caif-hsi: Added sanity check for length of CAIF frames

Added sanity check for length of CAIF frames, and tear down of
CAIF link-layer device upon protocol error.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 49 insertions, 30 deletions

diff --git a/drivers/net/caif/caif_hsi.c b/drivers/net/caif/caif_hsi.c
index 1e1f0a372ffa..e9e7cbf01a5f 100644
--- a/drivers/net/caif/caif_hsi.c
+++ b/drivers/net/caif/caif_hsi.c
@@ -18,6 +18,7 @@
 #include <linux/sched.h>
 #include <linux/if_arp.h>
 #include <linux/timer.h>
+#include <linux/rtnetlink.h>
 #include <net/caif/caif_layer.h>
 #include <net/caif/caif_hsi.h>
 
@@ -348,8 +349,7 @@ static void cfhsi_tx_done_cb(struct cfhsi_drv *drv)
         cfhsi_tx_done(cfhsi);
 }
 
-static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
-                                bool *dump)
+static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
 {
         int xfer_sz = 0;
         int nfrms = 0;
@@ -360,8 +360,7 @@ static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
                         (desc->offset > CFHSI_MAX_EMB_FRM_SZ)) {
                 dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
                         __func__);
-                *dump = true;
-                return 0;
+                return -EPROTO;
         }
 
         /* Check for embedded CAIF frame. */
@@ -379,6 +378,12 @@ static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
                 len |= ((*(pfrm+1)) << 8) & 0xFF00;
                 len += 2;       /* Add FCS fields. */
 
+                /* Sanity check length of CAIF frame. */
+                if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
+                        dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
+                                __func__);
+                        return -EPROTO;
+                }
 
                 /* Allocate SKB (OK even in IRQ context). */
                 skb = alloc_skb(len + 1, GFP_ATOMIC);
@@ -423,18 +428,16 @@ static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
         if (desc->header & CFHSI_PIGGY_DESC)
                 xfer_sz += CFHSI_DESC_SZ;
 
-        if (xfer_sz % 4) {
+        if ((xfer_sz % 4) || (xfer_sz > (CFHSI_BUF_SZ_RX - CFHSI_DESC_SZ))) {
                 dev_err(&cfhsi->ndev->dev,
                                 "%s: Invalid payload len: %d, ignored.\n",
                         __func__, xfer_sz);
-                xfer_sz = 0;
-                *dump = true;
+                return -EPROTO;
         }
         return xfer_sz;
 }
 
-static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
-                                bool *dump)
+static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
 {
         int rx_sz = 0;
         int nfrms = 0;
@@ -446,8 +449,7 @@ static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
                         (desc->offset > CFHSI_MAX_EMB_FRM_SZ))) {
                 dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
                         __func__);
-                *dump = true;
-                return -EINVAL;
+                return -EPROTO;
         }
 
         /* Set frame pointer to start of payload. */
@@ -469,13 +471,6 @@ static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
                 u8 *pcffrm = NULL;
                 int len = 0;
 
-                if (WARN_ON(desc->cffrm_len[nfrms] > CFHSI_MAX_PAYLOAD_SZ)) {
-                        dev_err(&cfhsi->ndev->dev, "%s: Invalid payload.\n",
-                                __func__);
-                        *dump = true;
-                        return -EINVAL;
-                }
-
                 /* CAIF frame starts after head padding. */
                 pcffrm = pfrm + *pfrm + 1;
 
@@ -484,6 +479,13 @@ static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi,
                 len |= ((*(pcffrm + 1)) << 8) & 0xFF00;
                 len += 2;       /* Add FCS fields. */
 
+                /* Sanity check length of CAIF frames. */
+                if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
+                        dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
+                                __func__);
+                        return -EPROTO;
+                }
+
                 /* Allocate SKB (OK even in IRQ context). */
                 skb = alloc_skb(len + 1, GFP_ATOMIC);
                 if (!skb) {
@@ -528,7 +530,6 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
         int res;
         int desc_pld_len = 0;
         struct cfhsi_desc *desc = NULL;
-        bool dump = false;
 
         desc = (struct cfhsi_desc *)cfhsi->rx_buf;
 
@@ -544,16 +545,20 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
         spin_unlock_bh(&cfhsi->lock);
 
         if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
-                desc_pld_len = cfhsi_rx_desc(desc, cfhsi, &dump);
+                desc_pld_len = cfhsi_rx_desc(desc, cfhsi);
                 if (desc_pld_len == -ENOMEM)
                         goto restart;
+                if (desc_pld_len == -EPROTO)
+                        goto out_of_sync;
         } else {
                 int pld_len;
 
                 if (!cfhsi->rx_state.piggy_desc) {
-                        pld_len = cfhsi_rx_pld(desc, cfhsi, &dump);
+                        pld_len = cfhsi_rx_pld(desc, cfhsi);
                         if (pld_len == -ENOMEM)
                                 goto restart;
+                        if (pld_len == -EPROTO)
+                                goto out_of_sync;
                         cfhsi->rx_state.pld_len = pld_len;
                 } else {
                         pld_len = cfhsi->rx_state.pld_len;
@@ -567,7 +572,7 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
                         cfhsi->rx_state.piggy_desc = true;
 
                         /* Extract piggy-backed descriptor. */
-                        desc_pld_len = cfhsi_rx_desc(piggy_desc, cfhsi, &dump);
+                        desc_pld_len = cfhsi_rx_desc(piggy_desc, cfhsi);
                         if (desc_pld_len == -ENOMEM)
                                 goto restart;
 
@@ -577,15 +582,10 @@ static void cfhsi_rx_done(struct cfhsi *cfhsi)
                          */
                         memcpy((u8 *)desc, (u8 *)piggy_desc,
                                         CFHSI_DESC_SHORT_SZ);
-                }
-        }
 
-        if (unlikely(dump)) {
-                size_t rx_offset = cfhsi->rx_ptr - cfhsi->rx_buf;
-                dev_err(&cfhsi->ndev->dev, "%s: RX offset: %u.\n",
-                        __func__, (unsigned) rx_offset);
-                print_hex_dump_bytes("--> ", DUMP_PREFIX_NONE,
-                                cfhsi->rx_buf, cfhsi->rx_len + rx_offset);
+                        if (desc_pld_len == -EPROTO)
+                                goto out_of_sync;
+                }
         }
 
         memset(&cfhsi->rx_state, 0, sizeof(cfhsi->rx_state));
@@ -622,6 +622,13 @@ restart:
                 BUG();
         }
         mod_timer(&cfhsi->rx_slowpath_timer, jiffies + 1);
+        return;
+
+out_of_sync:
+        dev_err(&cfhsi->ndev->dev, "%s: Out of sync.\n", __func__);
+        print_hex_dump_bytes("--> ", DUMP_PREFIX_NONE,
+                        cfhsi->rx_buf, CFHSI_DESC_SZ);
+        schedule_work(&cfhsi->out_of_sync_work);
 }
 
 static void cfhsi_rx_slowpath(unsigned long arg)
@@ -804,6 +811,17 @@ static void cfhsi_wake_down(struct work_struct *work)
 
 }
 
+static void cfhsi_out_of_sync(struct work_struct *work)
+{
+        struct cfhsi *cfhsi = NULL;
+
+        cfhsi = container_of(work, struct cfhsi, out_of_sync_work);
+
+        rtnl_lock();
+        dev_close(cfhsi->ndev);
+        rtnl_unlock();
+}
+
 static void cfhsi_wake_up_cb(struct cfhsi_drv *drv)
 {
         struct cfhsi *cfhsi = NULL;
@@ -1023,6 +1041,7 @@ int cfhsi_probe(struct platform_device *pdev)
         /* Initialize the work queues. */
         INIT_WORK(&cfhsi->wake_up_work, cfhsi_wake_up);
         INIT_WORK(&cfhsi->wake_down_work, cfhsi_wake_down);
+        INIT_WORK(&cfhsi->out_of_sync_work, cfhsi_out_of_sync);
 
         /* Clear all bit fields. */
         clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);