Re: [PATCH v3] ipmi_si: fix use-after-free of resource->name

[Corey Minyard <minyard@acm.org>]

On Mon, Jan 28, 2019 at 11:08:54AM +0800, Yang Yingliang wrote:
> When we excute the following commands, we got oops
> rmmod ipmi_si
> cat /proc/ioports
> 

snip..

> 
> If io_setup is called successful in try_smi_init() but try_smi_init()
> goes out_err before calling ipmi_register_smi(), so ipmi_unregister_smi()
> will not be called while removing module. It leads to the resource that
> allocated in io_setup() can not be freed, but the name(DEVICE_NAME) of
> resource is freed while removing the module. It causes use-after-free
> when cat /proc/ioports.
> 
> Fix this by calling io_cleanup() while try_smi_init() goes to out_err.
> and don't call io_cleanup() until io_setup() returns successful to avoid
> warning prints.

Thanks a bunch for working on this.  Fix is in my next tree now, if it
is stable in there then I will send up to Linus.

-corey

> 
> Fixes: 93c303d2045b ("ipmi_si: Clean up shutdown a bit")
> Cc: stable@vger.kernel.org
> Reported-by: NuoHan Qiao <qiaonuohan@huawei.com>
> Suggested-by: Corey Minyard <cminyard@mvista.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/char/ipmi/ipmi_si_intf.c    | 5 +++++
>  drivers/char/ipmi/ipmi_si_mem_io.c  | 5 +++--
>  drivers/char/ipmi/ipmi_si_port_io.c | 5 +++--
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
> index dc8603d..f1b9fda 100644
> --- a/drivers/char/ipmi/ipmi_si_intf.c
> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> @@ -2085,6 +2085,11 @@ static int try_smi_init(struct smi_info *new_smi)
>  	WARN_ON(new_smi->io.dev->init_name != NULL);
>  
>   out_err:
> +	if (rv && new_smi->io.io_cleanup) {
> +		new_smi->io.io_cleanup(&new_smi->io);
> +		new_smi->io.io_cleanup = NULL;
> +	}
> +
>  	kfree(init_name);
>  	return rv;
>  }
> diff --git a/drivers/char/ipmi/ipmi_si_mem_io.c b/drivers/char/ipmi/ipmi_si_mem_io.c
> index fd0ec8d..7558361 100644
> --- a/drivers/char/ipmi/ipmi_si_mem_io.c
> +++ b/drivers/char/ipmi/ipmi_si_mem_io.c
> @@ -81,8 +81,6 @@ int ipmi_si_mem_setup(struct si_sm_io *io)
>  	if (!addr)
>  		return -ENODEV;
>  
> -	io->io_cleanup = mem_cleanup;
> -
>  	/*
>  	 * Figure out the actual readb/readw/readl/etc routine to use based
>  	 * upon the register size.
> @@ -141,5 +139,8 @@ int ipmi_si_mem_setup(struct si_sm_io *io)
>  		mem_region_cleanup(io, io->io_size);
>  		return -EIO;
>  	}
> +
> +	io->io_cleanup = mem_cleanup;
> +
>  	return 0;
>  }
> diff --git a/drivers/char/ipmi/ipmi_si_port_io.c b/drivers/char/ipmi/ipmi_si_port_io.c
> index ef6dffc..03924c3 100644
> --- a/drivers/char/ipmi/ipmi_si_port_io.c
> +++ b/drivers/char/ipmi/ipmi_si_port_io.c
> @@ -68,8 +68,6 @@ int ipmi_si_port_setup(struct si_sm_io *io)
>  	if (!addr)
>  		return -ENODEV;
>  
> -	io->io_cleanup = port_cleanup;
> -
>  	/*
>  	 * Figure out the actual inb/inw/inl/etc routine to use based
>  	 * upon the register size.
> @@ -109,5 +107,8 @@ int ipmi_si_port_setup(struct si_sm_io *io)
>  			return -EIO;
>  		}
>  	}
> +
> +	io->io_cleanup = port_cleanup;
> +
>  	return 0;
>  }
> -- 
> 1.8.3
> 
>