From c01ff965b48bb9693dcd77cbc748b5d8676766b0 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 9 Jul 2015 14:46:20 -0300 Subject: nss-mymachines: map userns users of containers to real user names Given a container "foo", that maps user id $UID to container user, using user namespaces, this NSS module extenstion will now map the $UID to a name "vu-foo-$TUID" for the translated UID $UID. Similar, userns groups are mapped to "vg-foo-$TGID" for translated GIDs of $GID. This simple change should make userns users more discoverable. Also, given that many tools like "adduser" check NSS before allocating a UID, should lower the chance of UID range conflicts between tools. --- src/machine/machined-dbus.c | 231 +++++++++++++++++++++++++++++- src/machine/org.freedesktop.machine1.conf | 16 +++ 2 files changed, 246 insertions(+), 1 deletion(-) (limited to 'src/machine') diff --git a/src/machine/machined-dbus.c b/src/machine/machined-dbus.c index 0e971a6789..3637815fc9 100644 --- a/src/machine/machined-dbus.c +++ b/src/machine/machined-dbus.c @@ -31,12 +31,13 @@ #include "bus-common-errors.h" #include "cgroup-util.h" #include "btrfs-util.h" +#include "formats-util.h" +#include "process-util.h" #include "machine-image.h" #include "machine-pool.h" #include "image-dbus.h" #include "machined.h" #include "machine-dbus.h" -#include "formats-util.h" static int property_get_pool_path( sd_bus *bus, @@ -840,6 +841,230 @@ static int method_set_image_limit(sd_bus_message *message, void *userdata, sd_bu return bus_image_method_set_limit(message, i, error); } +static int method_map_from_machine_user(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_fclose_ FILE *f = NULL; + Manager *m = userdata; + const char *name, *p; + Machine *machine; + uint32_t uid; + int r; + + r = sd_bus_message_read(message, "su", &name, &uid); + if (r < 0) + return r; + + if (UID_IS_INVALID(uid)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid user ID " UID_FMT, uid); + + machine = hashmap_get(m->machines, name); + if (!machine) + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_MACHINE, "No machine '%s' known", name); + + p = procfs_file_alloca(machine->leader, "uid_map"); + f = fopen(p, "re"); + if (!f) + return -errno; + + for (;;) { + uid_t uid_base, uid_shift, uid_range, converted; + int k; + + errno = 0; + k = fscanf(f, UID_FMT " " UID_FMT " " UID_FMT, &uid_base, &uid_shift, &uid_range); + if (k < 0 && feof(f)) + break; + if (k != 3) { + if (ferror(f) && errno != 0) + return -errno; + + return -EIO; + } + + if (uid < uid_base || uid >= uid_base + uid_range) + continue; + + converted = uid - uid_base + uid_shift; + if (UID_IS_INVALID(converted)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid user ID " UID_FMT, uid); + + return sd_bus_reply_method_return(message, "u", (uint32_t) converted); + } + + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER_MAPPING, "Machine '%s' has no matching user mappings.", name); +} + +static int method_map_to_machine_user(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Manager *m = userdata; + Machine *machine; + uid_t uid; + Iterator i; + int r; + + r = sd_bus_message_read(message, "u", &uid); + if (r < 0) + return r; + if (UID_IS_INVALID(uid)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid user ID " UID_FMT, uid); + if (uid < 0x10000) + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER_MAPPING, "User " UID_FMT " belongs to host UID range", uid); + + HASHMAP_FOREACH(machine, m->machines, i) { + _cleanup_fclose_ FILE *f = NULL; + char p[strlen("/proc//uid_map") + DECIMAL_STR_MAX(pid_t) + 1]; + + xsprintf(p, "/proc/" UID_FMT "/uid_map", machine->leader); + f = fopen(p, "re"); + if (!f) { + log_warning_errno(errno, "Failed top open %s, ignoring,", p); + continue; + } + + for (;;) { + _cleanup_free_ char *o = NULL; + uid_t uid_base, uid_shift, uid_range, converted; + int k; + + errno = 0; + k = fscanf(f, UID_FMT " " UID_FMT " " UID_FMT, &uid_base, &uid_shift, &uid_range); + if (k < 0 && feof(f)) + break; + if (k != 3) { + if (ferror(f) && errno != 0) + return -errno; + + return -EIO; + } + + if (uid < uid_shift || uid >= uid_shift + uid_range) + continue; + + converted = (uid - uid_shift + uid_base); + if (UID_IS_INVALID(converted)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid user ID " UID_FMT, uid); + + o = machine_bus_path(machine); + if (!o) + return -ENOMEM; + + return sd_bus_reply_method_return(message, "sou", machine->name, o, (uint32_t) converted); + } + } + + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER_MAPPING, "No matching user mapping for " UID_FMT ".", uid); +} + +static int method_map_from_machine_group(sd_bus_message *message, void *groupdata, sd_bus_error *error) { + _cleanup_fclose_ FILE *f = NULL; + Manager *m = groupdata; + const char *name, *p; + Machine *machine; + uint32_t gid; + int r; + + r = sd_bus_message_read(message, "su", &name, &gid); + if (r < 0) + return r; + + if (GID_IS_INVALID(gid)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid group ID " GID_FMT, gid); + + machine = hashmap_get(m->machines, name); + if (!machine) + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_MACHINE, "No machine '%s' known", name); + + p = procfs_file_alloca(machine->leader, "gid_map"); + f = fopen(p, "re"); + if (!f) + return -errno; + + for (;;) { + gid_t gid_base, gid_shift, gid_range, converted; + int k; + + errno = 0; + k = fscanf(f, GID_FMT " " GID_FMT " " GID_FMT, &gid_base, &gid_shift, &gid_range); + if (k < 0 && feof(f)) + break; + if (k != 3) { + if (ferror(f) && errno != 0) + return -errno; + + return -EIO; + } + + if (gid < gid_base || gid >= gid_base + gid_range) + continue; + + converted = gid - gid_base + gid_shift; + if (GID_IS_INVALID(converted)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid group ID " GID_FMT, gid); + + return sd_bus_reply_method_return(message, "u", (uint32_t) converted); + } + + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_GROUP_MAPPING, "Machine '%s' has no matching group mappings.", name); +} + +static int method_map_to_machine_group(sd_bus_message *message, void *groupdata, sd_bus_error *error) { + Manager *m = groupdata; + Machine *machine; + gid_t gid; + Iterator i; + int r; + + r = sd_bus_message_read(message, "u", &gid); + if (r < 0) + return r; + if (GID_IS_INVALID(gid)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid group ID " GID_FMT, gid); + if (gid < 0x10000) + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_GROUP_MAPPING, "Group " GID_FMT " belongs to host GID range", gid); + + HASHMAP_FOREACH(machine, m->machines, i) { + _cleanup_fclose_ FILE *f = NULL; + char p[strlen("/proc//gid_map") + DECIMAL_STR_MAX(pid_t) + 1]; + + xsprintf(p, "/proc/" GID_FMT "/gid_map", machine->leader); + f = fopen(p, "re"); + if (!f) { + log_warning_errno(errno, "Failed top open %s, ignoring,", p); + continue; + } + + for (;;) { + _cleanup_free_ char *o = NULL; + gid_t gid_base, gid_shift, gid_range, converted; + int k; + + errno = 0; + k = fscanf(f, GID_FMT " " GID_FMT " " GID_FMT, &gid_base, &gid_shift, &gid_range); + if (k < 0 && feof(f)) + break; + if (k != 3) { + if (ferror(f) && errno != 0) + return -errno; + + return -EIO; + } + + if (gid < gid_shift || gid >= gid_shift + gid_range) + continue; + + converted = (gid - gid_shift + gid_base); + if (GID_IS_INVALID(converted)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid group ID " GID_FMT, gid); + + o = machine_bus_path(machine); + if (!o) + return -ENOMEM; + + return sd_bus_reply_method_return(message, "sou", machine->name, o, (uint32_t) converted); + } + } + + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_GROUP_MAPPING, "No matching group mapping for " GID_FMT ".", gid); +} + const sd_bus_vtable manager_vtable[] = { SD_BUS_VTABLE_START(0), SD_BUS_PROPERTY("PoolPath", "s", property_get_pool_path, 0, 0), @@ -869,6 +1094,10 @@ const sd_bus_vtable manager_vtable[] = { SD_BUS_METHOD("MarkImageReadOnly", "sb", NULL, method_mark_image_read_only, SD_BUS_VTABLE_UNPRIVILEGED), SD_BUS_METHOD("SetPoolLimit", "t", NULL, method_set_pool_limit, SD_BUS_VTABLE_UNPRIVILEGED), SD_BUS_METHOD("SetImageLimit", "st", NULL, method_set_image_limit, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("MapFromMachineUser", "su", "u", method_map_from_machine_user, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("MapToMachineUser", "u", "sou", method_map_to_machine_user, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("MapFromMachineGroup", "su", "u", method_map_from_machine_group, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("MapToMachineGroup", "u", "sou", method_map_to_machine_group, SD_BUS_VTABLE_UNPRIVILEGED), SD_BUS_SIGNAL("MachineNew", "so", 0), SD_BUS_SIGNAL("MachineRemoved", "so", 0), SD_BUS_VTABLE_END diff --git a/src/machine/org.freedesktop.machine1.conf b/src/machine/org.freedesktop.machine1.conf index 93aaf6a377..d58f01507b 100644 --- a/src/machine/org.freedesktop.machine1.conf +++ b/src/machine/org.freedesktop.machine1.conf @@ -112,6 +112,22 @@ send_interface="org.freedesktop.machine1.Manager" send_member="SetImageLimit"/> + + + + + + + + -- cgit v1.2.3-54-g00ecf