From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:52422 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751297AbcKGKVW (ORCPT ); Mon, 7 Nov 2016 05:21:22 -0500 From: Li Wang To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] vfs: fix statfs64() does not handle errors Date: Mon, 7 Nov 2016 18:21:17 +0800 Message-Id: <1478514077-24855-1-git-send-email-liwang@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: statfs64() does NOT return -1 and setting errno to EOVERFLOW when some variables(like: f_bsize) overflowed in the returned struct. reproducer: step1. mount hugetlbfs with two different pagesize on ppc64 arch. $ hugeadm --pool-pages-max 16M:0 $ hugeadm --create-mount $ mount | grep -i hugetlbfs none on /var/lib/hugetlbfs/pagesize-16MB type hugetlbfs (rw,relatime,seclabel,pagesize=16777216) none on /var/lib/hugetlbfs/pagesize-16GB type hugetlbfs (rw,relatime,seclabel,pagesize=17179869184) step2. compile & run this C program. $ cat statfs64_test.c #define _LARGEFILE64_SOURCE #include #include int main() { struct statfs64 sb; int err; err = statfs64("/var/lib/hugetlbfs/pagesize-16GB", &sb); if (err) return -1; printf("sizeof f_bsize = %d, f_bsize=%ld\n", sizeof(sb.f_bsize), sb.f_bsize); return 0; } $ gcc -m32 statfs64_test.c $ ./a.out sizeof f_bsize = 4, f_bsize=0 Signed-off-by: Li Wang --- Notes: This is my first patch to kernel fs part, I'm not sure if this one useful, but just want someone have a look. thanks~ fs/statfs.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/fs/statfs.c b/fs/statfs.c index 083dc0a..849dde95 100644 --- a/fs/statfs.c +++ b/fs/statfs.c @@ -151,6 +151,23 @@ static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) if (sizeof(buf) == sizeof(*st)) memcpy(&buf, st, sizeof(*st)); else { + if (sizeof buf.f_bsize == 4) { + if ((st->f_blocks | st->f_bfree | st->f_bavail | + st->f_bsize | st->f_frsize) & + 0xffffffff00000000ULL) + return -EOVERFLOW; + /* + * f_files and f_ffree may be -1; it's okay to stuff + * that into 32 bits + */ + if (st->f_files != -1 && + (st->f_files & 0xffffffff00000000ULL)) + return -EOVERFLOW; + if (st->f_ffree != -1 && + (st->f_ffree & 0xffffffff00000000ULL)) + return -EOVERFLOW; + } + buf.f_type = st->f_type; buf.f_bsize = st->f_bsize; buf.f_blocks = st->f_blocks; -- 1.8.3.1