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, 73 insertions, 105 deletions

diff --git a/net/ncsi/ncsi-rsp.c b/net/ncsi/ncsi-rsp.c
index efd933ff5570..ce9497966ebe 100644
--- a/net/ncsi/ncsi-rsp.c
+++ b/net/ncsi/ncsi-rsp.c
@@ -334,9 +334,9 @@ static int ncsi_rsp_handler_svf(struct ncsi_request *nr)
 	struct ncsi_rsp_pkt *rsp;
 	struct ncsi_dev_priv *ndp = nr->ndp;
 	struct ncsi_channel *nc;
-	struct ncsi_channel_filter *ncf;
-	unsigned short vlan;
-	int ret;
+	struct ncsi_channel_vlan_filter *ncf;
+	unsigned long flags;
+	void *bitmap;
 
 	/* Find the package and channel */
 	rsp = (struct ncsi_rsp_pkt *)skb_network_header(nr->rsp);
@@ -346,22 +346,23 @@ static int ncsi_rsp_handler_svf(struct ncsi_request *nr)
 		return -ENODEV;
 
 	cmd = (struct ncsi_cmd_svf_pkt *)skb_network_header(nr->cmd);
-	ncf = nc->filters[NCSI_FILTER_VLAN];
-	if (!ncf)
-		return -ENOENT;
-	if (cmd->index >= ncf->total)
+	ncf = &nc->vlan_filter;
+	if (cmd->index > ncf->n_vids)
 		return -ERANGE;
 
-	/* Add or remove the VLAN filter */
+	/* Add or remove the VLAN filter. Remember HW indexes from 1 */
+	spin_lock_irqsave(&nc->lock, flags);
+	bitmap = &ncf->bitmap;
 	if (!(cmd->enable & 0x1)) {
-		/* HW indexes from 1 */
-		ret = ncsi_remove_filter(nc, NCSI_FILTER_VLAN, cmd->index - 1);
+		if (test_and_clear_bit(cmd->index - 1, bitmap))
+			ncf->vids[cmd->index - 1] = 0;
 	} else {
-		vlan = ntohs(cmd->vlan);
-		ret = ncsi_add_filter(nc, NCSI_FILTER_VLAN, &vlan);
+		set_bit(cmd->index - 1, bitmap);
+		ncf->vids[cmd->index - 1] = ntohs(cmd->vlan);
 	}
+	spin_unlock_irqrestore(&nc->lock, flags);
 
-	return ret;
+	return 0;
 }
 
 static int ncsi_rsp_handler_ev(struct ncsi_request *nr)
@@ -422,8 +423,12 @@ static int ncsi_rsp_handler_sma(struct ncsi_request *nr)
 	struct ncsi_rsp_pkt *rsp;
 	struct ncsi_dev_priv *ndp = nr->ndp;
 	struct ncsi_channel *nc;
-	struct ncsi_channel_filter *ncf;
+	struct ncsi_channel_mac_filter *ncf;
+	unsigned long flags;
 	void *bitmap;
+	bool enabled;
+	int index;
+
 
 	/* Find the package and channel */
 	rsp = (struct ncsi_rsp_pkt *)skb_network_header(nr->rsp);
@@ -436,31 +441,23 @@ static int ncsi_rsp_handler_sma(struct ncsi_request *nr)
 	 * isn't supported yet.
 	 */
 	cmd = (struct ncsi_cmd_sma_pkt *)skb_network_header(nr->cmd);
-	switch (cmd->at_e >> 5) {
-	case 0x0:	/* UC address */
-		ncf = nc->filters[NCSI_FILTER_UC];
-		break;
-	case 0x1:	/* MC address */
-		ncf = nc->filters[NCSI_FILTER_MC];
-		break;
-	default:
-		return -EINVAL;
-	}
+	enabled = cmd->at_e & 0x1;
+	ncf = &nc->mac_filter;
+	bitmap = &ncf->bitmap;
 
-	/* Sanity check on the filter */
-	if (!ncf)
-		return -ENOENT;
-	else if (cmd->index >= ncf->total)
+	if (cmd->index > ncf->n_uc + ncf->n_mc + ncf->n_mixed)
 		return -ERANGE;
 
-	bitmap = &ncf->bitmap;
-	if (cmd->at_e & 0x1) {
-		set_bit(cmd->index, bitmap);
-		memcpy(ncf->data + 6 * cmd->index, cmd->mac, 6);
+	index = (cmd->index - 1) * ETH_ALEN;
+	spin_lock_irqsave(&nc->lock, flags);
+	if (enabled) {
+		set_bit(cmd->index - 1, bitmap);
+		memcpy(&ncf->addrs[index], cmd->mac, ETH_ALEN);
 	} else {
-		clear_bit(cmd->index, bitmap);
-		memset(ncf->data + 6 * cmd->index, 0, 6);
+		clear_bit(cmd->index - 1, bitmap);
+		memset(&ncf->addrs[index], 0, ETH_ALEN);
 	}
+	spin_unlock_irqrestore(&nc->lock, flags);
 
 	return 0;
 }
@@ -631,9 +628,7 @@ static int ncsi_rsp_handler_gc(struct ncsi_request *nr)
 	struct ncsi_rsp_gc_pkt *rsp;
 	struct ncsi_dev_priv *ndp = nr->ndp;
 	struct ncsi_channel *nc;
-	struct ncsi_channel_filter *ncf;
-	size_t size, entry_size;
-	int cnt, i;
+	size_t size;
 
 	/* Find the channel */
 	rsp = (struct ncsi_rsp_gc_pkt *)skb_network_header(nr->rsp);
@@ -655,64 +650,40 @@ static int ncsi_rsp_handler_gc(struct ncsi_request *nr)
 	nc->caps[NCSI_CAP_VLAN].cap = rsp->vlan_mode &
 				      NCSI_CAP_VLAN_MASK;
 
-	/* Build filters */
-	for (i = 0; i < NCSI_FILTER_MAX; i++) {
-		switch (i) {
-		case NCSI_FILTER_VLAN:
-			cnt = rsp->vlan_cnt;
-			entry_size = 2;
-			break;
-		case NCSI_FILTER_MIXED:
-			cnt = rsp->mixed_cnt;
-			entry_size = 6;
-			break;
-		case NCSI_FILTER_MC:
-			cnt = rsp->mc_cnt;
-			entry_size = 6;
-			break;
-		case NCSI_FILTER_UC:
-			cnt = rsp->uc_cnt;
-			entry_size = 6;
-			break;
-		default:
-			continue;
-		}
-
-		if (!cnt || nc->filters[i])
-			continue;
-
-		size = sizeof(*ncf) + cnt * entry_size;
-		ncf = kzalloc(size, GFP_ATOMIC);
-		if (!ncf) {
-			pr_warn("%s: Cannot alloc filter table (%d)\n",
-				__func__, i);
-			return -ENOMEM;
-		}
-
-		ncf->index = i;
-		ncf->total = cnt;
-		if (i == NCSI_FILTER_VLAN) {
-			/* Set VLAN filters active so they are cleared in
-			 * first configuration state
-			 */
-			ncf->bitmap = U64_MAX;
-		} else {
-			ncf->bitmap = 0x0ul;
-		}
-		nc->filters[i] = ncf;
-	}
+	size = (rsp->uc_cnt + rsp->mc_cnt + rsp->mixed_cnt) * ETH_ALEN;
+	nc->mac_filter.addrs = kzalloc(size, GFP_KERNEL);
+	if (!nc->mac_filter.addrs)
+		return -ENOMEM;
+	nc->mac_filter.n_uc = rsp->uc_cnt;
+	nc->mac_filter.n_mc = rsp->mc_cnt;
+	nc->mac_filter.n_mixed = rsp->mixed_cnt;
+
+	nc->vlan_filter.vids = kcalloc(rsp->vlan_cnt,
+				       sizeof(*nc->vlan_filter.vids),
+				       GFP_KERNEL);
+	if (!nc->vlan_filter.vids)
+		return -ENOMEM;
+	/* Set VLAN filters active so they are cleared in the first
+	 * configuration state
+	 */
+	nc->vlan_filter.bitmap = U64_MAX;
+	nc->vlan_filter.n_vids = rsp->vlan_cnt;
 
 	return 0;
 }
 
 static int ncsi_rsp_handler_gp(struct ncsi_request *nr)
 {
-	struct ncsi_rsp_gp_pkt *rsp;
+	struct ncsi_channel_vlan_filter *ncvf;
+	struct ncsi_channel_mac_filter *ncmf;
 	struct ncsi_dev_priv *ndp = nr->ndp;
+	struct ncsi_rsp_gp_pkt *rsp;
 	struct ncsi_channel *nc;
-	unsigned short enable, vlan;
+	unsigned short enable;
 	unsigned char *pdata;
-	int table, i;
+	unsigned long flags;
+	void *bitmap;
+	int i;
 
 	/* Find the channel */
 	rsp = (struct ncsi_rsp_gp_pkt *)skb_network_header(nr->rsp);
@@ -746,36 +717,33 @@ static int ncsi_rsp_handler_gp(struct ncsi_request *nr)
 	/* MAC addresses filter table */
 	pdata = (unsigned char *)rsp + 48;
 	enable = rsp->mac_enable;
+	ncmf = &nc->mac_filter;
+	spin_lock_irqsave(&nc->lock, flags);
+	bitmap = &ncmf->bitmap;
 	for (i = 0; i < rsp->mac_cnt; i++, pdata += 6) {
-		if (i >= (nc->filters[NCSI_FILTER_UC]->total +
-			  nc->filters[NCSI_FILTER_MC]->total))
-			table = NCSI_FILTER_MIXED;
-		else if (i >= nc->filters[NCSI_FILTER_UC]->total)
-			table = NCSI_FILTER_MC;
-		else
-			table = NCSI_FILTER_UC;
-
 		if (!(enable & (0x1 << i)))
-			continue;
-
-		if (ncsi_find_filter(nc, table, pdata) >= 0)
-			continue;
+			clear_bit(i, bitmap);
+		else
+			set_bit(i, bitmap);
 
-		ncsi_add_filter(nc, table, pdata);
+		memcpy(&ncmf->addrs[i * ETH_ALEN], pdata, ETH_ALEN);
 	}
+	spin_unlock_irqrestore(&nc->lock, flags);
 
 	/* VLAN filter table */
 	enable = ntohs(rsp->vlan_enable);
+	ncvf = &nc->vlan_filter;
+	bitmap = &ncvf->bitmap;
+	spin_lock_irqsave(&nc->lock, flags);
 	for (i = 0; i < rsp->vlan_cnt; i++, pdata += 2) {
 		if (!(enable & (0x1 << i)))
-			continue;
-
-		vlan = ntohs(*(__be16 *)pdata);
-		if (ncsi_find_filter(nc, NCSI_FILTER_VLAN, &vlan) >= 0)
-			continue;
+			clear_bit(i, bitmap);
+		else
+			set_bit(i, bitmap);
 
-		ncsi_add_filter(nc, NCSI_FILTER_VLAN, &vlan);
+		ncvf->vids[i] = ntohs(*(__be16 *)pdata);
 	}
+	spin_unlock_irqrestore(&nc->lock, flags);
 
 	return 0;
 }