[nativeaot] Disable FEATURE_READOLY_GS_COOKIE on macOS

[lambdageek]

It's already disabled on ios, tvos and catalyst.

Fixes #99172

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Issue Details

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It's already disabled on ios, tvos and catalyst.

Fixes #99172

Author:	lambdageek
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[filipnavara]

This is not going to make things worse, so let’s make the change. That said, are we supposed to mess with the value of __security_cookie as a shared library? I thought it’s per process and this feels weird. I am no expert though, so I would be happy to hear some explanation why is it fine.

[lambdageek]

That said, are we supposed to mess with the value of __security_cookie as a shared library? I thought it’s a per process and this feels weird.

In a NativeAOT shared library __security_cookie ends up as a private symbol in __DATA_CONST,__const (the source code says __DATA,__const but OSX ld helpfully moves that segment to __DATA_CONST,__const - see Xcode11 Release Notes). And ILCompiler directly references it from the generated code.

If you have multiple NativeAOT libraries in a process, they each have their own cookie.