From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753119AbaIXMvo (ORCPT ); Wed, 24 Sep 2014 08:51:44 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:47941 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752344AbaIXMvf (ORCPT ); Wed, 24 Sep 2014 08:51:35 -0400 X-AuditID: cbfec7f5-b7f776d000003e54-2f-5422be55d110 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" , Dave Jones , x86@kernel.org, linux-mm@kvack.org, Alexander Viro Subject: [PATCH v3 10/13] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports Date: Wed, 24 Sep 2014 16:44:06 +0400 Message-id: <1411562649-28231-11-git-send-email-a.ryabinin@samsung.com> X-Mailer: git-send-email 2.1.1 In-reply-to: <1411562649-28231-1-git-send-email-a.ryabinin@samsung.com> References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1411562649-28231-1-git-send-email-a.ryabinin@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrOLMWRmVeSWpSXmKPExsVy+t/xy7qh+5RCDLq7DSy2/XrEZvF770xW iznr17BZHLn2nd3i+rc3jBafXj5gtNhyvYnJ4vnDh+wWEx62sVtM2yhusbK7mc1i+7O3TBYr Ox+wWlzeNYfN4t6a/6wWi4/cZrZ492wys8XVVQfZLc7/Pc5q8WPDY1YHEY/5Oz8yeuycdZfd Y8GmUo/Fe14yeWxa1cnmsenTJHaPrrdXmDxOzPjN4vHkynQmj49Pb7F4vN93lc2jb8sqRo/P m+Q8Nj15C1TR8oU1gD+KyyYlNSezLLVI3y6BK+PUgh2sBUe4Kib0/GBtYLzM0cXIySEhYCIx Y8l7JghbTOLCvfVsXYxcHEICSxklvt/sZIZw+pgkHrZtAatiE9CT+DdrOxuILSKgILG59xkr SBGzwAFWie5FJ9i7GDk4hAWyJQ6+TwQxWQRUJXrfWYGU8wq4Syz6dpkVYpmcxN7Jq1lAbE6g +IEfL9ghdjUxSizb+5tpAiPvAkaGVYyiqaXJBcVJ6blGesWJucWleel6yfm5mxghkfN1B+PS Y1aHGAU4GJV4eCeKK4UIsSaWFVfmHmKU4GBWEuEN2wMU4k1JrKxKLcqPLyrNSS0+xMjEwSnV wHjtsuZ+FsW4/X6Fear766f5aV3jtYmYvcb00HGZ7d+6lAKmHxflXmDgO/WH8VUrO78vh4wX R1sd/s/DJ2HIN3lF54OAq2suVUaXHL6pcZrHJ3DGc7PlJT96Fv3I/mzxtO/ttsOGjg8T4msZ 35VyZBi2yaqft5HYHlUeOEvkxokzKbKLVM+tD1JiKc5INNRiLipOBAA2EAkkegIAAA== 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 8552986..7811eb2 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -38,6 +38,7 @@ #include #include #include +#include #include "internal.h" #include "mount.h" @@ -1395,6 +1396,10 @@ 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; } -- 2.1.1