From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752849AbaIJOin (ORCPT ); Wed, 10 Sep 2014 10:38:43 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:34026 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751824AbaIJOik (ORCPT ); Wed, 10 Sep 2014 10:38:40 -0400 X-AuditID: cbfec7f4-b7f156d0000063c7-17-5410626ee72a From: Andrey Ryabinin To: linux-kernel@vger.kernel.org Cc: Andrey Ryabinin , Dmitry Vyukov , Konstantin Serebryany , Dmitry Chernenkov , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Sasha Levin , Christoph Lameter , Joonsoo Kim , Andrew Morton , Dave Hansen , Andi Kleen , Vegard Nossum , "H. Peter Anvin" , x86@kernel.org, linux-mm@kvack.org, Alexander Viro Subject: [RFC/PATCH v2 08/10] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports Date: Wed, 10 Sep 2014 18:31:25 +0400 Message-id: <1410359487-31938-9-git-send-email-a.ryabinin@samsung.com> X-Mailer: git-send-email 2.1.0 In-reply-to: <1410359487-31938-1-git-send-email-a.ryabinin@samsung.com> References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1410359487-31938-1-git-send-email-a.ryabinin@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrDLMWRmVeSWpSXmKPExsVy+t/xq7p5SQIhBmtmi1ts+/WIzeL33pms FnPWr2GzOHLtO7vF9W9vGC0+vXzAaPH84UN2iwkP29gtpm0Ut1jZ3cxmsf3ZWyaLlZ0PWC0u 75rDZnFvzX9Wi8VHbjNbvHs2mdni6qqD7Bbn/x5ntfix4TGrg7DH/J0fGT12zrrL7rFgU6nH 4j0vmTw2repk89j0aRK7R9fbK0weJ2b8ZvF4cmU6k8fHp7dYPPq2rGL0+LxJzmPTk7dAyZYv rAF8UVw2Kak5mWWpRfp2CVwZ775+Ziw4xlUxZYZIA+NVji5GDg4JAROJ+b/Euxg5gUwxiQv3 1rOB2EICSxklZpyt6WLkArL7mCTeLLrMDJJgE9CT+DdrO1iRiICCxObeZ6wgRcwC81kl7kxa wQiSEBbIl1jed4oVxGYRUJU4Me0WmM0r4CZx5U0LC8Q2OYkNu/+D1XMKuEucOrmCCWJbE6PE kgub2Ccw8i5gZFjFKJpamlxQnJSea6hXnJhbXJqXrpecn7uJERIjX3YwLj5mdYhRgINRiYe3 8CJ/iBBrYllxZe4hRgkOZiUR3iYHgRAh3pTEyqrUovz4otKc1OJDjEwcnFINjGFMlscO73Yt nnt3eqJvh9ZVbeV9xrnGKZMusqu47vVgfv7uVujrBR8ZMxql5k24ERlwW5ltefzLVVXcl2eY qBe5/t/7hLsnO3zp53tM1wv/B7Sp31z9y1NLad3R3JNMxzqUequ2TP+4bP46weUZbrucDn9x uRMuv75UI05O5v6BIwttw2RkdZVYijMSDbWYi4oTAUQYkSZvAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need to manually unpoison rounded up allocation size for dname to avoid kasan's reports in dentry_string_cmp(). When CONFIG_DCACHE_WORD_ACCESS=y dentry_string_cmp may access few bytes beyound requested in kmalloc() size. dentry_string_cmp() relates on that fact that dentry allocated using kmalloc and kmalloc internally round up allocation size. So this is not a bug, but this makes kasan to complain about such accesses. To avoid such reports we mark rounded up allocation size in shadow as accessible. Reported-by: Dmitry Vyukov Signed-off-by: Andrey Ryabinin --- fs/dcache.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index 35e61f6..b83dbc1 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -38,6 +38,7 @@ #include #include #include +#include #include "internal.h" #include "mount.h" @@ -1396,6 +1397,10 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) kmem_cache_free(dentry_cache, dentry); return NULL; } +#ifdef CONFIG_DCACHE_WORD_ACCESS + kasan_unpoison_shadow(dname, + round_up(name->len + 1, sizeof(unsigned long))); +#endif } else { dname = dentry->d_iname; } -- 1.8.5.5