Re: [PATCH] proc: Use seq_read_iter where possible

From: Arusekk
Date: Wed Apr 28 2021 - 09:00:19 EST


On Wed, Apr 28, 2021 at 08:12:59 CEST, Christoph Hellwig wrote:
> Patching what entry point?

The instructions at the entry point of the executable being inspected.
The flow of the tool:
- parse ELF headers of the binary to be inspected,
- locate its entry point position in the file,
- write short code at the location (this short code has used sendfile so far),
- execute the patched binary,
- parse the output and extract information about the relevant mappings.
This can be seen as equivalent to setting LD_TRACE_LOADED_OBJECTS,
but also works for static binaries, and is a bit safer.

The problem was reported at:
https://github.com/Gallopsled/pwntools/issues/1871

> Linus did object to blindly switching over all instances.

I know, I read that, but I thought that pointing a real use case, combined
with the new interface being used all throughout the other code, might be
convincing.
I would be happy with only changing the f_ops of /proc/.../maps, even if only
on MMU-enabled systems, but I thought that consistence would be better.
This is my first time contributing to Linux, so I am very sorry for any wrong
assumptions, and glad to learn more.

--
Arusekk