[v5,30/38] LSM: Infrastructure management of the file security

Message ID	06c9ef23-2846-c588-2f0a-95c6d2613bd4@schaufler-ca.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-fsdevel-owner@kernel.org> Subject: [PATCH v5 30/38] LSM: Infrastructure management of the file security To: James Morris <jmorris@namei.org>, LSM <linux-security-module@vger.kernel.org>, LKLM <linux-kernel@vger.kernel.org>, SE Linux <selinux@tycho.nsa.gov> Cc: John Johansen <john.johansen@canonical.com>, Kees Cook <keescook@chromium.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, Paul Moore <paul@paul-moore.com>, "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>, Stephen Smalley <sds@tycho.nsa.gov>, Alexey Dobriyan <adobriyan@gmail.com>, =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= <mic@digikod.net>, Salvatore Mesoraca <s.mesoraca16@gmail.com> References: <50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com> From: Casey Schaufler <casey@schaufler-ca.com> Message-ID: <06c9ef23-2846-c588-2f0a-95c6d2613bd4@schaufler-ca.com> Date: Mon, 26 Nov 2018 15:50:10 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk
Series	LSM: Module stacking for SARA and Landlock \| expand [v5,00/38] LSM: Module stacking for SARA and Landlock [v5,01/38] LSM: Introduce LSM_FLAG_LEGACY_MAJOR [v5,02/38] LSM: Provide separate ordered initialization [v5,03/38] LSM: Plumb visibility into optional "enabled" state [v5,04/38] LSM: Lift LSM selection out of individual LSMs [v5,05/38] LSM: Build ordered list of LSMs to initialize [v5,06/38] LSM: Introduce CONFIG_LSM [v5,07/38] LSM: Introduce "lsm=" for boottime LSM selection [v5,08/38] LSM: Tie enabling logic to presence in ordered list [v5,09/38] LSM: Prepare for reorganizing "security=" logic [v5,10/38] LSM: Refactor "security=" in terms of enable/disable [v5,11/38] LSM: Separate idea of "major" LSM from "exclusive" LSM [v5,12/38] apparmor: Remove SECURITY_APPARMOR_BOOTPARAM_VALUE [v5,13/38] selinux: Remove SECURITY_SELINUX_BOOTPARAM_VALUE [v5,14/38] LSM: Add all exclusive LSMs to ordered initialization [v5,15/38] LSM: Split LSM preparation from initialization [v5,16/38] LoadPin: Initialize as ordered LSM [v5,17/38] Yama: Initialize as ordered LSM [v5,18/38] LSM: Introduce enum lsm_order [v5,19/38] capability: Initialize as LSM_ORDER_FIRST [v5,20/38] procfs: add smack subdir to attrs [v5,21/38] Smack: Abstract use of cred security blob [v5,22/38] SELinux: Abstract use of cred security blob [v5,23/38] SELinux: Remove cred security blob poisoning [v5,24/38] SELinux: Remove unused selinux_is_enabled [v5,25/38] AppArmor: Abstract use of cred security blob [v5,26/38] TOMOYO: Abstract use of cred security blob [v5,27/38] Infrastructure management of the cred security blob [v5,28/38] SELinux: Abstract use of file security blob [v5,29/38] Smack: Abstract use of file security blob [v5,30/38] LSM: Infrastructure management of the file security [v5,31/38] SELinux: Abstract use of inode security blob [v5,32/38] Smack: Abstract use of inode security blob [v5,33/38] LSM: Infrastructure management of the inode security [v5,34/38] LSM: Infrastructure management of the task security [v5,35/38] SELinux: Abstract use of ipc security blobs [v5,36/38] Smack: Abstract use of ipc security blobs [v5,37/38] LSM: Infrastructure management of the ipc security blob [v5,38/38] TOMOYO: Update LSM flags to no longer be exclusive

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index c9458280214e..64499c2d44cd 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2029,6 +2029,7 @@ struct security_hook_list { */ struct lsm_blob_sizes { int lbs_cred; + int lbs_file; }; /* diff --git a/security/apparmor/include/file.h b/security/apparmor/include/file.h index 4c2c8ac8842f..8be09208cf7c 100644 --- a/security/apparmor/include/file.h +++ b/security/apparmor/include/file.h @@ -32,7 +32,10 @@ struct path; AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \ AA_EXEC_MMAP | AA_MAY_LINK) -#define file_ctx(X) ((struct aa_file_ctx *)(X)->f_security) +static inline struct aa_file_ctx *file_ctx(struct file *file) +{ + return file->f_security + apparmor_blob_sizes.lbs_file; +} /* struct aa_file_ctx - the AppArmor context the file was opened in * @lock: lock to update the ctx diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 70669e676212..3ae8c902d740 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -433,21 +433,21 @@ static int apparmor_file_open(struct file *file) static int apparmor_file_alloc_security(struct file *file) { - int error = 0; - - /* freed by apparmor_file_free_security */ + struct aa_file_ctx *ctx = file_ctx(file); struct aa_label *label = begin_current_label_crit_section(); - file->f_security = aa_alloc_file_ctx(label, GFP_KERNEL); - if (!file_ctx(file)) - error = -ENOMEM; - end_current_label_crit_section(label); - return error; + spin_lock_init(&ctx->lock); + rcu_assign_pointer(ctx->label, aa_get_label(label)); + end_current_label_crit_section(label); + return 0; } static void apparmor_file_free_security(struct file *file) { - aa_free_file_ctx(file_ctx(file)); + struct aa_file_ctx *ctx = file_ctx(file); + + if (ctx) + aa_put_label(rcu_access_pointer(ctx->label)); } static int common_file_perm(const char *op, struct file *file, u32 mask) @@ -1155,6 +1155,7 @@ static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb, */ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = { .lbs_cred = sizeof(struct aa_task_ctx *), + .lbs_file = sizeof(struct aa_file_ctx), }; static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { diff --git a/security/security.c b/security/security.c index c49d4a18c75f..499842ece0fb 100644 --- a/security/security.c +++ b/security/security.c @@ -40,6 +40,8 @@ struct security_hook_heads security_hook_heads __lsm_ro_after_init; static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain); +static struct kmem_cache *lsm_file_cache; + char *lsm_names; static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init; @@ -158,6 +160,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed) return; lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred); + lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file); } /* Prepare LSM for initialization. */ @@ -279,6 +282,15 @@ static void __init ordered_lsm_init(void) prepare_lsm(*lsm); init_debug("cred blob size = %d\n", blob_sizes.lbs_cred); + init_debug("file blob size = %d\n", blob_sizes.lbs_file); + + /* + * Create any kmem_caches needed for blobs + */ + if (blob_sizes.lbs_file) + lsm_file_cache = kmem_cache_create("lsm_file_cache", + blob_sizes.lbs_file, 0, + SLAB_PANIC, NULL); for (lsm = ordered_lsms; *lsm; lsm++) initialize_lsm(*lsm); @@ -448,6 +460,27 @@ void __init lsm_early_cred(struct cred *cred) panic("%s: Early cred alloc failed.\n", __func__); } +/** + * lsm_file_alloc - allocate a composite file blob + * @file: the file that needs a blob + * + * Allocate the file blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_file_alloc(struct file *file) +{ + if (!lsm_file_cache) { + file->f_security = NULL; + return 0; + } + + file->f_security = kmem_cache_zalloc(lsm_file_cache, GFP_KERNEL); + if (file->f_security == NULL) + return -ENOMEM; + return 0; +} + /* * Hook list operation macros. * @@ -1131,12 +1164,27 @@ int security_file_permission(struct file *file, int mask) int security_file_alloc(struct file *file) { - return call_int_hook(file_alloc_security, 0, file); + int rc = lsm_file_alloc(file); + + if (rc) + return rc; + rc = call_int_hook(file_alloc_security, 0, file); + if (unlikely(rc)) + security_file_free(file); + return rc; } void security_file_free(struct file *file) { + void *blob; + call_void_hook(file_free_security, file); + + blob = file->f_security; + if (blob) { + file->f_security = NULL; + kmem_cache_free(lsm_file_cache, blob); + } } int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) @@ -1254,7 +1302,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp) return rc; rc = call_int_hook(cred_alloc_blank, 0, cred, gfp); - if (rc) + if (unlikely(rc)) security_cred_free(cred); return rc; } @@ -1275,7 +1323,7 @@ int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp) return rc; rc = call_int_hook(cred_prepare, 0, new, old, gfp); - if (rc) + if (unlikely(rc)) security_cred_free(new); return rc; } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ce1d37378eb5..9669a059ce0f 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -145,7 +145,6 @@ static int __init checkreqprot_setup(char *str) __setup("checkreqprot=", checkreqprot_setup); static struct kmem_cache *sel_inode_cache; -static struct kmem_cache *file_security_cache; /** * selinux_secmark_enabled - Check to see if SECMARK is currently enabled @@ -377,27 +376,15 @@ static void inode_free_security(struct inode *inode) static int file_alloc_security(struct file *file) { - struct file_security_struct *fsec; + struct file_security_struct *fsec = selinux_file(file); u32 sid = current_sid(); - fsec = kmem_cache_zalloc(file_security_cache, GFP_KERNEL); - if (!fsec) - return -ENOMEM; - fsec->sid = sid; fsec->fown_sid = sid; - file->f_security = fsec; return 0; } -static void file_free_security(struct file *file) -{ - struct file_security_struct *fsec = selinux_file(file); - file->f_security = NULL; - kmem_cache_free(file_security_cache, fsec); -} - static int superblock_alloc_security(struct super_block *sb) { struct superblock_security_struct *sbsec; @@ -3559,11 +3546,6 @@ static int selinux_file_alloc_security(struct file *file) return file_alloc_security(file); } -static void selinux_file_free_security(struct file *file) -{ - file_free_security(file); -} - /* * Check whether a task has the ioctl permission and cmd * operation to an inode. @@ -6857,6 +6839,7 @@ static void selinux_bpf_prog_free(struct bpf_prog_aux *aux) struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = { .lbs_cred = sizeof(struct task_security_struct), + .lbs_file = sizeof(struct file_security_struct), }; static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { @@ -6927,7 +6910,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(file_permission, selinux_file_permission), LSM_HOOK_INIT(file_alloc_security, selinux_file_alloc_security), - LSM_HOOK_INIT(file_free_security, selinux_file_free_security), LSM_HOOK_INIT(file_ioctl, selinux_file_ioctl), LSM_HOOK_INIT(mmap_file, selinux_mmap_file), LSM_HOOK_INIT(mmap_addr, selinux_mmap_addr), @@ -7112,9 +7094,6 @@ static __init int selinux_init(void) sel_inode_cache = kmem_cache_create("selinux_inode_security", sizeof(struct inode_security_struct), 0, SLAB_PANIC, NULL); - file_security_cache = kmem_cache_create("selinux_file_security", - sizeof(struct file_security_struct), - 0, SLAB_PANIC, NULL); avc_init(); avtab_cache_init(); diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index e0ac2992e059..96374dbf4ace 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -167,7 +167,7 @@ static inline struct task_security_struct *selinux_cred(const struct cred *cred) static inline struct file_security_struct *selinux_file(const struct file *file) { - return file->f_security; + return file->f_security + selinux_blob_sizes.lbs_file; } #endif /* _SELINUX_OBJSEC_H_ */ diff --git a/security/smack/smack.h b/security/smack/smack.h index 50854969a391..2007d38d0e46 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -364,7 +364,8 @@ static inline struct task_smack *smack_cred(const struct cred *cred) static inline struct smack_known **smack_file(const struct file *file) { - return (struct smack_known **)&file->f_security; + return (struct smack_known **)(file->f_security + + smack_blob_sizes.lbs_file); } /* diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 3e11be8cce7e..c560cb8e155c 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1579,18 +1579,6 @@ static int smack_file_alloc_security(struct file *file) return 0; } -/** - * smack_file_free_security - clear a file security blob - * @file: the object - * - * The security blob for a file is a pointer to the master - * label list, so no memory is freed. - */ -static void smack_file_free_security(struct file *file) -{ - file->f_security = NULL; -} - /** * smack_file_ioctl - Smack check on ioctls * @file: the object @@ -4637,6 +4625,7 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { .lbs_cred = sizeof(struct task_smack), + .lbs_file = sizeof(struct smack_known *), }; static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { @@ -4674,7 +4663,6 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(inode_getsecid, smack_inode_getsecid), LSM_HOOK_INIT(file_alloc_security, smack_file_alloc_security), - LSM_HOOK_INIT(file_free_security, smack_file_free_security), LSM_HOOK_INIT(file_ioctl, smack_file_ioctl), LSM_HOOK_INIT(file_lock, smack_file_lock), LSM_HOOK_INIT(file_fcntl, smack_file_fcntl),

[v5,30/38] LSM: Infrastructure management of the file security

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