From e56d18a976dda653194218df6d40d8122c775712 Mon Sep 17 00:00:00 2001 From: Jisheng Zhang Date: Sat, 29 Oct 2022 19:34:50 +0800 Subject: [PATCH] riscv: process: fix kernel info leakage [ Upstream commit 6510c78490c490a6636e48b61eeaa6fb65981f4b ] thread_struct's s[12] may contain random kernel memory content, which may be finally leaked to userspace. This is a security hole. Fix it by clearing the s[12] array in thread_struct when fork. As for kthread case, it's better to clear the s[12] array as well. Fixes: 7db91e57a0ac ("RISC-V: Task implementation") Signed-off-by: Jisheng Zhang Tested-by: Guo Ren Link: https://lore.kernel.org/r/20221029113450.4027-1-jszhang@kernel.org Reviewed-by: Guo Ren Link: https://lore.kernel.org/r/CAJF2gTSdVyAaM12T%2B7kXAdRPGS4VyuO08X1c7paE-n4Fr8OtRA@mail.gmail.com/ Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/kernel/process.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index dd5f985b1f40..9a8b2e60adcf 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -111,6 +111,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg, { struct pt_regs *childregs = task_pt_regs(p); + memset(&p->thread.s, 0, sizeof(p->thread.s)); + /* p->thread holds context to be restored by __switch_to() */ if (unlikely(p->flags & PF_KTHREAD)) { /* Kernel thread */