Re: [PATCH] scsi: megaraid_sas: struct MR_HOST_DEVICE_LIST: Replace 1-element array with flexible array
From: Gustavo A. R. Silva
Date: Thu Jul 11 2024 - 12:56:09 EST
On 11/07/24 09:58, Kees Cook wrote:
Replace the deprecated[1] use of a 1-element array in
struct MR_HOST_DEVICE_LIST with a modern flexible array.
One binary difference appears in megasas_host_device_list_query():
struct MR_HOST_DEVICE_LIST *ci;
...
ci = instance->host_device_list_buf;
...
memset(ci, 0, sizeof(*ci));
The memset() clears only the non-flexible array fields. Looking at the
rest of the function, this appears to be fine: firmware is using this
region to communicate with the kernel, so it likely never made sense to
clear the first MR_HOST_DEVICE_LIST_ENTRY.
Yeah, clearing that fist entry seems odd/buggy. So, this patch is probably
even fixing a bug. :)
Link: https://github.com/KSPP/linux/issues/79 [1]
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Thanks
--
Gustavo
---
Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx>
Cc: Shivasharan S <shivasharan.srikanteshwara@xxxxxxxxxxxx>
Cc: Chandrakanth patil <chandrakanth.patil@xxxxxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: megaraidlinux.pdl@xxxxxxxxxxxx
Cc: linux-scsi@xxxxxxxxxxxxxxx
---
drivers/scsi/megaraid/megaraid_sas.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 84cf77c48c0d..088cc40ae866 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -814,12 +814,12 @@ struct MR_HOST_DEVICE_LIST {
__le32 size;
__le32 count;
__le32 reserved[2];
- struct MR_HOST_DEVICE_LIST_ENTRY host_device_list[1];
+ struct MR_HOST_DEVICE_LIST_ENTRY host_device_list[] __counted_by_le(count);
} __packed;
#define HOST_DEVICE_LIST_SZ (sizeof(struct MR_HOST_DEVICE_LIST) + \
(sizeof(struct MR_HOST_DEVICE_LIST_ENTRY) * \
- (MEGASAS_MAX_PD + MAX_LOGICAL_DRIVES_EXT - 1)))
+ (MEGASAS_MAX_PD + MAX_LOGICAL_DRIVES_EXT)))
/*