--- zzzz-none-000/linux-3.10.107/security/keys/request_key.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/security/keys/request_key.c 2021-02-04 17:41:59.000000000 +0000 @@ -21,24 +21,6 @@ #define key_negative_timeout 60 /* default timeout on a negative key's existence */ -/* - * wait_on_bit() sleep function for uninterruptible waiting - */ -static int key_wait_bit(void *flags) -{ - schedule(); - return 0; -} - -/* - * wait_on_bit() sleep function for interruptible waiting - */ -static int key_wait_bit_intr(void *flags) -{ - schedule(); - return signal_pending(current) ? -ERESTARTSYS : 0; -} - /** * complete_request_key - Complete the construction of a key. * @cons: The key construction record. @@ -268,11 +250,12 @@ * The keyring selected is returned with an extra reference upon it which the * caller must release. */ -static void construct_get_dest_keyring(struct key **_dest_keyring) +static int construct_get_dest_keyring(struct key **_dest_keyring) { struct request_key_auth *rka; const struct cred *cred = current_cred(); struct key *dest_keyring = *_dest_keyring, *authkey; + int ret; kenter("%p", dest_keyring); @@ -281,6 +264,8 @@ /* the caller supplied one */ key_get(dest_keyring); } else { + bool do_perm_check = true; + /* use a default keyring; falling through the cases until we * find one that we actually have */ switch (cred->jit_keyring) { @@ -289,14 +274,16 @@ if (cred->request_key_auth) { authkey = cred->request_key_auth; down_read(&authkey->sem); - rka = authkey->payload.data; + rka = authkey->payload.data[0]; if (!test_bit(KEY_FLAG_REVOKED, &authkey->flags)) dest_keyring = key_get(rka->dest_keyring); up_read(&authkey->sem); - if (dest_keyring) + if (dest_keyring) { + do_perm_check = false; break; + } } case KEY_REQKEY_DEFL_THREAD_KEYRING: @@ -331,11 +318,29 @@ default: BUG(); } + + /* + * Require Write permission on the keyring. This is essential + * because the default keyring may be the session keyring, and + * joining a keyring only requires Search permission. + * + * However, this check is skipped for the "requestor keyring" so + * that /sbin/request-key can itself use request_key() to add + * keys to the original requestor's destination keyring. + */ + if (dest_keyring && do_perm_check) { + ret = key_permission(make_key_ref(dest_keyring, 1), + KEY_NEED_WRITE); + if (ret) { + key_put(dest_keyring); + return ret; + } + } } *_dest_keyring = dest_keyring; kleave(" [dk %d]", key_serial(dest_keyring)); - return; + return 0; } /* @@ -345,33 +350,34 @@ * May return a key that's already under construction instead if there was a * race between two thread calling request_key(). */ -static int construct_alloc_key(struct key_type *type, - const char *description, +static int construct_alloc_key(struct keyring_search_context *ctx, struct key *dest_keyring, unsigned long flags, struct key_user *user, struct key **_key) { - const struct cred *cred = current_cred(); - unsigned long prealloc; + struct assoc_array_edit *edit; struct key *key; key_perm_t perm; key_ref_t key_ref; int ret; - kenter("%s,%s,,,", type->name, description); + kenter("%s,%s,,,", + ctx->index_key.type->name, ctx->index_key.description); *_key = NULL; mutex_lock(&user->cons_lock); perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; perm |= KEY_USR_VIEW; - if (type->read) + if (ctx->index_key.type->read) perm |= KEY_POS_READ; - if (type == &key_type_keyring || type->update) + if (ctx->index_key.type == &key_type_keyring || + ctx->index_key.type->update) perm |= KEY_POS_WRITE; - key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred, + key = key_alloc(ctx->index_key.type, ctx->index_key.description, + ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred, perm, flags); if (IS_ERR(key)) goto alloc_failed; @@ -379,8 +385,7 @@ set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); if (dest_keyring) { - ret = __key_link_begin(dest_keyring, type, description, - &prealloc); + ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit); if (ret < 0) goto link_prealloc_failed; } @@ -390,16 +395,16 @@ * waited for locks */ mutex_lock(&key_construction_mutex); - key_ref = search_process_keyrings(type, description, type->match, cred); + key_ref = search_process_keyrings(ctx); if (!IS_ERR(key_ref)) goto key_already_present; if (dest_keyring) - __key_link(dest_keyring, key, &prealloc); + __key_link(key, &edit); mutex_unlock(&key_construction_mutex); if (dest_keyring) - __key_link_end(dest_keyring, type, prealloc); + __key_link_end(dest_keyring, &ctx->index_key, edit); mutex_unlock(&user->cons_lock); *_key = key; kleave(" = 0 [%d]", key_serial(key)); @@ -414,8 +419,8 @@ 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); + __key_link(key, &edit); + __key_link_end(dest_keyring, &ctx->index_key, edit); if (ret < 0) goto link_check_failed; } @@ -432,6 +437,7 @@ link_prealloc_failed: mutex_unlock(&user->cons_lock); + key_put(key); kleave(" = %d [prelink]", ret); return ret; @@ -444,8 +450,7 @@ /* * Commence key construction. */ -static struct key *construct_key_and_link(struct key_type *type, - const char *description, +static struct key *construct_key_and_link(struct keyring_search_context *ctx, const char *callout_info, size_t callout_len, void *aux, @@ -458,14 +463,20 @@ kenter(""); - user = key_user_lookup(current_fsuid()); - if (!user) - return ERR_PTR(-ENOMEM); + if (ctx->index_key.type == &key_type_keyring) + return ERR_PTR(-EPERM); + + ret = construct_get_dest_keyring(&dest_keyring); + if (ret) + goto error; - construct_get_dest_keyring(&dest_keyring); + user = key_user_lookup(current_fsuid()); + if (!user) { + ret = -ENOMEM; + goto error_put_dest_keyring; + } - ret = construct_alloc_key(type, description, dest_keyring, flags, user, - &key); + ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); key_user_put(user); if (ret == 0) { @@ -478,7 +489,7 @@ } else if (ret == -EINPROGRESS) { ret = 0; } else { - goto couldnt_alloc_key; + goto error_put_dest_keyring; } key_put(dest_keyring); @@ -488,8 +499,9 @@ construction_failed: key_negate_and_link(key, key_negative_timeout, NULL, NULL); key_put(key); -couldnt_alloc_key: +error_put_dest_keyring: key_put(dest_keyring); +error: kleave(" = %d", ret); return ERR_PTR(ret); } @@ -529,17 +541,34 @@ struct key *dest_keyring, unsigned long flags) { - const struct cred *cred = current_cred(); + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.description = description, + .cred = current_cred(), + .match_data.cmp = key_default_cmp, + .match_data.raw_data = description, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = (KEYRING_SEARCH_DO_STATE_CHECK | + KEYRING_SEARCH_SKIP_EXPIRED), + }; struct key *key; key_ref_t key_ref; int ret; kenter("%s,%s,%p,%zu,%p,%p,%lx", - type->name, description, callout_info, callout_len, aux, - dest_keyring, flags); + ctx.index_key.type->name, ctx.index_key.description, + callout_info, callout_len, aux, dest_keyring, flags); + + if (type->match_preparse) { + ret = type->match_preparse(&ctx.match_data); + if (ret < 0) { + key = ERR_PTR(ret); + goto error; + } + } /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(type, description, type->match, cred); + key_ref = search_process_keyrings(&ctx); if (!IS_ERR(key_ref)) { key = key_ref_to_ptr(key_ref); @@ -550,7 +579,7 @@ if (ret < 0) { key_put(key); key = ERR_PTR(ret); - goto error; + goto error_free; } } } else if (PTR_ERR(key_ref) != -EAGAIN) { @@ -560,13 +589,15 @@ * should consult userspace if we can */ key = ERR_PTR(-ENOKEY); if (!callout_info) - goto error; + goto error_free; - key = construct_key_and_link(type, description, callout_info, - callout_len, aux, dest_keyring, - flags); + key = construct_key_and_link(&ctx, callout_info, callout_len, + aux, dest_keyring, flags); } +error_free: + if (type->match_free) + type->match_free(&ctx.match_data); error: kleave(" = %p", key); return key; @@ -588,12 +619,13 @@ int ret; ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT, - intr ? key_wait_bit_intr : key_wait_bit, intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); - if (ret < 0) - return ret; - if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) - return key->type_data.reject_error; + if (ret) + return -ERESTARTSYS; + if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) { + smp_rmb(); + return key->reject_error; + } return key_validate(key); } EXPORT_SYMBOL(wait_for_key_construction);