From: Jisheng Zhang <jszhang@xxxxxxxxxx>
[ 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 <jszhang@xxxxxxxxxx>
Tested-by: Guo Ren <guoren@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221029113450.4027-1-jszhang@xxxxxxxxxx
Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
Link: https://lore.kernel.org/r/CAJF2gTSdVyAaM12T%2B7kXAdRPGS4VyuO08X1c7paE-n4Fr8OtRA@xxxxxxxxxxxxxx/
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 */
--
2.35.1
