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 5CA7E28EB for ; Mon, 30 Jan 2023 14:06:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4152C433EF; Mon, 30 Jan 2023 14:06:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675087578; bh=v84peDmP8zZ7T0DmHVDZf8FLD5XUNOd62oI7QusZVw8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X/hJOV4m7F506eI0Dst+gmAS8aA6SNV6ASS0XkosJLDfvDzpvoWFtie1CZvMcwCfi IOwVezlhsHJRDkOcaf4jo8gGu4Eznyd7I2UGdV67bgrgaRwLkgB386znZ5et8KeWqD H+g5iZV/uj44OcTQd+TxnXJNQfFhu62VQ5JqLNfY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 254/313] netlink: prevent potential spectre v1 gadgets Date: Mon, 30 Jan 2023 14:51:29 +0100 Message-Id: <20230130134348.548152904@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134336.532886729@linuxfoundation.org> References: <20230130134336.532886729@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: Eric Dumazet [ Upstream commit f0950402e8c76e7dcb08563f1b4e8000fbc62455 ] Most netlink attributes are parsed and validated from __nla_validate_parse() or validate_nla() u16 type = nla_type(nla); if (type == 0 || type > maxtype) { /* error or continue */ } @type is then used as an array index and can be used as a Spectre v1 gadget. array_index_nospec() can be used to prevent leaking content of kernel memory to malicious users. This should take care of vast majority of netlink uses, but an audit is needed to take care of others where validation is not yet centralized in core netlink functions. Fixes: bfa83a9e03cf ("[NETLINK]: Type-safe netlink messages/attributes interface") Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20230119110150.2678537-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- lib/nlattr.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/nlattr.c b/lib/nlattr.c index b67a53e29b8f..dffd60e4065f 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -381,6 +382,7 @@ static int validate_nla(const struct nlattr *nla, int maxtype, if (type <= 0 || type > maxtype) return 0; + type = array_index_nospec(type, maxtype + 1); pt = &policy[type]; BUG_ON(pt->type > NLA_TYPE_MAX); @@ -596,6 +598,7 @@ static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, } continue; } + type = array_index_nospec(type, maxtype + 1); if (policy) { int err = validate_nla(nla, maxtype, policy, validate, extack, depth); -- 2.39.0