[PATCH] ALSA: asihpi: work around clang-17+ false positive fortify-string warning

From: Arnd Bergmann
Date: Wed Feb 28 2024 - 09:02:20 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

One of the memory copies in this driver triggers a warning about a
possible out of range access:

In file included from /home/arnd/arm-soc/sound/pci/asihpi/hpimsgx.c:13:
/home/arnd/arm-soc/include/linux/fortify-string.h:553:4: error: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
553 | __write_overflow_field(p_size_field, size);
| ^

Adding a range check avoids the problem, though I don't quite see
why it warns in the first place if clang has no knowledge of the
actual range of the type, or why I never saw the warning in previous
randconfig tests.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
sound/pci/asihpi/hpimsgx.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/sound/pci/asihpi/hpimsgx.c b/sound/pci/asihpi/hpimsgx.c
index d0caef299481..4f245c3956b1 100644
--- a/sound/pci/asihpi/hpimsgx.c
+++ b/sound/pci/asihpi/hpimsgx.c
@@ -576,6 +576,9 @@ static u16 adapter_prepare(u16 adapter)
/* Open the adapter and streams */
u16 i;

+ if (adapter >= ARRAY_SIZE(rESP_HPI_ADAPTER_OPEN))
+ return 0;
+
/* call to HPI_ADAPTER_OPEN */
hpi_init_message_response(&hm, &hr, HPI_OBJ_ADAPTER,
HPI_ADAPTER_OPEN);
--
2.39.2