ipv4: Avoid reading user iov twice after raw_probe_proto_opt

[pandora-kernel.git] / net / ipv4 / raw.c

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 5679ba7..f250aa7 100644 (file)
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -78,6 +78,16 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/compat.h>
+#include <linux/uio.h>
+
+struct raw_frag_vec {
+       struct iovec *iov;
+       union {
+               struct icmphdr icmph;
+               char c[1];
+       } hdr;
+       int hlen;
+};
 
 static struct raw_hashinfo raw_v4_hashinfo = {
        .lock = __RW_LOCK_UNLOCKED(raw_v4_hashinfo.lock),
@@ -409,25 +419,57 @@ error:
        return err;
 }
 
-static int raw_probe_proto_opt(struct flowi4 *fl4, struct msghdr *msg)
+static int raw_probe_proto_opt(struct raw_frag_vec *rfv, struct flowi4 *fl4)
 {
-       struct icmphdr icmph;
        int err;
 
        if (fl4->flowi4_proto != IPPROTO_ICMP)
                return 0;
 
        /* We only need the first two bytes. */
-       err = memcpy_fromiovecend((void *)&icmph, msg->msg_iov, 0, 2);
+       rfv->hlen = 2;
+
+       err = memcpy_fromiovec(rfv->hdr.c, rfv->iov, rfv->hlen);
        if (err)
                return err;
 
-       fl4->fl4_icmp_type = icmph.type;
-       fl4->fl4_icmp_code = icmph.code;
+       fl4->fl4_icmp_type = rfv->hdr.icmph.type;
+       fl4->fl4_icmp_code = rfv->hdr.icmph.code;
 
        return 0;
 }
 
+static int raw_getfrag(void *from, char *to, int offset, int len, int odd,
+                      struct sk_buff *skb)
+{
+       struct raw_frag_vec *rfv = from;
+
+       if (offset < rfv->hlen) {
+               int copy = min(rfv->hlen - offset, len);
+
+               if (skb->ip_summed == CHECKSUM_PARTIAL)
+                       memcpy(to, rfv->hdr.c + offset, copy);
+               else
+                       skb->csum = csum_block_add(
+                               skb->csum,
+                               csum_partial_copy_nocheck(rfv->hdr.c + offset,
+                                                         to, copy, 0),
+                               odd);
+
+               odd = 0;
+               offset += copy;
+               to += copy;
+               len -= copy;
+
+               if (!len)
+                       return 0;
+       }
+
+       offset -= rfv->hlen;
+
+       return ip_generic_getfrag(rfv->iov, to, offset, len, odd, skb);
+}
+
 static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                       size_t len)
 {
@@ -441,6 +483,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
        u8  tos;
        int err;
        struct ip_options_data opt_copy;
+       struct raw_frag_vec rfv;
 
        err = -EMSGSIZE;
        if (len > 0xFFFF)
@@ -547,7 +590,10 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                           daddr, saddr, 0, 0);
 
        if (!inet->hdrincl) {
-               err = raw_probe_proto_opt(&fl4, msg);
+               rfv.iov = msg->msg_iov;
+               rfv.hlen = 0;
+
+               err = raw_probe_proto_opt(&rfv, &fl4);
                if (err)
                        goto done;
        }
@@ -576,8 +622,8 @@ back_from_confirm:
                if (!ipc.addr)
                        ipc.addr = fl4.daddr;
                lock_sock(sk);
-               err = ip_append_data(sk, &fl4, ip_generic_getfrag,
-                                    msg->msg_iov, len, 0,
+               err = ip_append_data(sk, &fl4, raw_getfrag,
+                                    &rfv, len, 0,
                                     &ipc, &rt, msg->msg_flags);
                if (err)
                        ip_flush_pending_frames(sk);