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TLkDSzy2atStFQ.XDqyZonixHh4VSbR_ItjO9GMX9RknsyUKk3qSz3lvegM5PlPzHcl.zoDD6Q6Q PauWIY1c8k.RQikznLMD3hocEvu461Jb8MKwFGYqFX1NN49Jx_9eLP1DhLu0RmX1kkZbuKB56qGh OWtu675wlVUmpC_D2iRP8qL3HTTxrInLy30Q.qwvv58e2aXVRlsvVS6RlXDvTZ06oLUJvy6o.gjg 22zoVI3y7Lyy4lEunQun_2V9l7lDqdiAE.h7Ljaqe41kp_1kEZKn9c.l1EpHZ436kYl7UZ.R8Twj 6cmpPp2231m4nAlwv1qh9fRwWI5tPGtyUs_9SKv6Kqhelg1XYCIPbyrr41PPz4n0hFc1JFv0xUAf pv0fG2ijdWSlNVog4bFX3fhnccE8Tsry7KzrP380.FEKc.1_dO7oPoVP7DezG5XUt_beDOwuHWVV bfwoQ2.W8EMBXBwbFLIxOOZW6vJr8z34VTUr58CwanG17ihpeEJDnrpHnSsAwZ.WZBIowYvmUGRr _MlrxTyDxAyB8gjGF3VUI.7_oZP9B3f.UZzo_nOVAPqe7TnvjYfnwNmiwmalikTJr55BNEMuTUwo uoTJlsdxegbVgTFkMW4xRusOYvXViOsUMG2GdPvEklyiPF0.HfVGk_ecVDc7AzQvLl75gKsWBNp3 frMn0sOi2_sqZ1ZJul5z0a1FWMZieJImrCgTqhQEzyN4WDZtX0WsUY6G4ZGR98PTMpk4U0qjFAcp 2FwR5XGWNzHRU7cn4NWjLjgi82lnd_YNhlo9imeX9lKjjylhK.v4BE5h7bduLKAFgMy9WrryhGLr JRGD2VW_9L0XvqP3GIWQEnbWDaQBrLlMIBe.j57li4Uw7UpaJoLc0eo2rzWz8zd9rqf_pBpUtOcV pOnNMROGz9tIGbPQoT.qGnbCtobkJbIRfGIWbpyeg3A-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic305.consmr.mail.bf2.yahoo.com with HTTP; Sat, 22 Sep 2018 00:19:08 +0000 Received: from c-67-169-65-224.hsd1.ca.comcast.net (EHLO [192.168.0.102]) ([67.169.65.224]) by smtp431.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID d63621613b76c90661f1c74afe6e1004; Sat, 22 Sep 2018 00:19:06 +0000 (UTC) Subject: [PATCH v4 11/19] LSM: Infrastructure management of the file security To: LSM , James Morris , SE Linux , LKLM , John Johansen , Kees Cook , Tetsuo Handa , Paul Moore , Stephen Smalley , "linux-fsdevel@vger.kernel.org" , Alexey Dobriyan , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Salvatore Mesoraca References: From: Casey Schaufler Message-ID: <1ca14e0b-6a95-4efe-7a23-e82d7562df26@schaufler-ca.com> Date: Fri, 21 Sep 2018 17:19:00 -0700 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: Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Move management of the file->f_security blob out of the individual security modules and into the infrastructure. The modules no longer allocate or free the data, instead they tell the infrastructure how much space they require. Signed-off-by: Casey Schaufler Reviewed-by: Kees Cook --- include/linux/lsm_hooks.h | 1 + security/apparmor/lsm.c | 19 +++++++------- security/security.c | 54 +++++++++++++++++++++++++++++++++++--- security/selinux/hooks.c | 25 ++---------------- security/smack/smack.h | 2 +- security/smack/smack_lsm.c | 14 +--------- 6 files changed, 66 insertions(+), 49 deletions(-) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 0bef312efd45..167ffbd4d0c0 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/lsm.c b/security/apparmor/lsm.c index c2566aaa138e..15716b6ff860 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -431,21 +431,21 @@ 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) @@ -1131,6 +1131,7 @@ static void apparmor_sock_graft(struct sock *sk, struct socket *parent) */ struct lsm_blob_sizes apparmor_blob_sizes = { .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 ff7df14f6db1..5430cae73cf6 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; @@ -92,6 +94,13 @@ int __init security_init(void) */ do_security_initcalls(); + /* + * 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); /* * The second call to a module specific init function * adds hooks to the hook lists and does any other early @@ -101,6 +110,7 @@ int __init security_init(void) #ifdef CONFIG_SECURITY_LSM_DEBUG pr_info("LSM: cred blob size = %d\n", blob_sizes.lbs_cred); + pr_info("LSM: file blob size = %d\n", blob_sizes.lbs_file); #endif return 0; @@ -277,6 +287,28 @@ static void __init lsm_set_size(int *need, int *lbs) 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_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. + */ +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; } /* @@ -962,12 +994,28 @@ 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; + + if (!lsm_file_cache) + return; + call_void_hook(file_free_security, file); + + blob = file->f_security; + file->f_security = NULL; + kmem_cache_free(lsm_file_cache, blob); } int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) @@ -1085,7 +1133,7 @@ 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; } @@ -1106,7 +1154,7 @@ 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 641a8ce726ff..fdda53552224 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -148,7 +148,6 @@ 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 @@ -380,27 +379,15 @@ 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; @@ -3557,11 +3544,6 @@ 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. @@ -6855,6 +6837,7 @@ static void selinux_bpf_prog_free(struct bpf_prog_aux *aux) struct lsm_blob_sizes selinux_blob_sizes = { .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 = { @@ -6925,7 +6908,6 @@ 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), @@ -7128,9 +7110,6 @@ 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/smack/smack.h b/security/smack/smack.h index 22ca30379209..62a22ad8ce92 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -363,7 +363,7 @@ 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 file->f_security; } /* diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 9ec595f0c3f1..d1430341798f 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1577,18 +1577,6 @@ 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 @@ -4630,6 +4618,7 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, struct lsm_blob_sizes smack_blob_sizes = { .lbs_cred = sizeof(struct task_smack), + .lbs_file = sizeof(struct smack_known *), }; static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { @@ -4667,7 +4656,6 @@ 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),