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Subject[PATCH] ACPI / util: cast data to u64 before shifting to fix sign extension
Date
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 --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);

/*
--
2.7.3
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