ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one

We want to know if copyout has succeeded before we commit to
freeing msg.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 115 insertions, 133 deletions

diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index f45119c5337d..7007beba918b 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -231,6 +231,102 @@ static int handle_send_req(ipmi_user_t     user,
         return rv;
 }
 
+static int handle_recv(struct ipmi_file_private *priv,
+                        bool trunc, struct ipmi_recv *rsp,
+                        int (*copyout)(struct ipmi_recv *, void __user *),
+                        void __user *to)
+{
+        int              addr_len;
+        struct list_head *entry;
+        struct ipmi_recv_msg  *msg;
+        unsigned long    flags;
+        int rv = 0;
+
+        /* We claim a mutex because we don't want two
+           users getting something from the queue at a time.
+           Since we have to release the spinlock before we can
+           copy the data to the user, it's possible another
+           user will grab something from the queue, too.  Then
+           the messages might get out of order if something
+           fails and the message gets put back onto the
+           queue.  This mutex prevents that problem. */
+        mutex_lock(&priv->recv_mutex);
+
+        /* Grab the message off the list. */
+        spin_lock_irqsave(&(priv->recv_msg_lock), flags);
+        if (list_empty(&(priv->recv_msgs))) {
+                spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
+                rv = -EAGAIN;
+                goto recv_err;
+        }
+        entry = priv->recv_msgs.next;
+        msg = list_entry(entry, struct ipmi_recv_msg, link);
+        list_del(entry);
+        spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
+
+        addr_len = ipmi_addr_length(msg->addr.addr_type);
+        if (rsp->addr_len < addr_len)
+        {
+                rv = -EINVAL;
+                goto recv_putback_on_err;
+        }
+
+        if (copy_to_user(rsp->addr, &(msg->addr), addr_len)) {
+                rv = -EFAULT;
+                goto recv_putback_on_err;
+        }
+        rsp->addr_len = addr_len;
+
+        rsp->recv_type = msg->recv_type;
+        rsp->msgid = msg->msgid;
+        rsp->msg.netfn = msg->msg.netfn;
+        rsp->msg.cmd = msg->msg.cmd;
+
+        if (msg->msg.data_len > 0) {
+                if (rsp->msg.data_len < msg->msg.data_len) {
+                        rv = -EMSGSIZE;
+                        if (trunc)
+                                msg->msg.data_len = rsp->msg.data_len;
+                        else
+                                goto recv_putback_on_err;
+                }
+
+                if (copy_to_user(rsp->msg.data,
+                                 msg->msg.data,
+                                 msg->msg.data_len))
+                {
+                        rv = -EFAULT;
+                        goto recv_putback_on_err;
+                }
+                rsp->msg.data_len = msg->msg.data_len;
+        } else {
+                rsp->msg.data_len = 0;
+        }
+
+        rv = copyout(rsp, to);
+        if (rv)
+                goto recv_putback_on_err;
+
+        mutex_unlock(&priv->recv_mutex);
+        ipmi_free_recv_msg(msg);
+        return 0;
+
+recv_putback_on_err:
+        /* If we got an error, put the message back onto
+           the head of the queue. */
+        spin_lock_irqsave(&(priv->recv_msg_lock), flags);
+        list_add(entry, &(priv->recv_msgs));
+        spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
+recv_err:
+        mutex_unlock(&priv->recv_mutex);
+        return rv;
+}
+
+static int copyout_recv(struct ipmi_recv *rsp, void __user *to)
+{
+        return copy_to_user(to, rsp, sizeof(struct ipmi_recv)) ? -EFAULT : 0;
+}
+
 static int ipmi_ioctl(struct file   *file,
                       unsigned int  cmd,
                       unsigned long data)
@@ -277,100 +373,12 @@ static int ipmi_ioctl(struct file   *file,
         case IPMICTL_RECEIVE_MSG_TRUNC:
         {
                 struct ipmi_recv      rsp;
-                int              addr_len;
-                struct list_head *entry;
-                struct ipmi_recv_msg  *msg;
-                unsigned long    flags;
-                
-
-                rv = 0;
-                if (copy_from_user(&rsp, arg, sizeof(rsp))) {
-                        rv = -EFAULT;
-                        break;
-                }
-
-                /* We claim a mutex because we don't want two
-                   users getting something from the queue at a time.
-                   Since we have to release the spinlock before we can
-                   copy the data to the user, it's possible another
-                   user will grab something from the queue, too.  Then
-                   the messages might get out of order if something
-                   fails and the message gets put back onto the
-                   queue.  This mutex prevents that problem. */
-                mutex_lock(&priv->recv_mutex);
-
-                /* Grab the message off the list. */
-                spin_lock_irqsave(&(priv->recv_msg_lock), flags);
-                if (list_empty(&(priv->recv_msgs))) {
-                        spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
-                        rv = -EAGAIN;
-                        goto recv_err;
-                }
-                entry = priv->recv_msgs.next;
-                msg = list_entry(entry, struct ipmi_recv_msg, link);
-                list_del(entry);
-                spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
-
-                addr_len = ipmi_addr_length(msg->addr.addr_type);
-                if (rsp.addr_len < addr_len)
-                {
-                        rv = -EINVAL;
-                        goto recv_putback_on_err;
-                }
-
-                if (copy_to_user(rsp.addr, &(msg->addr), addr_len)) {
-                        rv = -EFAULT;
-                        goto recv_putback_on_err;
-                }
-                rsp.addr_len = addr_len;
-
-                rsp.recv_type = msg->recv_type;
-                rsp.msgid = msg->msgid;
-                rsp.msg.netfn = msg->msg.netfn;
-                rsp.msg.cmd = msg->msg.cmd;
-
-                if (msg->msg.data_len > 0) {
-                        if (rsp.msg.data_len < msg->msg.data_len) {
-                                rv = -EMSGSIZE;
-                                if (cmd == IPMICTL_RECEIVE_MSG_TRUNC) {
-                                        msg->msg.data_len = rsp.msg.data_len;
-                                } else {
-                                        goto recv_putback_on_err;
-                                }
-                        }
-
-                        if (copy_to_user(rsp.msg.data,
-                                         msg->msg.data,
-                                         msg->msg.data_len))
-                        {
-                                rv = -EFAULT;
-                                goto recv_putback_on_err;
-                        }
-                        rsp.msg.data_len = msg->msg.data_len;
-                } else {
-                        rsp.msg.data_len = 0;
-                }
 
-                if (copy_to_user(arg, &rsp, sizeof(rsp))) {
+                if (copy_from_user(&rsp, arg, sizeof(rsp)))
                         rv = -EFAULT;
-                        goto recv_putback_on_err;
-                }
-
-                mutex_unlock(&priv->recv_mutex);
-                ipmi_free_recv_msg(msg);
-                break;
-
-        recv_putback_on_err:
-                /* If we got an error, put the message back onto
-                   the head of the queue. */
-                spin_lock_irqsave(&(priv->recv_msg_lock), flags);
-                list_add(entry, &(priv->recv_msgs));
-                spin_unlock_irqrestore(&(priv->recv_msg_lock), flags);
-                mutex_unlock(&priv->recv_mutex);
-                break;
-
-        recv_err:
-                mutex_unlock(&priv->recv_mutex);
+                else
+                        rv = handle_recv(priv, cmd == IPMICTL_RECEIVE_MSG_TRUNC,
+                                         &rsp, copyout_recv, arg);
                 break;
         }
 
@@ -711,17 +719,6 @@ static long get_compat_ipmi_msg(struct ipmi_msg *p64,
         return 0;
 }
 
-static long put_compat_ipmi_msg(struct ipmi_msg *p64,
-                                struct compat_ipmi_msg __user *p32)
-{
-        if (!access_ok(VERIFY_WRITE, p32, sizeof(*p32)) ||
-                        __put_user(p64->netfn, &p32->netfn) ||
-                        __put_user(p64->cmd, &p32->cmd) ||
-                        __put_user(p64->data_len, &p32->data_len))
-                return -EFAULT;
-        return 0;
-}
-
 static long get_compat_ipmi_req(struct ipmi_req *p64,
                                 struct compat_ipmi_req __user *p32)
 {
@@ -765,16 +762,19 @@ static long get_compat_ipmi_recv(struct ipmi_recv *p64,
         return 0;
 }
 
-static long put_compat_ipmi_recv(struct ipmi_recv *p64,
-                                 struct compat_ipmi_recv __user *p32)
+static int copyout_recv32(struct ipmi_recv *p64, void __user *to)
 {
-        if (!access_ok(VERIFY_WRITE, p32, sizeof(*p32)) ||
-                        __put_user(p64->recv_type, &p32->recv_type) ||
-                        __put_user(p64->addr_len, &p32->addr_len) ||
-                        __put_user(p64->msgid, &p32->msgid) ||
-                        put_compat_ipmi_msg(&p64->msg, &p32->msg))
-                return -EFAULT;
-        return 0;
+        struct compat_ipmi_recv v32;
+        memset(&v32, 0, sizeof(struct compat_ipmi_recv));
+        v32.recv_type = p64->recv_type;
+        v32.addr = ptr_to_compat(p64->addr);
+        v32.addr_len = p64->addr_len;
+        v32.msgid = p64->msgid;
+        v32.msg.netfn = p64->msg.netfn;
+        v32.msg.cmd = p64->msg.cmd;
+        v32.msg.data_len = p64->msg.data_len;
+        v32.msg.data = ptr_to_compat(p64->msg.data);
+        return copy_to_user(to, &v32, sizeof(v32)) ? -EFAULT : 0;
 }
 
 /*
@@ -783,7 +783,6 @@ static long put_compat_ipmi_recv(struct ipmi_recv *p64,
 static long compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
                               unsigned long arg)
 {
-        int rc;
         struct ipmi_file_private *priv = filep->private_data;
 
         switch(cmd) {
@@ -811,32 +810,15 @@ static long compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
         case COMPAT_IPMICTL_RECEIVE_MSG:
         case COMPAT_IPMICTL_RECEIVE_MSG_TRUNC:
         {
-                struct ipmi_recv   __user *precv64;
                 struct ipmi_recv   recv64;
 
                 memset(&recv64, 0, sizeof(recv64));
                 if (get_compat_ipmi_recv(&recv64, compat_ptr(arg)))
                         return -EFAULT;
 
-                precv64 = compat_alloc_user_space(sizeof(recv64));
-                if (copy_to_user(precv64, &recv64, sizeof(recv64)))
-                        return -EFAULT;
-
-                rc = ipmi_ioctl(filep,
-                                ((cmd == COMPAT_IPMICTL_RECEIVE_MSG)
-                                 ? IPMICTL_RECEIVE_MSG
-                                 : IPMICTL_RECEIVE_MSG_TRUNC),
-                                (unsigned long) precv64);
-                if (rc != 0)
-                        return rc;
-
-                if (copy_from_user(&recv64, precv64, sizeof(recv64)))
-                        return -EFAULT;
-
-                if (put_compat_ipmi_recv(&recv64, compat_ptr(arg)))
-                        return -EFAULT;
-
-                return rc;
+                return handle_recv(priv,
+                                 cmd == COMPAT_IPMICTL_RECEIVE_MSG_TRUNC,
+                                 &recv64, copyout_recv32, compat_ptr(arg));
         }
         default:
                 return ipmi_ioctl(filep, cmd, arg);