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Google To Auto-Migrate Some Users To 64-bit Chrome
Google says it will automatically upgrade the version of Chrome that some Windows users are running, in what it describes as a bet to improve stability, performance, and security. From a report on ZDNet: In a blog post on Tuesday, the search engine giant explained that Chrome users running 64-bit Windows with 4GB or more of memory will be automatically migrated to the 64-bit version of Chrome if they are running the 32-bit version.
what a load of crap.
Chrome is Chrome is Chrome. Moving to 64 bit makes sense simply because of memory management issue. My current Chrome usage of RAM is well over 4 GB (lots of windows open), and I suspect that most people are using way more RAM than they think.
Agent K: A *person* is smart. People are dumb, stupid, panicky animals, and you know it.
Google says it will automatically upgrade the version of Chrome that some Windows users are running, in what it describes as a bet to improve stability, performance, and security.
In other news, Google will automatically search for results that it considers relevant, regardless of what you type in the search bar, in what it describes as a bet to improve quality of searches.
(I know on average they are right and users can't spell, but I find it really annoying when my perfectly correct search term is changed to something more common automatically)
and I suspect that most people are using way more RAM than they think.
I agree, but I think you mean that Chrome is using way more RAM than a sane person would expect.
I just opened a tab listing folders on a web server (5 files and 5 directories, no index.html). According to Chrome task manager, this tab is taking 18.94 MB! That's for 10 lines of text and white background all around.
Not loading 32 bit shared objects to support Chrome could result in less memory use.
ACKCHYUALLY,
Each Chrome tab is limited to 4GB, even in 64-bit. "For security reasons."
And I've hit the limit before. Scrolling endless webpages is an easy way to hit the limit. Also, some addons like AdBlock use up a lot of memory.
Address space layout randomization. To make it harder for buffer-related exploits to actually start executing arbitrary code, the memory pages get shuffled around at startup so all the memory addresses are different each time. This still works with a 32-bit address space but there's less total space to use, so with some brute force (eg. really long NOP slides) you can overcome ASLR. With a 64-bit address space, odds are a random jump won't even hit a valid memory address.
What does 32 vs 64 bit have to do with security? I'm genuinely curious...
What is has to do is that the architecture that brought 64bits (AMD64), also brought several security features (like NX bit) among others.
32bits software might be targeting architecture that predate the NX bit (e.g.: if you still have an old 32bits .EXE that dates back from the Pentium 4 era, it might be writing to and executing from the same memory area), and perhaps Windows could theoretically not enable NX for 32bits legacy software on these grounds? (to avoid to break old 32bits software ?)
By accelerating the deprecation of 32bits software, they might try to deprecate the non-NX software ?
(That is pure speculation on my part. I have not enough experience with Windows)
(register vs. stack pressure is also different between the 2 architecture. AMD64, in addition to 64bits, also brought twice the number of registers. meaning that more things can be kept on CPU and less needs to be written to the stack. Which could mean less potential candidate in case of stack smashing exploit. But I'm really going on a limb here. Return address is way more interesting to abuse in this case than register value.
It's definitely less probable reason than NX).
I doubt that software would be affected easily by any other difference between the two
(e.g.: warp around at different values, 0x7fffffff vs. 0x7fffffffffffffff
That is highly unlikely : win64 is a LLP64 platform - all integers are still 32bits (both int and long), unless explicitely required (long long, hence the LL) and thus all value still wrap similarily between same source code software compiled for 32bits and 64bits.
only pointers are promoted to 64bits (hence the P) and thus only point math would wrap differently)
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