On 30/04/25 13:41, Gustavo A. R. Silva wrote:
On 27/03/25 08:03, Dan Williams wrote:
Gustavo A. R. Silva wrote:
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
Use the `DEFINE_RAW_FLEX()` helper for on-stack definitions of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.
So, with these changes, fix a dozen of the following warnings:
drivers/acpi/nfit/intel.c:692:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
Changes in v2:
- Use DEFINE_RAW_FLEX() instead of __struct_group().
v1:
- Link: https://lore.kernel.org/linux-hardening/Z618ILbAR8YAvTkd@kspp/
drivers/acpi/nfit/intel.c | 388 ++++++++++++++++++--------------------
1 file changed, 179 insertions(+), 209 deletions(-)
diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c
index 3902759abcba..114d5b3bb39b 100644
--- a/drivers/acpi/nfit/intel.c
+++ b/drivers/acpi/nfit/intel.c
@@ -55,21 +55,17 @@ static unsigned long intel_security_flags(struct nvdimm *nvdimm,
{
struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
unsigned long security_flags = 0;
- struct {
- struct nd_cmd_pkg pkg;
- struct nd_intel_get_security_state cmd;
- } nd_cmd = {
- .pkg = {
- .nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
- .nd_family = NVDIMM_FAMILY_INTEL,
- .nd_size_out =
- sizeof(struct nd_intel_get_security_state),
- .nd_fw_size =
- sizeof(struct nd_intel_get_security_state),
- },
- };
+ DEFINE_RAW_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
+ sizeof(struct nd_intel_get_security_state));
+ struct nd_intel_get_security_state *cmd =
+ (struct nd_intel_get_security_state *)nd_cmd->nd_payload;
int rc;
+ nd_cmd->nd_command = NVDIMM_INTEL_GET_SECURITY_STATE;
+ nd_cmd->nd_family = NVDIMM_FAMILY_INTEL;
+ nd_cmd->nd_size_out = sizeof(struct nd_intel_get_security_state);
+ nd_cmd->nd_fw_size = sizeof(struct nd_intel_get_security_state);
Can this keep the C99 init-style with something like (untested):
_DEFINE_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
sizeof(struct nd_intel_get_security_state), {
.pkg = {
.nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
.nd_family = NVDIMM_FAMILY_INTEL,
.nd_size_out =
sizeof(struct nd_intel_get_security_state),
.nd_fw_size =
sizeof(struct nd_intel_get_security_state),
},
});
?
The code below works - however, notice that in this case we should
go through 'obj', which is an object defined in _DEFINE_FLEX().
_DEFINE_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
sizeof(struct nd_intel_get_security_state), = {
.obj = {
.nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
.nd_family = NVDIMM_FAMILY_INTEL,
.nd_size_out =
sizeof(struct nd_intel_get_security_state),
.nd_fw_size =
sizeof(struct nd_intel_get_security_state),
},
});
Now, I can modify the helper like this:
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 69533e703be5..170d3cfe7ecc 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -404,7 +404,7 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
union { \
u8 bytes[struct_size_t(type, member, count)]; \
type obj; \
- } name##_u initializer; \
+ } name##_u = { .obj initializer }; \
type *name = (type *)&name##_u
/**
and then we can use the helper as follows:
_DEFINE_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
sizeof(struct nd_intel_get_security_state), = {
.nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
.nd_family = NVDIMM_FAMILY_INTEL,
.nd_size_out =
sizeof(struct nd_intel_get_security_state),
.nd_fw_size =
sizeof(struct nd_intel_get_security_state),
});
OK, I'll go and update the helper.
-Gustavo
