os-posix: set groups properly for -runas

Andrew Griffiths reports that -runas does not set supplementary group
IDs.  This means that gid 0 (root) is not dropped when switching to an
unprivileged user.

Add an initgroups(3) call to use the -runas user's /etc/groups
membership to update the supplementary group IDs.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This commit is contained in:
Stefan Hajnoczi 2011-07-09 10:22:07 +01:00 committed by Blue Swirl
parent 429bef6912
commit cc4662f964

View file

@ -31,6 +31,7 @@
/*needed for MAP_POPULATE before including qemu-options.h */
#include <sys/mman.h>
#include <pwd.h>
#include <grp.h>
#include <libgen.h>
/* Needed early for CONFIG_BSD etc. */
@ -199,6 +200,11 @@ static void change_process_uid(void)
fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
exit(1);
}
if (initgroups(user_pwd->pw_name, user_pwd->pw_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) {
fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
exit(1);