Re: [Qemu-devel] [PATCH 7/8] os-posix: Provide new -runasid option

[Ross Lagerwall]

On 10/04/2017 05:18 PM, Ian Jackson wrote:
> This allows the caller to specify a uid and gid to use, even if there
> is no corresponding password entry.  This will be useful in certain
> Xen configurations.
>
> Signed-off-by: Ian Jackson <address@hidden>
snip
> @@ -166,17 +187,19 @@ void os_parse_cmd_args(int index, const char *optarg)
>   
>   static void change_process_uid(void)
>   {
> -    if (user_pwd) {
> -        if (setgid(user_pwd->pw_gid) < 0) {
> +    if (user_pwd || user_uid != (uid_t)-1) {
> +        if (setgid(user_pwd ? user_pwd->pw_gid : user_gid) < 0) {
>               fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
>               exit(1);
>           }
> -        if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
> +        if ((user_pwd
> +             ? initgroups(user_pwd->pw_name, user_pwd->pw_gid)
> +             : setgroups(1, &user_gid)) < 0) {
>               fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n",
>                       user_pwd->pw_name, user_pwd->pw_gid);
>               exit(1);
>           }
> -        if (setuid(user_pwd->pw_uid) < 0) {
> +        if (setuid(user_pwd ? user_pwd->pw_uid : user_gid) < 0) {
>               fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
>               exit(1);
>           }

This last one should be user_uid, not user_gid.

--
Ross Lagerwall