On Mon, Mar 29, 2021 at 01:59:48PM +0300, Zidenberg, Tsahi wrote:
>
> commit 9de1fec50b23117f0a19f7609cc837ca72e764a6 upstream.
>
> This is an adaptation of parts from the above commit to kernel 5.4.
>
> Allow Kprobes to access userspace data correctly in architectures with no
> overlap between kernel and userspace addresses.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.4.x
> Signed-off-by: Tsahi Zidenberg <tsahee@xxxxxxxxxx>
> ---
> kernel/trace/trace_kprobe.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 233322c77b76..cbd72a1c9530 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1043,6 +1043,11 @@ fetch_store_strlen(unsigned long addr)
> int ret, len = 0;
> u8 c;
>
> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> + if (addr < TASK_SIZE)
> + return fetch_store_strlen_user(addr);
> +#endif
> +
> do {
> ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
> len++;
> @@ -1071,6 +1076,11 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
> void *__dest;
> long ret;
>
> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> + if (addr < TASK_SIZE)
> + return fetch_store_string_user(addr, dest, base);
> +#endif
> +
> if (unlikely(!maxlen))
> return -ENOMEM;
>
> @@ -1114,6 +1124,11 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base)
> static nokprobe_inline int
> probe_mem_read(void *dest, void *src, size_t size)
> {
> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> + if ((unsigned long)src < TASK_SIZE)
> + return probe_mem_read_user(dest, src, size);
> +#endif
> +
> return probe_kernel_read(dest, src, size);
> }
>
> --
> 2.25.1
What problem is this fixing?
thanks,
greg k-h
