[libvirt PATCH] remote: Avoid crash in remoteSplitURIScheme()

[Peter Krempa]

On Fri, Dec 10, 2021 at 10:59:27 +0100, Andrea Bolognani wrote:
> We need to make sure the URI scheme is present before passing
> it to strchr(), otherwise we're going to get
> 
>   $ virt-ssh-helper foo
>   Segmentation fault (core dumped)
> 
> Signed-off-by: Andrea Bolognani <abologna at redhat.com>
> ---
>  src/remote/remote_sockets.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/src/remote/remote_sockets.c b/src/remote/remote_sockets.c
> index 2979576680..c315b24d30 100644
> --- a/src/remote/remote_sockets.c
> +++ b/src/remote/remote_sockets.c
> @@ -69,7 +69,15 @@ remoteSplitURIScheme(virURI *uri,
>                       char **driver,
>                       remoteDriverTransport *transport)
>  {
> -    char *p = strchr(uri->scheme, '+');
> +    char *p = NULL;
> +
> +    if (!uri->scheme) {
> +        virReportError(VIR_ERR_INVALID_ARG, "%s",
> +                       _("missing scheme for URI"));

The other place which leads to the call of this helper (virConnectOpenInternal)
uses the following error to reject the uri if scheme is missing:

virReportError(VIR_ERR_NO_CONNECT,
               _("URI '%s' does not include a driver name"),
               name);

It looks like it's unlikely that anybody would use virt-ssh-helper
manually though.

Reviewed-by: Peter Krempa <pkrempa at redhat.com>