On Wed, Aug 04, 2021 at 11:20:04PM -0500, Gustavo A. R. Silva wrote: > Replace one-element array with a flexible-array member in struct > MR_DRV_RAID_MAP and use the flex_array_size() helper. > > This helps with the ongoing efforts to globally enable -Warray-bounds > and get us closer to being able to tighten the FORTIFY_SOURCE routines > on memcpy(). > > Link: https://en.wikipedia.org/wiki/Flexible_array_member > Link: https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays > Link: https://github.com/KSPP/linux/issues/79 > Link: https://github.com/KSPP/linux/issues/109 > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> I'd really like to see this fixed. :) I'm running into this 1-element array problem now with UBSAN_BOUNDS: [ 10.011173] UBSAN: array-index-out-of-bounds in /build/linux-WLUive/linux-5.15.0/drivers/scsi/megaraid/megaraid_sas_fp.c:103:32 [ 10.087824] index 1 is out of range for type 'MR_LD_SPAN_MAP [1]' and I'm not the only one: https://bugzilla.kernel.org/show_bug.cgi?id=215943 > --- > Changes in v2: > - None. > > drivers/scsi/megaraid/megaraid_sas_fp.c | 6 +++--- > drivers/scsi/megaraid/megaraid_sas_fusion.h | 2 +- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/scsi/megaraid/megaraid_sas_fp.c b/drivers/scsi/megaraid/megaraid_sas_fp.c > index da1cad1ee123..9cb36ef96c2c 100644 > --- a/drivers/scsi/megaraid/megaraid_sas_fp.c > +++ b/drivers/scsi/megaraid/megaraid_sas_fp.c > @@ -229,8 +229,8 @@ static int MR_PopulateDrvRaidMap(struct megasas_instance *instance, u64 map_id) > le32_to_cpu(desc_table->raid_map_desc_offset)); > memcpy(pDrvRaidMap->ldSpanMap, > fw_map_dyn->ld_span_map, > - sizeof(struct MR_LD_SPAN_MAP) * > - le32_to_cpu(desc_table->raid_map_desc_elements)); > + flex_array_size(pDrvRaidMap, ldSpanMap, > + le32_to_cpu(desc_table->raid_map_desc_elements))); > break; > default: > dev_dbg(&instance->pdev->dev, "wrong number of desctableElements %d\n", > @@ -254,7 +254,7 @@ static int MR_PopulateDrvRaidMap(struct megasas_instance *instance, u64 map_id) > pDrvRaidMap->ldTgtIdToLd[i] = > (u16)fw_map_ext->ldTgtIdToLd[i]; > memcpy(pDrvRaidMap->ldSpanMap, fw_map_ext->ldSpanMap, > - sizeof(struct MR_LD_SPAN_MAP) * ld_count); > + flex_array_size(pDrvRaidMap, ldSpanMap, ld_count)); > memcpy(pDrvRaidMap->arMapInfo, fw_map_ext->arMapInfo, > sizeof(struct MR_ARRAY_INFO) * MAX_API_ARRAYS_EXT); > memcpy(pDrvRaidMap->devHndlInfo, fw_map_ext->devHndlInfo, > diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.h b/drivers/scsi/megaraid/megaraid_sas_fusion.h > index 9adb8b30f422..5fe2f7a6eebe 100644 > --- a/drivers/scsi/megaraid/megaraid_sas_fusion.h > +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.h > @@ -1182,7 +1182,7 @@ struct MR_DRV_RAID_MAP { > devHndlInfo[MAX_RAIDMAP_PHYSICAL_DEVICES_DYN]; > u16 ldTgtIdToLd[MAX_LOGICAL_DRIVES_DYN]; > struct MR_ARRAY_INFO arMapInfo[MAX_API_ARRAYS_DYN]; > - struct MR_LD_SPAN_MAP ldSpanMap[1]; > + struct MR_LD_SPAN_MAP ldSpanMap[]; > > }; > I think this patch is incomplete, and the wrapping struct needs to be adjusted too: @@ -1193,7 +1193,7 @@ struct MR_DRV_RAID_MAP { struct MR_DRV_RAID_MAP_ALL { struct MR_DRV_RAID_MAP raidMap; - struct MR_LD_SPAN_MAP ldSpanMap[MAX_LOGICAL_DRIVES_DYN - 1]; + struct MR_LD_SPAN_MAP ldSpanMap[MAX_LOGICAL_DRIVES_DYN]; } __packed; With that added, I get zero changes to the executable code. I assume the others need adjustment too. -- Kees Cook
