binary_sysctl(): fix memory leak
Michel Lespinasse [Tue, 20 Dec 2011 01:12:06 +0000 (17:12 -0800)]
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@google.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Change-Id: Ia6c066b0703eeafc61eafdd5addf157ee671bd68
Reviewed-on: http://git-master/r/74175
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>
Tested-by: Varun Wadekar <vwadekar@nvidia.com>

kernel/sysctl_binary.c

index e8bffbe..2ce1b30 100644 (file)
@@ -1354,7 +1354,7 @@ static ssize_t binary_sysctl(const int *name, int nlen,
 
        fput(file);
 out_putname:
-       putname(pathname);
+       __putname(pathname);
 out:
        return result;
 }