net/ncsi: Refactor MAC, VLAN filters

The NCSI driver defines a generic ncsi_channel_filter struct that can be
used to store arbitrarily formatted filters, and several generic methods
of accessing data stored in such a filter.
However in both the driver and as defined in the NCSI specification
there are only two actual filters: VLAN ID filters and MAC address
filters. The splitting of the MAC filter into unicast, multicast, and
mixed is also technically not necessary as these are stored in the same
location in hardware.

To save complexity, particularly in the set up and accessing of these
generic filters, remove them in favour of two specific structs. These
can be acted on directly and do not need several generic helper
functions to use.

This also fixes a memory error found by KASAN on ARM32 (which is not
upstream yet), where response handlers accessing a filter's data field
could write past allocated memory.

[  114.926512] ==================================================================
[  114.933861] BUG: KASAN: slab-out-of-bounds in ncsi_configure_channel+0x4b8/0xc58
[  114.941304] Read of size 2 at addr 94888558 by task kworker/0:2/546
[  114.947593]
[  114.949146] CPU: 0 PID: 546 Comm: kworker/0:2 Not tainted 4.16.0-rc6-00119-ge156398bfcad #13
...
[  115.170233] The buggy address belongs to the object at 94888540
[  115.170233]  which belongs to the cache kmalloc-32 of size 32
[  115.181917] The buggy address is located 24 bytes inside of
[  115.181917]  32-byte region [94888540, 94888560)
[  115.192115] The buggy address belongs to the page:
[  115.196943] page:9eeac100 count:1 mapcount:0 mapping:94888000 index:0x94888fc1
[  115.204200] flags: 0x100(slab)
[  115.207330] raw: 00000100 94888000 94888fc1 0000003f 00000001 9eea2014 9eecaa74 96c003e0
[  115.215444] page dumped because: kasan: bad access detected
[  115.221036]
[  115.222544] Memory state around the buggy address:
[  115.227384]  94888400: fb fb fb fb fc fc fc fc 04 fc fc fc fc fc fc fc
[  115.233959]  94888480: 00 00 00 fc fc fc fc fc 00 04 fc fc fc fc fc fc
[  115.240529] >94888500: 00 00 04 fc fc fc fc fc 00 00 04 fc fc fc fc fc
[  115.247077]                                             ^
[  115.252523]  94888580: 00 04 fc fc fc fc fc fc 06 fc fc fc fc fc fc fc
[  115.259093]  94888600: 00 00 06 fc fc fc fc fc 00 00 04 fc fc fc fc fc
[  115.265639] ==================================================================

Reported-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 52 insertions, 174 deletions

diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index c3695ba0cf94..5561e221b71f 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -27,125 +27,6 @@
 LIST_HEAD(ncsi_dev_list);
 DEFINE_SPINLOCK(ncsi_dev_lock);
 
-static inline int ncsi_filter_size(int table)
-{
-	int sizes[] = { 2, 6, 6, 6 };
-
-	BUILD_BUG_ON(ARRAY_SIZE(sizes) != NCSI_FILTER_MAX);
-	if (table < NCSI_FILTER_BASE || table >= NCSI_FILTER_MAX)
-		return -EINVAL;
-
-	return sizes[table];
-}
-
-u32 *ncsi_get_filter(struct ncsi_channel *nc, int table, int index)
-{
-	struct ncsi_channel_filter *ncf;
-	int size;
-
-	ncf = nc->filters[table];
-	if (!ncf)
-		return NULL;
-
-	size = ncsi_filter_size(table);
-	if (size < 0)
-		return NULL;
-
-	return ncf->data + size * index;
-}
-
-/* Find the first active filter in a filter table that matches the given
- * data parameter. If data is NULL, this returns the first active filter.
- */
-int ncsi_find_filter(struct ncsi_channel *nc, int table, void *data)
-{
-	struct ncsi_channel_filter *ncf;
-	void *bitmap;
-	int index, size;
-	unsigned long flags;
-
-	ncf = nc->filters[table];
-	if (!ncf)
-		return -ENXIO;
-
-	size = ncsi_filter_size(table);
-	if (size < 0)
-		return size;
-
-	spin_lock_irqsave(&nc->lock, flags);
-	bitmap = (void *)&ncf->bitmap;
-	index = -1;
-	while ((index = find_next_bit(bitmap, ncf->total, index + 1))
-	       < ncf->total) {
-		if (!data || !memcmp(ncf->data + size * index, data, size)) {
-			spin_unlock_irqrestore(&nc->lock, flags);
-			return index;
-		}
-	}
-	spin_unlock_irqrestore(&nc->lock, flags);
-
-	return -ENOENT;
-}
-
-int ncsi_add_filter(struct ncsi_channel *nc, int table, void *data)
-{
-	struct ncsi_channel_filter *ncf;
-	int index, size;
-	void *bitmap;
-	unsigned long flags;
-
-	size = ncsi_filter_size(table);
-	if (size < 0)
-		return size;
-
-	index = ncsi_find_filter(nc, table, data);
-	if (index >= 0)
-		return index;
-
-	ncf = nc->filters[table];
-	if (!ncf)
-		return -ENODEV;
-
-	spin_lock_irqsave(&nc->lock, flags);
-	bitmap = (void *)&ncf->bitmap;
-	do {
-		index = find_next_zero_bit(bitmap, ncf->total, 0);
-		if (index >= ncf->total) {
-			spin_unlock_irqrestore(&nc->lock, flags);
-			return -ENOSPC;
-		}
-	} while (test_and_set_bit(index, bitmap));
-
-	memcpy(ncf->data + size * index, data, size);
-	spin_unlock_irqrestore(&nc->lock, flags);
-
-	return index;
-}
-
-int ncsi_remove_filter(struct ncsi_channel *nc, int table, int index)
-{
-	struct ncsi_channel_filter *ncf;
-	int size;
-	void *bitmap;
-	unsigned long flags;
-
-	size = ncsi_filter_size(table);
-	if (size < 0)
-		return size;
-
-	ncf = nc->filters[table];
-	if (!ncf || index >= ncf->total)
-		return -ENODEV;
-
-	spin_lock_irqsave(&nc->lock, flags);
-	bitmap = (void *)&ncf->bitmap;
-	if (test_and_clear_bit(index, bitmap))
-		memset(ncf->data + size * index, 0, size);
-	spin_unlock_irqrestore(&nc->lock, flags);
-
-	return 0;
-}
-
 static void ncsi_report_link(struct ncsi_dev_priv *ndp, bool force_down)
 {
 	struct ncsi_dev *nd = &ndp->ndev;
@@ -339,20 +220,13 @@ struct ncsi_channel *ncsi_add_channel(struct ncsi_package *np, unsigned char id)
 static void ncsi_remove_channel(struct ncsi_channel *nc)
 {
 	struct ncsi_package *np = nc->package;
-	struct ncsi_channel_filter *ncf;
 	unsigned long flags;
-	int i;
 
-	/* Release filters */
 	spin_lock_irqsave(&nc->lock, flags);
-	for (i = 0; i < NCSI_FILTER_MAX; i++) {
-		ncf = nc->filters[i];
-		if (!ncf)
-			continue;
 
-		nc->filters[i] = NULL;
-		kfree(ncf);
-	}
+	/* Release filters */
+	kfree(nc->mac_filter.addrs);
+	kfree(nc->vlan_filter.vids);
 
 	nc->state = NCSI_CHANNEL_INACTIVE;
 	spin_unlock_irqrestore(&nc->lock, flags);
@@ -670,32 +544,26 @@ error:
 static int clear_one_vid(struct ncsi_dev_priv *ndp, struct ncsi_channel *nc,
 			 struct ncsi_cmd_arg *nca)
 {
+	struct ncsi_channel_vlan_filter *ncf;
+	unsigned long flags;
+	void *bitmap;
 	int index;
-	u32 *data;
 	u16 vid;
 
-	index = ncsi_find_filter(nc, NCSI_FILTER_VLAN, NULL);
-	if (index < 0) {
-		/* Filter table empty */
-		return -1;
-	}
+	ncf = &nc->vlan_filter;
+	bitmap = &ncf->bitmap;
 
-	data = ncsi_get_filter(nc, NCSI_FILTER_VLAN, index);
-	if (!data) {
-		netdev_err(ndp->ndev.dev,
-			   "NCSI: failed to retrieve filter %d\n", index);
-		/* Set the VLAN id to 0 - this will still disable the entry in
-		 * the filter table, but we won't know what it was.
-		 */
-		vid = 0;
-	} else {
-		vid = *(u16 *)data;
+	spin_lock_irqsave(&nc->lock, flags);
+	index = find_next_bit(bitmap, ncf->n_vids, 0);
+	if (index >= ncf->n_vids) {
+		spin_unlock_irqrestore(&nc->lock, flags);
+		return -1;
 	}
+	vid = ncf->vids[index];
 
-	netdev_printk(KERN_DEBUG, ndp->ndev.dev,
-		      "NCSI: removed vlan tag %u at index %d\n",
-		      vid, index + 1);
-	ncsi_remove_filter(nc, NCSI_FILTER_VLAN, index);
+	clear_bit(index, bitmap);
+	ncf->vids[index] = 0;
+	spin_unlock_irqrestore(&nc->lock, flags);
 
 	nca->type = NCSI_PKT_CMD_SVF;
 	nca->words[1] = vid;
@@ -711,45 +579,55 @@ static int clear_one_vid(struct ncsi_dev_priv *ndp, struct ncsi_channel *nc,
 static int set_one_vid(struct ncsi_dev_priv *ndp, struct ncsi_channel *nc,
 		       struct ncsi_cmd_arg *nca)
 {
+	struct ncsi_channel_vlan_filter *ncf;
 	struct vlan_vid *vlan = NULL;
-	int index = 0;
+	unsigned long flags;
+	int i, index;
+	void *bitmap;
+	u16 vid;
 
+	if (list_empty(&ndp->vlan_vids))
+		return -1;
+
+	ncf = &nc->vlan_filter;
+	bitmap = &ncf->bitmap;
+
+	spin_lock_irqsave(&nc->lock, flags);
+
+	rcu_read_lock();
 	list_for_each_entry_rcu(vlan, &ndp->vlan_vids, list) {
-		index = ncsi_find_filter(nc, NCSI_FILTER_VLAN, &vlan->vid);
-		if (index < 0) {
-			/* New tag to add */
-			netdev_printk(KERN_DEBUG, ndp->ndev.dev,
-				      "NCSI: new vlan id to set: %u\n",
-				      vlan->vid);
+		vid = vlan->vid;
+		for (i = 0; i < ncf->n_vids; i++)
+			if (ncf->vids[i] == vid) {
+				vid = 0;
+				break;
+			}
+		if (vid)
 			break;
-		}
-		netdev_printk(KERN_DEBUG, ndp->ndev.dev,
-			      "vid %u already at filter pos %d\n",
-			      vlan->vid, index);
 	}
+	rcu_read_unlock();
 
-	if (!vlan || index >= 0) {
-		netdev_printk(KERN_DEBUG, ndp->ndev.dev,
-			      "no vlan ids left to set\n");
+	if (!vid) {
+		/* No VLAN ID is not set */
+		spin_unlock_irqrestore(&nc->lock, flags);
 		return -1;
 	}
 
-	index = ncsi_add_filter(nc, NCSI_FILTER_VLAN, &vlan->vid);
-	if (index < 0) {
+	index = find_next_zero_bit(bitmap, ncf->n_vids, 0);
+	if (index < 0 || index >= ncf->n_vids) {
 		netdev_err(ndp->ndev.dev,
-			   "Failed to add new VLAN tag, error %d\n", index);
-		if (index == -ENOSPC)
-			netdev_err(ndp->ndev.dev,
-				   "Channel %u already has all VLAN filters set\n",
-				   nc->id);
+			   "Channel %u already has all VLAN filters set\n",
+			   nc->id);
+		spin_unlock_irqrestore(&nc->lock, flags);
 		return -1;
 	}
 
-	netdev_printk(KERN_DEBUG, ndp->ndev.dev,
-		      "NCSI: set vid %u in packet, index %u\n",
-		      vlan->vid, index + 1);
+	ncf->vids[index] = vid;
+	set_bit(index, bitmap);
+	spin_unlock_irqrestore(&nc->lock, flags);
+
 	nca->type = NCSI_PKT_CMD_SVF;
-	nca->words[1] = vlan->vid;
+	nca->words[1] = vid;
 	/* HW filter index starts at 1 */
 	nca->bytes[6] = index + 1;
 	nca->bytes[7] = 0x01;