Hi Egor, Am 20.08.2016 23:42 schrieb "Egor Pugin" <egor.pu...@gmail.com>: > You are right at many points. It's hard to really secure the system > from build system/build artifacts/3rd party apps. > But step by step it's possible to decrease number of potential sources > of vulnerabilities.
Retrofitting security into a product that was designed without any consideration for security from the start is going to be hard. I do not know what you want to do, so I am not going to claim it is impossible:-) > Described cmake features would be very helpful for this. > Right now I'm just investigating possible security improvements and > this is only 'nice-to-have' feature. What are the attack scenarios you want to defend against? What should not be possible in your system that currently is in CMake? How do these steps help in securing against those attacks? As a user of CMake I am very much opposed to disabling functionality based on the context: That forces me to keep more state in my head when reading CMakeLists.txt files. CMake does way too much in a way to obscure syntax already! Best regards, Tobias > On 21 August 2016 at 00:25, Tobias Hunger <tobias.hun...@gmail.com> wrote: > > Hi Egor, > > > > Am 20.08.2016 13:48 schrieb "Egor Pugin" <egor.pu...@gmail.com>: > >> > >> Hi, > >> > >> I'm working on a package manager based on cmake. > >> And some cmake instructions are downloaded with user packages. > >> I'd like to have an ability to deny some cmake features in such > >> external untrusted insertions. > > > > I am no CMake expert, but you are talking about securing a program that is > > meant to take arbitrary input and run user-defined commands on that to > > produce possibly executable output. > > > > I do not see any safe subset of CMake commands that is still able to do > > anything useful. > > > > I can see a way for "insertions" to be useful, that does not involve them > > changing the configuration (e.g. for a cross compiler), involve running some > > 3rd party program (e.g. to add support for a new documentation system, > > parser generator or whatnot), or the production of build artifacts (e.g. > > build some library for the developer to use). > > > > *All* of these are inheritently unsafe. > > > > Configuration change: Change the C compiler to rm and pass force -rf -- / as > > flags. > > > > 3rd party program: Run rm -rf / when some certain input file is seen. > > > > Build artifacts: Put running rm -rf / into the binary/library so that this > > is run during normal development workflow. > > > > I would try to run my package manager in an environment where running rm -rf > > is harmless to the overall system health. Virtual machines or containers > > spring to mind there. Not sure that is feasible. > > > > Or come up with insertions signing, etc. so that users can at least know > > they got what was uploaded and know whom to blame when their systems get > > wiped. > > > > Beat Regards, > > Tobias > > > > -- > Egor Pugin
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