NET: wimax, fix use after free

Stanse found that i2400m_rx frees skb, but still uses skb->len even
though it has skb_len defined. So use skb_len properly in the code.

And also define it unsinged int rather than size_t to solve
compilation warnings.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Cc: linux-wimax@intel.com
Acked-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wimax/i2400m/rx.c b/drivers/net/wimax/i2400m/rx.c
index 8cc9e31..1737d14 100644 (file)
--- a/drivers/net/wimax/i2400m/rx.c
+++ b/drivers/net/wimax/i2400m/rx.c
@@ -1244,16 +1244,16 @@ int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
        int i, result;
        struct device *dev = i2400m_dev(i2400m);
        const struct i2400m_msg_hdr *msg_hdr;
-       size_t pl_itr, pl_size, skb_len;
+       size_t pl_itr, pl_size;
        unsigned long flags;
-       unsigned num_pls, single_last;
+       unsigned num_pls, single_last, skb_len;
 
        skb_len = skb->len;
-       d_fnstart(4, dev, "(i2400m %p skb %p [size %zu])\n",
+       d_fnstart(4, dev, "(i2400m %p skb %p [size %u])\n",
                  i2400m, skb, skb_len);
        result = -EIO;
        msg_hdr = (void *) skb->data;
-       result = i2400m_rx_msg_hdr_check(i2400m, msg_hdr, skb->len);
+       result = i2400m_rx_msg_hdr_check(i2400m, msg_hdr, skb_len);
        if (result < 0)
                goto error_msg_hdr_check;
        result = -EIO;
@@ -1261,10 +1261,10 @@ int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
        pl_itr = sizeof(*msg_hdr) +     /* Check payload descriptor(s) */
                num_pls * sizeof(msg_hdr->pld[0]);
        pl_itr = ALIGN(pl_itr, I2400M_PL_ALIGN);
-       if (pl_itr > skb->len) {        /* got all the payload descriptors? */
+       if (pl_itr > skb_len) { /* got all the payload descriptors? */
                dev_err(dev, "RX: HW BUG? message too short (%u bytes) for "
                        "%u payload descriptors (%zu each, total %zu)\n",
-                       skb->len, num_pls, sizeof(msg_hdr->pld[0]), pl_itr);
+                       skb_len, num_pls, sizeof(msg_hdr->pld[0]), pl_itr);
                goto error_pl_descr_short;
        }
        /* Walk each payload payload--check we really got it */
@@ -1272,7 +1272,7 @@ int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
                /* work around old gcc warnings */
                pl_size = i2400m_pld_size(&msg_hdr->pld[i]);
                result = i2400m_rx_pl_descr_check(i2400m, &msg_hdr->pld[i],
-                                                 pl_itr, skb->len);
+                                                 pl_itr, skb_len);
                if (result < 0)
                        goto error_pl_descr_check;
                single_last = num_pls == 1 || i == num_pls - 1;
@@ -1290,16 +1290,16 @@ int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
        if (i < i2400m->rx_pl_min)
                i2400m->rx_pl_min = i;
        i2400m->rx_num++;
-       i2400m->rx_size_acc += skb->len;
-       if (skb->len < i2400m->rx_size_min)
-               i2400m->rx_size_min = skb->len;
-       if (skb->len > i2400m->rx_size_max)
-               i2400m->rx_size_max = skb->len;
+       i2400m->rx_size_acc += skb_len;
+       if (skb_len < i2400m->rx_size_min)
+               i2400m->rx_size_min = skb_len;
+       if (skb_len > i2400m->rx_size_max)
+               i2400m->rx_size_max = skb_len;
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
 error_pl_descr_check:
 error_pl_descr_short:
 error_msg_hdr_check:
-       d_fnend(4, dev, "(i2400m %p skb %p [size %zu]) = %d\n",
+       d_fnend(4, dev, "(i2400m %p skb %p [size %u]) = %d\n",
                i2400m, skb, skb_len, result);
        return result;
 }