On 7/15/26 14:54, Alyssa Ross wrote: > Demi Marie Obenour writes: > >> On 7/13/26 05:04, Alyssa Ross wrote: >>> Demi Marie Obenour writes: >>> >>>> This seems to be a fairly significant hole in the VMM's sandbox. >>>> Various code operates in that directory and isn't secure against >>>> symlink attacks. >>>> >>>> Does the VMM really need write access to that directory? Could it >>>> be given access to a subdirectory that is mounted "nosymfollow"? >>> >>> I think it's just so it can create e.g. the serial file. That could >>> indeed be moved to a subdirectory. The ideal solution is of course for >>> Cloud Hypervisor to be able to accept every file it would otherwise >>> create as an open file descriptor, which I expect will happen >>> eventually. >> >> Should it be moved to a subdirectory for now? That would make the >> sandbox meaningful in practice. > > I suppose it could be. Might make more sense to dedicate efforts > towards fixing Cloud Hypervisor to accept file descriptors for the ~2 > paths it currently needs to create, though. (That's obviously more > work, but also more useful.) If we were to work around this in > Spectrum, we could keep symlinks outside the directory pointing into it, > to keep paths nice and avoid churn once we can put them back in the > parent directory. Do you happen to know which paths these are? -- Sincerely, Demi Marie Obenour (she/her/hers)