Re: Patch "tracing: Add length protection to histogram string copies" has been added to the 5.4-stable tree

[Greg KH <greg@kroah.com>]

On Sun, Nov 21, 2021 at 06:19:42PM -0500, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>     tracing: Add length protection to histogram string copies
> 
> to the 5.4-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      tracing-add-length-protection-to-histogram-string-co.patch
> and it can be found in the queue-5.4 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
> 
> 
> 
> commit 0a0e233a0c25593f817b6d9ed48fb2d2fd080870
> Author: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Date:   Sun Nov 14 13:28:34 2021 -0500
> 
>     tracing: Add length protection to histogram string copies
>     
>     [ Upstream commit 938aa33f14657c9ed9deea348b7d6f14b6d69cb7 ]
>     
>     The string copies to the histogram storage has a max size of 256 bytes
>     (defined by MAX_FILTER_STR_VAL). Only the string size of the event field
>     needs to be copied to the event storage, but no more than what is in the
>     event storage. Although nothing should be bigger than 256 bytes, there's
>     no protection against overwriting of the storage if one day there is.
>     
>     Copy no more than the destination size, and enforce it.
>     
>     Also had to turn MAX_FILTER_STR_VAL into an unsigned int, to keep the
>     min() comparison of the string sizes of comparable types.
>     
>     Link: https://lore.kernel.org/all/CAHk-=wjREUihCGrtRBwfX47y_KrLCGjiq3t6QtoNJpmVrAEb1w@mail.gmail.com/
>     Link: https://lkml.kernel.org/r/20211114132834.183429a4@rorschach.local.home
>     
>     Cc: Ingo Molnar <mingo@kernel.org>
>     Cc: Andrew Morton <akpm@linux-foundation.org>
>     Cc: Tom Zanussi <zanussi@kernel.org>
>     Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
>     Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
>     Fixes: 63f84ae6b82b ("tracing/histogram: Do not copy the fixed-size char array field over the field size")
>     Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>     Signed-off-by: Sasha Levin <sashal@kernel.org>

This commit causes a bunch of build warnings, so odds are the backport
is incorrect.

I'll drop it from the 5.4.y queue now.

thanks,

greg k-h