[PATCH v2 resend 09/12] proc: disable mem_write after exec

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From: Stephen Wilson <wilsons@start.ca>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Michel Lespinasse <walken@google.com>,
	Andi Kleen <ak@linux.intel.com>, Rik van Riel <riel@redhat.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Matt Mackall <mpm@selenic.com>,
	David Rientjes <rientjes@google.com>,
	Nick Piggin <npiggin@kernel.dk>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Mel Gorman <mel@csn.ul.ie>, Hugh Dickins <hughd@google.com>,
	x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Stephen Wilson <wilsons@start.ca>
Subject: [PATCH v2 resend 09/12] proc: disable mem_write after exec
Date: Wed, 23 Mar 2011 10:43:58 -0400	[thread overview]
Message-ID: <1300891441-16280-10-git-send-email-wilsons@start.ca> (raw)
In-Reply-To: <1300891441-16280-1-git-send-email-wilsons@start.ca>

This change makes mem_write() observe the same constraints as mem_read().  This
is particularly important for mem_write as an accidental leak of the fd across
an exec could result in arbitrary modification of the target process' memory.
IOW, /proc/pid/mem is implicitly close-on-exec.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
---
 fs/proc/base.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index d49c4b5..13c5e8c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -848,6 +848,10 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
 	if (check_mem_permission(task))
 		goto out;
 
+	copied = -EIO;
+	if (file->private_data != (void *)((long)current->self_exec_id))
+		goto out;
+
 	copied = -ENOMEM;
 	page = (char *)__get_free_page(GFP_TEMPORARY);
 	if (!page)
-- 
1.7.3.5

WARNING: multiple messages have this Message-ID (diff)

From: Stephen Wilson <wilsons@start.ca>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Michel Lespinasse <walken@google.com>,
	Andi Kleen <ak@linux.intel.com>, Rik van Riel <riel@redhat.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Matt Mackall <mpm@selenic.com>,
	David Rientjes <rientjes@google.com>,
	Nick Piggin <npiggin@kernel.dk>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Mel Gorman <mel@csn.ul.ie>, Hugh Dickins <hughd@google.com>,
	x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Stephen Wilson <wilsons@start.ca>
Subject: [PATCH v2 resend 09/12] proc: disable mem_write after exec
Date: Wed, 23 Mar 2011 10:43:58 -0400	[thread overview]
Message-ID: <1300891441-16280-10-git-send-email-wilsons@start.ca> (raw)
In-Reply-To: <1300891441-16280-1-git-send-email-wilsons@start.ca>

This change makes mem_write() observe the same constraints as mem_read().  This
is particularly important for mem_write as an accidental leak of the fd across
an exec could result in arbitrary modification of the target process' memory.
IOW, /proc/pid/mem is implicitly close-on-exec.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
---
 fs/proc/base.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index d49c4b5..13c5e8c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -848,6 +848,10 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
 	if (check_mem_permission(task))
 		goto out;
 
+	copied = -EIO;
+	if (file->private_data != (void *)((long)current->self_exec_id))
+		goto out;
+
 	copied = -ENOMEM;
 	page = (char *)__get_free_page(GFP_TEMPORARY);
 	if (!page)
-- 
1.7.3.5

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next prev parent reply	other threads:[~2011-03-23 14:50 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-23 14:43 [PATCH v2 resend 0/12] enable writing to /proc/pid/mem Stephen Wilson
2011-03-23 14:43 ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 01/12] x86: add context tag to mark mm when running a task in 32-bit compatibility mode Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 02/12] x86: mark associated mm when running a task in 32 bit " Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 03/12] mm: arch: make get_gate_vma take an mm_struct instead of a task_struct Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 04/12] mm: arch: make in_gate_area " Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 05/12] mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 06/12] mm: use mm_struct to resolve gate vma's in __get_user_pages Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 07/12] mm: factor out main logic of access_process_vm Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 08/12] mm: implement access_remote_vm Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:43 ` Stephen Wilson [this message]
2011-03-23 14:43   ` [PATCH v2 resend 09/12] proc: disable mem_write after exec Stephen Wilson
2011-03-23 14:43 ` [PATCH v2 resend 10/12] proc: hold cred_guard_mutex in check_mem_permission() Stephen Wilson
2011-03-23 14:43   ` Stephen Wilson
2011-03-23 14:44 ` [PATCH v2 resend 11/12] proc: make check_mem_permission() return an mm_struct on success Stephen Wilson
2011-03-23 14:44   ` Stephen Wilson
2011-03-23 14:44 ` [PATCH v2 resend 12/12] proc: enable writing to /proc/pid/mem Stephen Wilson
2011-03-23 14:44   ` Stephen Wilson
2011-03-23 14:57 ` [PATCH v2 resend 0/12] " Al Viro
2011-03-23 14:57   ` Al Viro
2011-03-23 15:04   ` Stephen Wilson
2011-03-23 15:04     ` Stephen Wilson

find likely ancestor, descendant, or conflicting patches for this message:
( dfblob:d49c4b5 dfblob:13c5e8c dfblob:d49c4b5 dfblob:13c5e8c )
 OR (
bs:"[PATCH v2 resend 09/12] proc: disable mem_write after exec" )
	(help)

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