From patchwork Wed Apr 24 16:14:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 10915163 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B70EB13B5 for ; Wed, 24 Apr 2019 16:14:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A77C92887D for ; Wed, 24 Apr 2019 16:14:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9B83D28A28; Wed, 24 Apr 2019 16:14:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1170F2887D for ; Wed, 24 Apr 2019 16:14:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730705AbfDXQOi (ORCPT ); Wed, 24 Apr 2019 12:14:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41416 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727913AbfDXQOi (ORCPT ); Wed, 24 Apr 2019 12:14:38 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C2B10DD9F4; Wed, 24 Apr 2019 16:14:37 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-98.rdu2.redhat.com [10.10.121.98]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2AA7C600C4; Wed, 24 Apr 2019 16:14:36 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 08/11] keys: Include target namespace in match criteria From: David Howells To: ebiederm@xmission.com Cc: keyrings@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, dwalsh@redhat.com, vgoyal@redhat.com Date: Wed, 24 Apr 2019 17:14:35 +0100 Message-ID: <155612247542.8564.1962415588707569592.stgit@warthog.procyon.org.uk> In-Reply-To: <155612240208.8564.13865046977065545591.stgit@warthog.procyon.org.uk> References: <155612240208.8564.13865046977065545591.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 24 Apr 2019 16:14:37 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Currently a key has a standard matching criteria of { type, description } and this is used to only allow keys with unique criteria in a keyring. This means, however, that you cannot have keys with the same type and description but a different target namespace in the same keyring. This is a potential problem for a containerised environment where, say, a container is made up of some parts of its mount space involving netfs superblocks from two different network namespaces. This is also a problem for shared system management keyrings such as the DNS records keyring or the NFS idmapper keyring that might contain keys from different network namespaces. Fix this by including a namespace component in a key's matching criteria. Keyring types are marked to indicate which, if any, namespace is relevant to keys of that type, and that namespace is set when the key is created from the current task's namespace set. Signed-off-by: David Howells --- include/linux/key.h | 11 +++++++++++ security/keys/gc.c | 2 +- security/keys/key.c | 1 + security/keys/keyring.c | 36 ++++++++++++++++++++++++++++++++++-- security/keys/persistent.c | 1 + 5 files changed, 48 insertions(+), 3 deletions(-) diff --git a/include/linux/key.h b/include/linux/key.h index 52334cc7c18d..2b298532dad0 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -82,9 +82,16 @@ struct cred; struct key_type; struct key_owner; +struct key_tag; struct keyring_list; struct keyring_name; +struct key_tag { + struct rcu_head rcu; + refcount_t usage; + bool removed; /* T when subject removed */ +}; + struct keyring_index_key { /* [!] If this structure is altered, the union in struct key must change too! */ unsigned long hash; /* Hash value */ @@ -101,6 +108,7 @@ struct keyring_index_key { unsigned long x; }; struct key_type *type; + struct key_tag *domain_tag; /* Domain of operation */ const char *description; }; @@ -218,6 +226,7 @@ struct key { unsigned long hash; unsigned long len_desc; struct key_type *type; /* type of key */ + struct key_tag *domain_tag; /* Domain of operation */ char *description; }; }; @@ -268,6 +277,7 @@ extern struct key *key_alloc(struct key_type *type, extern void key_revoke(struct key *key); extern void key_invalidate(struct key *key); extern void key_put(struct key *key); +extern bool key_put_tag(struct key_tag *tag); static inline struct key *__key_get(struct key *key) { @@ -428,6 +438,7 @@ extern void key_init(void); #define key_fsgid_changed(t) do { } while(0) #define key_init() do { } while(0) #define key_free_user_ns(ns) do { } while(0) +#define key_put_subject(s) do { } while(0) #endif /* CONFIG_KEYS */ #endif /* __KERNEL__ */ diff --git a/security/keys/gc.c b/security/keys/gc.c index 634e96b380e8..83d279fb7793 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -154,7 +154,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys) atomic_dec(&key->user->nikeys); key_user_put(key->user); - + key_put_tag(key->domain_tag); kfree(key->description); memzero_explicit(key, sizeof(*key)); diff --git a/security/keys/key.c b/security/keys/key.c index 1568b0028ba4..8cd0f98e4fa3 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -317,6 +317,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, goto security_error; /* publish the key by giving it a serial number */ + refcount_inc(&key->domain_tag->usage); atomic_inc(&user->nkeys); key_alloc_serial(key); diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 1fc9219ed002..0898d6d91d41 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -175,6 +175,9 @@ static void hash_key_type_and_desc(struct keyring_index_key *index_key) type = (unsigned long)index_key->type; acc = mult_64x32_and_fold(type, desc_len + 13); acc = mult_64x32_and_fold(acc, 9207); + piece = (unsigned long)index_key->domain_tag; + acc = mult_64x32_and_fold(acc, piece); + acc = mult_64x32_and_fold(acc, 9207); for (;;) { n = desc_len; @@ -208,16 +211,36 @@ static void hash_key_type_and_desc(struct keyring_index_key *index_key) /* * Finalise an index key to include a part of the description actually in the - * index key and to add in the hash too. + * index key, to set the domain tag and to calculate the hash. */ void key_set_index_key(struct keyring_index_key *index_key) { + static struct key_tag default_domain_tag = { .usage = REFCOUNT_INIT(1), }; size_t n = min_t(size_t, index_key->desc_len, sizeof(index_key->desc)); + memcpy(index_key->desc, index_key->description, n); + index_key->domain_tag = &default_domain_tag; hash_key_type_and_desc(index_key); } +/** + * key_put_tag - Release a ref on a tag. + * @tag: The tag to release. + * + * This releases a reference the given tag and returns true if that ref was the + * last one. + */ +bool key_put_tag(struct key_tag *tag) +{ + if (refcount_dec_and_test(&tag->usage)) { + kfree_rcu(tag, rcu); + return true; + } + + return false; +} + /* * Build the next index key chunk. * @@ -238,8 +261,10 @@ static unsigned long keyring_get_key_chunk(const void *data, int level) return index_key->x; case 2: return (unsigned long)index_key->type; + case 3: + return (unsigned long)index_key->domain_tag; default: - level -= 3; + level -= 4; if (desc_len <= sizeof(index_key->desc)) return 0; @@ -268,6 +293,7 @@ static bool keyring_compare_object(const void *object, const void *data) const struct key *key = keyring_ptr_to_key(object); return key->index_key.type == index_key->type && + key->index_key.domain_tag == index_key->domain_tag && key->index_key.desc_len == index_key->desc_len && memcmp(key->index_key.description, index_key->description, index_key->desc_len) == 0; @@ -309,6 +335,12 @@ static int keyring_diff_objects(const void *object, const void *data) goto differ; level += sizeof(unsigned long); + seg_a = (unsigned long)a->domain_tag; + seg_b = (unsigned long)b->domain_tag; + if ((seg_a ^ seg_b) != 0) + goto differ; + level += sizeof(unsigned long); + i = sizeof(a->desc); if (a->desc_len <= i) goto same; diff --git a/security/keys/persistent.c b/security/keys/persistent.c index 90303fe4a394..9944d855a28d 100644 --- a/security/keys/persistent.c +++ b/security/keys/persistent.c @@ -84,6 +84,7 @@ static long key_get_persistent(struct user_namespace *ns, kuid_t uid, long ret; /* Look in the register if it exists */ + memset(&index_key, 0, sizeof(index_key)); index_key.type = &key_type_keyring; index_key.description = buf; index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid));