From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753625AbdLMChq (ORCPT ); Tue, 12 Dec 2017 21:37:46 -0500 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:19646 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753289AbdLMB7D (ORCPT ); Tue, 12 Dec 2017 20:59:03 -0500 From: alexander.levin@verizon.com Cc: Dan Carpenter , David Sterba , alexander.levin@verizon.com X-Host: surveyor.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 065/100] Btrfs: fix an integer overflow check Thread-Topic: [PATCH AUTOSEL for 4.9 065/100] Btrfs: fix an integer overflow check Thread-Index: AQHTc7XBjCFlK+O4QkKFtnUxF8WVuA== Date: Wed, 13 Dec 2017 01:57:38 +0000 Message-ID: <20171213015722.6722-40-alexander.levin@verizon.com> References: <20171213015722.6722-1-alexander.levin@verizon.com> In-Reply-To: <20171213015722.6722-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vBD2bnAq019955 From: Dan Carpenter [ Upstream commit 457ae7268b29c33dee1c0feb143a15f6029d177b ] This isn't super serious because you need CAP_ADMIN to run this code. I added this integer overflow check last year but apparently I am rubbish at writing integer overflow checks... There are two issues. First, access_ok() works on unsigned long type and not u64 so on 32 bit systems the access_ok() could be checking a truncated size. The other issue is that we should be using a stricter limit so we don't overflow the kzalloc() setting ctx->clone_roots later in the function after the access_ok(): alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1); sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN); Fixes: f5ecec3ce21f ("btrfs: send: silence an integer overflow warning") Signed-off-by: Dan Carpenter Reviewed-by: David Sterba [ added comment ] Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/send.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 77f9efc1f7aa..9a47b5598df7 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -6196,8 +6196,13 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) goto out; } + /* + * Check that we don't overflow at later allocations, we request + * clone_sources_count + 1 items, and compare to unsigned long inside + * access_ok. + */ if (arg->clone_sources_count > - ULLONG_MAX / sizeof(*arg->clone_sources)) { + ULONG_MAX / sizeof(struct clone_root) - 1) { ret = -EINVAL; goto out; } -- 2.11.0