Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 29 Apr 2020 11:57:29 -0700 | Subject | Re: [GIT PULL] Please pull proc and exec work for 5.7-rc1 |
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On Wed, Apr 29, 2020 at 11:33 AM Jann Horn <jannh@google.com> wrote: > > > That sequence count approach would be a much simpler change. > > In that model, what should happen if someone tries to attach to a > process that's in execve(), but after the point of no return in > de_thread()? "Abort" after the point of no return normally means > force_sigsegv(), right?
It would by definition have to check the sequence number at the end of install_exec_creds() (where we currently release the cred_guard_mutex).
And yes, that's after the point of no return, so it would cause the usual "kill the process".
We could check earlier too (while still able to return errors) and return -EAGAIN or something, but that wouldn't obviate the need for that final check, iut would just shrink the window for the "fatal exec" case.
Linus
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