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Message-Id: <1300891441-16280-10-git-send-email-wilsons@start.ca>
Date: Wed, 23 Mar 2011 10:43:58 -0400
From: Stephen Wilson <wilsons@...rt.ca>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Michel Lespinasse <walken@...gle.com>,
Andi Kleen <ak@...ux.intel.com>,
Rik van Riel <riel@...hat.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Matt Mackall <mpm@...enic.com>,
David Rientjes <rientjes@...gle.com>,
Nick Piggin <npiggin@...nel.dk>,
Andrea Arcangeli <aarcange@...hat.com>,
Mel Gorman <mel@....ul.ie>, Hugh Dickins <hughd@...gle.com>,
x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Stephen Wilson <wilsons@...rt.ca>
Subject: [PATCH v2 resend 09/12] proc: disable mem_write after exec
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@...rt.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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