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net: heap overflow in __audit_sockaddr()

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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>
This commit is contained in:
Dan Carpenter 2013-10-03 00:27:20 +03:00 committed by David S. Miller
parent 196896d4bb
commit 1661bf364a
2 changed files with 22 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
net/compat.c
View file

@ -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_controllen, &umsg->msg_controllen) ||
__get_user(kmsg->msg_flags, &umsg->msg_flags)) __get_user(kmsg->msg_flags, &umsg->msg_flags))
return -EFAULT; return -EFAULT;
if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
return -EINVAL;
kmsg->msg_name = compat_ptr(tmp1); kmsg->msg_name = compat_ptr(tmp1);
kmsg->msg_iov = compat_ptr(tmp2); kmsg->msg_iov = compat_ptr(tmp2);
kmsg->msg_control = compat_ptr(tmp3); kmsg->msg_control = compat_ptr(tmp3);

24
net/socket.c
View file

@ -1964,6 +1964,16 @@ struct used_address {
unsigned int name_len; 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, static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
struct msghdr *msg_sys, unsigned int flags, struct msghdr *msg_sys, unsigned int flags,
struct used_address *used_address) 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 (MSG_CMSG_COMPAT & flags) {
if (get_compat_msghdr(msg_sys, msg_compat)) if (get_compat_msghdr(msg_sys, msg_compat))
return -EFAULT; return -EFAULT;
} else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr))) } else {
return -EFAULT; err = copy_msghdr_from_user(msg_sys, msg);
if (err)
return err;
}
if (msg_sys->msg_iovlen > UIO_FASTIOV) { if (msg_sys->msg_iovlen > UIO_FASTIOV) {
err = -EMSGSIZE; err = -EMSGSIZE;
@ -2191,8 +2204,11 @@ static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
if (MSG_CMSG_COMPAT & flags) { if (MSG_CMSG_COMPAT & flags) {
if (get_compat_msghdr(msg_sys, msg_compat)) if (get_compat_msghdr(msg_sys, msg_compat))
return -EFAULT; return -EFAULT;
} else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr))) } else {
return -EFAULT; err = copy_msghdr_from_user(msg_sys, msg);
if (err)
return err;
}
if (msg_sys->msg_iovlen > UIO_FASTIOV) { if (msg_sys->msg_iovlen > UIO_FASTIOV) {
err = -EMSGSIZE; err = -EMSGSIZE;