From patchwork Mon Oct 5 22:07:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Kicinski X-Patchwork-Id: 288964 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB1C9C4363A for ; Mon, 5 Oct 2020 22:08:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDABE20774 for ; Mon, 5 Oct 2020 22:08:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601935686; bh=rLAzRrPzCIffbWgQ6B3m159jDopLPkqEUnliW2Fc1Yg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FbzlEEWQiWU0C2pYh+4BlzOgRF/38qSoux2wTKeOnAVpaalMTAqhDXbjZXAwWbvcg 8VTjSOE/7aRpXIH7Rv+AZGrGKFJACki33thT/k9lKvnPpvELs0tDyCfrSKh93HcLid 3Y3KmPPjhSowVgQJc0b+4vlIo3Gta621KZhienq8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727097AbgJEWIF (ORCPT ); Mon, 5 Oct 2020 18:08:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:48272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727032AbgJEWHw (ORCPT ); Mon, 5 Oct 2020 18:07:52 -0400 Received: from kicinski-fedora-PC1C0HJN.thefacebook.com (unknown [163.114.132.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AD09820791; Mon, 5 Oct 2020 22:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601935672; bh=rLAzRrPzCIffbWgQ6B3m159jDopLPkqEUnliW2Fc1Yg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CuWvBGlu9HeYUuBCp56A69zw0EEzjoYqCcaXHVamIqMAnDsVtaqJ4LNQtbugAGyNy UmnUv5fU5sBUOXhzzOY9OcoJ7M1vurH1qZRvWBGLBDuzL8rOzR6vyuf4BRiIxgjhHq eRfZR0yFTd1OyzKWNzomkX+FCOrqW2J4Msg9AwXM= From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, kernel-team@fb.com, johannes@sipsolutions.net, jiri@resnulli.us, andrew@lunn.ch, mkubecek@suse.cz, Jakub Kicinski , dsahern@gmail.com, pablo@netfilter.org Subject: [PATCH net-next v2 6/7] netlink: add mask validation Date: Mon, 5 Oct 2020 15:07:38 -0700 Message-Id: <20201005220739.2581920-7-kuba@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201005220739.2581920-1-kuba@kernel.org> References: <20201005220739.2581920-1-kuba@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We don't have good validation policy for existing unsigned int attrs which serve as flags (for new ones we could use NLA_BITFIELD32). With increased use of policy dumping having the validation be expressed as part of the policy is important. Add validation policy in form of a mask of supported/valid bits. Support u64 in the uAPI to be future-proof, but really for now the embedded mask member can only hold 32 bits, so anything with bit 32+ set will always fail validation. Signed-off-by: Jakub Kicinski --- CC: jiri@resnulli.us CC: dsahern@gmail.com CC: pablo@netfilter.org --- include/net/netlink.h | 10 ++++++++++ include/uapi/linux/netlink.h | 2 ++ lib/nlattr.c | 36 ++++++++++++++++++++++++++++++++++++ net/netlink/policy.c | 8 ++++++++ 4 files changed, 56 insertions(+) diff --git a/include/net/netlink.h b/include/net/netlink.h index c5aa46f379bc..2b9e41075f19 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -200,6 +200,7 @@ enum nla_policy_validation { NLA_VALIDATE_RANGE_WARN_TOO_LONG, NLA_VALIDATE_MIN, NLA_VALIDATE_MAX, + NLA_VALIDATE_MASK, NLA_VALIDATE_RANGE_PTR, NLA_VALIDATE_FUNCTION, }; @@ -317,6 +318,7 @@ struct nla_policy { u16 len; union { const u32 bitfield32_valid; + const u32 mask; const char *reject_message; const struct nla_policy *nested_policy; struct netlink_range_validation *range; @@ -368,6 +370,8 @@ struct nla_policy { (tp == NLA_S8 || tp == NLA_S16 || tp == NLA_S32 || tp == NLA_S64) #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition)) +#define NLA_ENSURE_UINT_TYPE(tp) \ + (__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp)) + tp) #define NLA_ENSURE_UINT_OR_BINARY_TYPE(tp) \ (__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) || \ tp == NLA_MSECS || \ @@ -416,6 +420,12 @@ struct nla_policy { .max = _max, \ } +#define NLA_POLICY_MASK(tp, _mask) { \ + .type = NLA_ENSURE_UINT_TYPE(tp), \ + .validation_type = NLA_VALIDATE_MASK, \ + .mask = _mask, \ +} + #define NLA_POLICY_VALIDATE_FN(tp, fn, ...) { \ .type = NLA_ENSURE_NO_VALIDATION_PTR(tp), \ .validation_type = NLA_VALIDATE_FUNCTION, \ diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index eac8a6a648ea..d02e472ba54c 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -331,6 +331,7 @@ enum netlink_attribute_type { * the index, if limited inside the nesting (U32) * @NL_POLICY_TYPE_ATTR_BITFIELD32_MASK: valid mask for the * bitfield32 type (U32) + * @NL_POLICY_TYPE_ATTR_MASK: mask of valid bits for unsigned integers (U64) * @NL_POLICY_TYPE_ATTR_PAD: pad attribute for 64-bit alignment */ enum netlink_policy_type_attr { @@ -346,6 +347,7 @@ enum netlink_policy_type_attr { NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE, NL_POLICY_TYPE_ATTR_BITFIELD32_MASK, NL_POLICY_TYPE_ATTR_PAD, + NL_POLICY_TYPE_ATTR_MASK, /* keep last */ __NL_POLICY_TYPE_ATTR_MAX, diff --git a/lib/nlattr.c b/lib/nlattr.c index 80ff9fe83696..9c99f5daa4d2 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -323,6 +323,37 @@ static int nla_validate_int_range(const struct nla_policy *pt, } } +static int nla_validate_mask(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack) +{ + u64 value; + + switch (pt->type) { + case NLA_U8: + value = nla_get_u8(nla); + break; + case NLA_U16: + value = nla_get_u16(nla); + break; + case NLA_U32: + value = nla_get_u32(nla); + break; + case NLA_U64: + value = nla_get_u64(nla); + break; + default: + return -EINVAL; + } + + if (value & ~(u64)pt->mask) { + NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set"); + return -EINVAL; + } + + return 0; +} + static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy, unsigned int validate, struct netlink_ext_ack *extack, unsigned int depth) @@ -503,6 +534,11 @@ static int validate_nla(const struct nlattr *nla, int maxtype, if (err) return err; break; + case NLA_VALIDATE_MASK: + err = nla_validate_mask(pt, nla, extack); + if (err) + return err; + break; case NLA_VALIDATE_FUNCTION: if (pt->validate) { err = pt->validate(nla, extack); diff --git a/net/netlink/policy.c b/net/netlink/policy.c index cf23c0151721..ee26d01328ee 100644 --- a/net/netlink/policy.c +++ b/net/netlink/policy.c @@ -263,6 +263,14 @@ int netlink_policy_dump_write(struct sk_buff *skb, else type = NL_ATTR_TYPE_U64; + if (pt->validation_type == NLA_VALIDATE_MASK) { + if (nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MASK, + pt->mask, + NL_POLICY_TYPE_ATTR_PAD)) + goto nla_put_failure; + break; + } + nla_get_range_unsigned(pt, &range); if (nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MIN_VALUE_U,