[14/23] LSM: Infrastructure management of the key security blob

Message ID	1104b03d-c4c9-6245-6b5c-766b7d6c3a5d@schaufler-ca.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Subject: [PATCH 14/23] LSM: Infrastructure management of the key security blob To: LSM <linux-security-module@vger.kernel.org>, LKLM <linux-kernel@vger.kernel.org>, Paul Moore <paul@paul-moore.com>, Stephen Smalley <sds@tycho.nsa.gov>, SE Linux <selinux@tycho.nsa.gov>, "SMACK-discuss@lists.01.org" <SMACK-discuss@lists.01.org>, John Johansen <john.johansen@canonical.com>, Kees Cook <keescook@chromium.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, James Morris <jmorris@namei.org> References: <7e8702ce-2598-e0a3-31a2-bc29157fb73d@schaufler-ca.com> From: Casey Schaufler <casey@schaufler-ca.com> Message-ID: <1104b03d-c4c9-6245-6b5c-766b7d6c3a5d@schaufler-ca.com> Date: Thu, 10 May 2018 17:54:57 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <7e8702ce-2598-e0a3-31a2-bc29157fb73d@schaufler-ca.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 42535da852bc..5428485750b6 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2019,6 +2019,7 @@ struct lsm_blob_sizes { int lbs_file; int lbs_inode; int lbs_ipc; + int lbs_key; int lbs_msg_msg; int lbs_sock; int lbs_superblock; diff --git a/security/security.c b/security/security.c index 9414d1a78ee5..359ed1137c00 100644 --- a/security/security.c +++ b/security/security.c @@ -117,6 +117,9 @@ int __init security_init(void) pr_info("LSM: file blob size = %d\n", blob_sizes.lbs_file); pr_info("LSM: inode blob size = %d\n", blob_sizes.lbs_inode); pr_info("LSM: ipc blob size = %d\n", blob_sizes.lbs_ipc); +#ifdef CONFIG_KEYS + pr_info("LSM: key blob size = %d\n", blob_sizes.lbs_key); +#endif /* CONFIG_KEYS */ pr_info("LSM: msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg); pr_info("LSM: sock blob size = %d\n", blob_sizes.lbs_sock); pr_info("LSM: superblock blob size = %d\n", blob_sizes.lbs_superblock); @@ -297,6 +300,9 @@ void __init security_add_blobs(struct lsm_blob_sizes *needed) lsm_set_size(&needed->lbs_cred, &blob_sizes.lbs_cred); lsm_set_size(&needed->lbs_file, &blob_sizes.lbs_file); lsm_set_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc); +#ifdef CONFIG_KEYS + lsm_set_size(&needed->lbs_key, &blob_sizes.lbs_key); +#endif lsm_set_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg); lsm_set_size(&needed->lbs_sock, &blob_sizes.lbs_sock); lsm_set_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock); @@ -432,6 +438,29 @@ int lsm_ipc_alloc(struct kern_ipc_perm *kip) return 0; } +#ifdef CONFIG_KEYS +/** + * lsm_key_alloc - allocate a composite key blob + * @key: the key that needs a blob + * + * Allocate the key blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +int lsm_key_alloc(struct key *key) +{ + if (blob_sizes.lbs_key == 0) { + key->security = NULL; + return 0; + } + + key->security = kzalloc(blob_sizes.lbs_key, GFP_KERNEL); + if (key->security == NULL) + return -ENOMEM; + return 0; +} +#endif /* CONFIG_KEYS */ + /** * lsm_msg_msg_alloc - allocate a composite msg_msg blob * @mp: the msg_msg that needs a blob @@ -2137,12 +2166,21 @@ EXPORT_SYMBOL(security_skb_classify_flow); int security_key_alloc(struct key *key, const struct cred *cred, unsigned long flags) { - return call_int_hook(key_alloc, 0, key, cred, flags); + int rc = lsm_key_alloc(key); + + if (unlikely(rc)) + return rc; + rc = call_int_hook(key_alloc, 0, key, cred, flags); + if (unlikely(rc)) + security_key_free(key); + return rc; } void security_key_free(struct key *key) { call_void_hook(key_free, key); + kfree(key->security); + key->security = NULL; } int security_key_permission(key_ref_t key_ref, diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 3911e28e3907..f3531e5bc3d9 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6407,11 +6407,7 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred, unsigned long flags) { const struct task_security_struct *tsec; - struct key_security_struct *ksec; - - ksec = kzalloc(sizeof(struct key_security_struct), GFP_KERNEL); - if (!ksec) - return -ENOMEM; + struct key_security_struct *ksec = selinux_key(k); tsec = selinux_cred(cred); if (tsec->keycreate_sid) @@ -6419,18 +6415,9 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred, else ksec->sid = tsec->sid; - k->security = ksec; return 0; } -static void selinux_key_free(struct key *k) -{ - struct key_security_struct *ksec = k->security; - - k->security = NULL; - kfree(ksec); -} - static int selinux_key_permission(key_ref_t key_ref, const struct cred *cred, unsigned perm) @@ -6448,7 +6435,7 @@ static int selinux_key_permission(key_ref_t key_ref, sid = cred_sid(cred); key = key_ref_to_ptr(key_ref); - ksec = key->security; + ksec = selinux_key(key); return avc_has_perm(&selinux_state, sid, ksec->sid, SECCLASS_KEY, perm, NULL); @@ -6456,7 +6443,7 @@ static int selinux_key_permission(key_ref_t key_ref, static int selinux_key_getsecurity(struct key *key, char **_buffer) { - struct key_security_struct *ksec = key->security; + struct key_security_struct *ksec = selinux_key(key); char *context = NULL; unsigned len; int rc; @@ -6681,6 +6668,9 @@ struct lsm_blob_sizes selinux_blob_sizes = { .lbs_file = sizeof(struct file_security_struct), .lbs_inode = sizeof(struct inode_security_struct), .lbs_ipc = sizeof(struct ipc_security_struct), +#ifdef CONFIG_KEYS + .lbs_key = sizeof(struct key_security_struct), +#endif /* CONFIG_KEYS */ .lbs_msg_msg = sizeof(struct msg_security_struct), .lbs_sock = sizeof(struct sk_security_struct), .lbs_superblock = sizeof(struct superblock_security_struct), @@ -6890,7 +6880,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { #ifdef CONFIG_KEYS LSM_HOOK_INIT(key_alloc, selinux_key_alloc), - LSM_HOOK_INIT(key_free, selinux_key_free), LSM_HOOK_INIT(key_permission, selinux_key_permission), LSM_HOOK_INIT(key_getsecurity, selinux_key_getsecurity), #endif diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index d1d883f8c552..6092786c5828 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -192,6 +192,13 @@ static inline struct ipc_security_struct *selinux_ipc( return ipc->security; } +#ifdef CONFIG_KEYS +static inline struct key_security_struct *selinux_key(const struct key *key) +{ + return key->security; +} +#endif /* CONFIG_KEYS */ + static inline struct sk_security_struct *selinux_sock(const struct sock *sock) { return sock->sk_security; diff --git a/security/smack/smack.h b/security/smack/smack.h index 42c36e37b0bd..e50ed4945a40 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -393,6 +393,13 @@ static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc) return ipc->security; } +#ifdef CONFIG_KEYS +static inline struct smack_known **smack_key(const struct key *key) +{ + return key->security; +} +#endif /* CONFIG_KEYS */ + /* * Is the directory transmuting? */ diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index a419953c1004..c15861eb3606 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4136,23 +4136,13 @@ static void smack_inet_csk_clone(struct sock *sk, static int smack_key_alloc(struct key *key, const struct cred *cred, unsigned long flags) { + struct smack_known **blob = smack_key(key); struct smack_known *skp = smk_of_task(smack_cred(cred)); - key->security = skp; + *blob = skp; return 0; } -/** - * smack_key_free - Clear the key security blob - * @key: the object - * - * Clear the blob pointer - */ -static void smack_key_free(struct key *key) -{ - key->security = NULL; -} - /** * smack_key_permission - Smack access on a key * @key_ref: gets to the object @@ -4165,6 +4155,8 @@ static void smack_key_free(struct key *key) static int smack_key_permission(key_ref_t key_ref, const struct cred *cred, unsigned perm) { + struct smack_known **blob; + struct smack_known *skp; struct key *keyp; struct smk_audit_info ad; struct smack_known *tkp = smk_of_task(smack_cred(cred)); @@ -4178,7 +4170,9 @@ static int smack_key_permission(key_ref_t key_ref, * If the key hasn't been initialized give it access so that * it may do so. */ - if (keyp->security == NULL) + blob = smack_key(keyp); + skp = *blob; + if (skp == NULL) return 0; /* * This should not occur @@ -4198,8 +4192,8 @@ static int smack_key_permission(key_ref_t key_ref, request = MAY_READ; if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR)) request = MAY_WRITE; - rc = smk_access(tkp, keyp->security, request, &ad); - rc = smk_bu_note("key access", tkp, keyp->security, request, rc); + rc = smk_access(tkp, skp, request, &ad); + rc = smk_bu_note("key access", tkp, skp, request, rc); return rc; } @@ -4214,11 +4208,12 @@ static int smack_key_permission(key_ref_t key_ref, */ static int smack_key_getsecurity(struct key *key, char **_buffer) { - struct smack_known *skp = key->security; + struct smack_known **blob = smack_key(key); + struct smack_known *skp = *blob; size_t length; char *copy; - if (key->security == NULL) { + if (skp == NULL) { *_buffer = NULL; return 0; } @@ -4505,6 +4500,9 @@ struct lsm_blob_sizes smack_blob_sizes = { .lbs_file = sizeof(struct smack_known *), .lbs_inode = sizeof(struct inode_smack), .lbs_ipc = sizeof(struct smack_known *), +#ifdef CONFIG_KEYS + .lbs_key = sizeof(struct smack_known *), +#endif /* CONFIG_KEYS */ .lbs_msg_msg = sizeof(struct smack_known *), .lbs_sock = sizeof(struct socket_smack), .lbs_superblock = sizeof(struct superblock_smack), @@ -4623,7 +4621,6 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { /* key management security hooks */ #ifdef CONFIG_KEYS LSM_HOOK_INIT(key_alloc, smack_key_alloc), - LSM_HOOK_INIT(key_free, smack_key_free), LSM_HOOK_INIT(key_permission, smack_key_permission), LSM_HOOK_INIT(key_getsecurity, smack_key_getsecurity), #endif /* CONFIG_KEYS */

[14/23] LSM: Infrastructure management of the key security blob

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