git: 27b76413615a - stable/15 - sysctl(9): Booleans: Fix old value length discovery

The branch stable/15 has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=27b76413615a298d4aa2ae71bd98fbe116116db2

commit 27b76413615a298d4aa2ae71bd98fbe116116db2
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2026-02-03 22:25:46 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2026-02-19 12:28:52 +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 ease knob conversion")
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 895e1c6567d9561c86f8d20b47e924911bce989e)
---
 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;