Commit bfef93a5 authored by Al Viro's avatar Al Viro
Browse files

[PATCH] get rid of loginuid races 



Keeping loginuid in audit_context is racy and results in messier
code.  Taken to task_struct, out of the way of ->audit_context
changes.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 0c11b942

include/linux/audit.h

+1 −1
Original line number Diff line number Diff line
@@ -409,7 +409,7 @@ extern unsigned int audit_serial(void); 
extern void auditsc_get_stamp(struct audit_context *ctx,

			      struct timespec *t, unsigned int *serial);

extern int  audit_set_loginuid(struct task_struct *task, uid_t loginuid);

extern uid_t audit_get_loginuid(struct task_struct *task);

#define audit_get_loginuid(t) ((t)->loginuid)

extern void audit_log_task_context(struct audit_buffer *ab);

extern int __audit_ipc_obj(struct kern_ipc_perm *ipcp);

extern int __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode);

include/linux/init_task.h

+7 −0
Original line number Diff line number Diff line
@@ -114,6 +114,12 @@ extern struct group_info init_groups; 
	.pid = &init_struct_pid,				\

}



#ifdef CONFIG_AUDITSYSCALL

#define INIT_IDS \

	.loginuid = -1,

#else

#define INIT_IDS

#endif

/*

 *  INIT_TASK is used to set up the first task table, touch at

 * your own risk!. Base=0, limit=0x1fffff (=2MB)
@@ -173,6 +179,7 @@ extern struct group_info init_groups; 
		[PIDTYPE_SID]  = INIT_PID_LINK(PIDTYPE_SID),		\

	},								\

	.dirties = INIT_PROP_LOCAL_SINGLE(dirties),			\

	INIT_IDS							\

	INIT_TRACE_IRQFLAGS						\

	INIT_LOCKDEP							\

}

include/linux/sched.h

+3 −0
Original line number Diff line number Diff line
@@ -1139,6 +1139,9 @@ struct task_struct { 
	void *security;

#endif

	struct audit_context *audit_context;

#ifdef CONFIG_AUDITSYSCALL

	uid_t loginuid;

#endif

	seccomp_t seccomp;



/* Thread group tracking */

kernel/auditsc.c

+15 −41
Original line number Diff line number Diff line
@@ -192,7 +192,6 @@ struct audit_context { 
	enum audit_state    state;

	unsigned int	    serial;     /* serial number for record */

	struct timespec	    ctime;      /* time of syscall entry */

	uid_t		    loginuid;   /* login uid (identity) */

	int		    major;      /* syscall number */

	unsigned long	    argv[4];    /* syscall arguments */

	int		    return_valid; /* return code is valid */
@@ -506,7 +505,7 @@ static int audit_filter_rules(struct task_struct *tsk, 
		case AUDIT_LOGINUID:

			result = 0;

			if (ctx)

				result = audit_comparator(ctx->loginuid, f->op, f->val);

				result = audit_comparator(tsk->loginuid, f->op, f->val);

			break;

		case AUDIT_SUBJ_USER:

		case AUDIT_SUBJ_ROLE:
@@ -783,11 +782,8 @@ static inline void audit_free_aux(struct audit_context *context) 
static inline void audit_zero_context(struct audit_context *context,

				      enum audit_state state)

{

	uid_t loginuid = context->loginuid;



	memset(context, 0, sizeof(*context));

	context->state      = state;

	context->loginuid   = loginuid;

}



static inline struct audit_context *audit_alloc_context(enum audit_state state)
@@ -826,11 +822,6 @@ int audit_alloc(struct task_struct *tsk) 
		return -ENOMEM;

	}



				/* Preserve login uid */

	context->loginuid = -1;

	if (current->audit_context)

		context->loginuid = current->audit_context->loginuid;



	tsk->audit_context  = context;

	set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);

	return 0;
@@ -1047,7 +1038,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts 
		  context->name_count,

		  context->ppid,

		  context->pid,

		  context->loginuid,

		  tsk->loginuid,

		  context->uid,

		  context->gid,

		  context->euid, context->suid, context->fsuid,
@@ -1779,9 +1770,7 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid) 
{

	struct audit_context *context = task->audit_context;



	if (context) {

		/* Only log if audit is enabled */

		if (context->in_syscall) {

	if (context && context->in_syscall) {

		struct audit_buffer *ab;



		ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
@@ -1789,29 +1778,14 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid) 
			audit_log_format(ab, "login pid=%d uid=%u "

				"old auid=%u new auid=%u",

				task->pid, task->uid,

					context->loginuid, loginuid);

				task->loginuid, loginuid);

			audit_log_end(ab);

		}

	}

		context->loginuid = loginuid;

	}

	task->loginuid = loginuid;

	return 0;

}



/**

 * audit_get_loginuid - get the loginuid for an audit_context

 * @ctx: the audit_context

 *

 * Returns the context's loginuid or -1 if @ctx is NULL.

 */

uid_t audit_get_loginuid(struct task_struct *task)

{

	struct audit_context *ctx = task->audit_context;

	return ctx ? ctx->loginuid : -1;

}



EXPORT_SYMBOL(audit_get_loginuid);



/**

 * __audit_mq_open - record audit data for a POSIX MQ open

 * @oflag: open flag
@@ -2217,8 +2191,8 @@ int __audit_signal_info(int sig, struct task_struct *t) 
	if (audit_pid && t->tgid == audit_pid) {

		if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1) {

			audit_sig_pid = tsk->pid;

			if (ctx)

				audit_sig_uid = ctx->loginuid;

			if (tsk->loginuid != -1)

				audit_sig_uid = tsk->loginuid;

			else

				audit_sig_uid = tsk->uid;

			selinux_get_task_sid(tsk, &audit_sig_sid);