| From | Andi Kleen <> | Subject | [PATCH] [196/223] wmi: use memcmp instead of strncmp to compare GUIDs | Date | Mon, 13 Dec 2010 00:48:22 +0100 (CET) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
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 <cascardo@holoscopio.com> Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- drivers/platform/x86/wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux/drivers/platform/x86/wmi.c =================================================================== --- linux.orig/drivers/platform/x86/wmi.c +++ linux/drivers/platform/x86/wmi.c @@ -795,7 +795,7 @@ static bool guid_already_parsed(const ch 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;
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