On Mon, Sep 25, 2023 at 1:52 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > On Mon, Sep 25, 2023 at 08:30:30AM +0200, Christian König wrote: > > Am 22.09.23 um 19:41 schrieb Alex Deucher: > > > On Fri, Sep 22, 2023 at 1:32 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > Prepare for the coming implementation by GCC and Clang of the __counted_by > > > > attribute. Flexible array members annotated with __counted_by can have > > > > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > > > > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > > > > functions). > > > > > > > > As found with Coccinelle[1], add __counted_by for struct smu10_voltage_dependency_table. > > > > > > > > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > > > > > > > Cc: Evan Quan <evan.quan@xxxxxxx> > > > > Cc: Alex Deucher <alexander.deucher@xxxxxxx> > > > > Cc: "Christian König" <christian.koenig@xxxxxxx> > > > > Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx> > > > > Cc: David Airlie <airlied@xxxxxxxxx> > > > > Cc: Daniel Vetter <daniel@xxxxxxxx> > > > > Cc: Xiaojian Du <Xiaojian.Du@xxxxxxx> > > > > Cc: Huang Rui <ray.huang@xxxxxxx> > > > > Cc: Kevin Wang <kevin1.wang@xxxxxxx> > > > > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx > > > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > > Acked-by: Alex Deucher <alexander.deucher@xxxxxxx> > > > > Mhm, I'm not sure if this is a good idea. That is a structure filled in by > > the firmware, isn't it? > > > > That would imply that we might need to byte swap count before it is > > checkable. > > The script found this instance because of this: > > static int smu10_get_clock_voltage_dependency_table(struct pp_hwmgr *hwmgr, > struct smu10_voltage_dependency_table **pptable, > uint32_t num_entry, const DpmClock_t *pclk_dependency_table) > { > uint32_t i; > struct smu10_voltage_dependency_table *ptable; > > ptable = kzalloc(struct_size(ptable, entries, num_entry), GFP_KERNEL); > if (NULL == ptable) > return -ENOMEM; > > ptable->count = num_entry; > > So the implication is that it's native byte order... but you tell me! I > certainly don't want this annotation if it's going to break stuff. :) In this case, the code is for an integrated GPU in an x86 CPU so the firmware and driver endianness match. You wouldn't find a stand alone dGPU that uses this structure. In this case it's ok. False alarm. Alex
