title: Concept of verifying U-boot image from kernel booting
body: <p>If you know u-boot verified boot, it will easy to understand my idea and question. You may read from here - 
  <a href="http://git.denx.de/?p=u-boot.git;a=blob;f=doc/uImage.FIT/verified-boot.txt;h=e639e7ae71a1e6bbe0f421630959369ec15fcf3a;hb=HEAD" rel="nofollow">http://git.denx.de/?p=u-boot.git;a=blob;f=doc/uImage.FIT/verified-boot.txt;h=e639e7ae71a1e6bbe0f421630959369ec15fcf3a;hb=HEAD</a></p>
  
  <p>In verified boot scenario, u-boot read and compare the kernel and other (e.g. dtb) binary's hash value and allow those binary to execute, if hash value matched (through FIT image). But, if you can replace the u-boot binary with the one that is not implemented with verified boot functionality, you can overcome the hash value checking facility and able to boot the same kernel image.</p>
  
  <p>So, my idea is - whether is it possible to check the u-boot image from kernel while booting?</p>
  
  <p>I was reading, that reading a file from from kernel is a bad idea and risky. But I also read that using /proc or other feature it is possible to have IO operations from kernel space.</p>
  
  <p>Would like to have an expert suggestion, whether my idea of verifying u-boot from kernel may possible? And, if yes - some guideline.</p>
  
  <p>Thanks.</p>