GCC Format Security

Installing and Using OpenWrt
1

I have enabled the GCC Format Security feature in the menuconfig and manage to successfully make compilation. How do I check whether the GCC format security is active and able to protect the router from buffer overflow attack? Is there any tools that I could use to check?

2

Add a couple of lines with a vulnerability to some arbitrary .c file that you know gets compiled? There are some examples that should trigger the warning at https://fedoraproject.org/wiki/Format-Security-FAQ, seems like it could be as simple as this...

char foo[10240];
scanf("%s", foo);
printf(foo); /* Bzzzt! */
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