Re: Fw: [PATCH] Improve execl* functions

Hi Federico,

On Jan 31 17:42, Federico Terraneo wrote:
> Hi,
> updated patch 0002.

Both patches pushed.


Thanks,
Corinna


> From a13bf0a67ab85138cd31a6673494f30284fb9b60 Mon Sep 17 00:00:00 2001
> From: Terraneo Federico <[email protected]>
> Date: Tue, 28 Jan 2025 17:19:18 +0100
> Subject: [PATCH 2/2] Lift 256 arg limit in execl, execle and execlp, add
>  --enable-newlib-use-malloc-in-execl option
> 
> The previous version of these functions allocated a 256 entry array and copied
> arguments in that array with no bound checking. That implementation always
> occupied 1024 bytes of stack for the array even in the common case in which the
> number of passed arguments is far less than 256, risking stack overflows in
> environments with small stacks, and caused a stack buffer overflow if called
> with more than 256 arguments.
> 
> The improved implementation counts the actual number of passed arguments and
> allocates a suitable buffer. The default implementation uses alloca to allocate
> the buffer to satisfy the POSIX.1-2008 requirement that execl and execle should
> be callable from signal handlers, but it is possible to override this behavior
> and use malloc for targets where the risk of stack overflow due to unbounded
> stack allocations is a more pressing requirement than the corner case of
> allowing execl calls from signal handlers.
> ---
>  newlib/README              |  8 ++++++++
>  newlib/configure           | 19 +++++++++++++++++++
>  newlib/configure.ac        | 13 +++++++++++++
>  newlib/libc/posix/execl.c  | 36 ++++++++++++++++++++++++++++++++++--
>  newlib/libc/posix/execle.c | 36 ++++++++++++++++++++++++++++++++++--
>  newlib/libc/posix/execlp.c | 31 +++++++++++++++++++++++++++++--
>  newlib/newlib.hin          |  3 +++
>  7 files changed, 140 insertions(+), 6 deletions(-)