diff mbox

ACPI / util: cast data to u64 before shifting to fix sign extension

Message ID 1458313681-24239-1-git-send-email-colin.king@canonical.com (mailing list archive)
State Accepted, archived
Delegated to: Rafael Wysocki
Headers show

Commit Message

Colin King March 18, 2016, 3:08 p.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

obj->buffer.pointer[i] should be cast to u64 to prevent an unintentional
sign extension.  For example, if pointer[7] is 0x80, then the value
0xffffffffff000000 is or'd into mask rather than the intended value
0xff00000000000000

Detected with static analysis by CoverityScan

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/acpi/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index f12a724..050673f 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -692,7 +692,7 @@  bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
 		mask = obj->integer.value;
 	else if (obj->type == ACPI_TYPE_BUFFER)
 		for (i = 0; i < obj->buffer.length && i < 8; i++)
-			mask |= (((u8)obj->buffer.pointer[i]) << (i * 8));
+			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
 	ACPI_FREE(obj);
 
 	/*