OpenSSL 3 FIPS on iOS

pauli at pauli at
Thu Feb 3 06:38:47 UTC 2022

The FIPS provider will likely not work with iOS as it currently stands.

The development team are not up to speed on iOS and not much effort was 
put into supporting it (or Android for the same reason).  We didn't even 
get remotely close to having code signed.

Paul Dale

On 27/1/22 4:41 am, Kevin Millson wrote:
> Hello All,
> Has anyone tried using the FIPS provider on iOS and got it uploaded 
> and successfully reviewed by Apple?
> Apple won't let you just put the 'fips.dylib' in your app's bundle so 
> we've wrapped it in a iOS Framework Bundle, which solves some of the 
> problems. But Apple are scanning the dylib's mach-o header and finding 
> the type bit field set to 'bundle' rather than 'execute' and rejecting 
> it. I think they might also be looking for particular load commands in 
> the header and not finding them either. I guess changes to the FIPS 
> build process are required to effect any change to the file header?
> The Framework Bundle must be signed, as every iOS executable must be, 
> so this has to be done before the FIPS Configuration is created via 
> FIPS Install. If you try to perform these operations in the reverse 
> order, i.e. create configuration and then sign, then the values within 
> the configuration won't match the calculated values when the FIPS 
> Provider subsequently loads and runs. I haven't examined the 
> implementation of FIPS Install but I suspect it's not just examining 
> the mach-o segment with the executable code in it and is instead 
> detecting any change, i.e. also header changes as a result of iOS 
> signing. Currently we create configurations for all our signing 
> scenarios and then ensure individual FIPS frameworks are not re-signed 
> at any point subsequently. Sign for App Store Distribution remains 
> troublesome though and what if Apple re-sign the app and consequently 
> the FIPS framework? Failure to load the FIPS Provider would then result.
> So we're unsure how OpenSSL 3 FIPS can be deployed within iOS apps 
> from the Apple App Store. Would be great to hear whether anyone else 
> has got this working and through an Apple app review.
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