Re: [Qemu-devel] [PATCH RFC 3/3] linux-user: add netlink audit

[Peter Maydell]

On 30 January 2016 at 22:27, Laurent Vivier <address@hidden> wrote:
> This is, for instance, needed to log in a container.
>
> Without this, the user cannot be identified and the console login
> fails with "Login incorrect".
>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  linux-user/syscall.c | 57 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 790ae49..fa50299 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -102,6 +102,7 @@ int __clone2(int (*fn)(void *), void *child_stack_base,
>  #include "linux_loop.h"
>  #include <linux/netlink.h>
>  #include <linux/rtnetlink.h>
> +#include <linux/audit.h>
>  #include "uname.h"
>
>  #include "qemu.h"
> @@ -1878,6 +1879,44 @@ static abi_long target_to_host_nlmsg_route(struct 
> nlmsghdr *nlh, size_t len)
>      return target_to_host_for_each_nlmsg(nlh, len, 
> target_to_host_data_route);
>  }
>
> +static abi_long host_to_target_data_audit(struct nlmsghdr *nlh)
> +{
> +    switch (nlh->nlmsg_type) {
> +    default:
> +        fprintf(stderr, "Unknown host audit message type %d\n",
> +                nlh->nlmsg_type);

I think we mostly prefer gemu_log() for logging errors rather than
raw fprintf.

> +        return -TARGET_EINVAL;
> +    }
> +    return 0;
> +}
> +
> +static inline abi_long host_to_target_nlmsg_audit(struct nlmsghdr *nlh,
> +                                                  size_t len)
> +{
> +    return host_to_target_for_each_nlmsg(nlh, len, 
> host_to_target_data_audit);
> +}
> +
> +static abi_long target_to_host_data_audit(struct nlmsghdr *nlh)
> +{
> +    switch (nlh->nlmsg_type) {
> +    case AUDIT_USER:
> +    case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
> +    case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
> +        break;

I guess we just hope the magic user data being passed along here doesn't
have any endianness issues...

> +    default:
> +        fprintf(stderr, "Unknown target audit message type %d\n",
> +                nlh->nlmsg_type);
> +        return -TARGET_EINVAL;
> +    }
> +
> +    return 0;
> +}
> +
> +static abi_long target_to_host_nlmsg_audit(struct nlmsghdr *nlh, size_t len)
> +{
> +    return target_to_host_for_each_nlmsg(nlh, len, 
> target_to_host_data_audit);
> +}
> +
>  /* do_setsockopt() Must return target values and target errnos. */
>  static abi_long do_setsockopt(int sockfd, int level, int optname,
>                                abi_ulong optval_addr, socklen_t optlen)
> @@ -2543,6 +2582,21 @@ static TargetFdTrans target_netlink_route_trans = {
>      .host_to_target_data = netlink_route_host_to_target,
>  };
>
> +static abi_long netlink_audit_target_to_host(void *buf, size_t len)
> +{
> +    return target_to_host_nlmsg_audit(buf, len);
> +}
> +
> +static abi_long netlink_audit_host_to_target(void *buf, size_t len)
> +{
> +    return host_to_target_nlmsg_audit(buf, len);
> +}
> +
> +static TargetFdTrans target_netlink_audit_trans = {
> +    .target_to_host_data = netlink_audit_target_to_host,
> +    .host_to_target_data = netlink_audit_host_to_target,
> +};
> +
>  /* do_socket() Must return target values and target errnos. */
>  static abi_long do_socket(int domain, int type, int protocol)
>  {
> @@ -2575,6 +2629,9 @@ static abi_long do_socket(int domain, int type, int 
> protocol)
>              case NETLINK_KOBJECT_UEVENT:
>                  /* nothing to do: messages are strings */
>                  break;
> +            case NETLINK_AUDIT:
> +                fd_trans_register(ret, &target_netlink_audit_trans);
> +                break;
>              default:
>                  close(ret);
>                  ret = -EPFNOSUPPORT;
> --
> 2.5.0

Other than the fprintf thing,
Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM