Re: [PATCHSET][RFC] struct fd and memory safety

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Jul 30, 2024 at 06:09:27AM +0100, Al Viro wrote:

> 	* ib_uverbs_open_xrcd().  FWIW, a closer look shows that the
> damn thing is buggy - it accepts _any_ descriptor and pins the associated
> inode.  mount tmpfs, open a file there, feed it to that, unmount and
> watch the show...

What happens? There is still an igrab() while it is in the red black
tree?

> AFAICS, that's done for the sake of libibverbs and
> I've no idea how it's actually used - all examples I'd been able to
> find use -1 for descriptor here.  Needs to be discussed with infiniband
> folks (Sean Hefty?).  For now, leave that as-is.

The design seems insane, but it is what it is from 20 years ago..

Userspace can affiliate this "xrc domain" with a file in the
filesystem. Any file. That is actually a deliberate part of the API.

This is done as some ugly way to pass xrc domain object from process A
to process B. IIRC the idea is process A will affiliate the object
with a file and then B will be able to access the shared object if B
is able to open the file.

It looks like the code keeps a red/black tree of this association, and
holds an igrab while the inode is in that tree..

Jason




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]     [Monitors]

  Powered by Linux