[syslinux] Kernel Image CRC checking

H. Peter Anvin hpa at zytor.com
Fri Jun 7 22:25:00 PDT 2019

On 6/7/19 10:19 PM, H. Peter Anvin via Syslinux wrote:
>> It doesn't appear so.  I'm assuming you're referring to the CRC32
>> present in Linux x86 boot protocol 2.08+ found in Linux versions
>> 2.6.26+ ?  libupload has a CRC-16 function.  zlib has a CRC-32
>> function but looks like it's initialized with different
>> polynomial/remainder.
> Writing a generic CRC generator is not very hard; for a boot loader it makes
> sense to compute the tables at runtime anyway, so it isn't a hard thing to do.
> However, the CRC polynomial for zlib and the Linux kernel should both be the
> same: 0x04c11db7.

I just double-checked, and the CRC tables are indeed identical. I was pretty
sure, because I wrote that code a long time ago...


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