[12/25] LSM: Infrastructure managed file security blob

Message ID	19d0be16-37e9-edf5-d3df-57fe2a30ab85@schaufler-ca.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Subject: [PATCH 12/25] LSM: Infrastructure managed file security blob To: LSM <linux-security-module@vger.kernel.org>, James Morris <jmorris@namei.org> References: <801ef9a9-e594-387c-f285-8d90879ee2bf@schaufler-ca.com> Cc: John Johansen <john.johansen@canonical.com>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, Paul Moore <paul@paul-moore.com>, Stephen Smalley <sds@tycho.nsa.gov> From: Casey Schaufler <casey@schaufler-ca.com> Message-ID: <19d0be16-37e9-edf5-d3df-57fe2a30ab85@schaufler-ca.com> Date: Sat, 13 Aug 2016 13:36:33 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <801ef9a9-e594-387c-f285-8d90879ee2bf@schaufler-ca.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit 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 dde837f..bc8e0ac 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1849,6 +1849,7 @@ 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 c91ce01..8542517 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -352,23 +352,6 @@ static int apparmor_file_open(struct file *file, const struct cred *cred) return error; } -static int apparmor_file_alloc_security(struct file *file) -{ - /* freed by apparmor_file_free_security */ - file->f_security = aa_alloc_file_context(GFP_KERNEL); - if (!file->f_security) - return -ENOMEM; - return 0; - -} - -static void apparmor_file_free_security(struct file *file) -{ - struct aa_file_cxt *cxt = file_cxt(file); - - aa_free_file_context(cxt); -} - static int common_file_perm(int op, struct file *file, u32 mask) { struct aa_file_cxt *fcxt = file_cxt(file); @@ -592,6 +575,7 @@ static int apparmor_task_setrlimit(struct task_struct *task, struct lsm_blob_sizes apparmor_blob_sizes = { .lbs_cred = sizeof(struct aa_task_cxt), + .lbs_file = sizeof(struct aa_file_cxt), }; static struct security_hook_list apparmor_hooks[] = { @@ -614,8 +598,6 @@ static struct security_hook_list apparmor_hooks[] = { LSM_HOOK_INIT(file_open, apparmor_file_open), LSM_HOOK_INIT(file_permission, apparmor_file_permission), - LSM_HOOK_INIT(file_alloc_security, apparmor_file_alloc_security), - LSM_HOOK_INIT(file_free_security, apparmor_file_free_security), LSM_HOOK_INIT(mmap_file, apparmor_mmap_file), LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect), LSM_HOOK_INIT(file_lock, apparmor_file_lock), diff --git a/security/security.c b/security/security.c index 762726d..66a2fa6 100644 --- a/security/security.c +++ b/security/security.c @@ -80,6 +80,7 @@ int __init security_init(void) #ifdef CONFIG_SECURITY_STACKING_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; @@ -199,6 +200,32 @@ 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) +{ +#ifdef CONFIG_SECURITY_STACKING_DEBUG + if (file->f_security) { + pr_info("%s: Inbound file blob is not NULL.\n", __func__); + return 0; + } +#endif + if (blob_sizes.lbs_file == 0) + return 0; + + file->f_security = kzalloc(blob_sizes.lbs_file, GFP_KERNEL); + if (file->f_security == NULL) + return -ENOMEM; + return 0; } /* @@ -865,12 +892,19 @@ int security_file_permission(struct file *file, int mask) int security_file_alloc(struct file *file) { + int rc = lsm_file_alloc(file); + + if (rc) + return rc; return call_int_hook(file_alloc_security, 0, file); } void security_file_free(struct file *file) { call_void_hook(file_free_security, file); + + kfree(file->f_security); + file->f_security = NULL; } int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 04c8e9a..72121575 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -126,7 +126,6 @@ int selinux_enabled = 1; #endif 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 @@ -355,27 +354,15 @@ 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; @@ -3330,11 +3317,6 @@ 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. @@ -6004,6 +5986,7 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer) 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[] = { @@ -6072,7 +6055,6 @@ static struct security_hook_list selinux_hooks[] = { 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), @@ -6247,9 +6229,6 @@ 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(); security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux"); diff --git a/security/smack/smack.h b/security/smack/smack.h index d95c56d..d941c48 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -349,7 +349,7 @@ static inline struct task_smack *smack_cred(const struct cred *cred) return cred->security; } -static inline struct smack_known *smack_file(const struct file *file) +static inline struct smack_known **smack_file(const struct file *file) { return file->f_security; } diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index be7b3e6..3833e6e 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1588,25 +1588,13 @@ static void smack_inode_getsecid(struct inode *inode, u32 *secid) */ static int smack_file_alloc_security(struct file *file) { - struct smack_known *skp = smk_of_current(); + struct smack_known **blob = smack_file(file); - file->f_security = skp; + *blob = smk_of_current(); 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 * @cmd: what to do @@ -1818,7 +1806,9 @@ static int smack_mmap_file(struct file *file, */ static void smack_file_set_fowner(struct file *file) { - file->f_security = smk_of_current(); + struct smack_known **blob = smack_file(file); + + *blob = smk_of_current(); } /** @@ -1835,6 +1825,7 @@ static void smack_file_set_fowner(struct file *file) static int smack_file_send_sigiotask(struct task_struct *tsk, struct fown_struct *fown, int signum) { + struct smack_known **blob; struct smack_known *skp; struct smack_known *tkp = smk_of_task(smack_cred(tsk->cred)); struct file *file; @@ -1847,7 +1838,8 @@ static int smack_file_send_sigiotask(struct task_struct *tsk, file = container_of(fown, struct file, f_owner); /* we don't log here as rc can be overriden */ - skp = smack_file(file); + blob = smack_file(file); + skp = *blob; rc = smk_access(skp, tkp, MAY_WRITE, NULL); rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc); if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE)) @@ -4587,6 +4579,7 @@ static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) 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[] = { @@ -4626,7 +4619,6 @@ static struct security_hook_list smack_hooks[] = { 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),

[12/25] LSM: Infrastructure managed file security blob

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