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SubjectRe: [PATCH] wmi: use memcmp instead of strncmp to compare GUIDs
On Sun, 28 Nov 2010, Thadeu Lima de Souza Cascardo wrote:

> While looking for the duplicates in /sys/class/wmi/, I couldn't find
> them. The code that looks for duplicates uses strncmp in a binary GUID,
> which may contain zero bytes. The right function is memcmp, which is
> also used in another section of wmi code.
>
> It was finding 49142400-C6A3-40FA-BADB-8A2652834100 as a duplicate of
> 39142400-C6A3-40FA-BADB-8A2652834100. Since the first byte is the fourth
> printed, they were found as equal by strncmp.
>
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
> ---
> drivers/platform/x86/wmi.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 104b77c..aecd9a9 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -755,7 +755,7 @@ static bool guid_already_parsed(const char *guid_string)
> struct wmi_block *wblock;
>
> list_for_each_entry(wblock, &wmi_block_list, list)
> - if (strncmp(wblock->gblock.guid, guid_string, 16) == 0)
> + if (memcmp(wblock->gblock.guid, guid_string, 16) == 0)
> return true;
>
> return false;
>

Looks right to me.

--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
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