block: Use g_new() & friends to avoid multiplying sizes

g_new(T, n) is safer than g_malloc(sizeof(*v) * n) for two reasons.
One, it catches multiplication overflowing size_t.  Two, it returns
T * rather than void *, which lets the compiler catch more type
errors.

Perhaps a conversion to g_malloc_n() would be neater in places, but
that's merely four years old, and we can't use such newfangled stuff.

This commit only touches allocations with size arguments of the form
sizeof(T), plus two that use 4 instead of sizeof(uint32_t).  We can
make the others safe by converting to g_malloc_n() when it becomes
available to us in a couple of years.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

6 files changed, 6 insertions, 7 deletions

diff --git a/block/bochs.c b/block/bochs.c
index 6674b27438..199ac2b9af 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -131,7 +131,7 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         return -EFBIG;
     }
 
-    s->catalog_bitmap = g_try_malloc(s->catalog_size * 4);
+    s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
     if (s->catalog_size && s->catalog_bitmap == NULL) {
         error_setg(errp, "Could not allocate memory for catalog");
         return -ENOMEM;
diff --git a/block/parallels.c b/block/parallels.c
index 1774ab8e8e..2a814f3db4 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -121,7 +121,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
         ret = -EFBIG;
         goto fail;
     }
-    s->catalog_bitmap = g_try_malloc(s->catalog_size * 4);
+    s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size);
     if (s->catalog_size && s->catalog_bitmap == NULL) {
         ret = -ENOMEM;
         goto fail;
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index 5353b44828..fe0615a995 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -50,7 +50,7 @@ Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables)
 
     c = g_malloc0(sizeof(*c));
     c->size = num_tables;
-    c->entries = g_malloc0(sizeof(*c->entries) * num_tables);
+    c->entries = g_new0(Qcow2CachedTable, num_tables);
 
     for (i = 0; i < c->size; i++) {
         c->entries[i].table = qemu_try_blockalign(bs->file, s->cluster_size);
diff --git a/block/qed-check.c b/block/qed-check.c
index 40a882cc93..36ecd290d6 100644
--- a/block/qed-check.c
+++ b/block/qed-check.c
@@ -227,8 +227,7 @@ int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix)
     };
     int ret;
 
-    check.used_clusters = g_try_malloc0(((check.nclusters + 31) / 32) *
-                                        sizeof(check.used_clusters[0]));
+    check.used_clusters = g_try_new0(uint32_t, (check.nclusters + 31) / 32);
     if (check.nclusters && check.used_clusters == NULL) {
         return -ENOMEM;
     }
diff --git a/block/rbd.c b/block/rbd.c
index 3aaf8559dd..ea969e7beb 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -862,7 +862,7 @@ static int qemu_rbd_snap_list(BlockDriverState *bs,
     int max_snaps = RBD_MAX_SNAPS;
 
     do {
-        snaps = g_malloc(sizeof(*snaps) * max_snaps);
+        snaps = g_new(rbd_snap_info_t, max_snaps);
         snap_count = rbd_snap_list(s->image, snaps, &max_snaps);
         if (snap_count <= 0) {
             g_free(snaps);
diff --git a/block/sheepdog.c b/block/sheepdog.c
index ba1ef43502..12cbd9dcb4 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2357,7 +2357,7 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
         goto out;
     }
 
-    sn_tab = g_malloc0(nr * sizeof(*sn_tab));
+    sn_tab = g_new0(QEMUSnapshotInfo, nr);
 
     /* calculate a vdi id with hash function */
     hval = fnv_64a_buf(s->name, strlen(s->name), FNV1A_64_INIT);