hw/ufs: Fix code coverity issues

Fixed four ufs-related coverity issues.

The coverity issues and fixes are as follows

1. CID 1519042: Security issue with the rand() function
Changed to use a fixed value (0xab) instead of rand() as
the value for testing

2. CID 1519043: Dereference after null check
Removed useless (redundant) null checks

3. CID 1519050: Out-of-bounds access issue
Fix to pass an array type variable to find_first_bit and
find_next_bit using DECLARE_BITMAP()

4. CID 1519051: Out-of-bounds read issue
Fix incorrect range check for lun

Fix coverity CID: 1519042 1519043 1519050 1519051

Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>

2 files changed, 12 insertions, 14 deletions

diff --git a/hw/ufs/lu.c b/hw/ufs/lu.c
index e1c46bd..13b5e37 100644
--- a/hw/ufs/lu.c
+++ b/hw/ufs/lu.c
@@ -1345,13 +1345,12 @@ static void ufs_lu_realize(SCSIDevice *dev, Error **errp)
         return;
     }
 
-    if (lu->qdev.conf.blk) {
-        ctx = blk_get_aio_context(lu->qdev.conf.blk);
-        aio_context_acquire(ctx);
-        if (!blkconf_blocksizes(&lu->qdev.conf, errp)) {
-            goto out;
-        }
+    ctx = blk_get_aio_context(lu->qdev.conf.blk);
+    aio_context_acquire(ctx);
+    if (!blkconf_blocksizes(&lu->qdev.conf, errp)) {
+        goto out;
     }
+
     lu->qdev.blocksize = UFS_BLOCK_SIZE;
     blk_get_geometry(lu->qdev.conf.blk, &nb_sectors);
     nb_blocks = nb_sectors / (lu->qdev.blocksize / BDRV_SECTOR_SIZE);
@@ -1367,10 +1366,9 @@ static void ufs_lu_realize(SCSIDevice *dev, Error **errp)
     }
 
     ufs_lu_brdv_init(lu, errp);
+
 out:
-    if (ctx) {
-        aio_context_release(ctx);
-    }
+    aio_context_release(ctx);
 }
 
 static void ufs_lu_unrealize(SCSIDevice *dev)
diff --git a/hw/ufs/ufs.c b/hw/ufs/ufs.c
index 0ecedb9..2e6d582 100644
--- a/hw/ufs/ufs.c
+++ b/hw/ufs/ufs.c
@@ -258,7 +258,7 @@ static void ufs_irq_check(UfsHc *u)
 
 static void ufs_process_db(UfsHc *u, uint32_t val)
 {
-    unsigned long doorbell;
+    DECLARE_BITMAP(doorbell, UFS_MAX_NUTRS);
     uint32_t slot;
     uint32_t nutrs = u->params.nutrs;
     UfsRequest *req;
@@ -268,8 +268,8 @@ static void ufs_process_db(UfsHc *u, uint32_t val)
         return;
     }
 
-    doorbell = val;
-    slot = find_first_bit(&doorbell, nutrs);
+    doorbell[0] = val;
+    slot = find_first_bit(doorbell, nutrs);
 
     while (slot < nutrs) {
         req = &u->req_list[slot];
@@ -285,7 +285,7 @@ static void ufs_process_db(UfsHc *u, uint32_t val)
 
         trace_ufs_process_db(slot);
         req->state = UFS_REQUEST_READY;
-        slot = find_next_bit(&doorbell, nutrs, slot + 1);
+        slot = find_next_bit(doorbell, nutrs, slot + 1);
     }
 
     qemu_bh_schedule(u->doorbell_bh);
@@ -838,7 +838,7 @@ static QueryRespCode ufs_read_unit_desc(UfsRequest *req)
     uint8_t lun = req->req_upiu.qr.index;
 
     if (lun != UFS_UPIU_RPMB_WLUN &&
-        (lun > UFS_MAX_LUS || u->lus[lun] == NULL)) {
+        (lun >= UFS_MAX_LUS || u->lus[lun] == NULL)) {
         trace_ufs_err_query_invalid_index(req->req_upiu.qr.opcode, lun);
         return UFS_QUERY_RESULT_INVALID_INDEX;
     }