Will these Snow Leopard security bits work for 32 kernel?

[Schtibbie]

Apple's site about Snow Leopard says that 64-bit *apps* under Snow Leopard will be more secure than ever due to several things:

• A more secure function argument-passing mechanism and the use of hardware-based execute disable for heap memory.
• Memory on the system heap is marked using strengthened checksums, helping to prevent attacks that rely on corrupting memory.

Nerdly question, but does anyone know if any of these types of security enhancements require the 64-bit *kernel* (not just a given app)? My white Macbook (C2duo) is unlikely to run 64-bit unless Apple lets it in their final release (it apparently won't so far as they haven't written drivers for my lowly machine).

 

[MikhailT]

Apple's site about Snow Leopard says that 64-bit *apps* under Snow Leopard will be more secure than ever due to several things:

• A more secure function argument-passing mechanism and the use of hardware-based execute disable for heap memory.
• Memory on the system heap is marked using strengthened checksums, helping to prevent attacks that rely on corrupting memory.

Nerdly question, but does anyone know if any of these types of security enhancements require the 64-bit *kernel* (not just a given app)? My white Macbook (C2duo) is unlikely to run 64-bit unless Apple lets it in their final release (it apparently won't so far as they haven't written drivers for my lowly machine).

The first one is using the XD bit which only works in pure 64 bit long mode and the second one is probably due to using wider 64bit checksum calcs, so it probably won't work in 32 bit kernel unless Apple emulates it for the 32bit kernel which is possible.

Are you referring to the Intel X3100 graphic cards? I suggest wait until the final release to find out because x3100 has mixed of 32bit/64bit code, just not 64bit full. Apple is 2 full months ahead in coding than any of our leaked seeds.

 

[Schtibbie]

The first one is using the XD bit which only works in pure 64 bit long mode and the second one is probably due to using wider 64bit checksum calcs, so it probably won't work in 32 bit kernel unless Apple emulates it for the 32bit kernel which is possible.

Are you referring to the Intel X3100 graphic cards? I suggest wait until the final release to find out because x3100 has mixed of 32bit/64bit code, just not 64bit full. Apple is 2 full months ahead in coding than any of our leaked seeds.

My Macbook only has the GMA950. And someone on another thread tried to convince me that 64-bit kernel would only affect >4gigs ram (which my laptop can't have anyway). Of course, I suspect I'll lose the security features I mentioned if the final release of SL doesn't fully support "old" 64-bit laptops like mine.

 

[MikhailT]

My Macbook only has the GMA950. And someone on another thread tried to convince me that 64-bit kernel would only affect >4gigs ram (which my laptop can't have anyway). Of course, I suspect I'll lose the security features I mentioned if the final release of SL doesn't fully support "old" 64-bit laptops like mine.

Actually, it's 3.2GB, not 4GB limit for 32bit but either way, even if you can't run SL in 64bit, the 32bit is fast anyway. You will still get the benefits of GCD and so many other minor changes and can still run 64bit applications, so you're not going to miss out on SL optimized applications.