Re: [PATCH 17/21] audit: Use timespec64 to represent audit timestamps

[Richard Guy Briggs <rgb@redhat.com>]

On 16/06/09, Steve Grubb wrote:
> On Wednesday, June 08, 2016 10:05:01 PM Deepa Dinamani wrote:
> > struct timespec is not y2038 safe.
> > Audit timestamps are recorded in string format into
> > an audit buffer for a given context.
> > These mark the entry timestamps for the syscalls.
> > Use y2038 safe struct timespec64 to represent the times.
> > The log strings can handle this transition as strings can
> > hold upto 1024 characters.
> 
> Have you tested this with ausearch or any audit utilities? As an aside, a time 
> stamp that is up to 1024 characters long is terribly wasteful considering how 
> many events we get.

Steve,

I don't expect the size of the time stamp text to change since the
format isn't being changed and I don't expect the date stamp text length
to change until Y10K, but you never know what will happen in 8
millenia...  (Who knows, maybe that damn Linux server in my basement
will still be running then...)

Isn't the maximum message length MAX_AUDIT_MESSAGE_LENGTH (8970 octets)?

> -Steve
> 
> > Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> > Cc: Paul Moore <paul@paul-moore.com>
> > Cc: Eric Paris <eparis@redhat.com>
> > Cc: linux-audit@redhat.com
> > ---
> >  include/linux/audit.h |  4 ++--
> >  kernel/audit.c        | 10 +++++-----
> >  kernel/audit.h        |  2 +-
> >  kernel/auditsc.c      |  6 +++---
> >  4 files changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index 961a417..2f6a1123 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -335,7 +335,7 @@ static inline void audit_ptrace(struct task_struct *t)
> >  				/* Private API (for audit.c only) */
> >  extern unsigned int audit_serial(void);
> >  extern int auditsc_get_stamp(struct audit_context *ctx,
> > -			      struct timespec *t, unsigned int *serial);
> > +			      struct timespec64 *t, unsigned int *serial);
> >  extern int audit_set_loginuid(kuid_t loginuid);
> > 
> >  static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
> > @@ -510,7 +510,7 @@ static inline void __audit_seccomp(unsigned long
> > syscall, long signr, int code) static inline void audit_seccomp(unsigned
> > long syscall, long signr, int code) { }
> >  static inline int auditsc_get_stamp(struct audit_context *ctx,
> > -			      struct timespec *t, unsigned int *serial)
> > +			      struct timespec64 *t, unsigned int *serial)
> >  {
> >  	return 0;
> >  }
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 22bb4f2..6c2f405 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -1325,10 +1325,10 @@ unsigned int audit_serial(void)
> >  }
> > 
> >  static inline void audit_get_stamp(struct audit_context *ctx,
> > -				   struct timespec *t, unsigned int *serial)
> > +				   struct timespec64 *t, unsigned int *serial)
> >  {
> >  	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
> > -		*t = CURRENT_TIME;
> > +		ktime_get_real_ts64(t);
> >  		*serial = audit_serial();
> >  	}
> >  }
> > @@ -1370,7 +1370,7 @@ struct audit_buffer *audit_log_start(struct
> > audit_context *ctx, gfp_t gfp_mask, int type)
> >  {
> >  	struct audit_buffer	*ab	= NULL;
> > -	struct timespec		t;
> > +	struct timespec64	t;
> >  	unsigned int		uninitialized_var(serial);
> >  	int reserve = 5; /* Allow atomic callers to go up to five
> >  			    entries over the normal backlog limit */
> > @@ -1422,8 +1422,8 @@ struct audit_buffer *audit_log_start(struct
> > audit_context *ctx, gfp_t gfp_mask,
> > 
> >  	audit_get_stamp(ab->ctx, &t, &serial);
> > 
> > -	audit_log_format(ab, "audit(%lu.%03lu:%u): ",
> > -			 t.tv_sec, t.tv_nsec/1000000, serial);
> > +	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
> > +			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
> >  	return ab;
> >  }
> > 
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index cbbe6bb..029d674 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -111,7 +111,7 @@ struct audit_context {
> >  	enum audit_state    state, current_state;
> >  	unsigned int	    serial;     /* serial number for record */
> >  	int		    major;      /* syscall number */
> > -	struct timespec	    ctime;      /* time of syscall entry */
> > +	struct timespec64   ctime;      /* time of syscall entry */
> >  	unsigned long	    argv[4];    /* syscall arguments */
> >  	long		    return_code;/* syscall return code */
> >  	u64		    prio;
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 62ab53d..ecebb3c 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1523,7 +1523,7 @@ void __audit_syscall_entry(int major, unsigned long
> > a1, unsigned long a2, return;
> > 
> >  	context->serial     = 0;
> > -	context->ctime      = CURRENT_TIME;
> > +	ktime_get_real_ts64(&context->ctime);
> >  	context->in_syscall = 1;
> >  	context->current_state  = state;
> >  	context->ppid       = 0;
> > @@ -1932,13 +1932,13 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
> >  /**
> >   * auditsc_get_stamp - get local copies of audit_context values
> >   * @ctx: audit_context for the task
> > - * @t: timespec to store time recorded in the audit_context
> > + * @t: timespec64 to store time recorded in the audit_context
> >   * @serial: serial value that is recorded in the audit_context
> >   *
> >   * Also sets the context as auditable.
> >   */
> >  int auditsc_get_stamp(struct audit_context *ctx,
> > -		       struct timespec *t, unsigned int *serial)
> > +		       struct timespec64 *t, unsigned int *serial)
> >  {
> >  	if (!ctx->in_syscall)
> >  		return 0;
> 
> --
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> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635