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    Subject[ 06/32] net: heap overflow in __audit_sockaddr()
    Date
    3.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Dan Carpenter <dan.carpenter@oracle.com>

    [ Upstream commit 1661bf364ae9c506bc8795fef70d1532931be1e8 ]

    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: Jüri Aedla <juri.aedla@gmail.com>
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/compat.c | 2 ++
    net/socket.c | 24 ++++++++++++++++++++----
    2 files changed, 22 insertions(+), 4 deletions(-)

    --- a/net/compat.c
    +++ b/net/compat.c
    @@ -71,6 +71,8 @@ int get_compat_msghdr(struct msghdr *kms
    __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);
    --- a/net/socket.c
    +++ b/net/socket.c
    @@ -1899,6 +1899,16 @@ 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 flags,
    struct used_address *used_address)
    @@ -1917,8 +1927,11 @@ static int ___sys_sendmsg(struct socket
    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;
    + }

    /* do not move before msg_sys is valid */
    err = -EMSGSIZE;
    @@ -2129,8 +2142,11 @@ static int ___sys_recvmsg(struct socket
    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;
    + }

    err = -EMSGSIZE;
    if (msg_sys->msg_iovlen > UIO_MAXIOV)

    --
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