[PATCH ghak81 RFC V1 0/5] audit: group task params

[PATCH ghak81 RFC V1 0/5] audit: group task params

[Richard Guy Briggs]

Group the audit parameters for each task into one structure.
In particular, remove the loginuid and sessionid values and the audit
context pointer from the task structure, replacing them with an audit
task information structure to contain them.  Use access functions to
access audit values.

Note:  Use static allocation of the audit task information structure
initially.  Dynamic allocation was considered and attempted, but isn't
ready yet.  Static allocation has the limitation that future audit task
information structure changes would cause a visible change to the rest
of the kernel, whereas dynamic allocation would mostly hide any future
changes.

The first four access normalization patches could stand alone.

Passes audit-testsuite.

Richard Guy Briggs (5):
  audit: normalize loginuid read access
  audit: convert sessionid unset to a macro
  audit: use inline function to get audit context
  audit: use inline function to set audit context
  audit: collect audit task parameters

 MAINTAINERS                          |  2 +-
 include/linux/audit.h                | 30 ++++++++++---
 include/linux/audit_task.h           | 31 ++++++++++++++
 include/linux/sched.h                |  6 +--
 include/net/xfrm.h                   |  4 +-
 include/uapi/linux/audit.h           |  1 +
 init/init_task.c                     |  8 +++-
 kernel/audit.c                       |  4 +-
 kernel/audit_watch.c                 |  2 +-
 kernel/auditsc.c                     | 82 ++++++++++++++++++------------------
 kernel/fork.c                        |  2 +-
 net/bridge/netfilter/ebtables.c      |  2 +-
 net/core/dev.c                       |  2 +-
 net/netfilter/x_tables.c             |  2 +-
 net/netlabel/netlabel_user.c         |  2 +-
 security/integrity/ima/ima_api.c     |  2 +-
 security/integrity/integrity_audit.c |  2 +-
 security/lsm_audit.c                 |  2 +-
 security/selinux/hooks.c             |  4 +-
 security/selinux/selinuxfs.c         |  6 +--
 security/selinux/ss/services.c       | 12 +++---
 21 files changed, 129 insertions(+), 79 deletions(-)
 create mode 100644 include/linux/audit_task.h

-- 
1.8.3.1

[PATCH ghak81 RFC V1 1/5] audit: normalize loginuid read access

[Richard Guy Briggs]

Recognizing that the loginuid is an internal audit value, use an access
function to retrieve the audit loginuid value for the task rather than
reaching directly into the task struct to get it.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 kernel/auditsc.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 479c031..f3817d0 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -374,7 +374,7 @@ static int audit_field_compare(struct task_struct *tsk,
 	case AUDIT_COMPARE_EGID_TO_OBJ_GID:
 		return audit_compare_gid(cred->egid, name, f, ctx);
 	case AUDIT_COMPARE_AUID_TO_OBJ_UID:
-		return audit_compare_uid(tsk->loginuid, name, f, ctx);
+		return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
 	case AUDIT_COMPARE_SUID_TO_OBJ_UID:
 		return audit_compare_uid(cred->suid, name, f, ctx);
 	case AUDIT_COMPARE_SGID_TO_OBJ_GID:
@@ -385,7 +385,7 @@ static int audit_field_compare(struct task_struct *tsk,
 		return audit_compare_gid(cred->fsgid, name, f, ctx);
 	/* uid comparisons */
 	case AUDIT_COMPARE_UID_TO_AUID:
-		return audit_uid_comparator(cred->uid, f->op, tsk->loginuid);
+		return audit_uid_comparator(cred->uid, f->op, audit_get_loginuid(tsk));
 	case AUDIT_COMPARE_UID_TO_EUID:
 		return audit_uid_comparator(cred->uid, f->op, cred->euid);
 	case AUDIT_COMPARE_UID_TO_SUID:
@@ -394,11 +394,11 @@ static int audit_field_compare(struct task_struct *tsk,
 		return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
 	/* auid comparisons */
 	case AUDIT_COMPARE_AUID_TO_EUID:
-		return audit_uid_comparator(tsk->loginuid, f->op, cred->euid);
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->euid);
 	case AUDIT_COMPARE_AUID_TO_SUID:
-		return audit_uid_comparator(tsk->loginuid, f->op, cred->suid);
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->suid);
 	case AUDIT_COMPARE_AUID_TO_FSUID:
-		return audit_uid_comparator(tsk->loginuid, f->op, cred->fsuid);
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->fsuid);
 	/* euid comparisons */
 	case AUDIT_COMPARE_EUID_TO_SUID:
 		return audit_uid_comparator(cred->euid, f->op, cred->suid);
@@ -611,7 +611,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 				result = match_tree_refs(ctx, rule->tree);
 			break;
 		case AUDIT_LOGINUID:
-			result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
+			result = audit_uid_comparator(audit_get_loginuid(tsk), f->op, f->uid);
 			break;
 		case AUDIT_LOGINUID_SET:
 			result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
@@ -2287,8 +2287,8 @@ int audit_signal_info(int sig, struct task_struct *t)
 	    (sig == SIGTERM || sig == SIGHUP ||
 	     sig == SIGUSR1 || sig == SIGUSR2)) {
 		audit_sig_pid = task_tgid_nr(tsk);
-		if (uid_valid(tsk->loginuid))
-			audit_sig_uid = tsk->loginuid;
+		if (uid_valid(audit_get_loginuid(tsk)))
+			audit_sig_uid = audit_get_loginuid(tsk);
 		else
 			audit_sig_uid = uid;
 		security_task_getsecid(tsk, &audit_sig_sid);
-- 
1.8.3.1

[PATCH ghak81 RFC V1 2/5] audit: convert sessionid unset to a macro

[Richard Guy Briggs]

Use a macro, "AUDIT_SID_UNSET", to replace each instance of
initialization and comparison to an audit session ID.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 include/linux/audit.h      | 2 +-
 include/net/xfrm.h         | 2 +-
 include/uapi/linux/audit.h | 1 +
 init/init_task.c           | 2 +-
 kernel/auditsc.c           | 4 ++--
 5 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 75d5b03..5f86f7c 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -513,7 +513,7 @@ static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
 }
 static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 {
-	return -1;
+	return AUDIT_SID_UNSET;
 }
 static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
 { }
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index a872379..fcce8ee 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -751,7 +751,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
 					    audit_get_loginuid(current) :
 					    INVALID_UID);
 	const unsigned int ses = task_valid ? audit_get_sessionid(current) :
-		(unsigned int) -1;
+		AUDIT_SID_UNSET;
 
 	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
 	audit_log_task_context(audit_buf);
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 4e61a9e..04f9bd2 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -465,6 +465,7 @@ struct audit_tty_status {
 };
 
 #define AUDIT_UID_UNSET (unsigned int)-1
+#define AUDIT_SID_UNSET ((unsigned int)-1)
 
 /* audit_rule_data supports filter rules with both integer and string
  * fields.  It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and
diff --git a/init/init_task.c b/init/init_task.c
index 3ac6e75..c788f91 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -119,7 +119,7 @@ struct task_struct init_task
 	.thread_node	= LIST_HEAD_INIT(init_signals.thread_head),
 #ifdef CONFIG_AUDITSYSCALL
 	.loginuid	= INVALID_UID,
-	.sessionid	= (unsigned int)-1,
+	.sessionid	= AUDIT_SID_UNSET,
 #endif
 #ifdef CONFIG_PERF_EVENTS
 	.perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index f3817d0..6e3ceb9 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2050,7 +2050,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 int audit_set_loginuid(kuid_t loginuid)
 {
 	struct task_struct *task = current;
-	unsigned int oldsessionid, sessionid = (unsigned int)-1;
+	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
 	kuid_t oldloginuid;
 	int rc;
 
@@ -2064,7 +2064,7 @@ int audit_set_loginuid(kuid_t loginuid)
 	/* are we setting or clearing? */
 	if (uid_valid(loginuid)) {
 		sessionid = (unsigned int)atomic_inc_return(&session_id);
-		if (unlikely(sessionid == (unsigned int)-1))
+		if (unlikely(sessionid == AUDIT_SID_UNSET))
 			sessionid = (unsigned int)atomic_inc_return(&session_id);
 	}
 
-- 
1.8.3.1

[PATCH ghak81 RFC V1 3/5] audit: use inline function to get audit context

[Richard Guy Briggs]

Recognizing that the audit context is an internal audit value, use an
access function to retrieve the audit context pointer for the task
rather than reaching directly into the task struct to get it.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 include/linux/audit.h                | 16 ++++++++---
 include/net/xfrm.h                   |  2 +-
 kernel/audit.c                       |  4 +--
 kernel/audit_watch.c                 |  2 +-
 kernel/auditsc.c                     | 52 ++++++++++++++++++------------------
 net/bridge/netfilter/ebtables.c      |  2 +-
 net/core/dev.c                       |  2 +-
 net/netfilter/x_tables.c             |  2 +-
 net/netlabel/netlabel_user.c         |  2 +-
 security/integrity/ima/ima_api.c     |  2 +-
 security/integrity/integrity_audit.c |  2 +-
 security/lsm_audit.c                 |  2 +-
 security/selinux/hooks.c             |  4 +--
 security/selinux/selinuxfs.c         |  6 ++---
 security/selinux/ss/services.c       | 12 ++++-----
 15 files changed, 60 insertions(+), 52 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 5f86f7c..93e4c61 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -235,26 +235,30 @@ extern void __audit_inode_child(struct inode *parent,
 extern void __audit_seccomp(unsigned long syscall, long signr, int code);
 extern void __audit_ptrace(struct task_struct *t);
 
+static inline struct audit_context *audit_context(struct task_struct *task)
+{
+	return task->audit_context;
+}
 static inline bool audit_dummy_context(void)
 {
-	void *p = current->audit_context;
+	void *p = audit_context(current);
 	return !p || *(int *)p;
 }
 static inline void audit_free(struct task_struct *task)
 {
-	if (unlikely(task->audit_context))
+	if (unlikely(audit_context(task)))
 		__audit_free(task);
 }
 static inline void audit_syscall_entry(int major, unsigned long a0,
 				       unsigned long a1, unsigned long a2,
 				       unsigned long a3)
 {
-	if (unlikely(current->audit_context))
+	if (unlikely(audit_context(current)))
 		__audit_syscall_entry(major, a0, a1, a2, a3);
 }
 static inline void audit_syscall_exit(void *pt_regs)
 {
-	if (unlikely(current->audit_context)) {
+	if (unlikely(audit_context(current))) {
 		int success = is_syscall_success(pt_regs);
 		long return_code = regs_return_value(pt_regs);
 
@@ -468,6 +472,10 @@ static inline bool audit_dummy_context(void)
 {
 	return true;
 }
+static inline struct audit_context *audit_context(struct task_struct *task)
+{
+	return NULL;
+}
 static inline struct filename *audit_reusename(const __user char *name)
 {
 	return NULL;
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index fcce8ee..2788332 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -736,7 +736,7 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)
 
 	if (audit_enabled == 0)
 		return NULL;
-	audit_buf = audit_log_start(current->audit_context, GFP_ATOMIC,
+	audit_buf = audit_log_start(audit_context(current), GFP_ATOMIC,
 				    AUDIT_MAC_IPSEC_EVENT);
 	if (audit_buf == NULL)
 		return NULL;
diff --git a/kernel/audit.c b/kernel/audit.c
index e9f9a90..9a03603 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1099,7 +1099,7 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature
 
 	if (audit_enabled == AUDIT_OFF)
 		return;
-	ab = audit_log_start(current->audit_context,
+	ab = audit_log_start(audit_context(current),
 			     GFP_KERNEL, AUDIT_FEATURE_CHANGE);
 	if (!ab)
 		return;
@@ -2317,7 +2317,7 @@ void audit_log_link_denied(const char *operation)
 		return;
 
 	/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
-	ab = audit_log_start(current->audit_context, GFP_KERNEL,
+	ab = audit_log_start(audit_context(current), GFP_KERNEL,
 			     AUDIT_ANOM_LINK);
 	if (!ab)
 		return;
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 9eb8b35..8b596c4 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -274,7 +274,7 @@ static void audit_update_watch(struct audit_parent *parent,
 		/* If the update involves invalidating rules, do the inode-based
 		 * filtering now, so we don't omit records. */
 		if (invalidating && !audit_dummy_context())
-			audit_filter_inodes(current, current->audit_context);
+			audit_filter_inodes(current, audit_context(current));
 
 		/* updating ino will likely change which audit_hash_list we
 		 * are on so we need a new watch for the new list */
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 6e3ceb9..a4bbdcc 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -836,7 +836,7 @@ static inline struct audit_context *audit_take_context(struct task_struct *tsk,
 						      int return_valid,
 						      long return_code)
 {
-	struct audit_context *context = tsk->audit_context;
+	struct audit_context *context = audit_context(tsk);
 
 	if (!context)
 		return NULL;
@@ -1510,7 +1510,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
 			   unsigned long a3, unsigned long a4)
 {
 	struct task_struct *tsk = current;
-	struct audit_context *context = tsk->audit_context;
+	struct audit_context *context = audit_context(tsk);
 	enum audit_state     state;
 
 	if (!audit_enabled || !context)
@@ -1602,7 +1602,7 @@ static inline void handle_one(const struct inode *inode)
 	int count;
 	if (likely(!inode->i_fsnotify_marks))
 		return;
-	context = current->audit_context;
+	context = audit_context(current);
 	p = context->trees;
 	count = context->tree_count;
 	rcu_read_lock();
@@ -1633,7 +1633,7 @@ static void handle_path(const struct dentry *dentry)
 	unsigned long seq;
 	int count;
 
-	context = current->audit_context;
+	context = audit_context(current);
 	p = context->trees;
 	count = context->tree_count;
 retry:
@@ -1715,7 +1715,7 @@ static struct audit_names *audit_alloc_name(struct audit_context *context,
 struct filename *
 __audit_reusename(const __user char *uptr)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct audit_names *n;
 
 	list_for_each_entry(n, &context->names_list, list) {
@@ -1738,7 +1738,7 @@ struct filename *
  */
 void __audit_getname(struct filename *name)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct audit_names *n;
 
 	if (!context->in_syscall)
@@ -1766,7 +1766,7 @@ void __audit_getname(struct filename *name)
 void __audit_inode(struct filename *name, const struct dentry *dentry,
 		   unsigned int flags)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct inode *inode = d_backing_inode(dentry);
 	struct audit_names *n;
 	bool parent = flags & AUDIT_INODE_PARENT;
@@ -1865,7 +1865,7 @@ void __audit_inode_child(struct inode *parent,
 			 const struct dentry *dentry,
 			 const unsigned char type)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct inode *inode = d_backing_inode(dentry);
 	const char *dname = dentry->d_name.name;
 	struct audit_names *n, *found_parent = NULL, *found_child = NULL;
@@ -2084,7 +2084,7 @@ int audit_set_loginuid(kuid_t loginuid)
  */
 void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	if (attr)
 		memcpy(&context->mq_open.attr, attr, sizeof(struct mq_attr));
@@ -2108,7 +2108,7 @@ void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr)
 void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio,
 			const struct timespec64 *abs_timeout)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct timespec64 *p = &context->mq_sendrecv.abs_timeout;
 
 	if (abs_timeout)
@@ -2132,7 +2132,7 @@ void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio,
 
 void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	if (notification)
 		context->mq_notify.sigev_signo = notification->sigev_signo;
@@ -2151,7 +2151,7 @@ void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
  */
 void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	context->mq_getsetattr.mqdes = mqdes;
 	context->mq_getsetattr.mqstat = *mqstat;
 	context->type = AUDIT_MQ_GETSETATTR;
@@ -2164,7 +2164,7 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
  */
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
@@ -2184,7 +2184,7 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
  */
 void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	context->ipc.qbytes = qbytes;
 	context->ipc.perm_uid = uid;
@@ -2195,7 +2195,7 @@ void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mo
 
 void __audit_bprm(struct linux_binprm *bprm)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	context->type = AUDIT_EXECVE;
 	context->execve.argc = bprm->argc;
@@ -2210,7 +2210,7 @@ void __audit_bprm(struct linux_binprm *bprm)
  */
 int __audit_socketcall(int nargs, unsigned long *args)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	if (nargs <= 0 || nargs > AUDITSC_ARGS || !args)
 		return -EINVAL;
@@ -2228,7 +2228,7 @@ int __audit_socketcall(int nargs, unsigned long *args)
  */
 void __audit_fd_pair(int fd1, int fd2)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	context->fds[0] = fd1;
 	context->fds[1] = fd2;
 }
@@ -2242,7 +2242,7 @@ void __audit_fd_pair(int fd1, int fd2)
  */
 int __audit_sockaddr(int len, void *a)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	if (!context->sockaddr) {
 		void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);
@@ -2258,7 +2258,7 @@ int __audit_sockaddr(int len, void *a)
 
 void __audit_ptrace(struct task_struct *t)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
@@ -2280,7 +2280,7 @@ int audit_signal_info(int sig, struct task_struct *t)
 {
 	struct audit_aux_data_pids *axp;
 	struct task_struct *tsk = current;
-	struct audit_context *ctx = tsk->audit_context;
+	struct audit_context *ctx = audit_context(tsk);
 	kuid_t uid = current_uid(), t_uid = task_uid(t);
 
 	if (auditd_test_task(t) &&
@@ -2347,7 +2347,7 @@ int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
 			   const struct cred *new, const struct cred *old)
 {
 	struct audit_aux_data_bprm_fcaps *ax;
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	struct cpu_vfs_cap_data vcaps;
 
 	ax = kmalloc(sizeof(*ax), GFP_KERNEL);
@@ -2387,7 +2387,7 @@ int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
  */
 void __audit_log_capset(const struct cred *new, const struct cred *old)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	context->capset.pid = task_tgid_nr(current);
 	context->capset.cap.effective   = new->cap_effective;
 	context->capset.cap.inheritable = new->cap_effective;
@@ -2398,7 +2398,7 @@ void __audit_log_capset(const struct cred *new, const struct cred *old)
 
 void __audit_mmap_fd(int fd, int flags)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 	context->mmap.fd = fd;
 	context->mmap.flags = flags;
 	context->type = AUDIT_MMAP;
@@ -2406,7 +2406,7 @@ void __audit_mmap_fd(int fd, int flags)
 
 void __audit_log_kern_module(char *name)
 {
-	struct audit_context *context = current->audit_context;
+	struct audit_context *context = audit_context(current);
 
 	context->module.name = kmalloc(strlen(name) + 1, GFP_KERNEL);
 	strcpy(context->module.name, name);
@@ -2415,7 +2415,7 @@ void __audit_log_kern_module(char *name)
 
 void __audit_fanotify(unsigned int response)
 {
-	audit_log(current->audit_context, GFP_KERNEL,
+	audit_log(audit_context(current), GFP_KERNEL,
 		AUDIT_FANOTIFY,	"resp=%u", response);
 }
 
@@ -2482,7 +2482,7 @@ void __audit_seccomp(unsigned long syscall, long signr, int code)
 
 struct list_head *audit_killed_trees(void)
 {
-	struct audit_context *ctx = current->audit_context;
+	struct audit_context *ctx = audit_context(current);
 	if (likely(!ctx || !ctx->in_syscall))
 		return NULL;
 	return &ctx->killed_trees;
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 032e0fe..ff8450b 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1062,7 +1062,7 @@ static int do_replace_finish(struct net *net, struct ebt_replace *repl,
 
 #ifdef CONFIG_AUDIT
 	if (audit_enabled) {
-		audit_log(current->audit_context, GFP_KERNEL,
+		audit_log(audit_context(current), GFP_KERNEL,
 			  AUDIT_NETFILTER_CFG,
 			  "table=%s family=%u entries=%u",
 			  repl->name, AF_BRIDGE, repl->nentries);
diff --git a/net/core/dev.c b/net/core/dev.c
index 969462e..2837086 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6749,7 +6749,7 @@ static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify)
 			dev->flags & IFF_PROMISC ? "entered" : "left");
 		if (audit_enabled) {
 			current_uid_gid(&uid, &gid);
-			audit_log(current->audit_context, GFP_ATOMIC,
+			audit_log(audit_context(current), GFP_ATOMIC,
 				AUDIT_ANOM_PROMISCUOUS,
 				"dev=%s prom=%d old_prom=%d auid=%u uid=%u gid=%u ses=%u",
 				dev->name, (dev->flags & IFF_PROMISC),
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 71325fe..f271630 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1414,7 +1414,7 @@ struct xt_table_info *
 
 #ifdef CONFIG_AUDIT
 	if (audit_enabled) {
-		audit_log(current->audit_context, GFP_KERNEL,
+		audit_log(audit_context(current), GFP_KERNEL,
 			  AUDIT_NETFILTER_CFG,
 			  "table=%s family=%u entries=%u",
 			  table->name, table->af, private->number);
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 58495f4..6cd5573 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -104,7 +104,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 	if (audit_enabled == 0)
 		return NULL;
 
-	audit_buf = audit_log_start(current->audit_context, GFP_ATOMIC, type);
+	audit_buf = audit_log_start(audit_context(current), GFP_ATOMIC, type);
 	if (audit_buf == NULL)
 		return NULL;
 
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index bf88236..a727ae0 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -326,7 +326,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
 		hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]);
 	hash[i * 2] = '\0';
 
-	ab = audit_log_start(current->audit_context, GFP_KERNEL,
+	ab = audit_log_start(audit_context(current), GFP_KERNEL,
 			     AUDIT_INTEGRITY_RULE);
 	if (!ab)
 		goto out;
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index 90987d1..79adc98a 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -38,7 +38,7 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
 	if (!integrity_audit_info && audit_info == 1)	/* Skip info messages */
 		return;
 
-	ab = audit_log_start(current->audit_context, GFP_KERNEL, audit_msgno);
+	ab = audit_log_start(audit_context(current), GFP_KERNEL, audit_msgno);
 	audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u",
 			 task_pid_nr(current),
 			 from_kuid(&init_user_ns, current_cred()->uid),
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 67703db..ccae258 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -447,7 +447,7 @@ void common_lsm_audit(struct common_audit_data *a,
 	if (a == NULL)
 		return;
 	/* we use GFP_ATOMIC so we won't sleep */
-	ab = audit_log_start(current->audit_context, GFP_ATOMIC | __GFP_NOWARN,
+	ab = audit_log_start(audit_context(current), GFP_ATOMIC | __GFP_NOWARN,
 			     AUDIT_AVC);
 
 	if (ab == NULL)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 4cafe6a..f1de97a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3294,7 +3294,7 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
 			} else {
 				audit_size = 0;
 			}
-			ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
+			ab = audit_log_start(audit_context(current), GFP_ATOMIC, AUDIT_SELINUX_ERR);
 			audit_log_format(ab, "op=setxattr invalid_context=");
 			audit_log_n_untrustedstring(ab, value, audit_size);
 			audit_log_end(ab);
@@ -6431,7 +6431,7 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
 					audit_size = size - 1;
 				else
 					audit_size = size;
-				ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
+				ab = audit_log_start(audit_context(current), GFP_ATOMIC, AUDIT_SELINUX_ERR);
 				audit_log_format(ab, "op=fscreate invalid_context=");
 				audit_log_n_untrustedstring(ab, value, audit_size);
 				audit_log_end(ab);
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index efdc633..e5f90da 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -167,7 +167,7 @@ static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
 				      NULL);
 		if (length)
 			goto out;
-		audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
+		audit_log(audit_context(current), GFP_KERNEL, AUDIT_MAC_STATUS,
 			"enforcing=%d old_enforcing=%d auid=%u ses=%u"
 			" enabled=%d old-enabled=%d lsm=selinux res=1",
 			new_value, old_value,
@@ -303,7 +303,7 @@ static ssize_t sel_write_disable(struct file *file, const char __user *buf,
 		length = selinux_disable(fsi->state);
 		if (length)
 			goto out;
-		audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
+		audit_log(audit_context(current), GFP_KERNEL, AUDIT_MAC_STATUS,
 			"enforcing=%d old_enforcing=%d auid=%u ses=%u"
 			" enabled=%d old-enabled=%d lsm=selinux res=1",
 			enforcing, enforcing,
@@ -581,7 +581,7 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
 	length = count;
 
 out1:
-	audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
+	audit_log(audit_context(current), GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
 		"auid=%u ses=%u lsm=selinux res=1",
 		from_kuid(&init_user_ns, audit_get_loginuid(current)),
 		audit_get_sessionid(current));
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 8057e19..83f40e2 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -501,7 +501,7 @@ static void security_dump_masked_av(struct policydb *policydb,
 		goto out;
 
 	/* audit a message */
-	ab = audit_log_start(current->audit_context,
+	ab = audit_log_start(audit_context(current),
 			     GFP_ATOMIC, AUDIT_SELINUX_ERR);
 	if (!ab)
 		goto out;
@@ -743,7 +743,7 @@ static int security_validtrans_handle_fail(struct selinux_state *state,
 		goto out;
 	if (context_struct_to_string(p, tcontext, &t, &tlen))
 		goto out;
-	audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
+	audit_log(audit_context(current), GFP_ATOMIC, AUDIT_SELINUX_ERR,
 		  "op=security_validate_transition seresult=denied"
 		  " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
 		  o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
@@ -929,7 +929,7 @@ int security_bounded_transition(struct selinux_state *state,
 					      &old_name, &length) &&
 		    !context_struct_to_string(policydb, new_context,
 					      &new_name, &length)) {
-			audit_log(current->audit_context,
+			audit_log(audit_context(current),
 				  GFP_ATOMIC, AUDIT_SELINUX_ERR,
 				  "op=security_bounded_transition "
 				  "seresult=denied "
@@ -1586,7 +1586,7 @@ static int compute_sid_handle_invalid_context(
 		goto out;
 	if (context_struct_to_string(policydb, newcontext, &n, &nlen))
 		goto out;
-	audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
+	audit_log(audit_context(current), GFP_ATOMIC, AUDIT_SELINUX_ERR,
 		  "op=security_compute_sid invalid_context=%s"
 		  " scontext=%s"
 		  " tcontext=%s"
@@ -2882,7 +2882,7 @@ int security_set_bools(struct selinux_state *state, int len, int *values)
 
 	for (i = 0; i < len; i++) {
 		if (!!values[i] != policydb->bool_val_to_struct[i]->state) {
-			audit_log(current->audit_context, GFP_ATOMIC,
+			audit_log(audit_context(current), GFP_ATOMIC,
 				AUDIT_MAC_CONFIG_CHANGE,
 				"bool=%s val=%d old_val=%d auid=%u ses=%u",
 				sym_name(policydb, SYM_BOOLS, i),
@@ -3025,7 +3025,7 @@ int security_sid_mls_copy(struct selinux_state *state,
 		if (rc) {
 			if (!context_struct_to_string(policydb, &newcon, &s,
 						      &len)) {
-				audit_log(current->audit_context,
+				audit_log(audit_context(current),
 					  GFP_ATOMIC, AUDIT_SELINUX_ERR,
 					  "op=security_sid_mls_copy "
 					  "invalid_context=%s", s);
-- 
1.8.3.1

[PATCH ghak81 RFC V1 4/5] audit: use inline function to set audit context

[Richard Guy Briggs]

Recognizing that the audit context is an internal audit value, use an
access function to set the audit context pointer for the task
rather than reaching directly into the task struct to set it.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 include/linux/audit.h | 8 ++++++++
 kernel/auditsc.c      | 6 +++---
 kernel/fork.c         | 2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 93e4c61..dba0d45 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -235,6 +235,10 @@ extern void __audit_inode_child(struct inode *parent,
 extern void __audit_seccomp(unsigned long syscall, long signr, int code);
 extern void __audit_ptrace(struct task_struct *t);
 
+static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
+{
+	task->audit_context = ctx;
+}
 static inline struct audit_context *audit_context(struct task_struct *task)
 {
 	return task->audit_context;
@@ -472,6 +476,10 @@ static inline bool audit_dummy_context(void)
 {
 	return true;
 }
+static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
+{
+	task->audit_context = ctx;
+}
 static inline struct audit_context *audit_context(struct task_struct *task)
 {
 	return NULL;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index a4bbdcc..f294e4a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -865,7 +865,7 @@ static inline struct audit_context *audit_take_context(struct task_struct *tsk,
 		audit_filter_inodes(tsk, context);
 	}
 
-	tsk->audit_context = NULL;
+	audit_set_context(tsk, NULL);
 	return context;
 }
 
@@ -952,7 +952,7 @@ int audit_alloc(struct task_struct *tsk)
 	}
 	context->filterkey = key;
 
-	tsk->audit_context  = context;
+	audit_set_context(tsk, context);
 	set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 	return 0;
 }
@@ -1590,7 +1590,7 @@ void __audit_syscall_exit(int success, long return_code)
 		kfree(context->filterkey);
 		context->filterkey = NULL;
 	}
-	tsk->audit_context = context;
+	audit_set_context(tsk, context);
 }
 
 static inline void handle_one(const struct inode *inode)
diff --git a/kernel/fork.c b/kernel/fork.c
index 242c8c9..cd18448 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1713,7 +1713,7 @@ static __latent_entropy struct task_struct *copy_process(
 	p->start_time = ktime_get_ns();
 	p->real_start_time = ktime_get_boot_ns();
 	p->io_context = NULL;
-	p->audit_context = NULL;
+	audit_set_context(p, NULL);
 	cgroup_fork(p);
 #ifdef CONFIG_NUMA
 	p->mempolicy = mpol_dup(p->mempolicy);
-- 
1.8.3.1

[PATCH ghak81 RFC V1 5/5] audit: collect audit task parameters

[Richard Guy Briggs]

The audit-related parameters in struct task_struct should ideally be
collected together and accessed through a standard audit API.

Collect the existing loginuid, sessionid and audit_context together in a
new struct audit_task_info pointer called "audit" in struct task_struct.

Use kmem_cache to manage this pool of memory.
Un-inline audit_free() to be able to always recover that memory.

See: https://github.com/linux-audit/audit-kernel/issues/81

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 MAINTAINERS                |  2 +-
 include/linux/audit.h      |  8 ++++----
 include/linux/audit_task.h | 31 +++++++++++++++++++++++++++++++
 include/linux/sched.h      |  6 ++----
 init/init_task.c           |  8 ++++++--
 kernel/auditsc.c           |  4 ++--
 6 files changed, 46 insertions(+), 13 deletions(-)
 create mode 100644 include/linux/audit_task.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 0a1410d..8c7992d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2510,7 +2510,7 @@ L:	linux-audit@redhat.com (moderated for non-subscribers)
 W:	https://github.com/linux-audit
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git
 S:	Supported
-F:	include/linux/audit.h
+F:	include/linux/audit*.h
 F:	include/uapi/linux/audit.h
 F:	kernel/audit*
 
diff --git a/include/linux/audit.h b/include/linux/audit.h
index dba0d45..1324969 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -237,11 +237,11 @@ extern void __audit_inode_child(struct inode *parent,
 
 static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
 {
-	task->audit_context = ctx;
+	task->audit.ctx = ctx;
 }
 static inline struct audit_context *audit_context(struct task_struct *task)
 {
-	return task->audit_context;
+	return task->audit.ctx;
 }
 static inline bool audit_dummy_context(void)
 {
@@ -330,12 +330,12 @@ extern int auditsc_get_stamp(struct audit_context *ctx,
 
 static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
 {
-	return tsk->loginuid;
+	return tsk->audit.loginuid;
 }
 
 static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 {
-	return tsk->sessionid;
+	return tsk->audit.sessionid;
 }
 
 extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
diff --git a/include/linux/audit_task.h b/include/linux/audit_task.h
new file mode 100644
index 0000000..d4b3a20
--- /dev/null
+++ b/include/linux/audit_task.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* audit_task.h -- definition of audit_task_info structure
+ *
+ * Copyright 2018 Red Hat Inc., Raleigh, North Carolina.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by Richard Guy Briggs <rgb@redhat.com>
+ *
+ */
+
+#ifndef _LINUX_AUDIT_TASK_H_
+#define _LINUX_AUDIT_TASK_H_
+
+struct audit_context;
+struct audit_task_info {
+	kuid_t			loginuid;
+	unsigned int		sessionid;
+	struct audit_context	*ctx;
+};
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b3d697f..b58eca0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -27,9 +27,9 @@
 #include <linux/signal_types.h>
 #include <linux/mm_types_task.h>
 #include <linux/task_io_accounting.h>
+#include <linux/audit_task.h>
 
 /* task_struct member predeclarations (sorted alphabetically): */
-struct audit_context;
 struct backing_dev_info;
 struct bio_list;
 struct blk_plug;
@@ -832,10 +832,8 @@ struct task_struct {
 
 	struct callback_head		*task_works;
 
-	struct audit_context		*audit_context;
 #ifdef CONFIG_AUDITSYSCALL
-	kuid_t				loginuid;
-	unsigned int			sessionid;
+	struct audit_task_info		audit;
 #endif
 	struct seccomp			seccomp;
 
diff --git a/init/init_task.c b/init/init_task.c
index c788f91..d33260d 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/audit.h>
 
 #include <asm/pgtable.h>
 #include <linux/uaccess.h>
@@ -118,8 +119,11 @@ struct task_struct init_task
 	.thread_group	= LIST_HEAD_INIT(init_task.thread_group),
 	.thread_node	= LIST_HEAD_INIT(init_signals.thread_head),
 #ifdef CONFIG_AUDITSYSCALL
-	.loginuid	= INVALID_UID,
-	.sessionid	= AUDIT_SID_UNSET,
+	.audit		= {
+		.loginuid	= INVALID_UID,
+		.sessionid	= AUDIT_SID_UNSET,
+		.ctx		= NULL,
+	},
 #endif
 #ifdef CONFIG_PERF_EVENTS
 	.perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index f294e4a..b5d8bff 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2068,8 +2068,8 @@ int audit_set_loginuid(kuid_t loginuid)
 			sessionid = (unsigned int)atomic_inc_return(&session_id);
 	}
 
-	task->sessionid = sessionid;
-	task->loginuid = loginuid;
+	task->audit.sessionid = sessionid;
+	task->audit.loginuid = loginuid;
 out:
 	audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
 	return rc;
-- 
1.8.3.1

Re: [PATCH ghak81 RFC V1 2/5] audit: convert sessionid unset to a macro

[Richard Guy Briggs]

On 2018-05-04 16:54, Richard Guy Briggs wrote:
> Use a macro, "AUDIT_SID_UNSET", to replace each instance of
> initialization and comparison to an audit session ID.
> 
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>

There's a minor issue with this patch, adding a header include to
init/init_task.c in this patch and removing it from patch 5.  That'll be
in the next revision.

I have dynamic allocation working, so that has a good chance of
appearing  too.

> ---
>  include/linux/audit.h      | 2 +-
>  include/net/xfrm.h         | 2 +-
>  include/uapi/linux/audit.h | 1 +
>  init/init_task.c           | 2 +-
>  kernel/auditsc.c           | 4 ++--
>  5 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 75d5b03..5f86f7c 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -513,7 +513,7 @@ static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
>  }
>  static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
>  {
> -	return -1;
> +	return AUDIT_SID_UNSET;
>  }
>  static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
>  { }
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index a872379..fcce8ee 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -751,7 +751,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
>  					    audit_get_loginuid(current) :
>  					    INVALID_UID);
>  	const unsigned int ses = task_valid ? audit_get_sessionid(current) :
> -		(unsigned int) -1;
> +		AUDIT_SID_UNSET;
>  
>  	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
>  	audit_log_task_context(audit_buf);
> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index 4e61a9e..04f9bd2 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -465,6 +465,7 @@ struct audit_tty_status {
>  };
>  
>  #define AUDIT_UID_UNSET (unsigned int)-1
> +#define AUDIT_SID_UNSET ((unsigned int)-1)
>  
>  /* audit_rule_data supports filter rules with both integer and string
>   * fields.  It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and
> diff --git a/init/init_task.c b/init/init_task.c
> index 3ac6e75..c788f91 100644
> --- a/init/init_task.c
> +++ b/init/init_task.c
> @@ -119,7 +119,7 @@ struct task_struct init_task
>  	.thread_node	= LIST_HEAD_INIT(init_signals.thread_head),
>  #ifdef CONFIG_AUDITSYSCALL
>  	.loginuid	= INVALID_UID,
> -	.sessionid	= (unsigned int)-1,
> +	.sessionid	= AUDIT_SID_UNSET,
>  #endif
>  #ifdef CONFIG_PERF_EVENTS
>  	.perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index f3817d0..6e3ceb9 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2050,7 +2050,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
>  int audit_set_loginuid(kuid_t loginuid)
>  {
>  	struct task_struct *task = current;
> -	unsigned int oldsessionid, sessionid = (unsigned int)-1;
> +	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
>  	kuid_t oldloginuid;
>  	int rc;
>  
> @@ -2064,7 +2064,7 @@ int audit_set_loginuid(kuid_t loginuid)
>  	/* are we setting or clearing? */
>  	if (uid_valid(loginuid)) {
>  		sessionid = (unsigned int)atomic_inc_return(&session_id);
> -		if (unlikely(sessionid == (unsigned int)-1))
> +		if (unlikely(sessionid == AUDIT_SID_UNSET))
>  			sessionid = (unsigned int)atomic_inc_return(&session_id);
>  	}
>  
> -- 
> 1.8.3.1
> 
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH ghak81 RFC V1 4/5] audit: use inline function to set audit context

[Tobin C. Harding]

On Fri, May 04, 2018 at 04:54:37PM -0400, Richard Guy Briggs wrote:
> Recognizing that the audit context is an internal audit value, use an
> access function to set the audit context pointer for the task
> rather than reaching directly into the task struct to set it.
> 
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  include/linux/audit.h | 8 ++++++++
>  kernel/auditsc.c      | 6 +++---
>  kernel/fork.c         | 2 +-
>  3 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 93e4c61..dba0d45 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -235,6 +235,10 @@ extern void __audit_inode_child(struct inode *parent,
>  extern void __audit_seccomp(unsigned long syscall, long signr, int code);
>  extern void __audit_ptrace(struct task_struct *t);
>  
> +static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
> +{
> +	task->audit_context = ctx;
> +}
>  static inline struct audit_context *audit_context(struct task_struct *task)
>  {
>  	return task->audit_context;
> @@ -472,6 +476,10 @@ static inline bool audit_dummy_context(void)
>  {
>  	return true;
>  }
> +static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
> +{
> +	task->audit_context = ctx;
> +}

If audit_context is an internal audit value why do we set it when
CONFIG_AUDITSYSCALL is not set?

thanks,
Tobin.

Re: [PATCH ghak81 RFC V1 4/5] audit: use inline function to set audit context

[Richard Guy Briggs]

On 2018-05-09 12:07, Tobin C. Harding wrote:
> On Fri, May 04, 2018 at 04:54:37PM -0400, Richard Guy Briggs wrote:
> > Recognizing that the audit context is an internal audit value, use an
> > access function to set the audit context pointer for the task
> > rather than reaching directly into the task struct to set it.
> > 
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> >  include/linux/audit.h | 8 ++++++++
> >  kernel/auditsc.c      | 6 +++---
> >  kernel/fork.c         | 2 +-
> >  3 files changed, 12 insertions(+), 4 deletions(-)
> > 
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index 93e4c61..dba0d45 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -235,6 +235,10 @@ extern void __audit_inode_child(struct inode *parent,
> >  extern void __audit_seccomp(unsigned long syscall, long signr, int code);
> >  extern void __audit_ptrace(struct task_struct *t);
> >  
> > +static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
> > +{
> > +	task->audit_context = ctx;
> > +}
> >  static inline struct audit_context *audit_context(struct task_struct *task)
> >  {
> >  	return task->audit_context;
> > @@ -472,6 +476,10 @@ static inline bool audit_dummy_context(void)
> >  {
> >  	return true;
> >  }
> > +static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
> > +{
> > +	task->audit_context = ctx;
> > +}
> 
> If audit_context is an internal audit value why do we set it when
> CONFIG_AUDITSYSCALL is not set?

Agreed, that is unnecessary, but harmless since it won't be called, or
will be called with a value of NULL.  That has been fixed in my dynamic
allocation patchset since not even the audit_task_info struct is
available to assign the value.  It is now an empty function like the
rest.

> Tobin.

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH ghak81 RFC V1 1/5] audit: normalize loginuid read access

[Paul Moore]

On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> Recognizing that the loginuid is an internal audit value, use an access
> function to retrieve the audit loginuid value for the task rather than
> reaching directly into the task struct to get it.
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  kernel/auditsc.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 479c031..f3817d0 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -374,7 +374,7 @@ static int audit_field_compare(struct task_struct *tsk,
>         case AUDIT_COMPARE_EGID_TO_OBJ_GID:
>                 return audit_compare_gid(cred->egid, name, f, ctx);
>         case AUDIT_COMPARE_AUID_TO_OBJ_UID:
> -               return audit_compare_uid(tsk->loginuid, name, f, ctx);
> +               return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
>         case AUDIT_COMPARE_SUID_TO_OBJ_UID:
>                 return audit_compare_uid(cred->suid, name, f, ctx);
>         case AUDIT_COMPARE_SGID_TO_OBJ_GID:
> @@ -385,7 +385,7 @@ static int audit_field_compare(struct task_struct *tsk,
>                 return audit_compare_gid(cred->fsgid, name, f, ctx);
>         /* uid comparisons */
>         case AUDIT_COMPARE_UID_TO_AUID:
> -               return audit_uid_comparator(cred->uid, f->op, tsk->loginuid);
> +               return audit_uid_comparator(cred->uid, f->op, audit_get_loginuid(tsk));
>         case AUDIT_COMPARE_UID_TO_EUID:
>                 return audit_uid_comparator(cred->uid, f->op, cred->euid);
>         case AUDIT_COMPARE_UID_TO_SUID:
> @@ -394,11 +394,11 @@ static int audit_field_compare(struct task_struct *tsk,
>                 return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
>         /* auid comparisons */
>         case AUDIT_COMPARE_AUID_TO_EUID:
> -               return audit_uid_comparator(tsk->loginuid, f->op, cred->euid);
> +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->euid);
>         case AUDIT_COMPARE_AUID_TO_SUID:
> -               return audit_uid_comparator(tsk->loginuid, f->op, cred->suid);
> +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->suid);
>         case AUDIT_COMPARE_AUID_TO_FSUID:
> -               return audit_uid_comparator(tsk->loginuid, f->op, cred->fsuid);
> +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->fsuid);
>         /* euid comparisons */
>         case AUDIT_COMPARE_EUID_TO_SUID:
>                 return audit_uid_comparator(cred->euid, f->op, cred->suid);
> @@ -611,7 +611,7 @@ static int audit_filter_rules(struct task_struct *tsk,
>                                 result = match_tree_refs(ctx, rule->tree);
>                         break;
>                 case AUDIT_LOGINUID:
> -                       result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
> +                       result = audit_uid_comparator(audit_get_loginuid(tsk), f->op, f->uid);
>                         break;
>                 case AUDIT_LOGINUID_SET:
>                         result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
> @@ -2287,8 +2287,8 @@ int audit_signal_info(int sig, struct task_struct *t)
>             (sig == SIGTERM || sig == SIGHUP ||
>              sig == SIGUSR1 || sig == SIGUSR2)) {
>                 audit_sig_pid = task_tgid_nr(tsk);
> -               if (uid_valid(tsk->loginuid))
> -                       audit_sig_uid = tsk->loginuid;
> +               if (uid_valid(audit_get_loginuid(tsk)))
> +                       audit_sig_uid = audit_get_loginuid(tsk);

I realize this comment is a little silly given the nature of loginuid,
but if we are going to abstract away loginuid accesses (which I think
is good), we should probably access it once, store it in a local
variable, perform the validity check on the local variable, then
commit the local variable to audit_sig_uid.  I realize a TOCTOU
problem is unlikely here, but with this new layer of abstraction it
seems that some additional safety might be a good thing.

>                 else
>                         audit_sig_uid = uid;
>                 security_task_getsecid(tsk, &audit_sig_sid);
> --
> 1.8.3.1

-- 
paul moore
www.paul-moore.com

Re: [PATCH ghak81 RFC V1 2/5] audit: convert sessionid unset to a macro

[Paul Moore]

On Tue, May 8, 2018 at 9:34 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-05-04 16:54, Richard Guy Briggs wrote:
>> Use a macro, "AUDIT_SID_UNSET", to replace each instance of
>> initialization and comparison to an audit session ID.
>>
>> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
>
> There's a minor issue with this patch, adding a header include to
> init/init_task.c in this patch and removing it from patch 5.  That'll be
> in the next revision.

Okay, thanks for the heads-up.  FWIW, this patch looks reasonable in
principle; changing magic numbers to macros/constants is almost always
a step in the right direction.

> I have dynamic allocation working, so that has a good chance of
> appearing  too.

I'll comment on that in your patch 0, I just want to get through the
rest of the patches first.

>> ---
>>  include/linux/audit.h      | 2 +-
>>  include/net/xfrm.h         | 2 +-
>>  include/uapi/linux/audit.h | 1 +
>>  init/init_task.c           | 2 +-
>>  kernel/auditsc.c           | 4 ++--
>>  5 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/audit.h b/include/linux/audit.h
>> index 75d5b03..5f86f7c 100644
>> --- a/include/linux/audit.h
>> +++ b/include/linux/audit.h
>> @@ -513,7 +513,7 @@ static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
>>  }
>>  static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
>>  {
>> -     return -1;
>> +     return AUDIT_SID_UNSET;
>>  }
>>  static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
>>  { }
>> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
>> index a872379..fcce8ee 100644
>> --- a/include/net/xfrm.h
>> +++ b/include/net/xfrm.h
>> @@ -751,7 +751,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
>>                                           audit_get_loginuid(current) :
>>                                           INVALID_UID);
>>       const unsigned int ses = task_valid ? audit_get_sessionid(current) :
>> -             (unsigned int) -1;
>> +             AUDIT_SID_UNSET;
>>
>>       audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
>>       audit_log_task_context(audit_buf);
>> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
>> index 4e61a9e..04f9bd2 100644
>> --- a/include/uapi/linux/audit.h
>> +++ b/include/uapi/linux/audit.h
>> @@ -465,6 +465,7 @@ struct audit_tty_status {
>>  };
>>
>>  #define AUDIT_UID_UNSET (unsigned int)-1
>> +#define AUDIT_SID_UNSET ((unsigned int)-1)
>>
>>  /* audit_rule_data supports filter rules with both integer and string
>>   * fields.  It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and
>> diff --git a/init/init_task.c b/init/init_task.c
>> index 3ac6e75..c788f91 100644
>> --- a/init/init_task.c
>> +++ b/init/init_task.c
>> @@ -119,7 +119,7 @@ struct task_struct init_task
>>       .thread_node    = LIST_HEAD_INIT(init_signals.thread_head),
>>  #ifdef CONFIG_AUDITSYSCALL
>>       .loginuid       = INVALID_UID,
>> -     .sessionid      = (unsigned int)-1,
>> +     .sessionid      = AUDIT_SID_UNSET,
>>  #endif
>>  #ifdef CONFIG_PERF_EVENTS
>>       .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
>> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
>> index f3817d0..6e3ceb9 100644
>> --- a/kernel/auditsc.c
>> +++ b/kernel/auditsc.c
>> @@ -2050,7 +2050,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
>>  int audit_set_loginuid(kuid_t loginuid)
>>  {
>>       struct task_struct *task = current;
>> -     unsigned int oldsessionid, sessionid = (unsigned int)-1;
>> +     unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
>>       kuid_t oldloginuid;
>>       int rc;
>>
>> @@ -2064,7 +2064,7 @@ int audit_set_loginuid(kuid_t loginuid)
>>       /* are we setting or clearing? */
>>       if (uid_valid(loginuid)) {
>>               sessionid = (unsigned int)atomic_inc_return(&session_id);
>> -             if (unlikely(sessionid == (unsigned int)-1))
>> +             if (unlikely(sessionid == AUDIT_SID_UNSET))
>>                       sessionid = (unsigned int)atomic_inc_return(&session_id);
>>       }
>>
>> --
>> 1.8.3.1
>>
>> --
>> Linux-audit mailing list
>> Linux-audit@redhat.com
>> https://www.redhat.com/mailman/listinfo/linux-audit
>
> - RGB
>
> --
> Richard Guy Briggs <rgb@redhat.com>
> Sr. S/W Engineer, Kernel Security, Base Operating Systems
> Remote, Ottawa, Red Hat Canada
> IRC: rgb, SunRaycer
> Voice: +1.647.777.2635, Internal: (81) 32635
>
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit



-- 
paul moore
www.paul-moore.com

Re: [PATCH ghak81 RFC V1 3/5] audit: use inline function to get audit context

[Paul Moore]

On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> Recognizing that the audit context is an internal audit value, use an
> access function to retrieve the audit context pointer for the task
> rather than reaching directly into the task struct to get it.
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  include/linux/audit.h                | 16 ++++++++---
>  include/net/xfrm.h                   |  2 +-
>  kernel/audit.c                       |  4 +--
>  kernel/audit_watch.c                 |  2 +-
>  kernel/auditsc.c                     | 52 ++++++++++++++++++------------------
>  net/bridge/netfilter/ebtables.c      |  2 +-
>  net/core/dev.c                       |  2 +-
>  net/netfilter/x_tables.c             |  2 +-
>  net/netlabel/netlabel_user.c         |  2 +-
>  security/integrity/ima/ima_api.c     |  2 +-
>  security/integrity/integrity_audit.c |  2 +-
>  security/lsm_audit.c                 |  2 +-
>  security/selinux/hooks.c             |  4 +--
>  security/selinux/selinuxfs.c         |  6 ++---
>  security/selinux/ss/services.c       | 12 ++++-----
>  15 files changed, 60 insertions(+), 52 deletions(-)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 5f86f7c..93e4c61 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -235,26 +235,30 @@ extern void __audit_inode_child(struct inode *parent,
>  extern void __audit_seccomp(unsigned long syscall, long signr, int code);
>  extern void __audit_ptrace(struct task_struct *t);
>
> +static inline struct audit_context *audit_context(struct task_struct *task)
> +{
> +       return task->audit_context;
> +}

Another case where I think I agree with everything here on principle,
especially when one considers it in the larger context of the audit
container ID work.  However, I think we might be able to somply this a
bit by eliminating the parameter to the new audit_context() helper and
making it always reference the current task_struct.  Based on this
patch it would appear that this change would work for all callers
except for audit_take_context() and __audit_syscall_entry(), both of
which are contained within the core audit code and are enough of a
special case that I think it is acceptable for them to access the
context directly.  I'm trying to think of reasons why a non-audit
kernel subsystem would ever need to access the audit context of a
process other than current and I can't think of any ... removing the
task_struct pointer might help prevent mistakes/abuse in the future.

> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 6e3ceb9..a4bbdcc 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -836,7 +836,7 @@ static inline struct audit_context *audit_take_context(struct task_struct *tsk,
>                                                       int return_valid,
>                                                       long return_code)
>  {
> -       struct audit_context *context = tsk->audit_context;
> +       struct audit_context *context = audit_context(tsk);
>
>         if (!context)
>                 return NULL;
> @@ -1510,7 +1510,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
>                            unsigned long a3, unsigned long a4)
>  {
>         struct task_struct *tsk = current;
> -       struct audit_context *context = tsk->audit_context;
> +       struct audit_context *context = audit_context(tsk);
>         enum audit_state     state;
>
>         if (!audit_enabled || !context)

-- 
paul moore
www.paul-moore.com

Re: [PATCH ghak81 RFC V1 5/5] audit: collect audit task parameters

[Paul Moore]

On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> The audit-related parameters in struct task_struct should ideally be
> collected together and accessed through a standard audit API.
>
> Collect the existing loginuid, sessionid and audit_context together in a
> new struct audit_task_info pointer called "audit" in struct task_struct.
>
> Use kmem_cache to manage this pool of memory.
> Un-inline audit_free() to be able to always recover that memory.
>
> See: https://github.com/linux-audit/audit-kernel/issues/81
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  MAINTAINERS                |  2 +-
>  include/linux/audit.h      |  8 ++++----
>  include/linux/audit_task.h | 31 +++++++++++++++++++++++++++++++
>  include/linux/sched.h      |  6 ++----
>  init/init_task.c           |  8 ++++++--
>  kernel/auditsc.c           |  4 ++--
>  6 files changed, 46 insertions(+), 13 deletions(-)
>  create mode 100644 include/linux/audit_task.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0a1410d..8c7992d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2510,7 +2510,7 @@ L:        linux-audit@redhat.com (moderated for non-subscribers)
>  W:     https://github.com/linux-audit
>  T:     git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git
>  S:     Supported
> -F:     include/linux/audit.h
> +F:     include/linux/audit*.h
>  F:     include/uapi/linux/audit.h
>  F:     kernel/audit*
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index dba0d45..1324969 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -237,11 +237,11 @@ extern void __audit_inode_child(struct inode *parent,
>
>  static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
>  {
> -       task->audit_context = ctx;
> +       task->audit.ctx = ctx;
>  }
>  static inline struct audit_context *audit_context(struct task_struct *task)
>  {
> -       return task->audit_context;
> +       return task->audit.ctx;
>  }
>  static inline bool audit_dummy_context(void)
>  {
> @@ -330,12 +330,12 @@ extern int auditsc_get_stamp(struct audit_context *ctx,
>
>  static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
>  {
> -       return tsk->loginuid;
> +       return tsk->audit.loginuid;
>  }
>
>  static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
>  {
> -       return tsk->sessionid;
> +       return tsk->audit.sessionid;
>  }
>
>  extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
> diff --git a/include/linux/audit_task.h b/include/linux/audit_task.h
> new file mode 100644
> index 0000000..d4b3a20
> --- /dev/null
> +++ b/include/linux/audit_task.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* audit_task.h -- definition of audit_task_info structure
> + *
> + * Copyright 2018 Red Hat Inc., Raleigh, North Carolina.
> + * All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * Written by Richard Guy Briggs <rgb@redhat.com>
> + *
> + */
> +
> +#ifndef _LINUX_AUDIT_TASK_H_
> +#define _LINUX_AUDIT_TASK_H_
> +
> +struct audit_context;
> +struct audit_task_info {
> +       kuid_t                  loginuid;
> +       unsigned int            sessionid;
> +       struct audit_context    *ctx;
> +};
> +
> +#endif
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index b3d697f..b58eca0 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -27,9 +27,9 @@
>  #include <linux/signal_types.h>
>  #include <linux/mm_types_task.h>
>  #include <linux/task_io_accounting.h>
> +#include <linux/audit_task.h>
>
>  /* task_struct member predeclarations (sorted alphabetically): */
> -struct audit_context;
>  struct backing_dev_info;
>  struct bio_list;
>  struct blk_plug;
> @@ -832,10 +832,8 @@ struct task_struct {
>
>         struct callback_head            *task_works;
>
> -       struct audit_context            *audit_context;
>  #ifdef CONFIG_AUDITSYSCALL
> -       kuid_t                          loginuid;
> -       unsigned int                    sessionid;
> +       struct audit_task_info          audit;
>  #endif

Considering that the audit_context pointer is now in the
audit_task_info struct, should the audit_task_info struct be placed
outside the CONFIG_AUDITSYSCALL protections?  Or rather, shouldn't the
CONFIG_AUDITSYSCALL protections be moved inside audit_task_info or
removed entirely?

> diff --git a/init/init_task.c b/init/init_task.c
> index c788f91..d33260d 100644
> --- a/init/init_task.c
> +++ b/init/init_task.c
> @@ -9,6 +9,7 @@
>  #include <linux/init.h>
>  #include <linux/fs.h>
>  #include <linux/mm.h>
> +#include <linux/audit.h>
>
>  #include <asm/pgtable.h>
>  #include <linux/uaccess.h>
> @@ -118,8 +119,11 @@ struct task_struct init_task
>         .thread_group   = LIST_HEAD_INIT(init_task.thread_group),
>         .thread_node    = LIST_HEAD_INIT(init_signals.thread_head),
>  #ifdef CONFIG_AUDITSYSCALL
> -       .loginuid       = INVALID_UID,
> -       .sessionid      = AUDIT_SID_UNSET,
> +       .audit          = {
> +               .loginuid       = INVALID_UID,
> +               .sessionid      = AUDIT_SID_UNSET,
> +               .ctx            = NULL,
> +       },
>  #endif
>  #ifdef CONFIG_PERF_EVENTS
>         .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index f294e4a..b5d8bff 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2068,8 +2068,8 @@ int audit_set_loginuid(kuid_t loginuid)
>                         sessionid = (unsigned int)atomic_inc_return(&session_id);
>         }
>
> -       task->sessionid = sessionid;
> -       task->loginuid = loginuid;
> +       task->audit.sessionid = sessionid;
> +       task->audit.loginuid = loginuid;
>  out:
>         audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
>         return rc;
> --
> 1.8.3.1

-- 
paul moore
www.paul-moore.com

Re: [PATCH ghak81 RFC V1 0/5] audit: group task params

[Paul Moore]

On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> Group the audit parameters for each task into one structure.
> In particular, remove the loginuid and sessionid values and the audit
> context pointer from the task structure, replacing them with an audit
> task information structure to contain them.  Use access functions to
> access audit values.
>
> Note:  Use static allocation of the audit task information structure
> initially.  Dynamic allocation was considered and attempted, but isn't
> ready yet.  Static allocation has the limitation that future audit task
> information structure changes would cause a visible change to the rest
> of the kernel, whereas dynamic allocation would mostly hide any future
> changes.
>
> The first four access normalization patches could stand alone.

I agree that the first four patches have some standalone value, and
since we are currently at -rc4, did you want to post another patchset
of just those four patches with feedback incorporated?  I imagine that
should be quick work, and that way they aren't help up with any
problems/discussion regarding the take_struct changes.

> Passes audit-testsuite.
>
> Richard Guy Briggs (5):
>   audit: normalize loginuid read access
>   audit: convert sessionid unset to a macro
>   audit: use inline function to get audit context
>   audit: use inline function to set audit context
>   audit: collect audit task parameters
>
>  MAINTAINERS                          |  2 +-
>  include/linux/audit.h                | 30 ++++++++++---
>  include/linux/audit_task.h           | 31 ++++++++++++++
>  include/linux/sched.h                |  6 +--
>  include/net/xfrm.h                   |  4 +-
>  include/uapi/linux/audit.h           |  1 +
>  init/init_task.c                     |  8 +++-
>  kernel/audit.c                       |  4 +-
>  kernel/audit_watch.c                 |  2 +-
>  kernel/auditsc.c                     | 82 ++++++++++++++++++------------------
>  kernel/fork.c                        |  2 +-
>  net/bridge/netfilter/ebtables.c      |  2 +-
>  net/core/dev.c                       |  2 +-
>  net/netfilter/x_tables.c             |  2 +-
>  net/netlabel/netlabel_user.c         |  2 +-
>  security/integrity/ima/ima_api.c     |  2 +-
>  security/integrity/integrity_audit.c |  2 +-
>  security/lsm_audit.c                 |  2 +-
>  security/selinux/hooks.c             |  4 +-
>  security/selinux/selinuxfs.c         |  6 +--
>  security/selinux/ss/services.c       | 12 +++---
>  21 files changed, 129 insertions(+), 79 deletions(-)
>  create mode 100644 include/linux/audit_task.h
>
> --
> 1.8.3.1
>



-- 
paul moore
www.paul-moore.com

Re: [PATCH ghak81 RFC V1 3/5] audit: use inline function to get audit context

[Richard Guy Briggs]

On 2018-05-09 11:28, Paul Moore wrote:
> On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > Recognizing that the audit context is an internal audit value, use an
> > access function to retrieve the audit context pointer for the task
> > rather than reaching directly into the task struct to get it.
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> >  include/linux/audit.h                | 16 ++++++++---
> >  include/net/xfrm.h                   |  2 +-
> >  kernel/audit.c                       |  4 +--
> >  kernel/audit_watch.c                 |  2 +-
> >  kernel/auditsc.c                     | 52 ++++++++++++++++++------------------
> >  net/bridge/netfilter/ebtables.c      |  2 +-
> >  net/core/dev.c                       |  2 +-
> >  net/netfilter/x_tables.c             |  2 +-
> >  net/netlabel/netlabel_user.c         |  2 +-
> >  security/integrity/ima/ima_api.c     |  2 +-
> >  security/integrity/integrity_audit.c |  2 +-
> >  security/lsm_audit.c                 |  2 +-
> >  security/selinux/hooks.c             |  4 +--
> >  security/selinux/selinuxfs.c         |  6 ++---
> >  security/selinux/ss/services.c       | 12 ++++-----
> >  15 files changed, 60 insertions(+), 52 deletions(-)
> >
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index 5f86f7c..93e4c61 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -235,26 +235,30 @@ extern void __audit_inode_child(struct inode *parent,
> >  extern void __audit_seccomp(unsigned long syscall, long signr, int code);
> >  extern void __audit_ptrace(struct task_struct *t);
> >
> > +static inline struct audit_context *audit_context(struct task_struct *task)
> > +{
> > +       return task->audit_context;
> > +}
> 
> Another case where I think I agree with everything here on principle,
> especially when one considers it in the larger context of the audit
> container ID work.  However, I think we might be able to somply this a
> bit by eliminating the parameter to the new audit_context() helper and
> making it always reference the current task_struct.  Based on this
> patch it would appear that this change would work for all callers
> except for audit_take_context() and __audit_syscall_entry(), both of
> which are contained within the core audit code and are enough of a
> special case that I think it is acceptable for them to access the
> context directly.  I'm trying to think of reasons why a non-audit
> kernel subsystem would ever need to access the audit context of a
> process other than current and I can't think of any ... removing the
> task_struct pointer might help prevent mistakes/abuse in the future.

As for __audit_syscall_{entry,exit}() and audit_signal_info(), they are
using current.  current is assigned to local variable tsk only to be
used as the LHS in assignments and for locking.

But, audit_take_context() and audit_log_exit() are both called also from
__audit_free() which can have non-current handed to it by copy_process()
cleaning up, while do_exit() appears to still be in current.

So, Ok, ditch the parameter to audit_context() and use local access when
needed.

> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 6e3ceb9..a4bbdcc 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -836,7 +836,7 @@ static inline struct audit_context *audit_take_context(struct task_struct *tsk,
> >                                                       int return_valid,
> >                                                       long return_code)
> >  {
> > -       struct audit_context *context = tsk->audit_context;
> > +       struct audit_context *context = audit_context(tsk);
> >
> >         if (!context)
> >                 return NULL;
> > @@ -1510,7 +1510,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
> >                            unsigned long a3, unsigned long a4)
> >  {
> >         struct task_struct *tsk = current;
> > -       struct audit_context *context = tsk->audit_context;
> > +       struct audit_context *context = audit_context(tsk);
> >         enum audit_state     state;
> >
> >         if (!audit_enabled || !context)
> 
> -- 
> paul moore
> www.paul-moore.com

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH ghak81 RFC V1 1/5] audit: normalize loginuid read access

[Richard Guy Briggs]

On 2018-05-09 11:13, Paul Moore wrote:
> On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > Recognizing that the loginuid is an internal audit value, use an access
> > function to retrieve the audit loginuid value for the task rather than
> > reaching directly into the task struct to get it.
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> >  kernel/auditsc.c | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 479c031..f3817d0 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -374,7 +374,7 @@ static int audit_field_compare(struct task_struct *tsk,
> >         case AUDIT_COMPARE_EGID_TO_OBJ_GID:
> >                 return audit_compare_gid(cred->egid, name, f, ctx);
> >         case AUDIT_COMPARE_AUID_TO_OBJ_UID:
> > -               return audit_compare_uid(tsk->loginuid, name, f, ctx);
> > +               return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
> >         case AUDIT_COMPARE_SUID_TO_OBJ_UID:
> >                 return audit_compare_uid(cred->suid, name, f, ctx);
> >         case AUDIT_COMPARE_SGID_TO_OBJ_GID:
> > @@ -385,7 +385,7 @@ static int audit_field_compare(struct task_struct *tsk,
> >                 return audit_compare_gid(cred->fsgid, name, f, ctx);
> >         /* uid comparisons */
> >         case AUDIT_COMPARE_UID_TO_AUID:
> > -               return audit_uid_comparator(cred->uid, f->op, tsk->loginuid);
> > +               return audit_uid_comparator(cred->uid, f->op, audit_get_loginuid(tsk));
> >         case AUDIT_COMPARE_UID_TO_EUID:
> >                 return audit_uid_comparator(cred->uid, f->op, cred->euid);
> >         case AUDIT_COMPARE_UID_TO_SUID:
> > @@ -394,11 +394,11 @@ static int audit_field_compare(struct task_struct *tsk,
> >                 return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
> >         /* auid comparisons */
> >         case AUDIT_COMPARE_AUID_TO_EUID:
> > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->euid);
> > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->euid);
> >         case AUDIT_COMPARE_AUID_TO_SUID:
> > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->suid);
> > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->suid);
> >         case AUDIT_COMPARE_AUID_TO_FSUID:
> > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->fsuid);
> > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->fsuid);
> >         /* euid comparisons */
> >         case AUDIT_COMPARE_EUID_TO_SUID:
> >                 return audit_uid_comparator(cred->euid, f->op, cred->suid);
> > @@ -611,7 +611,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> >                                 result = match_tree_refs(ctx, rule->tree);
> >                         break;
> >                 case AUDIT_LOGINUID:
> > -                       result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
> > +                       result = audit_uid_comparator(audit_get_loginuid(tsk), f->op, f->uid);
> >                         break;
> >                 case AUDIT_LOGINUID_SET:
> >                         result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
> > @@ -2287,8 +2287,8 @@ int audit_signal_info(int sig, struct task_struct *t)
> >             (sig == SIGTERM || sig == SIGHUP ||
> >              sig == SIGUSR1 || sig == SIGUSR2)) {
> >                 audit_sig_pid = task_tgid_nr(tsk);
> > -               if (uid_valid(tsk->loginuid))
> > -                       audit_sig_uid = tsk->loginuid;
> > +               if (uid_valid(audit_get_loginuid(tsk)))
> > +                       audit_sig_uid = audit_get_loginuid(tsk);
> 
> I realize this comment is a little silly given the nature of loginuid,
> but if we are going to abstract away loginuid accesses (which I think
> is good), we should probably access it once, store it in a local
> variable, perform the validity check on the local variable, then
> commit the local variable to audit_sig_uid.  I realize a TOCTOU
> problem is unlikely here, but with this new layer of abstraction it
> seems that some additional safety might be a good thing.

Ok, I'll just assign it to where it is going and check it there, holding
the audit_ctl_lock the whole time, since it should have been done
anyways for all of audit_sig_{pid,uid,sid} anyways to get a consistent
view from the AUDIT_SIGNAL_INFO fetch.

> >                 else
> >                         audit_sig_uid = uid;
> >                 security_task_getsecid(tsk, &audit_sig_sid);

> paul moore

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH ghak81 RFC V1 5/5] audit: collect audit task parameters

[Richard Guy Briggs]

On 2018-05-09 11:46, Paul Moore wrote:
> On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > The audit-related parameters in struct task_struct should ideally be
> > collected together and accessed through a standard audit API.
> >
> > Collect the existing loginuid, sessionid and audit_context together in a
> > new struct audit_task_info pointer called "audit" in struct task_struct.
> >
> > Use kmem_cache to manage this pool of memory.
> > Un-inline audit_free() to be able to always recover that memory.
> >
> > See: https://github.com/linux-audit/audit-kernel/issues/81
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> >  MAINTAINERS                |  2 +-
> >  include/linux/audit.h      |  8 ++++----
> >  include/linux/audit_task.h | 31 +++++++++++++++++++++++++++++++
> >  include/linux/sched.h      |  6 ++----
> >  init/init_task.c           |  8 ++++++--
> >  kernel/auditsc.c           |  4 ++--
> >  6 files changed, 46 insertions(+), 13 deletions(-)
> >  create mode 100644 include/linux/audit_task.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 0a1410d..8c7992d 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -2510,7 +2510,7 @@ L:        linux-audit@redhat.com (moderated for non-subscribers)
> >  W:     https://github.com/linux-audit
> >  T:     git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git
> >  S:     Supported
> > -F:     include/linux/audit.h
> > +F:     include/linux/audit*.h
> >  F:     include/uapi/linux/audit.h
> >  F:     kernel/audit*
> >
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index dba0d45..1324969 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -237,11 +237,11 @@ extern void __audit_inode_child(struct inode *parent,
> >
> >  static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
> >  {
> > -       task->audit_context = ctx;
> > +       task->audit.ctx = ctx;
> >  }
> >  static inline struct audit_context *audit_context(struct task_struct *task)
> >  {
> > -       return task->audit_context;
> > +       return task->audit.ctx;
> >  }
> >  static inline bool audit_dummy_context(void)
> >  {
> > @@ -330,12 +330,12 @@ extern int auditsc_get_stamp(struct audit_context *ctx,
> >
> >  static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
> >  {
> > -       return tsk->loginuid;
> > +       return tsk->audit.loginuid;
> >  }
> >
> >  static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
> >  {
> > -       return tsk->sessionid;
> > +       return tsk->audit.sessionid;
> >  }
> >
> >  extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
> > diff --git a/include/linux/audit_task.h b/include/linux/audit_task.h
> > new file mode 100644
> > index 0000000..d4b3a20
> > --- /dev/null
> > +++ b/include/linux/audit_task.h
> > @@ -0,0 +1,31 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/* audit_task.h -- definition of audit_task_info structure
> > + *
> > + * Copyright 2018 Red Hat Inc., Raleigh, North Carolina.
> > + * All Rights Reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * Written by Richard Guy Briggs <rgb@redhat.com>
> > + *
> > + */
> > +
> > +#ifndef _LINUX_AUDIT_TASK_H_
> > +#define _LINUX_AUDIT_TASK_H_
> > +
> > +struct audit_context;
> > +struct audit_task_info {
> > +       kuid_t                  loginuid;
> > +       unsigned int            sessionid;
> > +       struct audit_context    *ctx;
> > +};
> > +
> > +#endif
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index b3d697f..b58eca0 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -27,9 +27,9 @@
> >  #include <linux/signal_types.h>
> >  #include <linux/mm_types_task.h>
> >  #include <linux/task_io_accounting.h>
> > +#include <linux/audit_task.h>
> >
> >  /* task_struct member predeclarations (sorted alphabetically): */
> > -struct audit_context;
> >  struct backing_dev_info;
> >  struct bio_list;
> >  struct blk_plug;
> > @@ -832,10 +832,8 @@ struct task_struct {
> >
> >         struct callback_head            *task_works;
> >
> > -       struct audit_context            *audit_context;
> >  #ifdef CONFIG_AUDITSYSCALL
> > -       kuid_t                          loginuid;
> > -       unsigned int                    sessionid;
> > +       struct audit_task_info          audit;
> >  #endif
> 
> Considering that the audit_context pointer is now in the
> audit_task_info struct, should the audit_task_info struct be placed
> outside the CONFIG_AUDITSYSCALL protections?  Or rather, shouldn't the
> CONFIG_AUDITSYSCALL protections be moved inside audit_task_info or
> removed entirely?

Well, I wondered about that anyways.  audit_context is only meaningful
in CONFIG_AUDIT_SYSCALL, and loginuid and sessionid were already there,
so the whole thing should be inside, but given that CONFIG_AUDIT_SYSCALL
is forced on when CONFIG_AUDIT is set I don't see that it matters.
Perhaps CONFIG_AUDIT_SYSCALL should be ripped out completely and the
code flattenned to the CONFIG_AUDIT case.

I see your point though, moving CONFIG_AUDIT_SYSCALL protections to
within the audit_task_info struct definition makes more sense than this
above.

> > diff --git a/init/init_task.c b/init/init_task.c
> > index c788f91..d33260d 100644
> > --- a/init/init_task.c
> > +++ b/init/init_task.c
> > @@ -9,6 +9,7 @@
> >  #include <linux/init.h>
> >  #include <linux/fs.h>
> >  #include <linux/mm.h>
> > +#include <linux/audit.h>
> >
> >  #include <asm/pgtable.h>
> >  #include <linux/uaccess.h>
> > @@ -118,8 +119,11 @@ struct task_struct init_task
> >         .thread_group   = LIST_HEAD_INIT(init_task.thread_group),
> >         .thread_node    = LIST_HEAD_INIT(init_signals.thread_head),
> >  #ifdef CONFIG_AUDITSYSCALL
> > -       .loginuid       = INVALID_UID,
> > -       .sessionid      = AUDIT_SID_UNSET,
> > +       .audit          = {
> > +               .loginuid       = INVALID_UID,
> > +               .sessionid      = AUDIT_SID_UNSET,
> > +               .ctx            = NULL,
> > +       },
> >  #endif
> >  #ifdef CONFIG_PERF_EVENTS
> >         .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index f294e4a..b5d8bff 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -2068,8 +2068,8 @@ int audit_set_loginuid(kuid_t loginuid)
> >                         sessionid = (unsigned int)atomic_inc_return(&session_id);
> >         }
> >
> > -       task->sessionid = sessionid;
> > -       task->loginuid = loginuid;
> > +       task->audit.sessionid = sessionid;
> > +       task->audit.loginuid = loginuid;
> >  out:
> >         audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
> >         return rc;
> > --
> > 1.8.3.1
> 
> -- 
> paul moore
> www.paul-moore.com

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH ghak81 RFC V1 1/5] audit: normalize loginuid read access

[Richard Guy Briggs]

On 2018-05-10 17:21, Richard Guy Briggs wrote:
> On 2018-05-09 11:13, Paul Moore wrote:
> > On Fri, May 4, 2018 at 4:54 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Recognizing that the loginuid is an internal audit value, use an access
> > > function to retrieve the audit loginuid value for the task rather than
> > > reaching directly into the task struct to get it.
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > >  kernel/auditsc.c | 16 ++++++++--------
> > >  1 file changed, 8 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index 479c031..f3817d0 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -374,7 +374,7 @@ static int audit_field_compare(struct task_struct *tsk,
> > >         case AUDIT_COMPARE_EGID_TO_OBJ_GID:
> > >                 return audit_compare_gid(cred->egid, name, f, ctx);
> > >         case AUDIT_COMPARE_AUID_TO_OBJ_UID:
> > > -               return audit_compare_uid(tsk->loginuid, name, f, ctx);
> > > +               return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
> > >         case AUDIT_COMPARE_SUID_TO_OBJ_UID:
> > >                 return audit_compare_uid(cred->suid, name, f, ctx);
> > >         case AUDIT_COMPARE_SGID_TO_OBJ_GID:
> > > @@ -385,7 +385,7 @@ static int audit_field_compare(struct task_struct *tsk,
> > >                 return audit_compare_gid(cred->fsgid, name, f, ctx);
> > >         /* uid comparisons */
> > >         case AUDIT_COMPARE_UID_TO_AUID:
> > > -               return audit_uid_comparator(cred->uid, f->op, tsk->loginuid);
> > > +               return audit_uid_comparator(cred->uid, f->op, audit_get_loginuid(tsk));
> > >         case AUDIT_COMPARE_UID_TO_EUID:
> > >                 return audit_uid_comparator(cred->uid, f->op, cred->euid);
> > >         case AUDIT_COMPARE_UID_TO_SUID:
> > > @@ -394,11 +394,11 @@ static int audit_field_compare(struct task_struct *tsk,
> > >                 return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
> > >         /* auid comparisons */
> > >         case AUDIT_COMPARE_AUID_TO_EUID:
> > > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->euid);
> > > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->euid);
> > >         case AUDIT_COMPARE_AUID_TO_SUID:
> > > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->suid);
> > > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->suid);
> > >         case AUDIT_COMPARE_AUID_TO_FSUID:
> > > -               return audit_uid_comparator(tsk->loginuid, f->op, cred->fsuid);
> > > +               return audit_uid_comparator(audit_get_loginuid(tsk), f->op, cred->fsuid);
> > >         /* euid comparisons */
> > >         case AUDIT_COMPARE_EUID_TO_SUID:
> > >                 return audit_uid_comparator(cred->euid, f->op, cred->suid);
> > > @@ -611,7 +611,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> > >                                 result = match_tree_refs(ctx, rule->tree);
> > >                         break;
> > >                 case AUDIT_LOGINUID:
> > > -                       result = audit_uid_comparator(tsk->loginuid, f->op, f->uid);
> > > +                       result = audit_uid_comparator(audit_get_loginuid(tsk), f->op, f->uid);
> > >                         break;
> > >                 case AUDIT_LOGINUID_SET:
> > >                         result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
> > > @@ -2287,8 +2287,8 @@ int audit_signal_info(int sig, struct task_struct *t)
> > >             (sig == SIGTERM || sig == SIGHUP ||
> > >              sig == SIGUSR1 || sig == SIGUSR2)) {
> > >                 audit_sig_pid = task_tgid_nr(tsk);
> > > -               if (uid_valid(tsk->loginuid))
> > > -                       audit_sig_uid = tsk->loginuid;
> > > +               if (uid_valid(audit_get_loginuid(tsk)))
> > > +                       audit_sig_uid = audit_get_loginuid(tsk);
> > 
> > I realize this comment is a little silly given the nature of loginuid,
> > but if we are going to abstract away loginuid accesses (which I think
> > is good), we should probably access it once, store it in a local
> > variable, perform the validity check on the local variable, then
> > commit the local variable to audit_sig_uid.  I realize a TOCTOU
> > problem is unlikely here, but with this new layer of abstraction it
> > seems that some additional safety might be a good thing.
> 
> Ok, I'll just assign it to where it is going and check it there, holding
> the audit_ctl_lock the whole time, since it should have been done
> anyways for all of audit_sig_{pid,uid,sid} anyways to get a consistent
> view from the AUDIT_SIGNAL_INFO fetch.

Hmmm, holding audit_ctl_lock won't work because it could sleep trying to
get the lock and the signal info is set in a context where sleeping
isn't permitted.  I'll just use a local var...

> > >                 else
> > >                         audit_sig_uid = uid;
> > >                 security_task_getsecid(tsk, &audit_sig_sid);
> 
> > paul moore
> 
> - RGB

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635