2023-04-05 14:04:10

by Rafael J. Wysocki

Subject: [PATCH 23/32] ACPICA: struct acpi_nfit_interleave: Replace 1-element array with flexible array

From: Kees Cook <[email protected]>

ACPICA commit e66decc6fca36b59194b0947d87d6a9bec078bc3

Similar to "Replace one-element array with flexible-array", replace the
1-element array with a proper flexible array member as defined by C99.

This allows the code to operate without tripping compile-time and run-
time bounds checkers (e.g. via __builtin_object_size(), -fsanitize=bounds,
and/or -fstrict-flex-arrays=3).

Unlike struct acpi_nfit_flush_address and struct acpi_nfit_smbios, which
had their sizeof() uses adjusted in code, struct acpi_nfit_interleave did
not. This appears to have been a bug. After this change, there is a binary
difference in acpi_dm_dump_nfit() since the size of the structure now has
the correct size, as the prior result was including the trailing U32:

- mov $0x14,%ebp
+ mov $0x10,%ebp

Link: https://github.com/acpica/acpica/commit/e66decc6
Signed-off-by: Bob Moore <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/nfit/core.c | 2 +-
include/acpi/actbl2.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 981f8b0f595d..a398f32dfd68 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -3476,7 +3476,7 @@ static __init int nfit_init(void)
BUILD_BUG_ON(sizeof(struct acpi_table_nfit) != 40);
BUILD_BUG_ON(sizeof(struct acpi_nfit_system_address) != 64);
BUILD_BUG_ON(sizeof(struct acpi_nfit_memory_map) != 48);
- BUILD_BUG_ON(sizeof(struct acpi_nfit_interleave) != 20);
+ BUILD_BUG_ON(sizeof(struct acpi_nfit_interleave) != 16);
BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 8);
BUILD_BUG_ON(sizeof(struct acpi_nfit_control_region) != 80);
BUILD_BUG_ON(sizeof(struct acpi_nfit_data_region) != 40);
diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
index 6d3251ea4c53..a51fd4090d27 100644
--- a/include/acpi/actbl2.h
+++ b/include/acpi/actbl2.h
@@ -1700,7 +1700,7 @@ struct acpi_nfit_interleave {
u16 reserved; /* Reserved, must be zero */
u32 line_count;
u32 line_size;
- u32 line_offset[1]; /* Variable length */
+ u32 line_offset[]; /* Variable length */
};

/* 3: SMBIOS Management Information Structure */
--
2.35.3

2023-04-06 00:41:21

by Dan Williams

Subject: RE: [PATCH 23/32] ACPICA: struct acpi_nfit_interleave: Replace 1-element array with flexible array

Rafael J. Wysocki wrote:
> From: Kees Cook <[email protected]>
>
> ACPICA commit e66decc6fca36b59194b0947d87d6a9bec078bc3
>
> Similar to "Replace one-element array with flexible-array", replace the
> 1-element array with a proper flexible array member as defined by C99.
>
> This allows the code to operate without tripping compile-time and run-
> time bounds checkers (e.g. via __builtin_object_size(), -fsanitize=bounds,
> and/or -fstrict-flex-arrays=3).
>
> Unlike struct acpi_nfit_flush_address and struct acpi_nfit_smbios, which
> had their sizeof() uses adjusted in code, struct acpi_nfit_interleave did
> not. This appears to have been a bug. After this change, there is a binary
> difference in acpi_dm_dump_nfit() since the size of the structure now has
> the correct size, as the prior result was including the trailing U32:
>
> - mov $0x14,%ebp
> + mov $0x10,%ebp
>
> Link: https://github.com/acpica/acpica/commit/e66decc6
> Signed-off-by: Bob Moore <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>

Reviewed-by: Dan Williams <[email protected]>
Tested-by: Dan Williams <[email protected]>