From: Jeff Layton <jlayton@redhat.com>
Date: Wed, 10 Oct 2012 19:25:26 +0000 (-0400)
Subject: vfs: allocate page instead of names_cache buffer in mount_block_root
X-Git-Tag: v3.7-rc1~32^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a608ca21f58ee44df5a71ba140e98498f3ebc2cd;p=pandora-kernel.git

vfs: allocate page instead of names_cache buffer in mount_block_root

First, it's incorrect to call putname() after __getname_gfp() since the
bare __getname_gfp() call skips the auditing code, while putname()
doesn't.

mount_block_root allocates a PATH_MAX buffer via __getname_gfp, and then
calls get_fs_names to fill the buffer. That function can call
get_filesystem_list which assumes that that buffer is a full page in
size. On arches where PAGE_SIZE != 4k, then this could potentially
overrun.

In practice, it's hard to imagine the list of filesystem names even
approaching 4k, but it's best to be safe. Just allocate a page for this
purpose instead.

With this, we can also remove the __getname_gfp() definition since there
are no more callers.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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