From: Thadeu Lima de Souza Cascardo Date: Sun, 28 Nov 2010 21:46:50 +0000 (-0200) Subject: wmi: use memcmp instead of strncmp to compare GUIDs X-Git-Url: https://rtime.felk.cvut.cz/gitweb/lisovros/linux_canprio.git/commitdiff_plain/2dedf88ded12897aa394f09aa675038d96d79670 wmi: use memcmp instead of strncmp to compare GUIDs commit 8b14d7b22c61f17ccb869e0047d9df6dd9f50a9f upstream. 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 Signed-off-by: Matthew Garrett Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index b2978a04317..677783475d8 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -801,7 +801,7 @@ static bool guid_already_parsed(const char *guid_string) wblock = list_entry(p, struct wmi_block, list); gblock = &wblock->gblock; - if (strncmp(gblock->guid, guid_string, 16) == 0) + if (memcmp(gblock->guid, guid_string, 16) == 0) return true; } return false;