Commit 8b14d7b2 authored by Thadeu Lima de Souza Cascardo's avatar Thadeu Lima de Souza Cascardo Committed by Matthew Garrett

wmi: use memcmp instead of strncmp to compare GUIDs

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: default avatarThadeu Lima de Souza Cascardo <>
Signed-off-by: default avatarMatthew Garrett <>
parent 53c96dfd
......@@ -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;
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