Messages in this thread Patch in this message | | | From | Eric Lin <> | Subject | [PATCH] riscv/mm: Prevent kernel module access user-space memory without uaccess routines | Date | Mon, 30 Nov 2020 13:30:37 +0800 |
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In the page fault handler, an access to user-space memory without get/put_user() or copy_from/to_user() routines is not resolved properly. Like arm and other architectures, we need to let it die earlier in page fault handler.
Signed-off-by: Eric Lin <tesheng@andestech.com> Cc: Alan Kao <alankao@andestech.com> --- arch/riscv/mm/fault.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 3c8b9e433c67..a452cfa266a2 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -232,6 +232,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs) if (user_mode(regs)) flags |= FAULT_FLAG_USER; + if (!user_mode(regs) && addr < TASK_SIZE && unlikely(!(regs->status & SR_SUM))) + die(regs, "Accessing user space memory without uaccess routines\n"); + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); if (cause == EXC_STORE_PAGE_FAULT) -- 2.17.0
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