{compat_,}verify_iovec(): switch to generic copying of iovecs

use {compat_,}rw_copy_check_uvector().  As the result, we are
guaranteed that all iovecs seen in ->msg_iov by ->sendmsg()
and ->recvmsg() will pass access_ok().

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

diff --git a/net/compat.c b/net/compat.c
index 562e920..7b4b6ad 100644 (file)
--- a/net/compat.c
+++ b/net/compat.c
@@ -31,33 +31,6 @@
 #include <asm/uaccess.h>
 #include <net/compat.h>
 
-static inline int iov_from_user_compat_to_kern(struct iovec *kiov,
-                                         struct compat_iovec __user *uiov32,
-                                         int niov)
-{
-       int tot_len = 0;
-
-       while (niov > 0) {
-               compat_uptr_t buf;
-               compat_size_t len;
-
-               if (get_user(len, &uiov32->iov_len) ||
-                   get_user(buf, &uiov32->iov_base))
-                       return -EFAULT;
-
-               if (len > INT_MAX - tot_len)
-                       len = INT_MAX - tot_len;
-
-               tot_len += len;
-               kiov->iov_base = compat_ptr(buf);
-               kiov->iov_len = (__kernel_size_t) len;
-               uiov32++;
-               kiov++;
-               niov--;
-       }
-       return tot_len;
-}
-
 int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg)
 {
        compat_uptr_t tmp1, tmp2, tmp3;
@@ -80,13 +53,15 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg)
 }
 
 /* I've named the args so it is easy to tell whose space the pointers are in. */
-int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *kern_iov,
+int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *iov,
                   struct sockaddr_storage *kern_address, int mode)
 {
-       int tot_len;
+       struct compat_iovec __user *p;
+       struct iovec *res;
+       int err;
 
        if (kern_msg->msg_name && kern_msg->msg_namelen) {
-               if (mode == VERIFY_READ) {
+               if (mode == WRITE) {
                        int err = move_addr_to_kernel(kern_msg->msg_name,
                                                      kern_msg->msg_namelen,
                                                      kern_address);
@@ -99,13 +74,17 @@ int verify_compat_iovec(struct msghdr *kern_msg, struct iovec *kern_iov,
                kern_msg->msg_namelen = 0;
        }
 
-       tot_len = iov_from_user_compat_to_kern(kern_iov,
-                                         (struct compat_iovec __user *)kern_msg->msg_iov,
-                                         kern_msg->msg_iovlen);
-       if (tot_len >= 0)
-               kern_msg->msg_iov = kern_iov;
+       if (kern_msg->msg_iovlen > UIO_MAXIOV)
+               return -EMSGSIZE;
 
-       return tot_len;
+       p = (struct compat_iovec __user *)kern_msg->msg_iov;
+       err = compat_rw_copy_check_uvector(mode, p, kern_msg->msg_iovlen,
+                                          UIO_FASTIOV, iov, &res);
+       if (err >= 0)
+               kern_msg->msg_iov = res;
+       else if (res != iov)
+               kfree(res);
+       return err;
 }
 
 /* Bleech... */

diff --git a/net/core/iovec.c b/net/core/iovec.c
index e1ec45a..86beeea 100644 (file)
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -37,13 +37,13 @@
 
 int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *address, int mode)
 {
-       int size, ct, err;
+       struct iovec *res;
+       int err;
 
        if (m->msg_name && m->msg_namelen) {
-               if (mode == VERIFY_READ) {
-                       void __user *namep;
-                       namep = (void __user __force *) m->msg_name;
-                       err = move_addr_to_kernel(namep, m->msg_namelen,
+               if (mode == WRITE) {
+                       void __user *namep = (void __user __force *)m->msg_name;
+                       int err = move_addr_to_kernel(namep, m->msg_namelen,
                                                  address);
                        if (err < 0)
                                return err;
@@ -53,24 +53,15 @@ int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *a
                m->msg_name = NULL;
                m->msg_namelen = 0;
        }
-
-       size = m->msg_iovlen * sizeof(struct iovec);
-       if (copy_from_user(iov, (void __user __force *) m->msg_iov, size))
-               return -EFAULT;
-
-       m->msg_iov = iov;
-       err = 0;
-
-       for (ct = 0; ct < m->msg_iovlen; ct++) {
-               size_t len = iov[ct].iov_len;
-
-               if (len > INT_MAX - err) {
-                       len = INT_MAX - err;
-                       iov[ct].iov_len = len;
-               }
-               err += len;
-       }
-
+       if (m->msg_iovlen > UIO_MAXIOV)
+               return -EMSGSIZE;
+
+       err = rw_copy_check_uvector(mode, (void __user __force *)m->msg_iov,
+                                   m->msg_iovlen, UIO_FASTIOV, iov, &res);
+       if (err >= 0)
+               m->msg_iov = res;
+       else if (res != iov)
+               kfree(res);
        return err;
 }
 

diff --git a/net/socket.c b/net/socket.c
index 0ae8147..59020f0 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -2032,24 +2032,14 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
                        return err;
        }
 
-       if (msg_sys->msg_iovlen > UIO_FASTIOV) {
-               err = -EMSGSIZE;
-               if (msg_sys->msg_iovlen > UIO_MAXIOV)
-                       goto out;
-               err = -ENOMEM;
-               iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
-                             GFP_KERNEL);
-               if (!iov)
-                       goto out;
-       }
-
        /* This will also move the address data into kernel space */
-       if (MSG_CMSG_COMPAT & flags) {
-               err = verify_compat_iovec(msg_sys, iov, &address, VERIFY_READ);
-       } else
-               err = verify_iovec(msg_sys, iov, &address, VERIFY_READ);
+       if (MSG_CMSG_COMPAT & flags)
+               err = verify_compat_iovec(msg_sys, iovstack, &address, WRITE);
+       else
+               err = verify_iovec(msg_sys, iovstack, &address, WRITE);
        if (err < 0)
                goto out_freeiov;
+       iov = msg_sys->msg_iov;
        total_len = err;
 
        err = -ENOBUFS;
@@ -2118,7 +2108,6 @@ out_freectl:
 out_freeiov:
        if (iov != iovstack)
                kfree(iov);
-out:
        return err;
 }
 
@@ -2244,28 +2233,18 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
                        return err;
        }
 
-       if (msg_sys->msg_iovlen > UIO_FASTIOV) {
-               err = -EMSGSIZE;
-               if (msg_sys->msg_iovlen > UIO_MAXIOV)
-                       goto out;
-               err = -ENOMEM;
-               iov = kmalloc(msg_sys->msg_iovlen * sizeof(struct iovec),
-                             GFP_KERNEL);
-               if (!iov)
-                       goto out;
-       }
-
        /* 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, iov, &addr, VERIFY_WRITE);
+               err = verify_compat_iovec(msg_sys, iovstack, &addr, READ);
        else
-               err = verify_iovec(msg_sys, iov, &addr, VERIFY_WRITE);
+               err = verify_iovec(msg_sys, iovstack, &addr, READ);
        if (err < 0)
                goto out_freeiov;
+       iov = msg_sys->msg_iov;
        total_len = err;
 
        cmsg_ptr = (unsigned long)msg_sys->msg_control;
@@ -2306,7 +2285,6 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
 out_freeiov:
        if (iov != iovstack)
                kfree(iov);
-out:
        return err;
 }