8 files changed, 160 insertions, 7 deletions

diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index 15874f9812cc..7c4a94f43706 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -164,7 +164,7 @@ EXPORT(sysn32_call_table)
         PTR     sys_connect
         PTR     sys_accept
         PTR     sys_sendto
-        PTR     sys_recvfrom
+        PTR     compat_sys_recvfrom
         PTR     compat_sys_sendmsg              /* 6045 */
         PTR     compat_sys_recvmsg
         PTR     sys_shutdown
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 781e0f1e9533..821fc978673d 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -378,8 +378,8 @@ sys_call_table:
         PTR     sys_getsockname
         PTR     sys_getsockopt
         PTR     sys_listen
-        PTR     sys_recv                        /* 4175 */
-        PTR     sys_recvfrom
+        PTR     compat_sys_recv                 /* 4175 */
+        PTR     compat_sys_recvfrom
         PTR     compat_sys_recvmsg
         PTR     sys_send
         PTR     compat_sys_sendmsg
diff --git a/arch/sparc/kernel/sys32.S b/arch/sparc/kernel/sys32.S
index f061c4dda9ef..3762f6c78944 100644
--- a/arch/sparc/kernel/sys32.S
+++ b/arch/sparc/kernel/sys32.S
@@ -121,7 +121,7 @@ SIGN2(sys32_syslog, sys_syslog, %o0, %o2)
 SIGN1(sys32_umask, sys_umask, %o0)
 SIGN3(sys32_tgkill, sys_tgkill, %o0, %o1, %o2)
 SIGN1(sys32_sendto, sys_sendto, %o0)
-SIGN1(sys32_recvfrom, sys_recvfrom, %o0)
+SIGN1(sys32_recvfrom, compat_sys_recvfrom, %o0)
 SIGN3(sys32_socket, sys_socket, %o0, %o1, %o2)
 SIGN2(sys32_connect, sys_connect, %o0, %o2)
 SIGN2(sys32_bind, sys_bind, %o0, %o2)
diff --git a/include/linux/wireless.h b/include/linux/wireless.h
index cb24204851f7..5b4c6c772a9b 100644
--- a/include/linux/wireless.h
+++ b/include/linux/wireless.h
@@ -1132,6 +1132,14 @@ struct __compat_iw_event {
 };
 #define IW_EV_COMPAT_LCP_LEN offsetof(struct __compat_iw_event, pointer)
 #define IW_EV_COMPAT_POINT_OFF offsetof(struct compat_iw_point, length)
+
+/* Size of the various events for compat */
+#define IW_EV_COMPAT_CHAR_LEN   (IW_EV_COMPAT_LCP_LEN + IFNAMSIZ)
+#define IW_EV_COMPAT_UINT_LEN   (IW_EV_COMPAT_LCP_LEN + sizeof(__u32))
+#define IW_EV_COMPAT_FREQ_LEN   (IW_EV_COMPAT_LCP_LEN + sizeof(struct iw_freq))
+#define IW_EV_COMPAT_PARAM_LEN  (IW_EV_COMPAT_LCP_LEN + sizeof(struct iw_param))
+#define IW_EV_COMPAT_ADDR_LEN   (IW_EV_COMPAT_LCP_LEN + sizeof(struct sockaddr))
+#define IW_EV_COMPAT_QUAL_LEN   (IW_EV_COMPAT_LCP_LEN + sizeof(struct iw_quality))
 #define IW_EV_COMPAT_POINT_LEN  \
         (IW_EV_COMPAT_LCP_LEN + sizeof(struct compat_iw_point) - \
          IW_EV_COMPAT_POINT_OFF)
diff --git a/net/Kconfig b/net/Kconfig
index 7051b9710675..041c35edb763 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -23,6 +23,26 @@ menuconfig NET
 
 if NET
 
+config WANT_COMPAT_NETLINK_MESSAGES
+        bool
+        help
+          This option can be selected by other options that need compat
+          netlink messages.
+
+config COMPAT_NETLINK_MESSAGES
+        def_bool y
+        depends on COMPAT
+        depends on WIRELESS_EXT || WANT_COMPAT_NETLINK_MESSAGES
+        help
+          This option makes it possible to send different netlink messages
+          to tasks depending on whether the task is a compat task or not. To
+          achieve this, you need to set skb_shinfo(skb)->frag_list to the
+          compat skb before sending the skb, the netlink code will sort out
+          which message to actually pass to the task.
+
+          Newly written code should NEVER need this option but do
+          compat-independent messages instead!
+
 menu "Networking options"
 
 source "net/packet/Kconfig"
diff --git a/net/compat.c b/net/compat.c
index 8d739053afe4..12728b17a226 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -743,6 +743,18 @@ asmlinkage long compat_sys_recvmsg(int fd, struct compat_msghdr __user *msg, uns
         return sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
 }
 
+asmlinkage long compat_sys_recv(int fd, void __user *buf, size_t len, unsigned flags)
+{
+        return sys_recv(fd, buf, len, flags | MSG_CMSG_COMPAT);
+}
+
+asmlinkage long compat_sys_recvfrom(int fd, void __user *buf, size_t len,
+                                    unsigned flags, struct sockaddr __user *addr,
+                                    int __user *addrlen)
+{
+        return sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr, addrlen);
+}
+
 asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
 {
         int ret;
@@ -788,10 +800,11 @@ asmlinkage long compat_sys_socketcall(int call, u32 __user *args)
                 ret = sys_sendto(a0, compat_ptr(a1), a[2], a[3], compat_ptr(a[4]), a[5]);
                 break;
         case SYS_RECV:
-                ret = sys_recv(a0, compat_ptr(a1), a[2], a[3]);
+                ret = compat_sys_recv(a0, compat_ptr(a1), a[2], a[3]);
                 break;
         case SYS_RECVFROM:
-                ret = sys_recvfrom(a0, compat_ptr(a1), a[2], a[3], compat_ptr(a[4]), compat_ptr(a[5]));
+                ret = compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
+                                          compat_ptr(a[4]), compat_ptr(a[5]));
                 break;
         case SYS_SHUTDOWN:
                 ret = sys_shutdown(a0,a1);
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index d46da6cb92e4..da3163d15ef0 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1361,7 +1361,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
         struct netlink_sock *nlk = nlk_sk(sk);
         int noblock = flags&MSG_DONTWAIT;
         size_t copied;
-        struct sk_buff *skb;
+        struct sk_buff *skb, *frag __maybe_unused = NULL;
         int err;
 
         if (flags&MSG_OOB)
@@ -1373,6 +1373,35 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
         if (skb == NULL)
                 goto out;
 
+#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
+        if (unlikely(skb_shinfo(skb)->frag_list)) {
+                bool need_compat = !!(flags & MSG_CMSG_COMPAT);
+
+                /*
+                 * If this skb has a frag_list, then here that means that
+                 * we will have to use the frag_list skb for compat tasks
+                 * and the regular skb for non-compat tasks.
+                 *
+                 * The skb might (and likely will) be cloned, so we can't
+                 * just reset frag_list and go on with things -- we need to
+                 * keep that. For the compat case that's easy -- simply get
+                 * a reference to the compat skb and free the regular one
+                 * including the frag. For the non-compat case, we need to
+                 * avoid sending the frag to the user -- so assign NULL but
+                 * restore it below before freeing the skb.
+                 */
+                if (need_compat) {
+                        struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
+                        skb_get(compskb);
+                        kfree_skb(skb);
+                        skb = compskb;
+                } else {
+                        frag = skb_shinfo(skb)->frag_list;
+                        skb_shinfo(skb)->frag_list = NULL;
+                }
+        }
+#endif
+
         msg->msg_namelen = 0;
 
         copied = skb->len;
@@ -1403,6 +1432,11 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
         siocb->scm->creds = *NETLINK_CREDS(skb);
         if (flags & MSG_TRUNC)
                 copied = skb->len;
+
+#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
+        skb_shinfo(skb)->frag_list = frag;
+#endif
+
         skb_free_datagram(sk, skb);
 
         if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
diff --git a/net/wireless/wext.c b/net/wireless/wext.c
index ee35e6422f1f..3fe3c2c0ce11 100644
--- a/net/wireless/wext.c
+++ b/net/wireless/wext.c
@@ -417,6 +417,21 @@ static const int event_type_size[] = {
         IW_EV_QUAL_LEN,                 /* IW_HEADER_TYPE_QUAL */
 };
 
+#ifdef CONFIG_COMPAT
+static const int compat_event_type_size[] = {
+        IW_EV_COMPAT_LCP_LEN,           /* IW_HEADER_TYPE_NULL */
+        0,
+        IW_EV_COMPAT_CHAR_LEN,          /* IW_HEADER_TYPE_CHAR */
+        0,
+        IW_EV_COMPAT_UINT_LEN,          /* IW_HEADER_TYPE_UINT */
+        IW_EV_COMPAT_FREQ_LEN,          /* IW_HEADER_TYPE_FREQ */
+        IW_EV_COMPAT_ADDR_LEN,          /* IW_HEADER_TYPE_ADDR */
+        0,
+        IW_EV_COMPAT_POINT_LEN,         /* Without variable payload */
+        IW_EV_COMPAT_PARAM_LEN,         /* IW_HEADER_TYPE_PARAM */
+        IW_EV_COMPAT_QUAL_LEN,          /* IW_HEADER_TYPE_QUAL */
+};
+#endif
 
 /************************ COMMON SUBROUTINES ************************/
 /*
@@ -1348,6 +1363,22 @@ void wireless_send_event(struct net_device *	dev,
         struct sk_buff *skb;
         struct nlmsghdr *nlh;
         struct nlattr *nla;
+#ifdef CONFIG_COMPAT
+        struct __compat_iw_event *compat_event;
+        struct compat_iw_point compat_wrqu;
+        struct sk_buff *compskb;
+#endif
+
+        /*
+         * Nothing in the kernel sends scan events with data, be safe.
+         * This is necessary because we cannot fix up scan event data
+         * for compat, due to being contained in 'extra', but normally
+         * applications are required to retrieve the scan data anyway
+         * and no data is included in the event, this codifies that
+         * practice.
+         */
+        if (WARN_ON(cmd == SIOCGIWSCAN && extra))
+                extra = NULL;
 
         /* Get the description of the Event */
         if (cmd <= SIOCIWLAST) {
@@ -1446,7 +1477,54 @@ void wireless_send_event(struct net_device *	dev,
                 memcpy(((char *) event) + hdr_len, extra, extra_len);
 
         nlmsg_end(skb, nlh);
+#ifdef CONFIG_COMPAT
+        hdr_len = compat_event_type_size[descr->header_type];
+        event_len = hdr_len + extra_len;
 
+        compskb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+        if (!compskb) {
+                kfree_skb(skb);
+                return;
+        }
+
+        /* Send via the RtNetlink event channel */
+        nlh = rtnetlink_ifinfo_prep(dev, compskb);
+        if (WARN_ON(!nlh)) {
+                kfree_skb(skb);
+                kfree_skb(compskb);
+                return;
+        }
+
+        /* Add the wireless events in the netlink packet */
+        nla = nla_reserve(compskb, IFLA_WIRELESS, event_len);
+        if (!nla) {
+                kfree_skb(skb);
+                kfree_skb(compskb);
+                return;
+        }
+        compat_event = nla_data(nla);
+
+        compat_event->len = event_len;
+        compat_event->cmd = cmd;
+        if (descr->header_type == IW_HEADER_TYPE_POINT) {
+                compat_wrqu.length = wrqu->data.length;
+                compat_wrqu.flags = wrqu->data.flags;
+                memcpy(&compat_event->pointer,
+                        ((char *) &compat_wrqu) + IW_EV_COMPAT_POINT_OFF,
+                        hdr_len - IW_EV_COMPAT_LCP_LEN);
+                if (extra_len)
+                        memcpy(((char *) compat_event) + hdr_len,
+                                extra, extra_len);
+        } else {
+                /* extra_len must be zero, so no if (extra) needed */
+                memcpy(&compat_event->pointer, wrqu,
+                        hdr_len - IW_EV_COMPAT_LCP_LEN);
+        }
+
+        nlmsg_end(compskb, nlh);
+
+        skb_shinfo(skb)->frag_list = compskb;
+#endif
         skb_queue_tail(&dev_net(dev)->wext_nlevents, skb);
         schedule_work(&wireless_nlevent_work);
 }