On Wed, 2024-03-20 at 22:11 -0600, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting > ready to enable it globally. > > There is currently an object (`hdr)` in `struct ima_max_digest_data` > that contains a flexible structure (`struct ima_digest_data`): > > struct ima_max_digest_data { > struct ima_digest_data hdr; > u8 digest[HASH_MAX_DIGESTSIZE]; > } __packed; > > So, in order to avoid ending up with a flexible-array member in the > middle of a struct, we use the `__struct_group()` helper to separate > the flexible array from the rest of the members in the flexible > structure: > > struct ima_digest_data { > __struct_group(ima_digest_data_hdr, hdr, __packed, > > ... the rest of the members > > ); > u8 digest[]; > } __packed; > > With the change described above, we can now declare an object of the > type of the tagged `struct ima_digest_data_hdr`, without embedding the > flexible array in the middle of another struct: > > struct ima_max_digest_data { > struct ima_digest_data_hdr hdr; > u8 digest[HASH_MAX_DIGESTSIZE]; > } __packed; > And similarly for 'struct evm_digest'. > We also use `container_of()` whenever we need to retrieve a pointer to > the flexible structure. > > So, with these changes, fix the following warnings: > > security/integrity/evm/evm.h:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] > security/integrity/evm/evm.h:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] > security/integrity/evm/evm.h:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] I assume these messages are gone. thanks, Mimi > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > --- > Changes in v3: > - struct ima_digest_data is a packed structure. So, to keep things > consistent, use the attribute __packed on the tagged struct > ima_digest_data_hdr. For this, we use __struct_group() instead of > struct_group_tagged(). Update the changelog text, accordingly. > > Changes in v2: > - Include changes for `struct evm_digest` (Mimi Zohar) >