#include <linux/ctype.h>
#include <linux/projid.h>
#include <linux/fs_struct.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
static struct kmem_cache *user_ns_cachep __read_mostly;
static DEFINE_MUTEX(userns_state_mutex);
do {
struct ucounts *ucounts = ns->ucounts;
parent = ns->parent;
+ if (ns->gid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+ kfree(ns->gid_map.forward);
+ kfree(ns->gid_map.reverse);
+ }
+ if (ns->uid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+ kfree(ns->uid_map.forward);
+ kfree(ns->uid_map.reverse);
+ }
+ if (ns->projid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+ kfree(ns->projid_map.forward);
+ kfree(ns->projid_map.reverse);
+ }
retire_userns_sysctls(ns);
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
}
EXPORT_SYMBOL(__put_user_ns);
-static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
+/**
+ * idmap_key struct holds the information necessary to find an idmapping in a
+ * sorted idmap array. It is passed to cmp_map_id() as first argument.
+ */
+struct idmap_key {
+ bool map_up; /* true -> id from kid; false -> kid from id */
+ u32 id; /* id to find */
+ u32 count; /* == 0 unless used with map_id_range_down() */
+};
+
+/**
+ * cmp_map_id - Function to be passed to bsearch() to find the requested
+ * idmapping. Expects struct idmap_key to be passed via @k.
+ */
+static int cmp_map_id(const void *k, const void *e)
{
- unsigned idx, extents;
+ u32 first, last, id2;
+ const struct idmap_key *key = k;
+ const struct uid_gid_extent *el = e;
+
+ id2 = key->id + key->count - 1;
+
+ /* handle map_id_{down,up}() */
+ if (key->map_up)
+ first = el->lower_first;
+ else
+ first = el->first;
+
+ last = first + el->count - 1;
+
+ if (key->id >= first && key->id <= last &&
+ (id2 >= first && id2 <= last))
+ return 0;
+
+ if (key->id < first || id2 < first)
+ return -1;
+
+ return 1;
+}
+
+/**
+ * map_id_range_down_max - Find idmap via binary search in ordered idmap array.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_range_down_max(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
+{
+ struct idmap_key key;
+
+ key.map_up = false;
+ key.count = count;
+ key.id = id;
+
+ return bsearch(&key, map->forward, extents,
+ sizeof(struct uid_gid_extent), cmp_map_id);
+}
+
+/**
+ * map_id_range_down_base - Find idmap via binary search in static extent array.
+ * Can only be called if number of mappings is equal or less than
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_range_down_base(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
+{
+ unsigned idx;
u32 first, last, id2;
id2 = id + count - 1;
/* Find the matching extent */
- extents = map->nr_extents;
- smp_rmb();
for (idx = 0; idx < extents; idx++) {
first = map->extent[idx].first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last &&
(id2 >= first && id2 <= last))
- break;
+ return &map->extent[idx];
}
+ return NULL;
+}
+
+static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
+{
+ struct uid_gid_extent *extent;
+ unsigned extents = map->nr_extents;
+ smp_rmb();
+
+ if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ extent = map_id_range_down_base(extents, map, id, count);
+ else
+ extent = map_id_range_down_max(extents, map, id, count);
+
/* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].lower_first;
+ if (extent)
+ id = (id - extent->first) + extent->lower_first;
else
id = (u32) -1;
static u32 map_id_down(struct uid_gid_map *map, u32 id)
{
- unsigned idx, extents;
+ return map_id_range_down(map, id, 1);
+}
+
+/**
+ * map_id_up_base - Find idmap via binary search in static extent array.
+ * Can only be called if number of mappings is equal or less than
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_up_base(unsigned extents, struct uid_gid_map *map, u32 id)
+{
+ unsigned idx;
u32 first, last;
/* Find the matching extent */
- extents = map->nr_extents;
- smp_rmb();
for (idx = 0; idx < extents; idx++) {
- first = map->extent[idx].first;
+ first = map->extent[idx].lower_first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last)
- break;
+ return &map->extent[idx];
}
- /* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].lower_first;
- else
- id = (u32) -1;
+ return NULL;
+}
- return id;
+/**
+ * map_id_up_max - Find idmap via binary search in ordered idmap array.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_up_max(unsigned extents, struct uid_gid_map *map, u32 id)
+{
+ struct idmap_key key;
+
+ key.map_up = true;
+ key.count = 1;
+ key.id = id;
+
+ return bsearch(&key, map->reverse, extents,
+ sizeof(struct uid_gid_extent), cmp_map_id);
}
static u32 map_id_up(struct uid_gid_map *map, u32 id)
{
- unsigned idx, extents;
- u32 first, last;
-
- /* Find the matching extent */
- extents = map->nr_extents;
+ struct uid_gid_extent *extent;
+ unsigned extents = map->nr_extents;
smp_rmb();
- for (idx = 0; idx < extents; idx++) {
- first = map->extent[idx].lower_first;
- last = first + map->extent[idx].count - 1;
- if (id >= first && id <= last)
- break;
- }
+
+ if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ extent = map_id_up_base(extents, map, id);
+ else
+ extent = map_id_up_max(extents, map, id);
+
/* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].first;
+ if (extent)
+ id = (id - extent->lower_first) + extent->first;
else
id = (u32) -1;
static void *m_start(struct seq_file *seq, loff_t *ppos,
struct uid_gid_map *map)
{
- struct uid_gid_extent *extent = NULL;
loff_t pos = *ppos;
+ unsigned extents = map->nr_extents;
+ smp_rmb();
- if (pos < map->nr_extents)
- extent = &map->extent[pos];
+ if (pos >= extents)
+ return NULL;
- return extent;
+ if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ return &map->extent[pos];
+
+ return &map->forward[pos];
}
static void *uid_m_start(struct seq_file *seq, loff_t *ppos)
u32 prev_upper_last, prev_lower_last;
struct uid_gid_extent *prev;
- prev = &new_map->extent[idx];
+ if (new_map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ prev = &new_map->extent[idx];
+ else
+ prev = &new_map->forward[idx];
prev_upper_first = prev->first;
prev_lower_first = prev->lower_first;
return false;
}
+/**
+ * insert_extent - Safely insert a new idmap extent into struct uid_gid_map.
+ * Takes care to allocate a 4K block of memory if the number of mappings exceeds
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static int insert_extent(struct uid_gid_map *map, struct uid_gid_extent *extent)
+{
+ struct uid_gid_extent *dest;
+
+ if (map->nr_extents == UID_GID_MAP_MAX_BASE_EXTENTS) {
+ struct uid_gid_extent *forward;
+
+ /* Allocate memory for 340 mappings. */
+ forward = kmalloc(sizeof(struct uid_gid_extent) *
+ UID_GID_MAP_MAX_EXTENTS, GFP_KERNEL);
+ if (!forward)
+ return -ENOMEM;
+
+ /* Copy over memory. Only set up memory for the forward pointer.
+ * Defer the memory setup for the reverse pointer.
+ */
+ memcpy(forward, map->extent,
+ map->nr_extents * sizeof(map->extent[0]));
+
+ map->forward = forward;
+ map->reverse = NULL;
+ }
+
+ if (map->nr_extents < UID_GID_MAP_MAX_BASE_EXTENTS)
+ dest = &map->extent[map->nr_extents];
+ else
+ dest = &map->forward[map->nr_extents];
+
+ *dest = *extent;
+ map->nr_extents++;
+ return 0;
+}
+
+/* cmp function to sort() forward mappings */
+static int cmp_extents_forward(const void *a, const void *b)
+{
+ const struct uid_gid_extent *e1 = a;
+ const struct uid_gid_extent *e2 = b;
+
+ if (e1->first < e2->first)
+ return -1;
+
+ if (e1->first > e2->first)
+ return 1;
+
+ return 0;
+}
+
+/* cmp function to sort() reverse mappings */
+static int cmp_extents_reverse(const void *a, const void *b)
+{
+ const struct uid_gid_extent *e1 = a;
+ const struct uid_gid_extent *e2 = b;
+
+ if (e1->lower_first < e2->lower_first)
+ return -1;
+
+ if (e1->lower_first > e2->lower_first)
+ return 1;
+
+ return 0;
+}
+
+/**
+ * sort_idmaps - Sorts an array of idmap entries.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static int sort_idmaps(struct uid_gid_map *map)
+{
+ if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ return 0;
+
+ /* Sort forward array. */
+ sort(map->forward, map->nr_extents, sizeof(struct uid_gid_extent),
+ cmp_extents_forward, NULL);
+
+ /* Only copy the memory from forward we actually need. */
+ map->reverse = kmemdup(map->forward,
+ map->nr_extents * sizeof(struct uid_gid_extent),
+ GFP_KERNEL);
+ if (!map->reverse)
+ return -ENOMEM;
+
+ /* Sort reverse array. */
+ sort(map->reverse, map->nr_extents, sizeof(struct uid_gid_extent),
+ cmp_extents_reverse, NULL);
+
+ return 0;
+}
+
static ssize_t map_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos,
int cap_setid,
struct user_namespace *ns = seq->private;
struct uid_gid_map new_map;
unsigned idx;
- struct uid_gid_extent *extent = NULL;
+ struct uid_gid_extent extent;
char *kbuf = NULL, *pos, *next_line;
ssize_t ret = -EINVAL;
*/
mutex_lock(&userns_state_mutex);
+ memset(&new_map, 0, sizeof(struct uid_gid_map));
+
ret = -EPERM;
/* Only allow one successful write to the map */
if (map->nr_extents != 0)
/* Parse the user data */
ret = -EINVAL;
pos = kbuf;
- new_map.nr_extents = 0;
for (; pos; pos = next_line) {
- extent = &new_map.extent[new_map.nr_extents];
/* Find the end of line and ensure I don't look past it */
next_line = strchr(pos, '\n');
}
pos = skip_spaces(pos);
- extent->first = simple_strtoul(pos, &pos, 10);
+ extent.first = simple_strtoul(pos, &pos, 10);
if (!isspace(*pos))
goto out;
pos = skip_spaces(pos);
- extent->lower_first = simple_strtoul(pos, &pos, 10);
+ extent.lower_first = simple_strtoul(pos, &pos, 10);
if (!isspace(*pos))
goto out;
pos = skip_spaces(pos);
- extent->count = simple_strtoul(pos, &pos, 10);
+ extent.count = simple_strtoul(pos, &pos, 10);
if (*pos && !isspace(*pos))
goto out;
goto out;
/* Verify we have been given valid starting values */
- if ((extent->first == (u32) -1) ||
- (extent->lower_first == (u32) -1))
+ if ((extent.first == (u32) -1) ||
+ (extent.lower_first == (u32) -1))
goto out;
/* Verify count is not zero and does not cause the
* extent to wrap
*/
- if ((extent->first + extent->count) <= extent->first)
+ if ((extent.first + extent.count) <= extent.first)
goto out;
- if ((extent->lower_first + extent->count) <=
- extent->lower_first)
+ if ((extent.lower_first + extent.count) <=
+ extent.lower_first)
goto out;
/* Do the ranges in extent overlap any previous extents? */
- if (mappings_overlap(&new_map, extent))
+ if (mappings_overlap(&new_map, &extent))
goto out;
- new_map.nr_extents++;
-
- /* Fail if the file contains too many extents */
- if ((new_map.nr_extents == UID_GID_MAP_MAX_EXTENTS) &&
+ if ((new_map.nr_extents + 1) == UID_GID_MAP_MAX_EXTENTS &&
(next_line != NULL))
goto out;
+
+ ret = insert_extent(&new_map, &extent);
+ if (ret < 0)
+ goto out;
+ ret = -EINVAL;
}
/* Be very certaint the new map actually exists */
if (new_map.nr_extents == 0)
if (!new_idmap_permitted(file, ns, cap_setid, &new_map))
goto out;
+ ret = sort_idmaps(&new_map);
+ if (ret < 0)
+ goto out;
+
+ ret = -EPERM;
/* Map the lower ids from the parent user namespace to the
* kernel global id space.
*/
for (idx = 0; idx < new_map.nr_extents; idx++) {
+ struct uid_gid_extent *e;
u32 lower_first;
- extent = &new_map.extent[idx];
+
+ if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+ e = &new_map.extent[idx];
+ else
+ e = &new_map.forward[idx];
lower_first = map_id_range_down(parent_map,
- extent->lower_first,
- extent->count);
+ e->lower_first,
+ e->count);
/* Fail if we can not map the specified extent to
* the kernel global id space.
if (lower_first == (u32) -1)
goto out;
- extent->lower_first = lower_first;
+ e->lower_first = lower_first;
}
/* Install the map */
- memcpy(map->extent, new_map.extent,
- new_map.nr_extents*sizeof(new_map.extent[0]));
+ if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS) {
+ memcpy(map->extent, new_map.extent,
+ new_map.nr_extents * sizeof(new_map.extent[0]));
+ } else {
+ map->forward = new_map.forward;
+ map->reverse = new_map.reverse;
+ }
smp_wmb();
map->nr_extents = new_map.nr_extents;
*ppos = count;
ret = count;
out:
+ if (ret < 0 && new_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+ kfree(new_map.forward);
+ kfree(new_map.reverse);
+ map->forward = NULL;
+ map->reverse = NULL;
+ map->nr_extents = 0;
+ }
+
mutex_unlock(&userns_state_mutex);
kfree(kbuf);
return ret;
projects / mirror_ubuntu-bionic-kernel.git / blobdiff