x34/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x468ded
> --------------
> 
> When qrtr_ns_init fails in qrtr_proto_init, qrtr_ns_remove which would
> be called later on would raise a null-ptr-deref because qrtr_ns.workqueue
> has been destroyed.
> 
> Fix it by making qrtr_ns_init have a return value and adding a check in
> qrtr_proto_init.
> 
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
> ---
> v1->v2: remove redundant braces for single statement blocks.

Applied.