From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 03F52847A for ; Wed, 1 Mar 2023 18:07:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EC66C433D2; Wed, 1 Mar 2023 18:07:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1677694074; bh=iiPK7T1EqMObnDz3nUiRtuXd2lrqrU/nX4PMSHEMI+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U2FZ3EnSXZpifuENHc66gb5Rlymygk5sJ90q2gFX60acz+s2OcbZ1WBzzyRTk/OGW Klg3AowYjnWVYCyUVRhOlkWpmeV6/EsOsT+kNInEH+/beu8mmeBYa07rJ9rgYbMMPI TetMyk9tkZUWMdKkhhvNM94Q4p+udJRpzQK5qlCQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+4376a9a073770c173269@syzkaller.appspotmail.com, David Sterba , Sasha Levin Subject: [PATCH 4.19 3/9] btrfs: send: limit number of clones and allocated memory size Date: Wed, 1 Mar 2023 19:07:19 +0100 Message-Id: <20230301180650.526926914@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230301180650.395562988@linuxfoundation.org> References: <20230301180650.395562988@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: David Sterba [ Upstream commit 33e17b3f5ab74af12aca58c515bc8424ff69a343 ] The arg->clone_sources_count is u64 and can trigger a warning when a huge value is passed from user space and a huge array is allocated. Limit the allocated memory to 8MiB (can be increased if needed), which in turn limits the number of clone sources to 8M / sizeof(struct clone_root) = 8M / 40 = 209715. Real world number of clones is from tens to hundreds, so this is future proof. Reported-by: syzbot+4376a9a073770c173269@syzkaller.appspotmail.com Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/send.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 80d248e88761d..1f535cd990d3c 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -6826,10 +6826,10 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg) /* * Check that we don't overflow at later allocations, we request * clone_sources_count + 1 items, and compare to unsigned long inside - * access_ok. + * access_ok. Also set an upper limit for allocation size so this can't + * easily exhaust memory. Max number of clone sources is about 200K. */ - if (arg->clone_sources_count > - ULONG_MAX / sizeof(struct clone_root) - 1) { + if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) { ret = -EINVAL; goto out; } -- 2.39.0