[PATCH v2] [next] drm/radeon: Replace one-element array with flexible-array member
Paulo Miguel Almeida
paulo.miguel.almeida.rodenas at gmail.com
Sat Oct 29 03:32:05 UTC 2022
One-element arrays are deprecated, and we are replacing them with
flexible array members instead. So, replace one-element array with
flexible-array member in struct _ATOM_FAKE_EDID_PATCH_RECORD and
refactor the rest of the code accordingly.
It's worth mentioning that doing a build before/after this patch results
in no binary output differences.
This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].
Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/239
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas at gmail.com>
---
Changelog:
v2: no binary output differences patch; report binary changes findings
on commit log. Res: Kees Cook.
This request was made in an identical, yet different, patch but the
same feedback applies.
https://lore.kernel.org/lkml/Y1x3MtRJ8ckXxlJn@mail.google.com/
v1: https://lore.kernel.org/lkml/Y1trhRE3nK5iAY6q@mail.google.com/
---
drivers/gpu/drm/radeon/atombios.h | 2 +-
drivers/gpu/drm/radeon/radeon_atombios.c | 7 +++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/radeon/atombios.h b/drivers/gpu/drm/radeon/atombios.h
index da35a970fcc0..235e59b547a1 100644
--- a/drivers/gpu/drm/radeon/atombios.h
+++ b/drivers/gpu/drm/radeon/atombios.h
@@ -3615,7 +3615,7 @@ typedef struct _ATOM_FAKE_EDID_PATCH_RECORD
{
UCHAR ucRecordType;
UCHAR ucFakeEDIDLength;
- UCHAR ucFakeEDIDString[1]; // This actually has ucFakeEdidLength elements.
+ UCHAR ucFakeEDIDString[]; // This actually has ucFakeEdidLength elements.
} ATOM_FAKE_EDID_PATCH_RECORD;
typedef struct _ATOM_PANEL_RESOLUTION_PATCH_RECORD
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 204127bad89c..4ad5a328d920 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -1727,8 +1727,11 @@ struct radeon_encoder_atom_dig *radeon_atombios_get_lvds_info(struct
}
}
record += fake_edid_record->ucFakeEDIDLength ?
- fake_edid_record->ucFakeEDIDLength + 2 :
- sizeof(ATOM_FAKE_EDID_PATCH_RECORD);
+ struct_size(fake_edid_record,
+ ucFakeEDIDString,
+ fake_edid_record->ucFakeEDIDLength) :
+ /* empty fake edid record must be 3 bytes long */
+ sizeof(ATOM_FAKE_EDID_PATCH_RECORD) + 1;
break;
case LCD_PANEL_RESOLUTION_RECORD_TYPE:
panel_res_record = (ATOM_PANEL_RESOLUTION_PATCH_RECORD *)record;
--
2.37.3
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