git: 718746766c18 - stable/14 - proc: free kstack buffers when debug permission changes

The branch stable/14 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=718746766c18130f06602f1625d05ac514bb84a2

commit 718746766c18130f06602f1625d05ac514bb84a2
Author:     Andrew Griffiths <andrew@calif.io>
AuthorDate: 2026-09-14 07:55:01 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-09-28 13:38:23 +0000

    proc: free kstack buffers when debug permission changes
    
    The kern.proc.kstack handler allocates its output and stack buffers
    before deliberately checking p_candebug again under the process lock.
    If trace-control state changes between authorization checks, the failure
    path balances the process and exec state but leaks both buffers.
    
    Submitted by calif.io for the OpenAI Patch The Planet program
    
    Signed-off-by: Andrew Griffiths <andrew@calif.io>
    
    Fixes:          8b5abd9027b8 ("kern_proc.c: disallow execve around sysctl kern.proc.kstacks")
    Reviewed by:    markj
    MFC after:      1 week
    
    (cherry picked from commit 3484217cc47c1f77d2be2ed0e012b870d1cd3dca)
---
 sys/kern/kern_proc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index a722bac6185a..8fc52c6749e1 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -2891,6 +2891,8 @@ sysctl_kern_proc_kstack(SYSCTL_HANDLER_ARGS)
 		execve_unblock(ctd, p);
 		_PRELE(p);
 		PROC_UNLOCK(p);
+		stack_destroy(st);
+		free(kkstp, M_TEMP);
 		return (error);
 	}
 	do {