linux-kernel - [22/75] binary_sysctl(): fix memory leak

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Date:	Tue, 03 Jan 2012 14:32:55 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Michel Lespinasse <walken@...gle.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Christoph Hellwig <hch@...radead.org>,
	Eric Paris <eparis@...hat.com>
Subject: [22/75] binary_sysctl(): fix memory leak

3.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michel Lespinasse <walken@...gle.com>

commit 3d3c8f93a237b64580c5c5e138edeb1377e98230 upstream.

binary_sysctl() calls sysctl_getname() which allocates from names_cache
slab usin __getname()

The matching function to free the name is __putname(), and not putname()
which should be used only to match getname() allocations.

This is because when auditing is enabled, putname() calls audit_putname
*instead* (not in addition) to __putname().  Then, if a syscall is in
progress, audit_putname does not release the name - instead, it expects
the name to get released when the syscall completes, but that will happen
only if audit_getname() was called previously, i.e.  if the name was
allocated with getname() rather than the naked __getname().  So,
__getname() followed by putname() ends up leaking memory.

Signed-off-by: Michel Lespinasse <walken@...gle.com>
Acked-by: Al Viro <viro@...iv.linux.org.uk>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: Eric Paris <eparis@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 kernel/sysctl_binary.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1354,7 +1354,7 @@ static ssize_t binary_sysctl(const int *

 	fput(file);
 out_putname:
-	putname(pathname);
+	__putname(pathname);
 out:
 	return result;
 }

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