scsi: megaraid_sas: Add flexible array member for SGLs

struct MPI2_RAID_SCSI_IO_REQUEST ends with a single SGL, but expects to
copy multiple. Add a flexible array member so the compiler can reason about
the size of the memcpy(). This will avoid the run-time false positive
warning:

  memcpy: detected field-spanning write (size 128) of single field "&r1_cmd->io_request->SGL" at drivers/scsi/megaraid/megaraid_sas_fusion.c:3326 (size 16)

This change results in no binary output differences.

Reported-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Link: https://lore.kernel.org/all/88de8faa-56c4-693d-2d3-67152ee72057@diagnostix.dwd.de/
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: megaraidlinux.pdl@broadcom.com
Cc: linux-scsi@vger.kernel.org
Link: https://lore.kernel.org/r/20230106053153.never.999-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c
index fe70f8f..6597e11 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
@@ -3323,7 +3323,7 @@ static void megasas_prepare_secondRaid1_IO(struct megasas_instance *instance,
        /* copy the io request frame as well as 8 SGEs data for r1 command*/
        memcpy(r1_cmd->io_request, cmd->io_request,
               (sizeof(struct MPI2_RAID_SCSI_IO_REQUEST)));
-       memcpy(&r1_cmd->io_request->SGL, &cmd->io_request->SGL,
+       memcpy(r1_cmd->io_request->SGLs, cmd->io_request->SGLs,
               (fusion->max_sge_in_main_msg * sizeof(union MPI2_SGE_IO_UNION)));
        /*sense buffer is different for r1 command*/
        r1_cmd->io_request->SenseBufferLowAddress =

diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.h b/drivers/scsi/megaraid/megaraid_sas_fusion.h
index 49e9a90..b677d80 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.h
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.h
@@ -526,7 +526,10 @@ struct MPI2_RAID_SCSI_IO_REQUEST {
        __le32                  Control;                        /* 0x3C */
        union MPI2_SCSI_IO_CDB_UNION  CDB;                      /* 0x40 */
        union RAID_CONTEXT_UNION RaidContext;  /* 0x60 */
-       union MPI2_SGE_IO_UNION       SGL;                      /* 0x80 */
+       union {
+               union MPI2_SGE_IO_UNION       SGL;              /* 0x80 */
+               DECLARE_FLEX_ARRAY(union MPI2_SGE_IO_UNION, SGLs);
+       };
 };
 
 /*