add a fix for tun/tap related crashes (backported by Carlos Sobrinho)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@5352 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/generic-2.4/patches/230-tun_get_user_backport.patch b/target/linux/generic-2.4/patches/230-tun_get_user_backport.patch
new file mode 100644 (file)
index 0000000..636ffec
--- /dev/null
+++ b/target/linux/generic-2.4/patches/230-tun_get_user_backport.patch
@@ -0,0 +1,102 @@
+--- linux-2.4.32/drivers/net/tun.c 2006-10-28 18:21:45.000000000 +0100
++++ new.linux-2.4.32/drivers/net/tun.c 2006-10-28 18:50:53.000000000 +0100
+@@ -185,22 +185,31 @@
+ {
+       struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
+       struct sk_buff *skb;
+-      size_t len = count;
++      size_t len = count, align = 0;
+ 
+       if (!(tun->flags & TUN_NO_PI)) {
+               if ((len -= sizeof(pi)) > count)
+                       return -EINVAL;
+ 
+-              memcpy_fromiovec((void *)&pi, iv, sizeof(pi));
++              if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
++                      return -EFAULT;
+       }
+- 
+-      if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) {
++
++      if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
++              align = NET_IP_ALIGN;
++  
++      if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
+               tun->stats.rx_dropped++;
+               return -ENOMEM;
+       }
+ 
+-      skb_reserve(skb, 2);
+-      memcpy_fromiovec(skb_put(skb, len), iv, len);
++      if (align)
++              skb_reserve(skb, align);
++      if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
++              tun->stats.rx_dropped++;
++              kfree_skb(skb);
++              return -EFAULT;
++      }
+ 
+       skb->dev = &tun->dev;
+       switch (tun->flags & TUN_TYPE_MASK) {
+@@ -271,7 +271,8 @@
+                       pi.flags |= TUN_PKT_STRIP;
+               }
+  
+-              memcpy_toiovec(iv, (void *) &pi, sizeof(pi));
++              if(memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
++                      return -EFAULT;
+               total += sizeof(pi);
+       }       
+ 
+--- linux-2.4.32/include/linux/skbuff.h        2006-10-28 19:31:31.000000000 +0100
++++ new.linux-2.4.32/include/linux/skbuff.h    2006-10-28 19:29:27.000000000 +0100
+@@ -918,6 +918,49 @@
+       skb->tail+=len;
+ }
+ 
++/*
++ * CPUs often take a performance hit when accessing unaligned memory
++ * locations. The actual performance hit varies, it can be small if the
++ * hardware handles it or large if we have to take an exception and fix it
++ * in software.
++ *
++ * Since an ethernet header is 14 bytes network drivers often end up with
++ * the IP header at an unaligned offset. The IP header can be aligned by
++ * shifting the start of the packet by 2 bytes. Drivers should do this
++ * with:
++ *
++ * skb_reserve(NET_IP_ALIGN);
++ *
++ * The downside to this alignment of the IP header is that the DMA is now
++ * unaligned. On some architectures the cost of an unaligned DMA is high
++ * and this cost outweighs the gains made by aligning the IP header.
++ * 
++ * Since this trade off varies between architectures, we allow NET_IP_ALIGN
++ * to be overridden.
++ */
++#ifndef NET_IP_ALIGN
++#define NET_IP_ALIGN    2
++#endif
++
++/*
++ * The networking layer reserves some headroom in skb data (via
++ * dev_alloc_skb). This is used to avoid having to reallocate skb data when
++ * the header has to grow. In the default case, if the header has to grow
++ * 16 bytes or less we avoid the reallocation.
++ *
++ * Unfortunately this headroom changes the DMA alignment of the resulting
++ * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
++ * on some architectures. An architecture can override this value,
++ * perhaps setting it to a cacheline in size (since that will maintain
++ * cacheline alignment of the DMA). It must be a power of 2.
++ *
++ * Various parts of the networking layer expect at least 16 bytes of
++ * headroom, you should not reduce this.
++ */
++#ifndef NET_SKB_PAD
++#define NET_SKB_PAD     16
++#endif
++ 
+ extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
+ 
+ static inline void __skb_trim(struct sk_buff *skb, unsigned int len)