linux-kernel - Re: [PATCH 1/15] don't reallocate buffer in every audit

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Message-ID: <alpine.LRH.1.10.0812171820130.22856@tundra.namei.org>
Date:	Wed, 17 Dec 2008 18:20:42 +1100 (EST)
From:	James Morris <jmorris@...ei.org>
To:	Al Viro <viro@....linux.org.uk>
cc:	linux-audit@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/15] don't reallocate buffer in every audit_sockaddr()

On Wed, 17 Dec 2008, Al Viro wrote:

> 
> No need to do that more than once per process lifetime; allocating/freeing
> on each sendto/accept/etc. is bloody pointless.
> 
> Signed-off-by: Al Viro <viro@...iv.linux.org.uk>

Reviewed-by: James Morris <jmorris@...ei.org>

> ---
>  kernel/auditsc.c |   46 ++++++++++++++++++++++------------------------
>  1 files changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 2a3f0af..aca9ddb 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -162,12 +162,6 @@ struct audit_aux_data_socketcall {
>  	unsigned long		args[0];
>  };
>  
> -struct audit_aux_data_sockaddr {
> -	struct audit_aux_data	d;
> -	int			len;
> -	char			a[0];
> -};
> -
>  struct audit_aux_data_fd_pair {
>  	struct	audit_aux_data d;
>  	int	fd[2];
> @@ -208,7 +202,8 @@ struct audit_context {
>  	struct audit_context *previous; /* For nested syscalls */
>  	struct audit_aux_data *aux;
>  	struct audit_aux_data *aux_pids;
> -
> +	struct sockaddr_storage *sockaddr;
> +	size_t sockaddr_len;
>  				/* Save things to print about task_struct */
>  	pid_t		    pid, ppid;
>  	uid_t		    uid, euid, suid, fsuid;
> @@ -891,6 +886,7 @@ static inline void audit_free_context(struct audit_context *context)
>  		free_tree_refs(context);
>  		audit_free_aux(context);
>  		kfree(context->filterkey);
> +		kfree(context->sockaddr);
>  		kfree(context);
>  		context  = previous;
>  	} while (context);
> @@ -1322,13 +1318,6 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
>  				audit_log_format(ab, " a%d=%lx", i, axs->args[i]);
>  			break; }
>  
> -		case AUDIT_SOCKADDR: {
> -			struct audit_aux_data_sockaddr *axs = (void *)aux;
> -
> -			audit_log_format(ab, "saddr=");
> -			audit_log_n_hex(ab, axs->a, axs->len);
> -			break; }
> -
>  		case AUDIT_FD_PAIR: {
>  			struct audit_aux_data_fd_pair *axs = (void *)aux;
>  			audit_log_format(ab, "fd0=%d fd1=%d", axs->fd[0], axs->fd[1]);
> @@ -1338,6 +1327,16 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
>  		audit_log_end(ab);
>  	}
>  
> +	if (context->sockaddr_len) {
> +		ab = audit_log_start(context, GFP_KERNEL, AUDIT_SOCKADDR);
> +		if (ab) {
> +			audit_log_format(ab, "saddr=");
> +			audit_log_n_hex(ab, (void *)context->sockaddr,
> +					context->sockaddr_len);
> +			audit_log_end(ab);
> +		}
> +	}
> +
>  	for (aux = context->aux_pids; aux; aux = aux->next) {
>  		struct audit_aux_data_pids *axs = (void *)aux;
>  
> @@ -1604,6 +1603,7 @@ void audit_syscall_exit(int valid, long return_code)
>  		context->aux_pids = NULL;
>  		context->target_pid = 0;
>  		context->target_sid = 0;
> +		context->sockaddr_len = 0;
>  		kfree(context->filterkey);
>  		context->filterkey = NULL;
>  		tsk->audit_context = context;
> @@ -2354,22 +2354,20 @@ int __audit_fd_pair(int fd1, int fd2)
>   */
>  int audit_sockaddr(int len, void *a)
>  {
> -	struct audit_aux_data_sockaddr *ax;
>  	struct audit_context *context = current->audit_context;
>  
>  	if (likely(!context || context->dummy))
>  		return 0;
>  
> -	ax = kmalloc(sizeof(*ax) + len, GFP_KERNEL);
> -	if (!ax)
> -		return -ENOMEM;
> -
> -	ax->len = len;
> -	memcpy(ax->a, a, len);
> +	if (!context->sockaddr) {
> +		void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);
> +		if (!p)
> +			return -ENOMEM;
> +		context->sockaddr = p;
> +	}
>  
> -	ax->d.type = AUDIT_SOCKADDR;
> -	ax->d.next = context->aux;
> -	context->aux = (void *)ax;
> +	context->sockaddr_len = len;
> +	memcpy(context->sockaddr, a, len);
>  	return 0;
>  }
>  
> -- 
> 1.5.6.5
> 
> 
> --
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-- 
James Morris
<jmorris@...ei.org>
--
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