A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 02:32:09 -04:00
Code Issues Projects Releases Packages Wiki Activity

Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()

Browse source 
Some usermode helper applications are defined at kernel build time, while
others can be changed at runtime.  To provide a sane way to filter these, add a
new kernel option "STATIC_USERMODEHELPER".  This option routes all
call_usermodehelper() calls through this binary, no matter what the caller
wishes to have called.

The new binary (by default set to /sbin/usermode-helper, but can be changed
through the STATIC_USERMODEHELPER_PATH option) can properly filter the
requested programs to be run by the kernel by looking at the first argument
that is passed to it.  All other options should then be passed onto the proper
program if so desired.

To disable all call_usermodehelper() calls by the kernel, set
STATIC_USERMODEHELPER_PATH to an empty string.

Thanks to Neil Brown for the idea of this feature.

Cc: NeilBrown <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Greg Kroah-Hartman 2017-01-16 16:22:39 +01:00
commit 64e90a8acb
2 changed files with 49 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

14
kernel/kmod.c
View file

@ -528,7 +528,12 @@ struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
goto out;
INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
#ifdef CONFIG_STATIC_USERMODEHELPER
sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;
#else
sub_info->path = path;
#endif
sub_info->argv = argv;
sub_info->envp = envp;
@ -566,6 +571,15 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
retval = -EBUSY;
goto out;
}
/*
* If there is no binary for us to call, then just return and get out of
* here. This allows us to set STATIC_USERMODEHELPER_PATH to "" and
* disable all call_usermodehelper() calls.
*/
if (strlen(sub_info->path) == 0)
goto out;
/*
* Set the completion pointer only if there is a waiter.
* This makes it possible to use umh_complete to free