Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem updates from James Morris:

 - Extend LSM stacking to allow sharing of cred, file, ipc, inode, and
   task blobs. This paves the way for more full-featured LSMs to be
   merged, and is specifically aimed at LandLock and SARA LSMs. This
   work is from Casey and Kees.

 - There's a new LSM from Micah Morton: "SafeSetID gates the setid
   family of syscalls to restrict UID/GID transitions from a given
   UID/GID to only those approved by a system-wide whitelist." This
   feature is currently shipping in ChromeOS.

* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (62 commits)
  keys: fix missing __user in KEYCTL_PKEY_QUERY
  LSM: Update list of SECURITYFS users in Kconfig
  LSM: Ignore "security=" when "lsm=" is specified
  LSM: Update function documentation for cap_capable
  security: mark expected switch fall-throughs and add a missing break
  tomoyo: Bump version.
  LSM: fix return value check in safesetid_init_securityfs()
  LSM: SafeSetID: add selftest
  LSM: SafeSetID: remove unused include
  LSM: SafeSetID: 'depend' on CONFIG_SECURITY
  LSM: Add 'name' field for SafeSetID in DEFINE_LSM
  LSM: add SafeSetID module that gates setid calls
  LSM: add SafeSetID module that gates setid calls
  tomoyo: Allow multiple use_group lines.
  tomoyo: Coding style fix.
  tomoyo: Swicth from cred->security to task_struct->security.
  security: keys: annotate implicit fall throughs
  security: keys: annotate implicit fall throughs
  security: keys: annotate implicit fall through
  capabilities:: annotate implicit fall through
  ...

security/apparmor/Kconfig

@@ -14,22 +14,6 @@ config SECURITY_APPARMOR
 
 	  If you are unsure how to answer this question, answer N.
 
-config SECURITY_APPARMOR_BOOTPARAM_VALUE
-	int "AppArmor boot parameter default value"
-	depends on SECURITY_APPARMOR
-	range 0 1
-	default 1
-	help
-	  This option sets the default value for the kernel parameter
-	  'apparmor', which allows AppArmor to be enabled or disabled
-          at boot.  If this option is set to 0 (zero), the AppArmor
-	  kernel parameter will default to 0, disabling AppArmor at
-	  boot.  If this option is set to 1 (one), the AppArmor
-	  kernel parameter will default to 1, enabling AppArmor at
-	  boot.
-
-	  If you are unsure how to answer this question, answer 1.
-
 config SECURITY_APPARMOR_HASH
 	bool "Enable introspection of sha1 hashes for loaded profiles"
 	depends on SECURITY_APPARMOR

security/apparmor/capability.c

@@ -110,13 +110,13 @@ static int audit_caps(struct common_audit_data *sa, struct aa_profile *profile,
  * profile_capable - test if profile allows use of capability @cap
  * @profile: profile being enforced    (NOT NULL, NOT unconfined)
  * @cap: capability to test if allowed
- * @audit: whether an audit record should be generated
+ * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
  * @sa: audit data (MAY BE NULL indicating no auditing)
  *
  * Returns: 0 if allowed else -EPERM
  */
-static int profile_capable(struct aa_profile *profile, int cap, int audit,
-			   struct common_audit_data *sa)
+static int profile_capable(struct aa_profile *profile, int cap,
+			   unsigned int opts, struct common_audit_data *sa)
 {
 	int error;
 
@@ -126,7 +126,7 @@ static int profile_capable(struct aa_profile *profile, int cap, int audit,
 	else
 		error = -EPERM;
 
-	if (audit == SECURITY_CAP_NOAUDIT) {
+	if (opts & CAP_OPT_NOAUDIT) {
 		if (!COMPLAIN_MODE(profile))
 			return error;
 		/* audit the cap request in complain mode but note that it
@@ -142,13 +142,13 @@ static int profile_capable(struct aa_profile *profile, int cap, int audit,
  * aa_capable - test permission to use capability
  * @label: label being tested for capability (NOT NULL)
  * @cap: capability to be tested
- * @audit: whether an audit record should be generated
+ * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
  *
  * Look up capability in profile capability set.
  *
  * Returns: 0 on success, or else an error code.
  */
-int aa_capable(struct aa_label *label, int cap, int audit)
+int aa_capable(struct aa_label *label, int cap, unsigned int opts)
 {
 	struct aa_profile *profile;
 	int error = 0;
@@ -156,7 +156,7 @@ int aa_capable(struct aa_label *label, int cap, int audit)
 
 	sa.u.cap = cap;
 	error = fn_for_each_confined(label, profile,
-			profile_capable(profile, cap, audit, &sa));
+			profile_capable(profile, cap, opts, &sa));
 
 	return error;
 }

security/apparmor/domain.c

@@ -572,7 +572,7 @@ static struct aa_label *x_to_label(struct aa_profile *profile,
 			stack = NULL;
 			break;
 		}
-		/* fall through to X_NAME */
+		/* fall through - to X_NAME */
 	case AA_X_NAME:
 		if (xindex & AA_X_CHILD)
 			/* released by caller */
@@ -975,7 +975,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 	}
 	aa_put_label(cred_label(bprm->cred));
 	/* transfer reference, released when cred is freed */
-	cred_label(bprm->cred) = new;
+	set_cred_label(bprm->cred, new);
 
 done:
 	aa_put_label(label);

security/apparmor/include/capability.h

@@ -40,7 +40,7 @@ struct aa_caps {
 
 extern struct aa_sfs_entry aa_sfs_entry_caps[];
 
-int aa_capable(struct aa_label *label, int cap, int audit);
+int aa_capable(struct aa_label *label, int cap, unsigned int opts);
 
 static inline void aa_free_cap_rules(struct aa_caps *caps)
 {

security/apparmor/include/cred.h

@@ -23,8 +23,22 @@
 #include "policy_ns.h"
 #include "task.h"
 
-#define cred_label(X) ((X)->security)
+static inline struct aa_label *cred_label(const struct cred *cred)
+{
+	struct aa_label **blob = cred->security + apparmor_blob_sizes.lbs_cred;
 
+	AA_BUG(!blob);
+	return *blob;
+}
+
+static inline void set_cred_label(const struct cred *cred,
+				  struct aa_label *label)
+{
+	struct aa_label **blob = cred->security + apparmor_blob_sizes.lbs_cred;
+
+	AA_BUG(!blob);
+	*blob = label;
+}
 
 /**
  * aa_cred_raw_label - obtain cred's label

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

security/apparmor/include/lib.h

@@ -16,6 +16,7 @@
 
 #include <linux/slab.h>
 #include <linux/fs.h>
+#include <linux/lsm_hooks.h>
 
 #include "match.h"
 
@@ -55,6 +56,9 @@ const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
 			     size_t *ns_len);
 void aa_info_message(const char *str);
 
+/* Security blob offsets */
+extern struct lsm_blob_sizes apparmor_blob_sizes;
+
 /**
  * aa_strneq - compare null terminated @str to a non null terminated substring
  * @str: a null terminated string

security/apparmor/include/task.h

@@ -14,7 +14,10 @@
 #ifndef __AA_TASK_H
 #define __AA_TASK_H
 
-#define task_ctx(X) ((X)->security)
+static inline struct aa_task_ctx *task_ctx(struct task_struct *task)
+{
+	return task->security + apparmor_blob_sizes.lbs_task;
+}
 
 /*
  * struct aa_task_ctx - information for current task label change
@@ -36,17 +39,6 @@ int aa_set_current_hat(struct aa_label *label, u64 token);
 int aa_restore_previous_label(u64 cookie);
 struct aa_label *aa_get_task_label(struct task_struct *task);
 
-/**
- * aa_alloc_task_ctx - allocate a new task_ctx
- * @flags: gfp flags for allocation
- *
- * Returns: allocated buffer or NULL on failure
- */
-static inline struct aa_task_ctx *aa_alloc_task_ctx(gfp_t flags)
-{
-	return kzalloc(sizeof(struct aa_task_ctx), flags);
-}
-
 /**
  * aa_free_task_ctx - free a task_ctx
  * @ctx: task_ctx to free (MAYBE NULL)
@@ -57,8 +49,6 @@ static inline void aa_free_task_ctx(struct aa_task_ctx *ctx)
 		aa_put_label(ctx->nnp);
 		aa_put_label(ctx->previous);
 		aa_put_label(ctx->onexec);
-
-		kzfree(ctx);
 	}
 }
 

security/apparmor/ipc.c

@@ -107,7 +107,8 @@ static int profile_tracer_perm(struct aa_profile *tracer,
 	aad(sa)->label = &tracer->label;
 	aad(sa)->peer = tracee;
 	aad(sa)->request = 0;
-	aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 1);
+	aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE,
+				    CAP_OPT_NONE);
 
 	return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb);
 }

security/apparmor/lsm.c

@@ -60,7 +60,7 @@ DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
 static void apparmor_cred_free(struct cred *cred)
 {
 	aa_put_label(cred_label(cred));
-	cred_label(cred) = NULL;
+	set_cred_label(cred, NULL);
 }
 
 /*
@@ -68,7 +68,7 @@ static void apparmor_cred_free(struct cred *cred)
  */
 static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
 {
-	cred_label(cred) = NULL;
+	set_cred_label(cred, NULL);
 	return 0;
 }
 
@@ -78,7 +78,7 @@ static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
 static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
 				 gfp_t gfp)
 {
-	cred_label(new) = aa_get_newest_label(cred_label(old));
+	set_cred_label(new, aa_get_newest_label(cred_label(old)));
 	return 0;
 }
 
@@ -87,26 +87,21 @@ static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
  */
 static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
 {
-	cred_label(new) = aa_get_newest_label(cred_label(old));
+	set_cred_label(new, aa_get_newest_label(cred_label(old)));
 }
 
 static void apparmor_task_free(struct task_struct *task)
 {
 
 	aa_free_task_ctx(task_ctx(task));
-	task_ctx(task) = NULL;
 }
 
 static int apparmor_task_alloc(struct task_struct *task,
 			       unsigned long clone_flags)
 {
-	struct aa_task_ctx *new = aa_alloc_task_ctx(GFP_KERNEL);
-
-	if (!new)
-		return -ENOMEM;
+	struct aa_task_ctx *new = task_ctx(task);
 
 	aa_dup_task_ctx(new, task_ctx(current));
-	task_ctx(task) = new;
 
 	return 0;
 }
@@ -177,14 +172,14 @@ static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
 }
 
 static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
-			    int cap, int audit)
+			    int cap, unsigned int opts)
 {
 	struct aa_label *label;
 	int error = 0;
 
 	label = aa_get_newest_cred_label(cred);
 	if (!unconfined(label))
-		error = aa_capable(label, cap, audit);
+		error = aa_capable(label, cap, opts);
 	aa_put_label(label);
 
 	return error;
@@ -434,21 +429,21 @@ 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)
@@ -1151,6 +1146,15 @@ static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 }
 #endif
 
+/*
+ * The cred blob is a pointer to, not an instance of, an aa_task_ctx.
+ */
+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),
+	.lbs_task = sizeof(struct aa_task_ctx),
+};
+
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -1333,8 +1337,8 @@ bool aa_g_paranoid_load = true;
 module_param_named(paranoid_load, aa_g_paranoid_load, aabool, S_IRUGO);
 
 /* Boot time disable flag */
-static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
-module_param_named(enabled, apparmor_enabled, bool, S_IRUGO);
+static int apparmor_enabled __lsm_ro_after_init = 1;
+module_param_named(enabled, apparmor_enabled, int, 0444);
 
 static int __init apparmor_enabled_setup(char *str)
 {
@@ -1479,14 +1483,8 @@ static int param_set_mode(const char *val, const struct kernel_param *kp)
 static int __init set_init_ctx(void)
 {
 	struct cred *cred = (struct cred *)current->real_cred;
-	struct aa_task_ctx *ctx;
 
-	ctx = aa_alloc_task_ctx(GFP_KERNEL);
-	if (!ctx)
-		return -ENOMEM;
-
-	cred_label(cred) = aa_get_label(ns_unconfined(root_ns));
-	task_ctx(current) = ctx;
+	set_cred_label(cred, aa_get_label(ns_unconfined(root_ns)));
 
 	return 0;
 }
@@ -1665,12 +1663,6 @@ static int __init apparmor_init(void)
 {
 	int error;
 
-	if (!apparmor_enabled || !security_module_enable("apparmor")) {
-		aa_info_message("AppArmor disabled by boot time parameter");
-		apparmor_enabled = false;
-		return 0;
-	}
-
 	aa_secids_init();
 
 	error = aa_setup_dfa_engine();
@@ -1731,5 +1723,8 @@ alloc_out:
 
 DEFINE_LSM(apparmor) = {
 	.name = "apparmor",
+	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
+	.enabled = &apparmor_enabled,
+	.blobs = &apparmor_blob_sizes,
 	.init = apparmor_init,
 };

security/apparmor/resource.c

@@ -124,7 +124,7 @@ int aa_task_setrlimit(struct aa_label *label, struct task_struct *task,
 	 */
 
 	if (label != peer &&
-	    aa_capable(label, CAP_SYS_RESOURCE, SECURITY_CAP_NOAUDIT) != 0)
+	    aa_capable(label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0)
 		error = fn_for_each(label, profile,
 				audit_resource(profile, resource,
 					       new_rlim->rlim_max, peer,

security/apparmor/task.c

@@ -81,7 +81,7 @@ int aa_replace_current_label(struct aa_label *label)
 	 */
 	aa_get_label(label);
 	aa_put_label(cred_label(new));
-	cred_label(new) = label;
+	set_cred_label(new, label);
 
 	commit_creds(new);
 	return 0;
@@ -138,7 +138,7 @@ int aa_set_current_hat(struct aa_label *label, u64 token)
 		return -EACCES;
 	}
 
-	cred_label(new) = aa_get_newest_label(label);
+	set_cred_label(new, aa_get_newest_label(label));
 	/* clear exec on switching context */
 	aa_put_label(ctx->onexec);
 	ctx->onexec = NULL;
@@ -172,7 +172,7 @@ int aa_restore_previous_label(u64 token)
 		return -ENOMEM;
 
 	aa_put_label(cred_label(new));
-	cred_label(new) = aa_get_newest_label(ctx->previous);
+	set_cred_label(new, aa_get_newest_label(ctx->previous));
 	AA_BUG(!cred_label(new));
 	/* clear exec && prev information when restoring to previous context */
 	aa_clear_task_ctx_trans(ctx);