fold verify_iovec() into copy_msghdr_from_user()

... and do the same on the compat side of things.

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

1 files changed, 53 insertions, 40 deletions

diff --git a/net/socket.c b/net/socket.c
index 59020f0b583b..ee3ee39eefa5 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1988,16 +1988,26 @@ struct used_address {
         unsigned int name_len;
 };
 
-static int copy_msghdr_from_user(struct msghdr *kmsg,
-                                 struct user_msghdr __user *umsg)
+static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
+                                     struct user_msghdr __user *umsg,
+                                     struct sockaddr __user **save_addr,
+                                     struct iovec **iov)
 {
-        /* We are relying on the (currently) identical layouts.  Once
-         * the kernel-side changes, this place will need to be updated
-         */
-        if (copy_from_user(kmsg, umsg, sizeof(struct msghdr)))
+        struct sockaddr __user *uaddr;
+        struct iovec __user *uiov;
+        ssize_t err;
+
+        if (!access_ok(VERIFY_READ, umsg, sizeof(*umsg)) ||
+            __get_user(uaddr, &umsg->msg_name) ||
+            __get_user(kmsg->msg_namelen, &umsg->msg_namelen) ||
+            __get_user(uiov, &umsg->msg_iov) ||
+            __get_user(kmsg->msg_iovlen, &umsg->msg_iovlen) ||
+            __get_user(kmsg->msg_control, &umsg->msg_control) ||
+            __get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||
+            __get_user(kmsg->msg_flags, &umsg->msg_flags))
                 return -EFAULT;
 
-        if (kmsg->msg_name == NULL)
+        if (!uaddr)
                 kmsg->msg_namelen = 0;
 
         if (kmsg->msg_namelen < 0)
@@ -2005,7 +2015,31 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
 
         if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
                 kmsg->msg_namelen = sizeof(struct sockaddr_storage);
-        return 0;
+
+        if (save_addr)
+                *save_addr = uaddr;
+
+        if (uaddr && kmsg->msg_namelen) {
+                if (!save_addr) {
+                        err = move_addr_to_kernel(uaddr, kmsg->msg_namelen,
+                                                  kmsg->msg_name);
+                        if (err < 0)
+                                return err;
+                }
+        } else {
+                kmsg->msg_name = NULL;
+                kmsg->msg_namelen = 0;
+        }
+
+        if (kmsg->msg_iovlen > UIO_MAXIOV)
+                return -EMSGSIZE;
+
+        err = rw_copy_check_uvector(save_addr ? READ : WRITE,
+                                    uiov, kmsg->msg_iovlen,
+                                    UIO_FASTIOV, *iov, iov);
+        if (err >= 0)
+                kmsg->msg_iov = *iov;
+        return err;
 }
 
 static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
@@ -2020,26 +2054,17 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
             __attribute__ ((aligned(sizeof(__kernel_size_t))));
         /* 20 is size of ipv6_pktinfo */
         unsigned char *ctl_buf = ctl;
-        int err, ctl_len, total_len;
+        int ctl_len, total_len;
+        ssize_t err;
 
-        err = -EFAULT;
-        if (MSG_CMSG_COMPAT & flags) {
-                if (get_compat_msghdr(msg_sys, msg_compat))
-                        return -EFAULT;
-        } else {
-                err = copy_msghdr_from_user(msg_sys, msg);
-                if (err)
-                        return err;
-        }
+        msg_sys->msg_name = &address;
 
-        /* This will also move the address data into kernel space */
         if (MSG_CMSG_COMPAT & flags)
-                err = verify_compat_iovec(msg_sys, iovstack, &address, WRITE);
+                err = get_compat_msghdr(msg_sys, msg_compat, NULL, &iov);
         else
-                err = verify_iovec(msg_sys, iovstack, &address, WRITE);
+                err = copy_msghdr_from_user(msg_sys, msg, NULL, &iov);
         if (err < 0)
                 goto out_freeiov;
-        iov = msg_sys->msg_iov;
         total_len = err;
 
         err = -ENOBUFS;
@@ -2215,36 +2240,24 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
         struct iovec iovstack[UIO_FASTIOV];
         struct iovec *iov = iovstack;
         unsigned long cmsg_ptr;
-        int err, total_len, len;
+        int total_len, len;
+        ssize_t err;
 
         /* kernel mode address */
         struct sockaddr_storage addr;
 
         /* user mode address pointers */
         struct sockaddr __user *uaddr;
-        int __user *uaddr_len;
+        int __user *uaddr_len = COMPAT_NAMELEN(msg);
 
-        if (MSG_CMSG_COMPAT & flags) {
-                if (get_compat_msghdr(msg_sys, msg_compat))
-                        return -EFAULT;
-        } else {
-                err = copy_msghdr_from_user(msg_sys, msg);
-                if (err)
-                        return err;
-        }
+        msg_sys->msg_name = &addr;
 
-        /* Save the user-mode address (verify_iovec will change the
-         * kernel msghdr to use the kernel address space)
-         */
-        uaddr = (__force void __user *)msg_sys->msg_name;
-        uaddr_len = COMPAT_NAMELEN(msg);
         if (MSG_CMSG_COMPAT & flags)
-                err = verify_compat_iovec(msg_sys, iovstack, &addr, READ);
+                err = get_compat_msghdr(msg_sys, msg_compat, &uaddr, &iov);
         else
-                err = verify_iovec(msg_sys, iovstack, &addr, READ);
+                err = copy_msghdr_from_user(msg_sys, msg, &uaddr, &iov);
         if (err < 0)
                 goto out_freeiov;
-        iov = msg_sys->msg_iov;
         total_len = err;
 
         cmsg_ptr = (unsigned long)msg_sys->msg_control;