On Thu, Aug 19, 2021 at 4:14 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > In preparation for FORTIFY_SOURCE performing compile-time and run-time > field bounds checking for memcpy(), memmove(), and memset(), avoid > intentionally writing across neighboring fields. > > The "Board Parameters" members of the structs: > struct atom_smc_dpm_info_v4_5 > struct atom_smc_dpm_info_v4_6 > struct atom_smc_dpm_info_v4_7 > struct atom_smc_dpm_info_v4_10 > are written to the corresponding members of the corresponding PPTable_t > variables, but they lack destination size bounds checking, which means > the compiler cannot verify at compile time that this is an intended and > safe memcpy(). > > Since the header files are effectively immutable[1] and a struct_group() > cannot be used, nor a common struct referenced by both sides of the > memcpy() arguments, add a new helper, memcpy_trailing(), to perform the > bounds checking at compile time. Replace the open-coded memcpy()s with > memcpy_trailing() which includes enough context for the bounds checking. > > "objdump -d" shows no object code changes. > > [1] https://lore.kernel.org/lkml/e56aad3c-a06f-da07-f491-a894a570d78f@xxxxxxx > > Cc: Lijo Lazar <lijo.lazar@xxxxxxx> > Cc: "Christian König" <christian.koenig@xxxxxxx> > Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx> > Cc: David Airlie <airlied@xxxxxxxx> > Cc: Daniel Vetter <daniel@xxxxxxxx> > Cc: Hawking Zhang <Hawking.Zhang@xxxxxxx> > Cc: Feifei Xu <Feifei.Xu@xxxxxxx> > Cc: Likun Gao <Likun.Gao@xxxxxxx> > Cc: Jiawei Gu <Jiawei.Gu@xxxxxxx> > Cc: Evan Quan <evan.quan@xxxxxxx> > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > Link: https://lore.kernel.org/lkml/CADnq5_Npb8uYvd+R4UHgf-w8-cQj3JoODjviJR_Y9w9wqJ71mQ@xxxxxxxxxxxxxx > --- > Alex, I dropped your prior Acked-by, since the implementation is very > different. If you're still happy with it, I can add it back. :) This looks reasonable to me: Acked-by: Alex Deucher <alexander.deucher@xxxxxxx> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu.h | 25 +++++++++++++++++++ > .../gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c | 6 ++--- > .../gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c | 8 +++--- > .../drm/amd/pm/swsmu/smu13/aldebaran_ppt.c | 5 ++-- > 4 files changed, 33 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > index 96e895d6be35..4605934a4fb7 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > @@ -1446,4 +1446,29 @@ static inline int amdgpu_in_reset(struct amdgpu_device *adev) > { > return atomic_read(&adev->in_gpu_reset); > } > + > +/** > + * memcpy_trailing - Copy the end of one structure into the middle of another > + * > + * @dst: Pointer to destination struct > + * @first_dst_member: The member name in @dst where the overwrite begins > + * @last_dst_member: The member name in @dst where the overwrite ends after > + * @src: Pointer to the source struct > + * @first_src_member: The member name in @src where the copy begins > + * > + */ > +#define memcpy_trailing(dst, first_dst_member, last_dst_member, \ > + src, first_src_member) \ > +({ \ > + size_t __src_offset = offsetof(typeof(*(src)), first_src_member); \ > + size_t __src_size = sizeof(*(src)) - __src_offset; \ > + size_t __dst_offset = offsetof(typeof(*(dst)), first_dst_member); \ > + size_t __dst_size = offsetofend(typeof(*(dst)), last_dst_member) - \ > + __dst_offset; \ > + BUILD_BUG_ON(__src_size != __dst_size); \ > + __builtin_memcpy((u8 *)(dst) + __dst_offset, \ > + (u8 *)(src) + __src_offset, \ > + __dst_size); \ > +}) > + > #endif > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c > index 8ab58781ae13..1918e6232319 100644 > --- a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c > @@ -465,10 +465,8 @@ static int arcturus_append_powerplay_table(struct smu_context *smu) > > if ((smc_dpm_table->table_header.format_revision == 4) && > (smc_dpm_table->table_header.content_revision == 6)) > - memcpy(&smc_pptable->MaxVoltageStepGfx, > - &smc_dpm_table->maxvoltagestepgfx, > - sizeof(*smc_dpm_table) - offsetof(struct atom_smc_dpm_info_v4_6, maxvoltagestepgfx)); > - > + memcpy_trailing(smc_pptable, MaxVoltageStepGfx, BoardReserved, > + smc_dpm_table, maxvoltagestepgfx); > return 0; > } > > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c > index 2e5d3669652b..b738042e064d 100644 > --- a/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c > @@ -431,16 +431,16 @@ static int navi10_append_powerplay_table(struct smu_context *smu) > > switch (smc_dpm_table->table_header.content_revision) { > case 5: /* nv10 and nv14 */ > - memcpy(smc_pptable->I2cControllers, smc_dpm_table->I2cControllers, > - sizeof(*smc_dpm_table) - sizeof(smc_dpm_table->table_header)); > + memcpy_trailing(smc_pptable, I2cControllers, BoardReserved, > + smc_dpm_table, I2cControllers); > break; > case 7: /* nv12 */ > ret = amdgpu_atombios_get_data_table(adev, index, NULL, NULL, NULL, > (uint8_t **)&smc_dpm_table_v4_7); > if (ret) > return ret; > - memcpy(smc_pptable->I2cControllers, smc_dpm_table_v4_7->I2cControllers, > - sizeof(*smc_dpm_table_v4_7) - sizeof(smc_dpm_table_v4_7->table_header)); > + memcpy_trailing(smc_pptable, I2cControllers, BoardReserved, > + smc_dpm_table_v4_7, I2cControllers); > break; > default: > dev_err(smu->adev->dev, "smc_dpm_info with unsupported content revision %d!\n", > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c > index c8eefacfdd37..a6fd7ee314a9 100644 > --- a/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/aldebaran_ppt.c > @@ -409,9 +409,8 @@ static int aldebaran_append_powerplay_table(struct smu_context *smu) > > if ((smc_dpm_table->table_header.format_revision == 4) && > (smc_dpm_table->table_header.content_revision == 10)) > - memcpy(&smc_pptable->GfxMaxCurrent, > - &smc_dpm_table->GfxMaxCurrent, > - sizeof(*smc_dpm_table) - offsetof(struct atom_smc_dpm_info_v4_10, GfxMaxCurrent)); > + memcpy_trailing(smc_pptable, GfxMaxCurrent, reserved, > + smc_dpm_table, GfxMaxCurrent); > return 0; > } > > -- > 2.30.2 >
