Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6
[safe/jmp/linux-2.6] / security / keys / request_key.c
index 6381e61..f5ec9ac 100644 (file)
 #include <linux/kmod.h>
 #include <linux/err.h>
 #include <linux/keyctl.h>
+#include <linux/slab.h>
 #include "internal.h"
 
+#define key_negative_timeout   60      /* default timeout on a negative key's existence */
+
 /*
  * wait_on_bit() sleep function for uninterruptible waiting
  */
@@ -55,6 +58,38 @@ void complete_request_key(struct key_construction *cons, int error)
 }
 EXPORT_SYMBOL(complete_request_key);
 
+static int umh_keys_init(struct subprocess_info *info)
+{
+       struct cred *cred = (struct cred*)current_cred();
+       struct key *keyring = info->data;
+       /*
+        * This is called in context of freshly forked kthread before
+        * kernel_execve(), we can just change our ->session_keyring.
+        */
+       return install_session_keyring_to_cred(cred, keyring);
+}
+
+static void umh_keys_cleanup(struct subprocess_info *info)
+{
+       struct key *keyring = info->data;
+       key_put(keyring);
+}
+
+static int call_usermodehelper_keys(char *path, char **argv, char **envp,
+                        struct key *session_keyring, enum umh_wait wait)
+{
+       gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+       struct subprocess_info *info =
+               call_usermodehelper_setup(path, argv, envp, gfp_mask);
+
+       if (!info)
+               return -ENOMEM;
+
+       call_usermodehelper_setfns(info, umh_keys_init, umh_keys_cleanup,
+                                       key_get(session_keyring));
+       return call_usermodehelper_exec(info, wait);
+}
+
 /*
  * request userspace finish the construction of a key
  * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
@@ -63,9 +98,10 @@ static int call_sbin_request_key(struct key_construction *cons,
                                 const char *op,
                                 void *aux)
 {
-       struct task_struct *tsk = current;
+       const struct cred *cred = current_cred();
        key_serial_t prkey, sskey;
-       struct key *key = cons->key, *authkey = cons->authkey, *keyring;
+       struct key *key = cons->key, *authkey = cons->authkey, *keyring,
+               *session;
        char *argv[9], *envp[3], uid_str[12], gid_str[12];
        char key_str[12], keyring_str[3][12];
        char desc[20];
@@ -73,45 +109,48 @@ static int call_sbin_request_key(struct key_construction *cons,
 
        kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
 
+       ret = install_user_keyrings();
+       if (ret < 0)
+               goto error_alloc;
+
        /* allocate a new session keyring */
        sprintf(desc, "_req.%u", key->serial);
 
-       keyring = keyring_alloc(desc, current->fsuid, current->fsgid, current,
+       cred = get_current_cred();
+       keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
                                KEY_ALLOC_QUOTA_OVERRUN, NULL);
+       put_cred(cred);
        if (IS_ERR(keyring)) {
                ret = PTR_ERR(keyring);
                goto error_alloc;
        }
 
        /* attach the auth key to the session keyring */
-       ret = __key_link(keyring, authkey);
+       ret = key_link(keyring, authkey);
        if (ret < 0)
                goto error_link;
 
        /* record the UID and GID */
-       sprintf(uid_str, "%d", current->fsuid);
-       sprintf(gid_str, "%d", current->fsgid);
+       sprintf(uid_str, "%d", cred->fsuid);
+       sprintf(gid_str, "%d", cred->fsgid);
 
        /* we say which key is under construction */
        sprintf(key_str, "%d", key->serial);
 
        /* we specify the process's default keyrings */
        sprintf(keyring_str[0], "%d",
-               tsk->thread_keyring ? tsk->thread_keyring->serial : 0);
+               cred->thread_keyring ? cred->thread_keyring->serial : 0);
 
        prkey = 0;
-       if (tsk->signal->process_keyring)
-               prkey = tsk->signal->process_keyring->serial;
+       if (cred->tgcred->process_keyring)
+               prkey = cred->tgcred->process_keyring->serial;
 
-       sprintf(keyring_str[1], "%d", prkey);
-
-       if (tsk->signal->session_keyring) {
-               rcu_read_lock();
-               sskey = rcu_dereference(tsk->signal->session_keyring)->serial;
-               rcu_read_unlock();
-       } else {
-               sskey = tsk->user->session_keyring->serial;
-       }
+       rcu_read_lock();
+       session = rcu_dereference(cred->tgcred->session_keyring);
+       if (!session)
+               session = cred->user->session_keyring;
+       sskey = session->serial;
+       rcu_read_unlock();
 
        sprintf(keyring_str[2], "%d", sskey);
 
@@ -152,8 +191,8 @@ error_link:
        key_put(keyring);
 
 error_alloc:
-       kleave(" = %d", ret);
        complete_request_key(cons, ret);
+       kleave(" = %d", ret);
        return ret;
 }
 
@@ -161,21 +200,24 @@ error_alloc:
  * call out to userspace for key construction
  * - we ignore program failure and go on key status instead
  */
-static int construct_key(struct key *key, const char *callout_info, void *aux)
+static int construct_key(struct key *key, const void *callout_info,
+                        size_t callout_len, void *aux,
+                        struct key *dest_keyring)
 {
        struct key_construction *cons;
        request_key_actor_t actor;
        struct key *authkey;
        int ret;
 
-       kenter("%d,%s,%p", key->serial, callout_info, aux);
+       kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
 
        cons = kmalloc(sizeof(*cons), GFP_KERNEL);
        if (!cons)
                return -ENOMEM;
 
        /* allocate an authorisation key */
-       authkey = request_key_auth_new(key, callout_info);
+       authkey = request_key_auth_new(key, callout_info, callout_len,
+                                      dest_keyring);
        if (IS_ERR(authkey)) {
                kfree(cons);
                ret = PTR_ERR(authkey);
@@ -203,46 +245,67 @@ static int construct_key(struct key *key, const char *callout_info, void *aux)
 }
 
 /*
- * link a key to the appropriate destination keyring
- * - the caller must hold a write lock on the destination keyring
+ * get the appropriate destination keyring for the request
+ * - we return whatever keyring we select with an extra reference upon it which
+ *   the caller must release
  */
-static void construct_key_make_link(struct key *key, struct key *dest_keyring)
+static void construct_get_dest_keyring(struct key **_dest_keyring)
 {
-       struct task_struct *tsk = current;
-       struct key *drop = NULL;
+       struct request_key_auth *rka;
+       const struct cred *cred = current_cred();
+       struct key *dest_keyring = *_dest_keyring, *authkey;
 
-       kenter("{%d},%p", key->serial, dest_keyring);
+       kenter("%p", dest_keyring);
 
        /* find the appropriate keyring */
-       if (!dest_keyring) {
-               switch (tsk->jit_keyring) {
+       if (dest_keyring) {
+               /* the caller supplied one */
+               key_get(dest_keyring);
+       } else {
+               /* use a default keyring; falling through the cases until we
+                * find one that we actually have */
+               switch (cred->jit_keyring) {
                case KEY_REQKEY_DEFL_DEFAULT:
+               case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
+                       if (cred->request_key_auth) {
+                               authkey = cred->request_key_auth;
+                               down_read(&authkey->sem);
+                               rka = authkey->payload.data;
+                               if (!test_bit(KEY_FLAG_REVOKED,
+                                             &authkey->flags))
+                                       dest_keyring =
+                                               key_get(rka->dest_keyring);
+                               up_read(&authkey->sem);
+                               if (dest_keyring)
+                                       break;
+                       }
+
                case KEY_REQKEY_DEFL_THREAD_KEYRING:
-                       dest_keyring = tsk->thread_keyring;
+                       dest_keyring = key_get(cred->thread_keyring);
                        if (dest_keyring)
                                break;
 
                case KEY_REQKEY_DEFL_PROCESS_KEYRING:
-                       dest_keyring = tsk->signal->process_keyring;
+                       dest_keyring = key_get(cred->tgcred->process_keyring);
                        if (dest_keyring)
                                break;
 
                case KEY_REQKEY_DEFL_SESSION_KEYRING:
                        rcu_read_lock();
                        dest_keyring = key_get(
-                               rcu_dereference(tsk->signal->session_keyring));
+                               rcu_dereference(cred->tgcred->session_keyring));
                        rcu_read_unlock();
-                       drop = dest_keyring;
 
                        if (dest_keyring)
                                break;
 
                case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
-                       dest_keyring = tsk->user->session_keyring;
+                       dest_keyring =
+                               key_get(cred->user->session_keyring);
                        break;
 
                case KEY_REQKEY_DEFL_USER_KEYRING:
-                       dest_keyring = tsk->user->uid_keyring;
+                       dest_keyring = key_get(cred->user->uid_keyring);
                        break;
 
                case KEY_REQKEY_DEFL_GROUP_KEYRING:
@@ -251,10 +314,9 @@ static void construct_key_make_link(struct key *key, struct key *dest_keyring)
                }
        }
 
-       /* and attach the key to it */
-       __key_link(dest_keyring, key);
-       key_put(drop);
-       kleave("");
+       *_dest_keyring = dest_keyring;
+       kleave(" [dk %d]", key_serial(dest_keyring));
+       return;
 }
 
 /*
@@ -269,58 +331,84 @@ static int construct_alloc_key(struct key_type *type,
                               struct key_user *user,
                               struct key **_key)
 {
+       struct keyring_list *prealloc;
+       const struct cred *cred = current_cred();
        struct key *key;
        key_ref_t key_ref;
+       int ret;
 
        kenter("%s,%s,,,", type->name, description);
 
+       *_key = NULL;
        mutex_lock(&user->cons_lock);
 
-       key = key_alloc(type, description,
-                       current->fsuid, current->fsgid, current, KEY_POS_ALL,
-                       flags);
+       key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
+                       KEY_POS_ALL, flags);
        if (IS_ERR(key))
                goto alloc_failed;
 
        set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
 
-       if (dest_keyring)
-               down_write(&dest_keyring->sem);
+       if (dest_keyring) {
+               ret = __key_link_begin(dest_keyring, type, description,
+                                      &prealloc);
+               if (ret < 0)
+                       goto link_prealloc_failed;
+       }
 
        /* attach the key to the destination keyring under lock, but we do need
         * to do another check just in case someone beat us to it whilst we
         * waited for locks */
        mutex_lock(&key_construction_mutex);
 
-       key_ref = search_process_keyrings(type, description, type->match,
-                                         current);
+       key_ref = search_process_keyrings(type, description, type->match, cred);
        if (!IS_ERR(key_ref))
                goto key_already_present;
 
        if (dest_keyring)
-               construct_key_make_link(key, dest_keyring);
+               __key_link(dest_keyring, key, &prealloc);
 
        mutex_unlock(&key_construction_mutex);
        if (dest_keyring)
-               up_write(&dest_keyring->sem);
+               __key_link_end(dest_keyring, type, prealloc);
        mutex_unlock(&user->cons_lock);
        *_key = key;
        kleave(" = 0 [%d]", key_serial(key));
        return 0;
 
+       /* the key is now present - we tell the caller that we found it by
+        * returning -EINPROGRESS  */
 key_already_present:
+       key_put(key);
        mutex_unlock(&key_construction_mutex);
-       if (dest_keyring)
-               up_write(&dest_keyring->sem);
+       key = key_ref_to_ptr(key_ref);
+       if (dest_keyring) {
+               ret = __key_link_check_live_key(dest_keyring, key);
+               if (ret == 0)
+                       __key_link(dest_keyring, key, &prealloc);
+               __key_link_end(dest_keyring, type, prealloc);
+               if (ret < 0)
+                       goto link_check_failed;
+       }
        mutex_unlock(&user->cons_lock);
-       key_put(key);
-       *_key = key = key_ref_to_ptr(key_ref);
+       *_key = key;
        kleave(" = -EINPROGRESS [%d]", key_serial(key));
        return -EINPROGRESS;
 
+link_check_failed:
+       mutex_unlock(&user->cons_lock);
+       key_put(key);
+       kleave(" = %d [linkcheck]", ret);
+       return ret;
+
+link_prealloc_failed:
+       up_write(&dest_keyring->sem);
+       mutex_unlock(&user->cons_lock);
+       kleave(" = %d [prelink]", ret);
+       return ret;
+
 alloc_failed:
        mutex_unlock(&user->cons_lock);
-       *_key = NULL;
        kleave(" = %ld", PTR_ERR(key));
        return PTR_ERR(key);
 }
@@ -331,6 +419,7 @@ alloc_failed:
 static struct key *construct_key_and_link(struct key_type *type,
                                          const char *description,
                                          const char *callout_info,
+                                         size_t callout_len,
                                          void *aux,
                                          struct key *dest_keyring,
                                          unsigned long flags)
@@ -339,25 +428,40 @@ static struct key *construct_key_and_link(struct key_type *type,
        struct key *key;
        int ret;
 
-       user = key_user_lookup(current->fsuid);
+       kenter("");
+
+       user = key_user_lookup(current_fsuid(), current_user_ns());
        if (!user)
                return ERR_PTR(-ENOMEM);
 
+       construct_get_dest_keyring(&dest_keyring);
+
        ret = construct_alloc_key(type, description, dest_keyring, flags, user,
                                  &key);
        key_user_put(user);
 
        if (ret == 0) {
-               ret = construct_key(key, callout_info, aux);
-               if (ret < 0)
+               ret = construct_key(key, callout_info, callout_len, aux,
+                                   dest_keyring);
+               if (ret < 0) {
+                       kdebug("cons failed");
                        goto construction_failed;
+               }
+       } else if (ret == -EINPROGRESS) {
+               ret = 0;
+       } else {
+               key = ERR_PTR(ret);
        }
 
+       key_put(dest_keyring);
+       kleave(" = key %d", key_serial(key));
        return key;
 
 construction_failed:
        key_negate_and_link(key, key_negative_timeout, NULL, NULL);
        key_put(key);
+       key_put(dest_keyring);
+       kleave(" = %d", ret);
        return ERR_PTR(ret);
 }
 
@@ -370,26 +474,39 @@ construction_failed:
  */
 struct key *request_key_and_link(struct key_type *type,
                                 const char *description,
-                                const char *callout_info,
+                                const void *callout_info,
+                                size_t callout_len,
                                 void *aux,
                                 struct key *dest_keyring,
                                 unsigned long flags)
 {
+       const struct cred *cred = current_cred();
        struct key *key;
        key_ref_t key_ref;
+       int ret;
 
-       kenter("%s,%s,%s,%p,%p,%lx",
-              type->name, description, callout_info, aux,
+       kenter("%s,%s,%p,%zu,%p,%p,%lx",
+              type->name, description, callout_info, callout_len, aux,
               dest_keyring, flags);
 
        /* search all the process keyrings for a key */
        key_ref = search_process_keyrings(type, description, type->match,
-                                         current);
+                                         cred);
 
        if (!IS_ERR(key_ref)) {
                key = key_ref_to_ptr(key_ref);
+               if (dest_keyring) {
+                       construct_get_dest_keyring(&dest_keyring);
+                       ret = key_link(dest_keyring, key);
+                       key_put(dest_keyring);
+                       if (ret < 0) {
+                               key_put(key);
+                               key = ERR_PTR(ret);
+                               goto error;
+                       }
+               }
        } else if (PTR_ERR(key_ref) != -EAGAIN) {
-               key = ERR_PTR(PTR_ERR(key_ref));
+               key = ERR_CAST(key_ref);
        } else  {
                /* the search failed, but the keyrings were searchable, so we
                 * should consult userspace if we can */
@@ -398,7 +515,8 @@ struct key *request_key_and_link(struct key_type *type,
                        goto error;
 
                key = construct_key_and_link(type, description, callout_info,
-                                            aux, dest_keyring, flags);
+                                            callout_len, aux, dest_keyring,
+                                            flags);
        }
 
 error:
@@ -434,10 +552,13 @@ struct key *request_key(struct key_type *type,
                        const char *callout_info)
 {
        struct key *key;
+       size_t callout_len = 0;
        int ret;
 
-       key = request_key_and_link(type, description, callout_info, NULL,
-                                  NULL, KEY_ALLOC_IN_QUOTA);
+       if (callout_info)
+               callout_len = strlen(callout_info);
+       key = request_key_and_link(type, description, callout_info, callout_len,
+                                  NULL, NULL, KEY_ALLOC_IN_QUOTA);
        if (!IS_ERR(key)) {
                ret = wait_for_key_construction(key, false);
                if (ret < 0) {
@@ -458,14 +579,15 @@ EXPORT_SYMBOL(request_key);
  */
 struct key *request_key_with_auxdata(struct key_type *type,
                                     const char *description,
-                                    const char *callout_info,
+                                    const void *callout_info,
+                                    size_t callout_len,
                                     void *aux)
 {
        struct key *key;
        int ret;
 
-       key = request_key_and_link(type, description, callout_info, aux,
-                                  NULL, KEY_ALLOC_IN_QUOTA);
+       key = request_key_and_link(type, description, callout_info, callout_len,
+                                  aux, NULL, KEY_ALLOC_IN_QUOTA);
        if (!IS_ERR(key)) {
                ret = wait_for_key_construction(key, false);
                if (ret < 0) {
@@ -485,10 +607,12 @@ EXPORT_SYMBOL(request_key_with_auxdata);
  */
 struct key *request_key_async(struct key_type *type,
                              const char *description,
-                             const char *callout_info)
+                             const void *callout_info,
+                             size_t callout_len)
 {
-       return request_key_and_link(type, description, callout_info, NULL,
-                                   NULL, KEY_ALLOC_IN_QUOTA);
+       return request_key_and_link(type, description, callout_info,
+                                   callout_len, NULL, NULL,
+                                   KEY_ALLOC_IN_QUOTA);
 }
 EXPORT_SYMBOL(request_key_async);
 
@@ -500,10 +624,11 @@ EXPORT_SYMBOL(request_key_async);
  */
 struct key *request_key_async_with_auxdata(struct key_type *type,
                                           const char *description,
-                                          const char *callout_info,
+                                          const void *callout_info,
+                                          size_t callout_len,
                                           void *aux)
 {
-       return request_key_and_link(type, description, callout_info, aux,
-                                   NULL, KEY_ALLOC_IN_QUOTA);
+       return request_key_and_link(type, description, callout_info,
+                                   callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
 }
 EXPORT_SYMBOL(request_key_async_with_auxdata);