Re: git: 895e1c6567d9 - main - sysctl(9): Booleans: Fix old value length discovery

In message <69827a46.18880.6ee8f9c8@gitrepo.freebsd.org>, Olivier Certner 
write
s:
> The branch main has been updated by olce:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=895e1c6567d9561c86f8d20b47e92491
> 1bce989e
>
> commit 895e1c6567d9561c86f8d20b47e924911bce989e
> Author:     Olivier Certner <olce@FreeBSD.org>
> AuthorDate: 2026-02-03 22:25:46 +0000
> Commit:     Olivier Certner <olce@FreeBSD.org>
> CommitDate: 2026-02-03 22:43:49 +0000
>
>     sysctl(9): Booleans: Fix old value length discovery
>     
>     When calling sysctl(3) with a null 'oldp', i.e., length discovery mode,
>     'oldix' can be equal to 'oldlen', and we should not fail.
>     
>     More generally, let SYSCTL_OUT() and SYSCTL_IN() handle corner cases,
>     simply removing the comparisons between 'oldidx' and 'oldlen' and
>     'newidx' and 'newlen' done by hand as the test just after is an equality
>     that does not require to know if 'idx' is smaller than 'len'.
>     
>     PR:             292917
>     Reported by:    cy
>     Fixes:          406da392ef8d ("sysctl(9): Booleans: Accept integers to ea
> se knob conversion")
>     Sponsored by:   The FreeBSD Foundation
> ---
>  sys/kern/kern_sysctl.c | 4 ----
>  1 file changed, 4 deletions(-)
>
> diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
> index dbe509b3e8e2..be0acb0a4a55 100644
> --- a/sys/kern/kern_sysctl.c
> +++ b/sys/kern/kern_sysctl.c
> @@ -1637,8 +1637,6 @@ sysctl_handle_bool(SYSCTL_HANDLER_ARGS)
>  	 * the output buffer, we assume that the caller expected an 'int'
>  	 * instead of a 'uint8_t'.
>  	 */
> -	if (req->oldidx >= req->oldlen)
> -		return (ENOMEM);
>  	if (req->oldlen - req->oldidx == sizeof(int)) {
>  		int temp_int = temp;
>  
> @@ -1655,8 +1653,6 @@ sysctl_handle_bool(SYSCTL_HANDLER_ARGS)
>  		 * Conversely, if the input buffer has exactly 4 bytes to read,
>  		 * use them all to produce a bool.
>  		 */
> -		if (req->newidx >= req->newlen)
> -			return (ENOMEM);
>  		if (req->newlen - req->newidx == sizeof(int)) {
>  			int temp_int;
>  
>

Thank you.
-- 
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy@nwtime.org>    Web:  https://nwtime.org

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