Messages in this thread | | | Date | Mon, 8 Nov 2021 14:58:04 +0300 | Subject | Re: [PATCH] tty: vt: keyboard: do not copy an extra-byte in copy_to_user | From | Pavel Skripkin <> |
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On 11/8/21 11:59, Ajay Garg wrote: > Dropping all further discussions on this thread, as a RFC for a new > string-copy method has been posted at : > https://lore.kernel.org/linux-hardening/CAHP4M8U=0aTHgfREGJpSboV6J4X+E3Y6+H_kb-PvXxDKtV=n-g@mail.gmail.com/T/#t > > which, if accepted, will make the clients' lives a lot easier. >
Honestly, I can't get what you are trying to achieve with new string function.
If caller knows, that there is no possible overflow, it can omit bounds checking (like in vt_do_kdgkb_ioctl). If caller needs return value equal to destination length it can use strscpy().
There is a bunch of str*cpy() functions and every month I see new conversations between them on ML. As Andy said it's really chaos. These conversation are needed, of course, from security point of view, but lib/string is already big. It contains functions for every possible scenario, caller just needs to pick right one.
I might be too dumb in this topic, so it's just my IMHO, since I am on CC list.
With regards, Pavel Skripkin
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