diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 39 |
1 files changed, 39 insertions, 0 deletions
@@ -1113,3 +1113,42 @@ long clamped_scale(long x, long y, long lo, long hi, long f) return x - (x * (y - lo) / (hi - lo)) * (100 - f) / 100; } + +/** + * make_ugid_map() - Create userns UID & GID mappings + * @pid: PID of process owning the userns, or 0 for self + * @uid: Parent UID to map to 0 within userns + * @gid: Parent GID to map to 0 within userns + */ +void make_ugid_map(pid_t pid, uid_t uid, gid_t gid) +{ + char setgroups_path[PATH_MAX] = "/proc/self/setgroups"; + char uidmap_path[PATH_MAX] = "/proc/self/uid_map"; + char gidmap_path[PATH_MAX] = "/proc/self/gid_map"; + char uidmap[BUFSIZ], gidmap[BUFSIZ]; + + if (pid) { + if (snprintf_check(uidmap_path, sizeof(uidmap_path), + "/proc/%u/uid_map", pid)) + die_perror("Can't build uidmap path"); + + if (snprintf_check(gidmap_path, sizeof(gidmap_path), + "/proc/%u/gid_map", pid)) + die_perror("Can't build gidmap path"); + + if (snprintf_check(setgroups_path, sizeof(setgroups_path), + "/proc/%u/setgroups", pid)) + die_perror("Can't build setgroups path"); + } + + if (snprintf_check(uidmap, sizeof(uidmap), "0 %u 1", uid)) + die_perror("Can't build uidmap"); + + if (snprintf_check(gidmap, BUFSIZ, "0 %u 1", gid)) + die_perror("Can't build gidmap"); + + if (write_file(uidmap_path, uidmap) || + write_file(setgroups_path, "deny") || + write_file(gidmap_path, gidmap)) + die("Couldn't configure user mappings"); +} |