scsi: mpi3mr: Fix issues in mpi3mr_get_all_tgt_info()

The function mpi3mr_get_all_tgt_info() has four issues:

1) It calculates valid entry length in alltgt_info assuming the header part
   of the struct mpi3mr_device_map_info would equal to sizeof(u32).  The
   correct size is sizeof(u64).

2) When it calculates the valid entry length kern_entrylen, it excludes one
   entry by subtracting 1 from num_devices.

3) It copies num_device by calling memcpy(). Substitution is enough.

4) It does not specify the calculated length to sg_copy_from_buffer().
   Instead, it specifies the payload length which is larger than the
   alltgt_info size. It causes "BUG: KASAN: slab-out-of-bounds".

Fix the issues by using the correct header size, removing the subtraction
from num_devices, replacing the memcpy() with substitution and specifying
the correct length to sg_copy_from_buffer().

Link: https://lore.kernel.org/r/20230214005019.1897251-2-shinichiro.kawasaki@wdc.com
Cc: stable@vger.kernel.org
Fixes: f5e6d5a ("scsi: mpi3mr: Add support for driver commands")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Acked-by: Sathya Prakash Veerichetty <sathya.prakash@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: kawasaki

drivers/scsi/mpi3mr/mpi3mr_app.c

@@ -312,22 +312,22 @@ static long mpi3mr_get_all_tgt_info(struct mpi3mr_ioc *mrioc,
 		num_devices++;
 	spin_unlock_irqrestore(&mrioc->tgtdev_lock, flags);
 
-	if ((job->request_payload.payload_len == sizeof(u32)) ||
+	if ((job->request_payload.payload_len <= sizeof(u64)) ||
 		list_empty(&mrioc->tgtdev_list)) {
 		sg_copy_from_buffer(job->request_payload.sg_list,
 				    job->request_payload.sg_cnt,
 				    &num_devices, sizeof(num_devices));
 		return 0;
 	}
 
-	kern_entrylen = (num_devices - 1) * sizeof(*devmap_info);
-	size = sizeof(*alltgt_info) + kern_entrylen;
+	kern_entrylen = num_devices * sizeof(*devmap_info);
+	size = sizeof(u64) + kern_entrylen;
 	alltgt_info = kzalloc(size, GFP_KERNEL);
 	if (!alltgt_info)
 		return -ENOMEM;
 
 	devmap_info = alltgt_info->dmi;
-	memset((u8 *)devmap_info, 0xFF, (kern_entrylen + sizeof(*devmap_info)));
+	memset((u8 *)devmap_info, 0xFF, kern_entrylen);
 	spin_lock_irqsave(&mrioc->tgtdev_lock, flags);
 	list_for_each_entry(tgtdev, &mrioc->tgtdev_list, list) {
 		if (i < num_devices) {
@@ -344,9 +344,10 @@ static long mpi3mr_get_all_tgt_info(struct mpi3mr_ioc *mrioc,
 	num_devices = i;
 	spin_unlock_irqrestore(&mrioc->tgtdev_lock, flags);
 
-	memcpy(&alltgt_info->num_devices, &num_devices, sizeof(num_devices));
+	alltgt_info->num_devices = num_devices;
 
-	usr_entrylen = (job->request_payload.payload_len - sizeof(u32)) / sizeof(*devmap_info);
+	usr_entrylen = (job->request_payload.payload_len - sizeof(u64)) /
+		sizeof(*devmap_info);
 	usr_entrylen *= sizeof(*devmap_info);
 	min_entrylen = min(usr_entrylen, kern_entrylen);
 	if (min_entrylen && (!memcpy(&alltgt_info->dmi, devmap_info, min_entrylen))) {
@@ -358,7 +359,7 @@ static long mpi3mr_get_all_tgt_info(struct mpi3mr_ioc *mrioc,
 
 	sg_copy_from_buffer(job->request_payload.sg_list,
 			    job->request_payload.sg_cnt,
-			    alltgt_info, job->request_payload.payload_len);
+			    alltgt_info, (min_entrylen + sizeof(u64)));
 	rval = 0;
 out:
 	kfree(alltgt_info);