Brief items
Security
Control Flow Integrity in the Android kernel (Android Developers)
The Android Developers Blog describes the control-flow integrity work that is shipping on the Pixel 3 handset. "LLVM's CFI implementation adds a check before each indirect branch to confirm that the target address points to a valid function with a correct signature. This prevents an indirect branch from jumping to an arbitrary code location and even limits the functions that can be called. As C compilers do not enforce similar restrictions on indirect branches, there were several CFI violations due to function type declaration mismatches even in the core kernel that we have addressed in our CFI patch sets for kernels 4.9 and 4.14."
Security quotes of the week
During the ensuing top-secret probe, which remains open more than three years later, investigators determined that the chips allowed the attackers to create a stealth doorway into any network that included the altered machines. Multiple people familiar with the matter say investigators found that the chips had been inserted at factories run by manufacturing subcontractors in China.
This attack was something graver than the software-based incidents the world has grown accustomed to seeing. Hardware hacks are more difficult to pull off and potentially more devastating, promising the kind of long-term, stealth access that spy agencies are willing to invest millions of dollars and many years to get.
Like it or not, the vast majority of electronics are made in China, and this is unlikely to change anytime soon. The central issue is that we don't have any other choice right now. The reason is that by nearly all accounts it would be punishingly expensive to replicate that manufacturing process here in the United States.
Even if the U.S. government and Silicon Valley somehow mustered the funding and political will to do that, insisting that products sold to U.S. consumers or the U.S. government be made only with components made here in the U.S.A. would massively drive up the cost of all forms of technology. Consumers would almost certainly balk at buying these way more expensive devices. Years of experience has shown that consumers aren't interested in paying a huge premium for security when a comparable product with the features they want is available much more cheaply.
Kernel development
Kernel release status
The current development kernel is 4.19-rc7, released on October 7. "Given the current rate of change, and looking at the travel/conference schedule happening this month, it seems like we will be having a -rc8 just to be sure 4.19 is solid as well as not having to be in the middle of a merge window during a conference week".
Stable updates: 4.18.12, 4.14.74, and 4.9.131 were released on October 4, followed by 4.18.13, 4.14.75, 4.9.132, and 4.4.160 on October 10.
Amit: How new-lines affect the Linux kernel performance
Nadav Amit decided to dig into why some small kernel functions were not being inlined by GCC; the result is a detailed investigation into how these things can go wrong. "Ignoring the assembly shenanigans that this code uses, we can see that in practice it generates a single ud2 instruction. However, the compiler considers this code to be 'big' and consequently oftentimes does not inline functions that use WARN() or similar functions. The reason turns to be the newline characters (marked as '\n' above). The kernel compiler, GCC, is unaware to the code size that will be generated by the inline assembly. It therefore tries to estimate its size based on newline characters and statement separators (';' on x86)."
Gregg: bpftrace (DTrace 2.0) for Linux 2018
Brendan Gregg introduces the bpftrace tracing tool. "bpftrace was created as an even higher-level front end for custom ad-hoc tracing, and can serve a similar role as DTrace. We've been adding bpftrace features as we need them, not just because DTrace had them. I can think of over a dozen things that DTrace can do that bpftrace currently cannot, including custom aggregation printing, shell arguments, translators, sizeof(), speculative tracing, and forced panics".
Distributions
Distribution quotes of the week
Development
Development quotes of the week
Miscellaneous
Microsoft joins LOT Network, helping protect developers against patent assertions
Microsoft has announced that it has joined the LOT Network, which is an organization set up to help thwart patent trolls by licensing any member's patents to all members if they end up in the hands of a troll. "What does all of this mean for you if you’re a software developer or in the technology business? It means that Microsoft is taking another step to help stop patents from being asserted against you by companies running aggressive monetization campaigns. It also means that Microsoft is aligning with other industry leaders on this topic and committing to do more in the future to address IP risk. By joining the LOT network, we are committing to license our patents for free to other members if we ever transfer them to companies in the business of asserting patents. This pledge has immediate value to the nearly 300 members of the LOT community today, which covers approximately 1.35 million patents."
Microsoft joins Open Invention Network
Microsoft has announced that it has joined the Open Invention Network (OIN). "We know Microsoft’s decision to join OIN may be viewed as surprising to some, as it is no secret that there has been friction in the past between Microsoft and the open source community over the issue of patents. For others who have followed our evolution as a company, we hope this will be viewed as the next logical step for a company that is listening to its customers and is firmly committed to Linux and other open source programs."
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