diff options
| author | Thomas Gleixner <tglx@kernel.org> | 2026-04-26 16:21:02 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-05-06 17:40:15 +0200 |
| commit | 82f572449cfe75f12ea985986da60e11f308f77d (patch) | |
| tree | 6fdfa3e6253916f9f5fb690c6ef9fb16f0ebb0f1 /kernel | |
| parent | fdf4eb632683bfc2840acebe62716cb468d43e10 (diff) | |
rseq: Implement read only ABI enforcement for optimized RSEQ V2 mode
The optimized RSEQ V2 mode requires that user space adheres to the ABI
specification and does not modify the read-only fields cpu_id_start,
cpu_id, node_id and mm_cid behind the kernel's back.
While the kernel does not rely on these fields, the adherence to this is a
fundamental prerequisite to allow multiple entities, e.g. libraries, in an
application to utilize the full potential of RSEQ without stepping on each
other toes.
Validate this adherence on every update of these fields. If the kernel
detects that user space modified the fields, the application is force
terminated.
Fixes: d6200245c75e ("rseq: Allow registering RSEQ with slice extension")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://patch.msgid.link/20260428224427.845230956%40kernel.org
Cc: stable@vger.kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rseq.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index aa25753ea135..101612027f6a 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -263,7 +263,6 @@ static void rseq_slowpath_update_usr(struct pt_regs *regs) }; struct task_struct *t = current; struct rseq_ids ids; - u32 node_id; bool event; if (unlikely(t->flags & PF_EXITING)) @@ -299,9 +298,9 @@ static void rseq_slowpath_update_usr(struct pt_regs *regs) if (!event) return; - node_id = cpu_to_node(ids.cpu_id); + ids.node_id = cpu_to_node(ids.cpu_id); - if (unlikely(!rseq_update_usr(t, regs, &ids, node_id))) { + if (unlikely(!rseq_update_usr(t, regs, &ids))) { /* * Clear the errors just in case this might survive magically, but * leave the rest intact. |