Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752547AbYADLPo (ORCPT ); Fri, 4 Jan 2008 06:15:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751072AbYADLPh (ORCPT ); Fri, 4 Jan 2008 06:15:37 -0500 Received: from smtp3-g19.free.fr ([212.27.42.29]:60063 "EHLO smtp3-g19.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751015AbYADLPg (ORCPT ); Fri, 4 Jan 2008 06:15:36 -0500 Date: Fri, 4 Jan 2008 12:15:02 +0100 From: Guillaume Chazarain To: Al Viro Cc: Rik van Riel , linux-kernel@vger.kernel.org Subject: Re: [PATCH] proc: advertise new restrictions on /proc/*/maps & /proc/*/smaps Message-ID: <20080104121502.2e6ccaa1@inria.fr> In-Reply-To: <20080103235736.GW27894@ZenIV.linux.org.uk> References: <20080103235150.2870.31703.stgit@localhost.localdomain> <20080103235736.GW27894@ZenIV.linux.org.uk> X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.3; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2806 Lines: 102 Al Viro wrote: > The whole point is that we have to reject it at read() time, not open() > time. Yes, my patch was a complement to yours to propagate the -EPERM in easy cases. As you noted it added restrictions on reading /proc/*/maps, even though I found them acceptable. How about this instead? Maybe you'd prefer to propagate the actual -EPERM from __ptrace_may_attach but that would be more invasive. Sidenote: do you think a sparse annotation to check IS_ERR/PTR_ERR usage would make sense? proc: return -EPERM when preventing read of /proc/*/maps Return an error instead of successfully reading an empty file. Signed-off-by: Guillaume Chazarain --- fs/proc/base.c | 2 +- fs/proc/task_mmu.c | 8 +++++--- fs/proc/task_nommu.c | 4 ++-- 3 files changed, 8 insertions(+), 6 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 7411bfb..3aebc85 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -219,7 +219,7 @@ out: task_unlock(task); up_read(&mm->mmap_sem); mmput(mm); - return NULL; + return ERR_PTR(-EPERM); } static int proc_pid_cmdline(struct task_struct *task, char * buffer) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8043a3e..db57e65 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -398,8 +398,8 @@ static void *m_start(struct seq_file *m, loff_t *pos) return NULL; mm = mm_for_maps(priv->task); - if (!mm) - return NULL; + if (IS_ERR(mm) || !mm) + return mm; priv->tail_vma = tail_vma = get_gate_vma(priv->task); @@ -437,7 +437,7 @@ out: static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma) { - if (vma && vma != priv->tail_vma) { + if (vma && !IS_ERR(vma) && vma != priv->tail_vma) { struct mm_struct *mm = vma->vm_mm; up_read(&mm->mmap_sem); mmput(mm); @@ -451,6 +451,8 @@ static void *m_next(struct seq_file *m, void *v, loff_t *pos) struct vm_area_struct *tail_vma = priv->tail_vma; (*pos)++; + if (IS_ERR(vma)) + return vma; if (vma && (vma != tail_vma) && vma->vm_next) return vma->vm_next; vma_stop(priv, vma); diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 1932c2c..53cb062 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -166,10 +166,10 @@ static void *m_start(struct seq_file *m, loff_t *pos) return NULL; mm = mm_for_maps(priv->task); - if (!mm) { + if (IS_ERR(mm) || !mm) { put_task_struct(priv->task); priv->task = NULL; - return NULL; + return mm; } /* start from the Nth VMA */ -- Guillaume -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/