linux-kernel - Re: [PATCH v4 4/6] Yama: consolidate error reporting

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Date:	Tue, 12 Apr 2016 16:26:42 -0500
From:	"Serge E. Hallyn" <serge@...lyn.com>
To:	Kees Cook <keescook@...omium.org>
Cc:	James Morris <jmorris@...ei.org>, Joe Perches <joe@...ches.com>,
	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Jonathan Corbet <corbet@....net>,
	Kalle Valo <kvalo@...eaurora.org>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	Guenter Roeck <linux@...ck-us.net>,
	Jiri Slaby <jslaby@...e.com>, Paul Moore <pmoore@...hat.com>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	Casey Schaufler <casey@...aufler-ca.com>,
	Andreas Gruenbacher <agruenba@...hat.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	linux-security-module@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v4 4/6] Yama: consolidate error reporting

Quoting Kees Cook (keescook@...omium.org):
> Use a common error reporting function for Yama violation reports, and give
> more detail into the process command lines.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>

Acked-by: Serge Hallyn <serge.hallyn@...onical.com>

> ---
>  security/yama/yama_lsm.c | 31 +++++++++++++++++++++----------
>  1 file changed, 21 insertions(+), 10 deletions(-)
> 
> diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
> index cb6ed10816d4..c19f6e5df9a3 100644
> --- a/security/yama/yama_lsm.c
> +++ b/security/yama/yama_lsm.c
> @@ -18,6 +18,7 @@
>  #include <linux/prctl.h>
>  #include <linux/ratelimit.h>
>  #include <linux/workqueue.h>
> +#include <linux/string_helpers.h>
>  
>  #define YAMA_SCOPE_DISABLED	0
>  #define YAMA_SCOPE_RELATIONAL	1
> @@ -41,6 +42,22 @@ static DEFINE_SPINLOCK(ptracer_relations_lock);
>  static void yama_relation_cleanup(struct work_struct *work);
>  static DECLARE_WORK(yama_relation_work, yama_relation_cleanup);
>  
> +static void report_access(const char *access, struct task_struct *target,
> +			  struct task_struct *agent)
> +{
> +	char *target_cmd, *agent_cmd;
> +
> +	target_cmd = kstrdup_quotable_cmdline(target, GFP_KERNEL);
> +	agent_cmd = kstrdup_quotable_cmdline(agent, GFP_KERNEL);
> +
> +	pr_notice_ratelimited(
> +		"ptrace %s of \"%s\"[%d] was attempted by \"%s\"[%d]\n",
> +		access, target_cmd, target->pid, agent_cmd, agent->pid);
> +
> +	kfree(agent_cmd);
> +	kfree(target_cmd);
> +}
> +
>  /**
>   * yama_relation_cleanup - remove invalid entries from the relation list
>   *
> @@ -307,11 +324,8 @@ static int yama_ptrace_access_check(struct task_struct *child,
>  		}
>  	}
>  
> -	if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0) {
> -		printk_ratelimited(KERN_NOTICE
> -			"ptrace of pid %d was attempted by: %s (pid %d)\n",
> -			child->pid, current->comm, current->pid);
> -	}
> +	if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0)
> +		report_access("attach", child, current);
>  
>  	return rc;
>  }
> @@ -337,11 +351,8 @@ int yama_ptrace_traceme(struct task_struct *parent)
>  		break;
>  	}
>  
> -	if (rc) {
> -		printk_ratelimited(KERN_NOTICE
> -			"ptraceme of pid %d was attempted by: %s (pid %d)\n",
> -			current->pid, parent->comm, parent->pid);
> -	}
> +	if (rc)
> +		report_access("traceme", current, parent);
>  
>  	return rc;
>  }
> -- 
> 2.6.3