On 02/01/2014, Patrick Georgi patrick@georgi-clan.de wrote:
Am 02.01.2014 21:31, schrieb Sam Kuper: Here we have one vendor, and the files are typically not transferrable across chip versions, so they can create a new key for every version, limiting the impact.
If I remember things correctly, Intel uses RSA-2048 signatures on a SHA256 hash. The capability to crack such a scheme probably provides more lucrative opportunities than firmware freedom and that makes me guess people would routinely do it, if possible.
Agreed, although the work by Molina and Arbaugh, and by Ben Hawkes, has started some little inroads towards perhaps eventually unpicking the microcode.
How about simply refusing to pay for malfeatures like these instead of increasing the platform's value for vendors that absolutely don't want you to do it for them (as expressed by both their conduct and their signature scheme)?
I'm actively researching alternatives, but because there's no perfect solution, I have to strike a balance between the freedom I want and the features/compatibility I want.
My earlier question about the Acer C7/C710 and HP Pavilion 14 was motivated by the following consideration: if they have not been found to have CPU errata warranting uploading of CPU microcode, then they might be (at least in this respect) preferable to the X60 which forces the user to choose between uploading microcode or running with known vulnerabilities.*
Regards,
Sam
* Yes, there's debate about the seriousness of some of these vulnerabilities[1][2]; and yes, Linus did downplay them[3], but I think he downplayed them on the assumption that users *would* use the microcode patches to handle those needing microcode patches[4] and that kernels and compilers would be checked, and updated if necessary, to handle the rest.
[1] http://hardware.slashdot.org/story/07/06/28/1124256/theo-de-raadt-details-in... [2] http://www.cs.dartmouth.edu/~sergey/cs258/2010/D2T1%20-%20Kris%20Kaspersky%2... [3] http://www.realworldtech.com/forum/?threadid=78455&curpostid=78469 [4] http://www.realworldtech.com/forum/?threadid=78455&curpostid=78477