On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
> Without this patch driver dell-wmi is trying to access elements of dynamically
> allocated array without checking array size. This can lead to memory corruption
> or kernel panic. This patch adds missing checks for array size.
>
> Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
Looks good to me. Rafael, any concerns?
Cc: linux-acpi
> ---
> This patch should be probably applied to stable kernel trees as it fixing
> possible memory corruption.
> ---
> drivers/platform/x86/dell-wmi.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index 390e8e3..25721bf 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -163,18 +163,24 @@ static void dell_wmi_notify(u32 value, void *context)
> const struct key_entry *key;
> int reported_key;
> u16 *buffer_entry = (u16 *)obj->buffer.pointer;
> + int buffer_size = obj->buffer.length/2;
>
> - if (dell_new_hk_type && (buffer_entry[1] != 0x10)) {
> + if (buffer_size >= 2 && dell_new_hk_type && buffer_entry[1] != 0x10) {
> pr_info("Received unknown WMI event (0x%x)\n",
> buffer_entry[1]);
> kfree(obj);
> return;
> }
>
> - if (dell_new_hk_type || buffer_entry[1] == 0x0)
> + if (buffer_size >= 3 && (dell_new_hk_type || buffer_entry[1] == 0x0))
> reported_key = (int)buffer_entry[2];
> - else
> + else if (buffer_size >= 2)
> reported_key = (int)buffer_entry[1] & 0xffff;
> + else {
> + pr_info("Received unknown WMI event\n");
> + kfree(obj);
> + return;
> + }
>
> key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
> reported_key);
> --
> 1.7.9.5
>
>
--
Darren Hart
Intel Open Source Technology Center
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