Re: File sealing

On Thursday, November 1, 2018 6:49 PM, Ted Unangst wrote: > I'be been reminded that there's a different way to solve this problem in > OpenBSD. > > The secret __MAP_NOFAULT flag to mmap. See for instance use in libxshmfence. Oh, thanks! That's what I've been searching for.

Re: File sealing

Simon Ser wrote: > Sometimes the two processes don't trust each other, for instance in the > case of Wayland. Bad clients may try to crash the compositor. > > One way to crash the compositor is to send a shared memory file descriptor > and then shrink the file. When the compositor tries to read th

Re: File sealing

Hi, On Thursday, November 1, 2018 6:25 PM, Ted Unangst wrote: > Simon Ser wrote: > > > Hi all> I'd like to know if there are plans to add a feature similar to file > > sealing [2] in OpenBSD. > > I don't think so. You explained a possible use, but didn&#x

Re: File sealing

Simon Ser wrote: > Hi all> I'd like to know if there are plans to add a feature similar to file > sealing [2] in OpenBSD. I don't think so. You explained a possible use, but didn't actually explain if code using file sealing already exists.

File sealing

Hi all, File sealing is a Linux-specific safety mechanism that can be used when sharing memory between two processes. In this scenario, one process typically calls shm_open(SHM_ANON), mmaps the result in its address space, writes interesting things in this slice of memory, sends the file