[02/27] LSM: Infrastructure management of the key blob

Message ID	20190726233923.2570-3-casey@schaufler-ca.com (mailing list archive)
State	Superseded
Headers	show Return-Path: <selinux-owner@kernel.org> From: Casey Schaufler <casey@schaufler-ca.com> To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: [PATCH 02/27] LSM: Infrastructure management of the key blob Date: Fri, 26 Jul 2019 16:38:58 -0700 Message-Id: <20190726233923.2570-3-casey@schaufler-ca.com> In-Reply-To: <20190726233923.2570-1-casey@schaufler-ca.com> References: <20190726233923.2570-1-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: selinux-owner@vger.kernel.org Precedence: bulk
Series	LSM: Module stacking for AppArmor \| expand [v5,00/27] LSM: Module stacking for AppArmor [01/27] LSM: Infrastructure management of the sock security [02/27] LSM: Infrastructure management of the key blob [03/27] LSM: Create and manage the lsmblob data structure. [04/27] LSM: Use lsmblob in security_audit_rule_match [05/27] LSM: Use lsmblob in security_kernel_act_as [06/27] net: Prepare UDS for security module stacking [07/27] LSM: Use lsmblob in security_secctx_to_secid [08/27] LSM: Use lsmblob in security_secid_to_secctx [09/27] LSM: Use lsmblob in security_ipc_getsecid [10/27] LSM: Use lsmblob in security_task_getsecid [11/27] LSM: Use lsmblob in security_inode_getsecid [12/27] LSM: Use lsmblob in security_cred_getsecid [13/27] IMA: Change internal interfaces to use lsmblobs [14/27] LSM: Specify which LSM to display [15/27] LSM: Ensure the correct LSM context releaser [16/27] LSM: Use lsmcontext in security_secid_to_secctx [17/27] LSM: Use lsmcontext in security_dentry_init_security [18/27] LSM: Use lsmcontext in security_inode_getsecctx [19/27] LSM: security_secid_to_secctx in netlink netfilter [20/27] NET: Store LSM netlabel data in a lsmblob [21/27] SELinux: Verify LSM display sanity in binder [22/27] Audit: Add subj_LSM fields when necessary [23/27] Audit: Include object data for all security modules [24/27] LSM: Provide an user space interface for the default display [25/27] NET: Add SO_PEERCONTEXT for multiple LSMs [26/27] LSM: Add /proc attr entry for full LSM context [27/27] AppArmor: Remove the exclusive flag

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index b353482ea348..3fe39abccc8f 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2050,6 +2050,7 @@ struct lsm_blob_sizes { int lbs_sock; int lbs_superblock; int lbs_ipc; + int lbs_key; int lbs_msg_msg; int lbs_task; }; diff --git a/security/security.c b/security/security.c index 2c0834db7976..7cfedb90210a 100644 --- a/security/security.c +++ b/security/security.c @@ -172,6 +172,9 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed) blob_sizes.lbs_inode = sizeof(struct rcu_head); lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode); lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc); +#ifdef CONFIG_KEYS + lsm_set_blob_size(&needed->lbs_key, &blob_sizes.lbs_key); +#endif lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg); lsm_set_blob_size(&needed->lbs_sock, &blob_sizes.lbs_sock); lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock); @@ -307,6 +310,9 @@ static void __init ordered_lsm_init(void) init_debug("file blob size = %d\n", blob_sizes.lbs_file); init_debug("inode blob size = %d\n", blob_sizes.lbs_inode); init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc); +#ifdef CONFIG_KEYS + init_debug("key blob size = %d\n", blob_sizes.lbs_key); +#endif /* CONFIG_KEYS */ init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg); init_debug("sock blob size = %d\n", blob_sizes.lbs_sock); init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock); @@ -573,6 +579,29 @@ static 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. + */ +static 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 @@ -2339,12 +2368,21 @@ 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 5d74ed35b728..c83ec2652eda 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6353,11 +6353,7 @@ 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) @@ -6365,18 +6361,9 @@ 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) @@ -6394,7 +6381,7 @@ 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); @@ -6402,7 +6389,7 @@ 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; @@ -6627,6 +6614,9 @@ struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = { .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), @@ -6842,7 +6832,6 @@ 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 29f02b8f8f31..3b78aa4ee98f 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -194,6 +194,13 @@ static inline struct superblock_security_struct *selinux_superblock( return superblock->s_security + selinux_blob_sizes.lbs_superblock; } +#ifdef CONFIG_KEYS +static inline struct key_security_struct *selinux_key(const struct key *key) +{ + return key->security + selinux_blob_sizes.lbs_key; +} +#endif /* CONFIG_KEYS */ + static inline struct sk_security_struct *selinux_sock(const struct sock *sock) { return sock->sk_security + selinux_blob_sizes.lbs_sock; diff --git a/security/smack/smack.h b/security/smack/smack.h index 4ac4bf3310d7..7cc3a3382fee 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -386,6 +386,13 @@ static inline struct superblock_smack *smack_superblock( return superblock->s_security + smack_blob_sizes.lbs_superblock; } +#ifdef CONFIG_KEYS +static inline struct smack_known **smack_key(const struct key *key) +{ + return key->security + smack_blob_sizes.lbs_key; +} +#endif /* CONFIG_KEYS */ + /* * Is the directory transmuting? */ diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index fd69e1bd841b..e9560b078efe 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4179,23 +4179,13 @@ 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 @@ -4208,6 +4198,8 @@ 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)); @@ -4227,7 +4219,9 @@ 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 @@ -4247,8 +4241,8 @@ 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; } @@ -4263,11 +4257,12 @@ 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; } @@ -4550,6 +4545,9 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { .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), @@ -4671,7 +4669,6 @@ 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 */

[02/27] LSM: Infrastructure management of the key blob

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