[PATCH v2] acpi_table: Fix coverity defect in acpi_write_spcr

[PATCH v2] acpi_table: Fix coverity defect in acpi_write_spcr

[Patrick Rudolph]

Fix "Integer handling issues  (SIGN_EXTENSION)" in newly added code:
Cast serial_info.reg_offset to u64 to prevent an integer overflow when
shifted too many bits to the left. Currently this never happens as the
shift is supposed to be less than 4.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
 lib/acpi/acpi_table.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/acpi/acpi_table.c b/lib/acpi/acpi_table.c
index 6473d95c10..150f75027a 100644
--- a/lib/acpi/acpi_table.c
+++ b/lib/acpi/acpi_table.c
@@ -420,7 +420,7 @@ int acpi_write_dbg2_pci_uart(struct acpi_ctx *ctx, struct udevice *dev,
 static int acpi_write_spcr(struct acpi_ctx *ctx, const struct acpi_writer *entry)
 {
 	struct serial_device_info serial_info = {0};
-	ulong serial_address, serial_offset;
+	u64 serial_address, serial_offset;
 	struct acpi_table_header *header;
 	struct acpi_spcr *spcr;
 	struct udevice *dev;
@@ -473,7 +473,7 @@ static int acpi_write_spcr(struct acpi_ctx *ctx, const struct acpi_writer *entry
 	}
 
 	serial_width = serial_info.reg_width * 8;
-	serial_offset = serial_info.reg_offset << serial_info.reg_shift;
+	serial_offset = ((u64)serial_info.reg_offset) << serial_info.reg_shift;
 	serial_address = serial_info.addr + serial_offset;
 
 	/* Encode register access size */
@@ -495,7 +495,7 @@ static int acpi_write_spcr(struct acpi_ctx *ctx, const struct acpi_writer *entry
 		break;
 	}
 
-	debug("UART type %u @ %lx\n", spcr->interface_type, serial_address);
+	debug("UART type %u @ %llx\n", spcr->interface_type, serial_address);
 
 	/* Fill GAS */
 	spcr->serial_port.space_id = space_id;
-- 
2.46.2

Re: [PATCH v2] acpi_table: Fix coverity defect in acpi_write_spcr

[Tom Rini]

On Wed, 30 Oct 2024 14:11:46 +0100, Patrick Rudolph wrote:

> Fix "Integer handling issues  (SIGN_EXTENSION)" in newly added code:
> Cast serial_info.reg_offset to u64 to prevent an integer overflow when
> shifted too many bits to the left. Currently this never happens as the
> shift is supposed to be less than 4.
> 
> 

Applied to local tree/v2-tidy-test-dir, thanks!

-- 
Tom