From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 122DE6B0253 for ; Thu, 4 Aug 2016 09:31:17 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id p129so146966396wmp.3 for ; Thu, 04 Aug 2016 06:31:17 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id rb4si13628936wjb.208.2016.08.04.06.31.15 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 04 Aug 2016 06:31:16 -0700 (PDT) Subject: Re: [PATCH] fs:Fix kmemleak leak warning in getname_flags about working on unitialized memory References: <1470260896-31767-1-git-send-email-xerofoify@gmail.com> From: Vlastimil Babka Message-ID: <6b369f5c-6a9d-febf-81fe-2e1a4b408814@suse.cz> Date: Thu, 4 Aug 2016 15:31:01 +0200 MIME-Version: 1.0 In-Reply-To: <1470260896-31767-1-git-send-email-xerofoify@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Nicholas Krause , viro@zeniv.linux.org.uk Cc: akpm@linux-foundation.org, msalter@redhat.com, kuleshovmail@gmail.com, david.vrabel@citrix.com, ard.biesheuvel@linaro.org, jgross@suse.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On 08/03/2016 11:48 PM, Nicholas Krause wrote: > This fixes a kmemleak leak warning complaining about working on > unitializied memory as found in the function, getname_flages. Seems What exactly is the kmemleak warning saying? > that we are indeed working on unitialized memory, as the filename > char pointer is never made to point to the filname structure's result > member for holding it's name, fix this by using memcpy to copy the > filname structure pointer's, name to the char pointer passed to this > function. I don't understand what you're saying here. "the char pointer passed to this function" is the source, not destination. > Signed-off-by: Nicholas Krause > --- > fs/namei.c | 1 + > mm/early_ioremap.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/fs/namei.c b/fs/namei.c > index c386a32..6b18d57 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -196,6 +196,7 @@ getname_flags(const char __user *filename, int flags, int *empty) > } > } > > + memcpy((char *)result->name, filename, len); This will be wrong even with strncpy_from_user instead of memcpy. AFAICS result->name already points to a copy of filename. Also if you think that the above is "copy[ing] the filname structure pointer's, name to the char pointer passed to this function" then you are wrong. > result->uptr = filename; > result->aname = NULL; > audit_getname(result); > diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c > index 6d5717b..92c5235 100644 > --- a/mm/early_ioremap.c > +++ b/mm/early_ioremap.c > @@ -215,6 +215,7 @@ early_ioremap(resource_size_t phys_addr, unsigned long size) > void __init * > early_memremap(resource_size_t phys_addr, unsigned long size) > { > + dump_stack(); > return (__force void *)__early_ioremap(phys_addr, size, > FIXMAP_PAGE_NORMAL); > } > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org