From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
Add data structures and functions necessary to map a uid and gid to SID.
These functions are very similar to the ones used to map a SID to uid and gid.
This time, instead of storing sid to id mapping sorted on sid value,
id to sid is stored, sorted on id.
A cifs upcall sends an id (uid or gid) and expects a SID structure
in return, if mapping was done successfully.
Changed the return code of failed id to sid mapping to EINVAL.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
---
fs/cifs/cifsacl.c | 198 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/cifsglob.h | 4 +
2 files changed, 202 insertions(+), 0 deletions(-)
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 21de1d6..b7e723a 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -91,9 +91,76 @@ cifs_idmap_shrinker(struct shrinker *shrink, struct shrink_control *sc)
shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del);
spin_unlock(&sidgidlock);
+ root = &siduidtree;
+ spin_lock(&uidsidlock);
+ shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del);
+ spin_unlock(&uidsidlock);
+
+ root = &sidgidtree;
+ spin_lock(&gidsidlock);
+ shrink_idmap_tree(root, nr_to_scan, &nr_rem, &nr_del);
+ spin_unlock(&gidsidlock);
+
return nr_rem;
}
+static void
+sid_rb_insert(struct rb_root *root, unsigned long cid,
+ struct cifs_sid_id **psidid, char *typestr)
+{
+ char *strptr;
+ struct rb_node *node = root->rb_node;
+ struct rb_node *parent = NULL;
+ struct rb_node **linkto = &(root->rb_node);
+ struct cifs_sid_id *lsidid;
+
+ while (node) {
+ lsidid = rb_entry(node, struct cifs_sid_id, rbnode);
+ parent = node;
+ if (cid > lsidid->id) {
+ linkto = &(node->rb_left);
+ node = node->rb_left;
+ }
+ if (cid < lsidid->id) {
+ linkto = &(node->rb_right);
+ node = node->rb_right;
+ }
+ }
+
+ (*psidid)->id = cid;
+ (*psidid)->time = jiffies - (SID_MAP_RETRY + 1);
+ (*psidid)->refcount = 0;
+
+ sprintf((*psidid)->sidstr, "%s", typestr);
+ strptr = (*psidid)->sidstr + strlen((*psidid)->sidstr);
+ sprintf(strptr, "%ld", cid);
+
+ clear_bit(SID_ID_PENDING, &(*psidid)->state);
+ clear_bit(SID_ID_MAPPED, &(*psidid)->state);
+
+ rb_link_node(&(*psidid)->rbnode, parent, linkto);
+ rb_insert_color(&(*psidid)->rbnode, root);
+}
+
+static struct cifs_sid_id *
+sid_rb_search(struct rb_root *root, unsigned long cid)
+{
+ struct rb_node *node = root->rb_node;
+ struct cifs_sid_id *lsidid;
+
+ while (node) {
+ lsidid = rb_entry(node, struct cifs_sid_id, rbnode);
+ if (cid > lsidid->id)
+ node = node->rb_left;
+ else if (cid < lsidid->id)
+ node = node->rb_right;
+ else /* node found */
+ return lsidid;
+ }
+
+ return NULL;
+}
+
static struct shrinker cifs_shrinker = {
.shrink = cifs_idmap_shrinker,
.seeks = DEFAULT_SEEKS,
@@ -110,6 +177,7 @@ cifs_idmap_key_instantiate(struct key *key, const void *data, size_t datalen)
memcpy(payload, data, datalen);
key->payload.data = payload;
+ key->datalen = datalen;
return 0;
}
@@ -224,6 +292,120 @@ sidid_pending_wait(void *unused)
}
static int
+id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid)
+{
+ int rc = 0;
+ struct key *sidkey;
+ const struct cred *saved_cred;
+ struct cifs_sid *lsid;
+ struct cifs_sid_id *psidid, *npsidid;
+ struct rb_root *cidtree;
+ spinlock_t *cidlock;
+
+ if (sidtype == SIDOWNER) {
+ cidlock = &siduidlock;
+ cidtree = &uidtree;
+ } else if (sidtype == SIDGROUP) {
+ cidlock = &sidgidlock;
+ cidtree = &gidtree;
+ } else
+ return -EINVAL;
+
+ spin_lock(cidlock);
+ psidid = sid_rb_search(cidtree, cid);
+
+ if (!psidid) { /* node does not exist, allocate one & attempt adding */
+ spin_unlock(cidlock);
+ npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL);
+ if (!npsidid)
+ return -ENOMEM;
+
+ npsidid->sidstr = kmalloc(SIDLEN, GFP_KERNEL);
+ if (!npsidid->sidstr) {
+ kfree(npsidid);
+ return -ENOMEM;
+ }
+
+ spin_lock(cidlock);
+ psidid = sid_rb_search(cidtree, cid);
+ if (psidid) { /* node happened to get inserted meanwhile */
+ ++psidid->refcount;
+ spin_unlock(cidlock);
+ kfree(npsidid->sidstr);
+ kfree(npsidid);
+ } else {
+ psidid = npsidid;
+ sid_rb_insert(cidtree, cid, &psidid,
+ sidtype == SIDOWNER ? "oi:" : "gi:");
+ ++psidid->refcount;
+ spin_unlock(cidlock);
+ }
+ } else {
+ ++psidid->refcount;
+ spin_unlock(cidlock);
+ }
+
+ /*
+ * If we are here, it is safe to access psidid and its fields
+ * since a reference was taken earlier while holding the spinlock.
+ * A reference on the node is put without holding the spinlock
+ * and it is OK to do so in this case, shrinker will not erase
+ * this node until all references are put and we do not access
+ * any fields of the node after a reference is put .
+ */
+ if (test_bit(SID_ID_MAPPED, &psidid->state)) {
+ memcpy(ssid, &psidid->sid, sizeof(struct cifs_sid));
+ psidid->time = jiffies; /* update ts for accessing */
+ goto id_sid_out;
+ }
+
+ if (time_after(psidid->time + SID_MAP_RETRY, jiffies)) {
+ rc = -EINVAL;
+ goto id_sid_out;
+ }
+
+ if (!test_and_set_bit(SID_ID_PENDING, &psidid->state)) {
+ saved_cred = override_creds(root_cred);
+ sidkey = request_key(&cifs_idmap_key_type, psidid->sidstr, "");
+ if (IS_ERR(sidkey)) {
+ rc = -EINVAL;
+ cFYI(1, "%s: Can't map and id to a SID", __func__);
+ } else {
+ lsid = (struct cifs_sid *)sidkey->payload.data;
+ memcpy(&psidid->sid, lsid,
+ sidkey->datalen < sizeof(struct cifs_sid) ?
+ sidkey->datalen : sizeof(struct cifs_sid));
+ memcpy(ssid, &psidid->sid,
+ sidkey->datalen < sizeof(struct cifs_sid) ?
+ sidkey->datalen : sizeof(struct cifs_sid));
+ set_bit(SID_ID_MAPPED, &psidid->state);
+ key_put(sidkey);
+ kfree(psidid->sidstr);
+ }
+ psidid->time = jiffies; /* update ts for accessing */
+ revert_creds(saved_cred);
+ clear_bit(SID_ID_PENDING, &psidid->state);
+ wake_up_bit(&psidid->state, SID_ID_PENDING);
+ } else {
+ rc = wait_on_bit(&psidid->state, SID_ID_PENDING,
+ sidid_pending_wait, TASK_INTERRUPTIBLE);
+ if (rc) {
+ cFYI(1, "%s: sidid_pending_wait interrupted %d",
+ __func__, rc);
+ --psidid->refcount;
+ return rc;
+ }
+ if (test_bit(SID_ID_MAPPED, &psidid->state))
+ memcpy(ssid, &psidid->sid, sizeof(struct cifs_sid));
+ else
+ rc = -EINVAL;
+ }
+id_sid_out:
+ --psidid->refcount;
+ return rc;
+}
+
+static int
sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
struct cifs_fattr *fattr, uint sidtype)
{
@@ -383,6 +565,10 @@ init_cifs_idmap(void)
spin_lock_init(&sidgidlock);
gidtree = RB_ROOT;
+ spin_lock_init(&uidsidlock);
+ siduidtree = RB_ROOT;
+ spin_lock_init(&gidsidlock);
+ sidgidtree = RB_ROOT;
register_shrinker(&cifs_shrinker);
cFYI(1, "cifs idmap keyring: %d\n", key_serial(keyring));
@@ -422,6 +608,18 @@ cifs_destroy_idmaptrees(void)
while ((node = rb_first(root)))
rb_erase(node, root);
spin_unlock(&sidgidlock);
+
+ root = &siduidtree;
+ spin_lock(&uidsidlock);
+ while ((node = rb_first(root)))
+ rb_erase(node, root);
+ spin_unlock(&uidsidlock);
+
+ root = &sidgidtree;
+ spin_lock(&gidsidlock);
+ while ((node = rb_first(root)))
+ rb_erase(node, root);
+ spin_unlock(&gidsidlock);
}
/* if the two SIDs (roughly equivalent to a UUID for a user or group) are
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 6255fa8..6b5e4a5 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -940,6 +940,10 @@ GLOBAL_EXTERN struct rb_root uidtree;
GLOBAL_EXTERN struct rb_root gidtree;
GLOBAL_EXTERN spinlock_t siduidlock;
GLOBAL_EXTERN spinlock_t sidgidlock;
+GLOBAL_EXTERN struct rb_root siduidtree;
+GLOBAL_EXTERN struct rb_root sidgidtree;
+GLOBAL_EXTERN spinlock_t uidsidlock;
+GLOBAL_EXTERN spinlock_t gidsidlock;
void cifs_oplock_break(struct work_struct *work);
void cifs_oplock_break_get(struct cifsFileInfo *cfile);
--
1.6.0.2
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