scsi: mpi3mr: Avoid memcpy field-spanning write WARNING

When the "storcli2 show" command is executed for eHBA-9600, mpi3mr driver
prints this WARNING message:

  memcpy: detected field-spanning write (size 128) of single field "bsg_reply_buf->reply_buf" at drivers/scsi/mpi3mr/mpi3mr_app.c:1658 (size 1)
  WARNING: CPU: 0 PID: 12760 at drivers/scsi/mpi3mr/mpi3mr_app.c:1658 mpi3mr_bsg_request+0x6b12/0x7f10 [mpi3mr]

The cause of the WARN is 128 bytes memcpy to the 1 byte size array "__u8
replay_buf[1]" in the struct mpi3mr_bsg_in_reply_buf. The array is intended
to be a flexible length array, so the WARN is a false positive.

To suppress the WARN, remove the constant number '1' from the array
declaration and clarify that it has flexible length. Also, adjust the
memory allocation size to match the change.

Suggested-by: Sathya Prakash Veerichetty <sathya.prakash@broadcom.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20240323084155.166835-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/mpi3mr/mpi3mr_app.c b/drivers/scsi/mpi3mr/mpi3mr_app.c
index 0380996b5ad27aee4740f03431b4157b3526f6bf..55d590b919476e191dd52c4993d1644945495f66 100644 (file)
--- a/drivers/scsi/mpi3mr/mpi3mr_app.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_app.c
@@ -1644,7 +1644,7 @@ static long mpi3mr_bsg_process_mpt_cmds(struct bsg_job *job)
        if ((mpirep_offset != 0xFF) &&
            drv_bufs[mpirep_offset].bsg_buf_len) {
                drv_buf_iter = &drv_bufs[mpirep_offset];
-               drv_buf_iter->kern_buf_len = (sizeof(*bsg_reply_buf) - 1 +
+               drv_buf_iter->kern_buf_len = (sizeof(*bsg_reply_buf) +
                                           mrioc->reply_sz);
                bsg_reply_buf = kzalloc(drv_buf_iter->kern_buf_len, GFP_KERNEL);
 

diff --git a/include/uapi/scsi/scsi_bsg_mpi3mr.h b/include/uapi/scsi/scsi_bsg_mpi3mr.h
index c72ce387286ad9506de5e93ec9147e46e85a7752..30a5c1a593764565212fc5fc2a1ec46ea2d3271a 100644 (file)
--- a/include/uapi/scsi/scsi_bsg_mpi3mr.h
+++ b/include/uapi/scsi/scsi_bsg_mpi3mr.h
@@ -382,7 +382,7 @@ struct mpi3mr_bsg_in_reply_buf {
        __u8    mpi_reply_type;
        __u8    rsvd1;
        __u16   rsvd2;
-       __u8    reply_buf[1];
+       __u8    reply_buf[];
 };
 
 /**