Messages in this thread | | | Date | Mon, 22 Feb 2010 15:37:00 +0800 | Subject | Re: [PATCH] module param_call: fix potential NULL pointer dereference | From | Américo Wang <> |
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On Sun, Feb 21, 2010 at 5:16 PM, DDD <dongdong.deng@windriver.com> wrote: > Américo Wang wrote: >> >> On Sun, Feb 21, 2010 at 3:24 PM, Dongdong Deng >> <dongdong.deng@windriver.com> wrote: >>> >>> The param_set_fn() function will get a parameter which is a NULL >>> pointer when insmod module with params via following method: >>> >>> $insmod module.ko module_params >>> >>> BTW: the normal method usually as following format: >>> $insmod module.ko module_params=example >>> >>> If the param_set_fn() function didn't check that parameter and used >>> it directly, it could caused an OOPS due to NULL pointer dereference. >>> >>> The solution is simple: >>> Just checking the parameter before using in param_set_fn(). >>> >>> Example: >>> int set_module_params(const char *val, struct kernel_param *kp) >>> { >>> /*Checking the val parameter before using */ >>> if (!val) >>> return -EINVAL; >>> ... >>> } >>> module_param_call(module_params, set_module_params, NULL, NULL, 0644); >>> >> >> Why not just checking all of them in the generic code? > > It is no problem that we check the params before invoking param_set_fn(). > > But I trend to do the checking in param_set_*fn(), because we can offer some > special prompt infos to user if we want and handle some special cases like > param_set_bool(). >
Yeah, I knew standard bool parameters can accept that, the problem is that KPARAM_ISBOOL is not enough to check if a parameter is bool or not. Probably we need a new flag...
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