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Commit 1661bf36 authored by Dan Carpenter's avatar Dan Carpenter Committed by David S. Miller
Browse files

net: heap overflow in __audit_sockaddr() 



We need to cap ->msg_namelen or it leads to a buffer overflow when we
to the memcpy() in __audit_sockaddr().  It requires CAP_AUDIT_CONTROL to
exploit this bug.

The call tree is:
___sys_recvmsg()
  move_addr_to_user()
    audit_sockaddr()
      __audit_sockaddr()

Reported-by: default avatarJüri Aedla <juri.aedla@gmail.com>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 196896d4

net/compat.c

+2 −0
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg) 
	    __get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||

	    __get_user(kmsg->msg_flags, &umsg->msg_flags))

		return -EFAULT;

	if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))

		return -EINVAL;

	kmsg->msg_name = compat_ptr(tmp1);

	kmsg->msg_iov = compat_ptr(tmp2);

	kmsg->msg_control = compat_ptr(tmp3);

net/socket.c

+20 −4
Original line number Diff line number Diff line
@@ -1964,6 +1964,16 @@ struct used_address { 
	unsigned int name_len;

};



static int copy_msghdr_from_user(struct msghdr *kmsg,

				 struct msghdr __user *umsg)

{

	if (copy_from_user(kmsg, umsg, sizeof(struct msghdr)))

		return -EFAULT;

	if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))

		return -EINVAL;

	return 0;

}



static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg,

			 struct msghdr *msg_sys, unsigned int flags,

			 struct used_address *used_address)
@@ -1982,8 +1992,11 @@ static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg, 
	if (MSG_CMSG_COMPAT & flags) {

		if (get_compat_msghdr(msg_sys, msg_compat))

			return -EFAULT;

	} else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr)))

		return -EFAULT;

	} else {

		err = copy_msghdr_from_user(msg_sys, msg);

		if (err)

			return err;

	}



	if (msg_sys->msg_iovlen > UIO_FASTIOV) {

		err = -EMSGSIZE;
@@ -2191,8 +2204,11 @@ static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg, 
	if (MSG_CMSG_COMPAT & flags) {

		if (get_compat_msghdr(msg_sys, msg_compat))

			return -EFAULT;

	} else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr)))

		return -EFAULT;

	} else {

		err = copy_msghdr_from_user(msg_sys, msg);

		if (err)

			return err;

	}



	if (msg_sys->msg_iovlen > UIO_FASTIOV) {

		err = -EMSGSIZE;