landlock: Report the actual ptrace tracer

The ptrace denial callback identifies only the tracee. Current is the
tracer during hook_ptrace_access_check(), but it is the tracee during
PTRACE_TRACEME, where the parent is the actual tracer. A consumer
therefore cannot infer both parties from the existing arguments.

Append the actual tracer task to the typed-BPF callback: current for
hook_ptrace_access_check() and parent for hook_ptrace_traceme(). Carry
it with the tracee domain ID in a private ptrace context. Both hooks
keep the selected tasks alive through synchronous dispatch, so no extra
task reference is needed.

Keep the tracefs record unchanged. The new context is available only to
typed BPF, while same_exec continues to describe the tracer that owns
the denying policy.

Cc: Günther Noack <gnoack@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Fixes: bb91730f16c0 ("landlock: Add tracepoints for ptrace and scope denials")
Link: https://patch.msgid.link/20260918185036.608651-6-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

0 files changed, 0 insertions, 0 deletions