From patchwork Thu Apr 30 20:13:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 220133 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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 3CC61C47254 for ; Thu, 30 Apr 2020 20:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23E2220774 for ; Thu, 30 Apr 2020 20:13:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727800AbgD3UN1 (ORCPT ); Thu, 30 Apr 2020 16:13:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727087AbgD3UNY (ORCPT ); Thu, 30 Apr 2020 16:13:24 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73523C08E859; Thu, 30 Apr 2020 13:13:24 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jUFYg-002qzz-F2; Thu, 30 Apr 2020 22:13:22 +0200 From: Johannes Berg To: netdev@vger.kernel.org Cc: Antonio Quartulli , linux-wireless@vger.kernel.org, Johannes Berg Subject: [PATCH v2 3/8] nl80211: link recursive netlink nested policy Date: Thu, 30 Apr 2020 22:13:07 +0200 Message-Id: <20200430221106.3dbafdcac667.I697e382aa8ac181afe32ffac50b330c558bc34b1@changeid> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200430201312.60143-1-johannes@sipsolutions.net> References: <20200430201312.60143-1-johannes@sipsolutions.net> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Johannes Berg Now that we have limited recursive policy validation to avoid stack overflows, change nl80211 to actually link the nested policy (linking back to itself eventually), which allows some code cleanups. Signed-off-by: Johannes Berg --- net/wireless/nl80211.c | 10 ++++------ net/wireless/nl80211.h | 2 -- net/wireless/pmsr.c | 3 +-- 3 files changed, 5 insertions(+), 10 deletions(-) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 692bcd35f809..57c618b6cb0e 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -253,6 +253,8 @@ static int validate_ie_attr(const struct nlattr *attr, } /* policy for the attributes */ +static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR]; + static const struct nla_policy nl80211_ftm_responder_policy[NL80211_FTM_RESP_ATTR_MAX + 1] = { [NL80211_FTM_RESP_ATTR_ENABLED] = { .type = NLA_FLAG, }, @@ -296,11 +298,7 @@ nl80211_pmsr_req_attr_policy[NL80211_PMSR_REQ_ATTR_MAX + 1] = { static const struct nla_policy nl80211_psmr_peer_attr_policy[NL80211_PMSR_PEER_ATTR_MAX + 1] = { [NL80211_PMSR_PEER_ATTR_ADDR] = NLA_POLICY_ETH_ADDR, - /* - * we could specify this again to be the top-level policy, - * but that would open us up to recursion problems ... - */ - [NL80211_PMSR_PEER_ATTR_CHAN] = { .type = NLA_NESTED }, + [NL80211_PMSR_PEER_ATTR_CHAN] = NLA_POLICY_NESTED(nl80211_policy), [NL80211_PMSR_PEER_ATTR_REQ] = NLA_POLICY_NESTED(nl80211_pmsr_req_attr_policy), [NL80211_PMSR_PEER_ATTR_RESP] = { .type = NLA_REJECT }, @@ -347,7 +345,7 @@ nl80211_tid_config_attr_policy[NL80211_TID_CONFIG_ATTR_MAX + 1] = { NLA_POLICY_MAX(NLA_U8, NL80211_TID_CONFIG_DISABLE), }; -const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { +static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [0] = { .strict_start_type = NL80211_ATTR_HE_OBSS_PD }, [NL80211_ATTR_WIPHY] = { .type = NLA_U32 }, [NL80211_ATTR_WIPHY_NAME] = { .type = NLA_NUL_STRING, diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h index a41e94a49a89..d3e8e426c486 100644 --- a/net/wireless/nl80211.h +++ b/net/wireless/nl80211.h @@ -11,8 +11,6 @@ int nl80211_init(void); void nl80211_exit(void); -extern const struct nla_policy nl80211_policy[NUM_NL80211_ATTR]; - void *nl80211hdr_put(struct sk_buff *skb, u32 portid, u32 seq, int flags, u8 cmd); bool nl80211_put_sta_rate(struct sk_buff *msg, struct rate_info *info, diff --git a/net/wireless/pmsr.c b/net/wireless/pmsr.c index 63dc8023447f..a95c79d18349 100644 --- a/net/wireless/pmsr.c +++ b/net/wireless/pmsr.c @@ -187,10 +187,9 @@ static int pmsr_parse_peer(struct cfg80211_registered_device *rdev, /* reuse info->attrs */ memset(info->attrs, 0, sizeof(*info->attrs) * (NL80211_ATTR_MAX + 1)); - /* need to validate here, we don't want to have validation recursion */ err = nla_parse_nested_deprecated(info->attrs, NL80211_ATTR_MAX, tb[NL80211_PMSR_PEER_ATTR_CHAN], - nl80211_policy, info->extack); + NULL, info->extack); if (err) return err; From patchwork Thu Apr 30 20:13:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 220130 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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 7DD2CC47247 for ; Thu, 30 Apr 2020 20:13:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6628620774 for ; Thu, 30 Apr 2020 20:13:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727841AbgD3UNo (ORCPT ); Thu, 30 Apr 2020 16:13:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727089AbgD3UNZ (ORCPT ); Thu, 30 Apr 2020 16:13:25 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3E9DC08ED7D; Thu, 30 Apr 2020 13:13:24 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jUFYh-002qzz-57; Thu, 30 Apr 2020 22:13:23 +0200 From: Johannes Berg To: netdev@vger.kernel.org Cc: Antonio Quartulli , linux-wireless@vger.kernel.org, Johannes Berg Subject: [PATCH v2 5/8] netlink: allow NLA_MSECS to have range validation Date: Thu, 30 Apr 2020 22:13:09 +0200 Message-Id: <20200430221106.3c17837abd4c.I46e9164d064042d49227b9af7a686b3a02080ff0@changeid> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200430201312.60143-1-johannes@sipsolutions.net> References: <20200430201312.60143-1-johannes@sipsolutions.net> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Johannes Berg Since NLA_MSECS is really equivalent to NLA_U64, allow it to have range validation as well. Signed-off-by: Johannes Berg --- include/net/netlink.h | 6 ++++-- lib/nlattr.c | 2 ++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/net/netlink.h b/include/net/netlink.h index 94a7df4ab122..4acd7165e900 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -371,7 +371,8 @@ struct nla_policy { #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition)) #define NLA_ENSURE_UINT_TYPE(tp) \ (__NLA_ENSURE(tp == NLA_U8 || tp == NLA_U16 || \ - tp == NLA_U32 || tp == NLA_U64) + tp) + tp == NLA_U32 || tp == NLA_U64 || \ + tp == NLA_MSECS) + tp) #define NLA_ENSURE_SINT_TYPE(tp) \ (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_S16 || \ tp == NLA_S32 || tp == NLA_S64) + tp) @@ -379,7 +380,8 @@ struct nla_policy { (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 || \ tp == NLA_S16 || tp == NLA_U16 || \ tp == NLA_S32 || tp == NLA_U32 || \ - tp == NLA_S64 || tp == NLA_U64) + tp) + tp == NLA_S64 || tp == NLA_U64 || \ + tp == NLA_MSECS) + tp) #define NLA_ENSURE_NO_VALIDATION_PTR(tp) \ (__NLA_ENSURE(tp != NLA_BITFIELD32 && \ tp != NLA_REJECT && \ diff --git a/lib/nlattr.c b/lib/nlattr.c index a8beb173f558..21ef3998b9d9 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -151,6 +151,7 @@ static int nla_validate_int_range_unsigned(const struct nla_policy *pt, value = nla_get_u32(nla); break; case NLA_U64: + case NLA_MSECS: value = nla_get_u64(nla); break; default: @@ -227,6 +228,7 @@ static int nla_validate_int_range(const struct nla_policy *pt, case NLA_U16: case NLA_U32: case NLA_U64: + case NLA_MSECS: return nla_validate_int_range_unsigned(pt, nla, extack); case NLA_S8: case NLA_S16: From patchwork Thu Apr 30 20:13:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 220131 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=-6.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, UNWANTED_LANGUAGE_BODY,UPPERCASE_50_75,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 36256C47257 for ; Thu, 30 Apr 2020 20:13:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13F5E20774 for ; Thu, 30 Apr 2020 20:13:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727837AbgD3UNk (ORCPT ); Thu, 30 Apr 2020 16:13:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727100AbgD3UNZ (ORCPT ); Thu, 30 Apr 2020 16:13:25 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32EDAC035494; Thu, 30 Apr 2020 13:13:25 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jUFYh-002qzz-FJ; Thu, 30 Apr 2020 22:13:23 +0200 From: Johannes Berg To: netdev@vger.kernel.org Cc: Antonio Quartulli , linux-wireless@vger.kernel.org, Johannes Berg Subject: [PATCH v2 6/8] netlink: remove NLA_EXACT_LEN_WARN Date: Thu, 30 Apr 2020 22:13:10 +0200 Message-Id: <20200430221106.370aafeaec9f.I9a91078267348ef563217cb525e8e357eba4b487@changeid> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200430201312.60143-1-johannes@sipsolutions.net> References: <20200430201312.60143-1-johannes@sipsolutions.net> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Johannes Berg Use a validation type instead, so we can later expose the NLA_* values to userspace for policy descriptions. Some transformations were done with this spatch: @@ identifier p; expression X, L, A; @@ struct nla_policy p[X] = { [A] = -{ .type = NLA_EXACT_LEN_WARN, .len = L }, +NLA_POLICY_EXACT_LEN_WARN(L), ... }; Signed-off-by: Johannes Berg --- include/net/netlink.h | 15 ++++---- lib/nlattr.c | 16 +++++---- net/wireless/nl80211.c | 81 ++++++++++-------------------------------- 3 files changed, 36 insertions(+), 76 deletions(-) diff --git a/include/net/netlink.h b/include/net/netlink.h index 4acd7165e900..4d4a733f1e8d 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -182,7 +182,6 @@ enum { NLA_BITFIELD32, NLA_REJECT, NLA_EXACT_LEN, - NLA_EXACT_LEN_WARN, NLA_MIN_LEN, __NLA_TYPE_MAX, }; @@ -204,6 +203,7 @@ enum nla_policy_validation { NLA_VALIDATE_MAX, NLA_VALIDATE_RANGE_PTR, NLA_VALIDATE_FUNCTION, + NLA_VALIDATE_WARN_TOO_LONG, }; /** @@ -237,10 +237,10 @@ enum nla_policy_validation { * just like "All other" * NLA_BITFIELD32 Unused * NLA_REJECT Unused - * NLA_EXACT_LEN Attribute must have exactly this length, otherwise - * it is rejected. - * NLA_EXACT_LEN_WARN Attribute should have exactly this length, a warning - * is logged if it is longer, shorter is rejected. + * NLA_EXACT_LEN Attribute should have exactly this length, otherwise + * it is rejected or warned about, the latter happening + * if and only if the `validation_type' is set to + * NLA_VALIDATE_WARN_TOO_LONG. * NLA_MIN_LEN Minimum length of attribute payload * All other Minimum length of attribute payload * @@ -350,8 +350,9 @@ struct nla_policy { }; #define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len } -#define NLA_POLICY_EXACT_LEN_WARN(_len) { .type = NLA_EXACT_LEN_WARN, \ - .len = _len } +#define NLA_POLICY_EXACT_LEN_WARN(_len) \ + { .type = NLA_EXACT_LEN, .len = _len, \ + .validation_type = NLA_VALIDATE_WARN_TOO_LONG, } #define NLA_POLICY_MIN_LEN(_len) { .type = NLA_MIN_LEN, .len = _len } #define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN) diff --git a/lib/nlattr.c b/lib/nlattr.c index 21ef3998b9d9..6dcbe1bedd3b 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -261,7 +261,9 @@ static int validate_nla(const struct nlattr *nla, int maxtype, BUG_ON(pt->type > NLA_TYPE_MAX); if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) || - (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) { + (pt->type == NLA_EXACT_LEN && + pt->validation_type == NLA_VALIDATE_WARN_TOO_LONG && + attrlen != pt->len)) { pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", current->comm, type); if (validate & NL_VALIDATE_STRICT_ATTRS) { @@ -287,11 +289,6 @@ static int validate_nla(const struct nlattr *nla, int maxtype, } switch (pt->type) { - case NLA_EXACT_LEN: - if (attrlen != pt->len) - goto out_err; - break; - case NLA_REJECT: if (extack && pt->reject_message) { NL_SET_BAD_ATTR(extack, nla); @@ -405,6 +402,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype, goto out_err; break; + case NLA_EXACT_LEN: + if (pt->validation_type != NLA_VALIDATE_WARN_TOO_LONG) { + if (attrlen != pt->len) + goto out_err; + break; + } + /* fall through */ default: if (pt->len) minlen = pt->len; diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 57c618b6cb0e..519414468b5d 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -376,11 +376,8 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_IFINDEX] = { .type = NLA_U32 }, [NL80211_ATTR_IFNAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ-1 }, - [NL80211_ATTR_MAC] = { .type = NLA_EXACT_LEN_WARN, .len = ETH_ALEN }, - [NL80211_ATTR_PREV_BSSID] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_ATTR_MAC] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), + [NL80211_ATTR_PREV_BSSID] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_ATTR_KEY] = { .type = NLA_NESTED, }, [NL80211_ATTR_KEY_DATA] = { .type = NLA_BINARY, @@ -432,10 +429,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_MESH_CONFIG] = { .type = NLA_NESTED }, [NL80211_ATTR_SUPPORT_MESH_AUTH] = { .type = NLA_FLAG }, - [NL80211_ATTR_HT_CAPABILITY] = { - .type = NLA_EXACT_LEN_WARN, - .len = NL80211_HT_CAPABILITY_LEN - }, + [NL80211_ATTR_HT_CAPABILITY] = NLA_POLICY_EXACT_LEN_WARN(NL80211_HT_CAPABILITY_LEN), [NL80211_ATTR_MGMT_SUBTYPE] = { .type = NLA_U8 }, [NL80211_ATTR_IE] = NLA_POLICY_VALIDATE_FN(NLA_BINARY, @@ -466,10 +460,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_WPA_VERSIONS] = { .type = NLA_U32 }, [NL80211_ATTR_PID] = { .type = NLA_U32 }, [NL80211_ATTR_4ADDR] = { .type = NLA_U8 }, - [NL80211_ATTR_PMKID] = { - .type = NLA_EXACT_LEN_WARN, - .len = WLAN_PMKID_LEN - }, + [NL80211_ATTR_PMKID] = NLA_POLICY_EXACT_LEN_WARN(WLAN_PMKID_LEN), [NL80211_ATTR_DURATION] = { .type = NLA_U32 }, [NL80211_ATTR_COOKIE] = { .type = NLA_U64 }, [NL80211_ATTR_TX_RATES] = { .type = NLA_NESTED }, @@ -533,10 +524,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_WDEV] = { .type = NLA_U64 }, [NL80211_ATTR_USER_REG_HINT_TYPE] = { .type = NLA_U32 }, [NL80211_ATTR_AUTH_DATA] = { .type = NLA_BINARY, }, - [NL80211_ATTR_VHT_CAPABILITY] = { - .type = NLA_EXACT_LEN_WARN, - .len = NL80211_VHT_CAPABILITY_LEN - }, + [NL80211_ATTR_VHT_CAPABILITY] = NLA_POLICY_EXACT_LEN_WARN(NL80211_VHT_CAPABILITY_LEN), [NL80211_ATTR_SCAN_FLAGS] = { .type = NLA_U32 }, [NL80211_ATTR_P2P_CTWINDOW] = NLA_POLICY_MAX(NLA_U8, 127), [NL80211_ATTR_P2P_OPPPS] = NLA_POLICY_MAX(NLA_U8, 1), @@ -574,10 +562,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_VENDOR_DATA] = { .type = NLA_BINARY }, [NL80211_ATTR_QOS_MAP] = { .type = NLA_BINARY, .len = IEEE80211_QOS_MAP_LEN_MAX }, - [NL80211_ATTR_MAC_HINT] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_ATTR_MAC_HINT] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_ATTR_WIPHY_FREQ_HINT] = { .type = NLA_U32 }, [NL80211_ATTR_TDLS_PEER_CAPABILITY] = { .type = NLA_U32 }, [NL80211_ATTR_SOCKET_OWNER] = { .type = NLA_FLAG }, @@ -589,10 +574,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_ADMITTED_TIME] = { .type = NLA_U16 }, [NL80211_ATTR_SMPS_MODE] = { .type = NLA_U8 }, [NL80211_ATTR_OPER_CLASS] = { .type = NLA_U8 }, - [NL80211_ATTR_MAC_MASK] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_ATTR_MAC_MASK] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_ATTR_WIPHY_SELF_MANAGED_REG] = { .type = NLA_FLAG }, [NL80211_ATTR_NETNS_FD] = { .type = NLA_U32 }, [NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 }, @@ -604,21 +586,15 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_MU_MIMO_GROUP_DATA] = { .len = VHT_MUMIMO_GROUPS_DATA_LEN }, - [NL80211_ATTR_MU_MIMO_FOLLOW_MAC_ADDR] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_ATTR_MU_MIMO_FOLLOW_MAC_ADDR] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_ATTR_NAN_MASTER_PREF] = NLA_POLICY_MIN(NLA_U8, 1), [NL80211_ATTR_BANDS] = { .type = NLA_U32 }, [NL80211_ATTR_NAN_FUNC] = { .type = NLA_NESTED }, [NL80211_ATTR_FILS_KEK] = { .type = NLA_BINARY, .len = FILS_MAX_KEK_LEN }, - [NL80211_ATTR_FILS_NONCES] = { - .type = NLA_EXACT_LEN_WARN, - .len = 2 * FILS_NONCE_LEN - }, + [NL80211_ATTR_FILS_NONCES] = NLA_POLICY_EXACT_LEN_WARN(2 * FILS_NONCE_LEN), [NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED] = { .type = NLA_FLAG, }, - [NL80211_ATTR_BSSID] = { .type = NLA_EXACT_LEN_WARN, .len = ETH_ALEN }, + [NL80211_ATTR_BSSID] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] = { .type = NLA_S8 }, [NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST] = { .len = sizeof(struct nl80211_bss_select_rssi_adjust) @@ -631,7 +607,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_FILS_ERP_NEXT_SEQ_NUM] = { .type = NLA_U16 }, [NL80211_ATTR_FILS_ERP_RRK] = { .type = NLA_BINARY, .len = FILS_ERP_MAX_RRK_LEN }, - [NL80211_ATTR_FILS_CACHE_ID] = { .type = NLA_EXACT_LEN_WARN, .len = 2 }, + [NL80211_ATTR_FILS_CACHE_ID] = NLA_POLICY_EXACT_LEN_WARN(2), [NL80211_ATTR_PMK] = { .type = NLA_BINARY, .len = PMK_MAX_LEN }, [NL80211_ATTR_SCHED_SCAN_MULTI] = { .type = NLA_FLAG }, [NL80211_ATTR_EXTERNAL_AUTH_SUPPORT] = { .type = NLA_FLAG }, @@ -701,10 +677,7 @@ static const struct nla_policy nl80211_wowlan_tcp_policy[NUM_NL80211_WOWLAN_TCP] = { [NL80211_WOWLAN_TCP_SRC_IPV4] = { .type = NLA_U32 }, [NL80211_WOWLAN_TCP_DST_IPV4] = { .type = NLA_U32 }, - [NL80211_WOWLAN_TCP_DST_MAC] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_WOWLAN_TCP_DST_MAC] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_WOWLAN_TCP_SRC_PORT] = { .type = NLA_U16 }, [NL80211_WOWLAN_TCP_DST_PORT] = { .type = NLA_U16 }, [NL80211_WOWLAN_TCP_DATA_PAYLOAD] = { .type = NLA_MIN_LEN, .len = 1 }, @@ -734,18 +707,9 @@ nl80211_coalesce_policy[NUM_NL80211_ATTR_COALESCE_RULE] = { /* policy for GTK rekey offload attributes */ static const struct nla_policy nl80211_rekey_policy[NUM_NL80211_REKEY_DATA] = { - [NL80211_REKEY_DATA_KEK] = { - .type = NLA_EXACT_LEN_WARN, - .len = NL80211_KEK_LEN, - }, - [NL80211_REKEY_DATA_KCK] = { - .type = NLA_EXACT_LEN_WARN, - .len = NL80211_KCK_LEN, - }, - [NL80211_REKEY_DATA_REPLAY_CTR] = { - .type = NLA_EXACT_LEN_WARN, - .len = NL80211_REPLAY_CTR_LEN - }, + [NL80211_REKEY_DATA_KEK] = NLA_POLICY_EXACT_LEN_WARN(NL80211_KEK_LEN), + [NL80211_REKEY_DATA_KCK] = NLA_POLICY_EXACT_LEN_WARN(NL80211_KCK_LEN), + [NL80211_REKEY_DATA_REPLAY_CTR] = NLA_POLICY_EXACT_LEN_WARN(NL80211_REPLAY_CTR_LEN), }; static const struct nla_policy @@ -760,10 +724,7 @@ static const struct nla_policy nl80211_match_policy[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1] = { [NL80211_SCHED_SCAN_MATCH_ATTR_SSID] = { .type = NLA_BINARY, .len = IEEE80211_MAX_SSID_LEN }, - [NL80211_SCHED_SCAN_MATCH_ATTR_BSSID] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_SCHED_SCAN_MATCH_ATTR_BSSID] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_SCHED_SCAN_MATCH_ATTR_RSSI] = { .type = NLA_U32 }, [NL80211_SCHED_SCAN_MATCH_PER_BAND_RSSI] = NLA_POLICY_NESTED(nl80211_match_band_rssi_policy), @@ -795,10 +756,7 @@ nl80211_nan_func_policy[NL80211_NAN_FUNC_ATTR_MAX + 1] = { [NL80211_NAN_FUNC_SUBSCRIBE_ACTIVE] = { .type = NLA_FLAG }, [NL80211_NAN_FUNC_FOLLOW_UP_ID] = { .type = NLA_U8 }, [NL80211_NAN_FUNC_FOLLOW_UP_REQ_ID] = { .type = NLA_U8 }, - [NL80211_NAN_FUNC_FOLLOW_UP_DEST] = { - .type = NLA_EXACT_LEN_WARN, - .len = ETH_ALEN - }, + [NL80211_NAN_FUNC_FOLLOW_UP_DEST] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN), [NL80211_NAN_FUNC_CLOSE_RANGE] = { .type = NLA_FLAG }, [NL80211_NAN_FUNC_TTL] = { .type = NLA_U32 }, [NL80211_NAN_FUNC_SERVICE_INFO] = { .type = NLA_BINARY, @@ -4404,10 +4362,7 @@ static const struct nla_policy nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] = { .len = NL80211_MAX_SUPP_RATES }, [NL80211_TXRATE_HT] = { .type = NLA_BINARY, .len = NL80211_MAX_SUPP_HT_RATES }, - [NL80211_TXRATE_VHT] = { - .type = NLA_EXACT_LEN_WARN, - .len = sizeof(struct nl80211_txrate_vht), - }, + [NL80211_TXRATE_VHT] = NLA_POLICY_EXACT_LEN_WARN(sizeof(struct nl80211_txrate_vht)), [NL80211_TXRATE_GI] = { .type = NLA_U8 }, }; From patchwork Thu Apr 30 20:13:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 220132 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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 CBCE2C47257 for ; Thu, 30 Apr 2020 20:13:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4AD520774 for ; Thu, 30 Apr 2020 20:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727812AbgD3UNe (ORCPT ); Thu, 30 Apr 2020 16:13:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726338AbgD3UN0 (ORCPT ); Thu, 30 Apr 2020 16:13:26 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 095DAC08E859; Thu, 30 Apr 2020 13:13:26 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jUFYi-002qzz-8d; Thu, 30 Apr 2020 22:13:24 +0200 From: Johannes Berg To: netdev@vger.kernel.org Cc: Antonio Quartulli , linux-wireless@vger.kernel.org, Johannes Berg Subject: [PATCH v2 8/8] netlink: add infrastructure to expose policies to userspace Date: Thu, 30 Apr 2020 22:13:12 +0200 Message-Id: <20200430221106.c28d28d9ddee.Icf6f8aa515bf625608fac70eec24739433b8ebd8@changeid> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200430201312.60143-1-johannes@sipsolutions.net> References: <20200430201312.60143-1-johannes@sipsolutions.net> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Johannes Berg Add, and use in generic netlink, helpers to dump out a netlink policy to userspace, including all the range validation data, nested policies etc. This lets userspace discover what the kernel understands. For families/commands other than generic netlink, the helpers need to be used directly in an appropriate command, or we can add some infrastructure (a new netlink family) that those can register their policies with for introspection. I'm not that familiar with non-generic netlink, so that's left out for now. The data exposed to userspace also includes min and max length for binary/string data, I've done that instead of letting the userspace tools figure out whether min/max is intended based on the type so that we can extend this later in the kernel, we might want to just use the range data for example. Because of this, I opted to not directly expose the NLA_* values, even if some of them are already exposed via BPF, as with min/max length we don't need to have different types here for NLA_BINARY/NLA_MIN_LEN/NLA_EXACT_LEN, we just make them all NL_ATTR_TYPE_BINARY with min/max length optionally set. Similarly, we don't really need NLA_MSECS, and perhaps can remove it in the future - but not if we encode it into the userspace API now. It gets mapped to NL_ATTR_TYPE_U64 here. Note that the exposing here corresponds to the strict policy interpretation, and NLA_UNSPEC items are omitted entirely. To get those, change them to NLA_MIN_LEN which behaves in exactly the same way, but is exposed. Signed-off-by: Johannes Berg --- include/net/netlink.h | 6 + include/uapi/linux/genetlink.h | 2 + include/uapi/linux/netlink.h | 103 +++++++++++ net/netlink/Makefile | 2 +- net/netlink/genetlink.c | 78 +++++++++ net/netlink/policy.c | 308 +++++++++++++++++++++++++++++++++ 6 files changed, 498 insertions(+), 1 deletion(-) create mode 100644 net/netlink/policy.c diff --git a/include/net/netlink.h b/include/net/netlink.h index 557b67f1db99..c0411f14fb53 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -1933,4 +1933,10 @@ void nla_get_range_unsigned(const struct nla_policy *pt, void nla_get_range_signed(const struct nla_policy *pt, struct netlink_range_validation_signed *range); +int netlink_policy_dump_start(const struct nla_policy *policy, + unsigned int maxtype, + unsigned long *state); +bool netlink_policy_dump_loop(unsigned long *state); +int netlink_policy_dump_write(struct sk_buff *skb, unsigned long state); + #endif diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h index 877f7fa95466..9c0636ec2286 100644 --- a/include/uapi/linux/genetlink.h +++ b/include/uapi/linux/genetlink.h @@ -48,6 +48,7 @@ enum { CTRL_CMD_NEWMCAST_GRP, CTRL_CMD_DELMCAST_GRP, CTRL_CMD_GETMCAST_GRP, /* unused */ + CTRL_CMD_GETPOLICY, __CTRL_CMD_MAX, }; @@ -62,6 +63,7 @@ enum { CTRL_ATTR_MAXATTR, CTRL_ATTR_OPS, CTRL_ATTR_MCAST_GROUPS, + CTRL_ATTR_POLICY, __CTRL_ATTR_MAX, }; diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 0a4d73317759..eac8a6a648ea 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -249,4 +249,107 @@ struct nla_bitfield32 { __u32 selector; }; +/* + * policy descriptions - it's specific to each family how this is used + * Normally, it should be retrieved via a dump inside another attribute + * specifying where it applies. + */ + +/** + * enum netlink_attribute_type - type of an attribute + * @NL_ATTR_TYPE_INVALID: unused + * @NL_ATTR_TYPE_FLAG: flag attribute (present/not present) + * @NL_ATTR_TYPE_U8: 8-bit unsigned attribute + * @NL_ATTR_TYPE_U16: 16-bit unsigned attribute + * @NL_ATTR_TYPE_U32: 32-bit unsigned attribute + * @NL_ATTR_TYPE_U64: 64-bit unsigned attribute + * @NL_ATTR_TYPE_S8: 8-bit signed attribute + * @NL_ATTR_TYPE_S16: 16-bit signed attribute + * @NL_ATTR_TYPE_S32: 32-bit signed attribute + * @NL_ATTR_TYPE_S64: 64-bit signed attribute + * @NL_ATTR_TYPE_BINARY: binary data, min/max length may be specified + * @NL_ATTR_TYPE_STRING: string, min/max length may be specified + * @NL_ATTR_TYPE_NUL_STRING: NUL-terminated string, + * min/max length may be specified + * @NL_ATTR_TYPE_NESTED: nested, i.e. the content of this attribute + * consists of sub-attributes. The nested policy and maxtype + * inside may be specified. + * @NL_ATTR_TYPE_NESTED_ARRAY: nested array, i.e. the content of this + * attribute contains sub-attributes whose type is irrelevant + * (just used to separate the array entries) and each such array + * entry has attributes again, the policy for those inner ones + * and the corresponding maxtype may be specified. + * @NL_ATTR_TYPE_BITFIELD32: &struct nla_bitfield32 attribute + */ +enum netlink_attribute_type { + NL_ATTR_TYPE_INVALID, + + NL_ATTR_TYPE_FLAG, + + NL_ATTR_TYPE_U8, + NL_ATTR_TYPE_U16, + NL_ATTR_TYPE_U32, + NL_ATTR_TYPE_U64, + + NL_ATTR_TYPE_S8, + NL_ATTR_TYPE_S16, + NL_ATTR_TYPE_S32, + NL_ATTR_TYPE_S64, + + NL_ATTR_TYPE_BINARY, + NL_ATTR_TYPE_STRING, + NL_ATTR_TYPE_NUL_STRING, + + NL_ATTR_TYPE_NESTED, + NL_ATTR_TYPE_NESTED_ARRAY, + + NL_ATTR_TYPE_BITFIELD32, +}; + +/** + * enum netlink_policy_type_attr - policy type attributes + * @NL_POLICY_TYPE_ATTR_UNSPEC: unused + * @NL_POLICY_TYPE_ATTR_TYPE: type of the attribute, + * &enum netlink_attribute_type (U32) + * @NL_POLICY_TYPE_ATTR_MIN_VALUE_S: minimum value for signed + * integers (S64) + * @NL_POLICY_TYPE_ATTR_MAX_VALUE_S: maximum value for signed + * integers (S64) + * @NL_POLICY_TYPE_ATTR_MIN_VALUE_U: minimum value for unsigned + * integers (U64) + * @NL_POLICY_TYPE_ATTR_MAX_VALUE_U: maximum value for unsigned + * integers (U64) + * @NL_POLICY_TYPE_ATTR_MIN_LENGTH: minimum length for binary + * attributes, no minimum if not given (U32) + * @NL_POLICY_TYPE_ATTR_MAX_LENGTH: maximum length for binary + * attributes, no maximum if not given (U32) + * @NL_POLICY_TYPE_ATTR_POLICY_IDX: sub policy for nested and + * nested array types (U32) + * @NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE: maximum sub policy + * attribute for nested and nested array types, this can + * in theory be < the size of the policy pointed to by + * 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_PAD: pad attribute for 64-bit alignment + */ +enum netlink_policy_type_attr { + NL_POLICY_TYPE_ATTR_UNSPEC, + NL_POLICY_TYPE_ATTR_TYPE, + NL_POLICY_TYPE_ATTR_MIN_VALUE_S, + NL_POLICY_TYPE_ATTR_MAX_VALUE_S, + NL_POLICY_TYPE_ATTR_MIN_VALUE_U, + NL_POLICY_TYPE_ATTR_MAX_VALUE_U, + NL_POLICY_TYPE_ATTR_MIN_LENGTH, + NL_POLICY_TYPE_ATTR_MAX_LENGTH, + NL_POLICY_TYPE_ATTR_POLICY_IDX, + NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE, + NL_POLICY_TYPE_ATTR_BITFIELD32_MASK, + NL_POLICY_TYPE_ATTR_PAD, + + /* keep last */ + __NL_POLICY_TYPE_ATTR_MAX, + NL_POLICY_TYPE_ATTR_MAX = __NL_POLICY_TYPE_ATTR_MAX - 1 +}; + #endif /* _UAPI__LINUX_NETLINK_H */ diff --git a/net/netlink/Makefile b/net/netlink/Makefile index de42df7f0068..e05202708c90 100644 --- a/net/netlink/Makefile +++ b/net/netlink/Makefile @@ -3,7 +3,7 @@ # Makefile for the netlink driver. # -obj-y := af_netlink.o genetlink.o +obj-y := af_netlink.o genetlink.o policy.o obj-$(CONFIG_NETLINK_DIAG) += netlink_diag.o netlink_diag-y := diag.o diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 9f357aa22b94..2f049692e012 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1043,6 +1043,80 @@ static int genl_ctrl_event(int event, const struct genl_family *family, return 0; } +static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) +{ + const struct genl_family *rt; + unsigned int fam_id = cb->args[0]; + int err; + + if (!fam_id) { + struct nlattr *tb[CTRL_ATTR_MAX + 1]; + + err = genlmsg_parse(cb->nlh, &genl_ctrl, tb, + genl_ctrl.maxattr, + genl_ctrl.policy, cb->extack); + if (err) + return err; + + if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME]) + return -EINVAL; + + if (tb[CTRL_ATTR_FAMILY_ID]) { + fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); + } else { + rt = genl_family_find_byname( + nla_data(tb[CTRL_ATTR_FAMILY_NAME])); + if (!rt) + return -ENOENT; + fam_id = rt->id; + } + } + + rt = genl_family_find_byid(fam_id); + if (!rt) + return -ENOENT; + + if (!rt->policy) + return -ENODATA; + + err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]); + if (err) + return err; + + while (netlink_policy_dump_loop(&cb->args[1])) { + void *hdr; + struct nlattr *nest; + + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, &genl_ctrl, + NLM_F_MULTI, CTRL_CMD_GETPOLICY); + if (!hdr) + goto nla_put_failure; + + if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id)) + goto nla_put_failure; + + nest = nla_nest_start(skb, CTRL_ATTR_POLICY); + if (!nest) + goto nla_put_failure; + + if (netlink_policy_dump_write(skb, cb->args[1])) + goto nla_put_failure; + + nla_nest_end(skb, nest); + + genlmsg_end(skb, hdr); + continue; + +nla_put_failure: + genlmsg_cancel(skb, hdr); + break; + } + + cb->args[0] = fam_id; + return skb->len; +} + static const struct genl_ops genl_ctrl_ops[] = { { .cmd = CTRL_CMD_GETFAMILY, @@ -1050,6 +1124,10 @@ static const struct genl_ops genl_ctrl_ops[] = { .doit = ctrl_getfamily, .dumpit = ctrl_dumpfamily, }, + { + .cmd = CTRL_CMD_GETPOLICY, + .dumpit = ctrl_dumppolicy, + }, }; static const struct genl_multicast_group genl_ctrl_groups[] = { diff --git a/net/netlink/policy.c b/net/netlink/policy.c new file mode 100644 index 000000000000..f6491853c797 --- /dev/null +++ b/net/netlink/policy.c @@ -0,0 +1,308 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * NETLINK Policy advertisement to userspace + * + * Authors: Johannes Berg + * + * Copyright 2019 Intel Corporation + */ + +#include +#include +#include +#include + +#define INITIAL_POLICIES_ALLOC 10 + +struct nl_policy_dump { + unsigned int policy_idx; + unsigned int attr_idx; + unsigned int n_alloc; + struct { + const struct nla_policy *policy; + unsigned int maxtype; + } policies[]; +}; + +static int add_policy(struct nl_policy_dump **statep, + const struct nla_policy *policy, + unsigned int maxtype) +{ + struct nl_policy_dump *state = *statep; + unsigned int n_alloc, i; + + if (!policy || !maxtype) + return 0; + + for (i = 0; i < state->n_alloc; i++) { + if (state->policies[i].policy == policy) + return 0; + + if (!state->policies[i].policy) { + state->policies[i].policy = policy; + state->policies[i].maxtype = maxtype; + return 0; + } + } + + n_alloc = state->n_alloc + INITIAL_POLICIES_ALLOC; + state = krealloc(state, struct_size(state, policies, n_alloc), + GFP_KERNEL); + if (!state) + return -ENOMEM; + + state->policies[state->n_alloc].policy = policy; + state->policies[state->n_alloc].maxtype = maxtype; + state->n_alloc = n_alloc; + *statep = state; + + return 0; +} + +static unsigned int get_policy_idx(struct nl_policy_dump *state, + const struct nla_policy *policy) +{ + unsigned int i; + + for (i = 0; i < state->n_alloc; i++) { + if (state->policies[i].policy == policy) + return i; + } + + WARN_ON_ONCE(1); + return -1; +} + +int netlink_policy_dump_start(const struct nla_policy *policy, + unsigned int maxtype, + unsigned long *_state) +{ + struct nl_policy_dump *state; + unsigned int policy_idx; + int err; + + /* also returns 0 if "*_state" is our ERR_PTR() end marker */ + if (*_state) + return 0; + + /* + * walk the policies and nested ones first, and build + * a linear list of them. + */ + + state = kzalloc(struct_size(state, policies, INITIAL_POLICIES_ALLOC), + GFP_KERNEL); + if (!state) + return -ENOMEM; + state->n_alloc = INITIAL_POLICIES_ALLOC; + + err = add_policy(&state, policy, maxtype); + if (err) + return err; + + for (policy_idx = 0; + policy_idx < state->n_alloc && state->policies[policy_idx].policy; + policy_idx++) { + const struct nla_policy *policy; + unsigned int type; + + policy = state->policies[policy_idx].policy; + + for (type = 0; + type <= state->policies[policy_idx].maxtype; + type++) { + switch (policy[type].type) { + case NLA_NESTED: + case NLA_NESTED_ARRAY: + err = add_policy(&state, + policy[type].nested_policy, + policy[type].len); + if (err) + return err; + break; + default: + break; + } + } + } + + *_state = (unsigned long)state; + + return 0; +} + +static bool netlink_policy_dump_finished(struct nl_policy_dump *state) +{ + return state->policy_idx >= state->n_alloc || + !state->policies[state->policy_idx].policy; +} + +bool netlink_policy_dump_loop(unsigned long *_state) +{ + struct nl_policy_dump *state = (void *)*_state; + + if (IS_ERR(state)) + return false; + + if (netlink_policy_dump_finished(state)) { + kfree(state); + /* store end marker instead of freed state */ + *_state = (unsigned long)ERR_PTR(-ENOENT); + return false; + } + + return true; +} + +int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state) +{ + struct nl_policy_dump *state = (void *)_state; + const struct nla_policy *pt; + struct nlattr *policy, *attr; + enum netlink_attribute_type type; + bool again; + +send_attribute: + again = false; + + pt = &state->policies[state->policy_idx].policy[state->attr_idx]; + + policy = nla_nest_start(skb, state->policy_idx); + if (!policy) + return -ENOBUFS; + + attr = nla_nest_start(skb, state->attr_idx); + if (!attr) + goto nla_put_failure; + + switch (pt->type) { + default: + case NLA_UNSPEC: + case NLA_REJECT: + /* skip - use NLA_MIN_LEN to advertise such */ + nla_nest_cancel(skb, policy); + again = true; + goto next; + case NLA_NESTED: + type = NL_ATTR_TYPE_NESTED; + /* fall through */ + case NLA_NESTED_ARRAY: + if (pt->type == NLA_NESTED_ARRAY) + type = NL_ATTR_TYPE_NESTED_ARRAY; + if (pt->nested_policy && pt->len && + (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_IDX, + get_policy_idx(state, pt->nested_policy)) || + nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE, + pt->len))) + goto nla_put_failure; + break; + case NLA_U8: + case NLA_U16: + case NLA_U32: + case NLA_U64: + case NLA_MSECS: { + struct netlink_range_validation range; + + if (pt->type == NLA_U8) + type = NL_ATTR_TYPE_U8; + else if (pt->type == NLA_U16) + type = NL_ATTR_TYPE_U16; + else if (pt->type == NLA_U32) + type = NL_ATTR_TYPE_U32; + else + type = NL_ATTR_TYPE_U64; + + nla_get_range_unsigned(pt, &range); + + if (nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MIN_VALUE_U, + range.min, NL_POLICY_TYPE_ATTR_PAD) || + nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MAX_VALUE_U, + range.max, NL_POLICY_TYPE_ATTR_PAD)) + goto nla_put_failure; + break; + } + case NLA_S8: + case NLA_S16: + case NLA_S32: + case NLA_S64: { + struct netlink_range_validation_signed range; + + if (pt->type == NLA_S8) + type = NL_ATTR_TYPE_S8; + else if (pt->type == NLA_S16) + type = NL_ATTR_TYPE_S16; + else if (pt->type == NLA_S32) + type = NL_ATTR_TYPE_S32; + else + type = NL_ATTR_TYPE_S64; + + nla_get_range_signed(pt, &range); + + if (nla_put_s64(skb, NL_POLICY_TYPE_ATTR_MIN_VALUE_S, + range.min, NL_POLICY_TYPE_ATTR_PAD) || + nla_put_s64(skb, NL_POLICY_TYPE_ATTR_MAX_VALUE_S, + range.max, NL_POLICY_TYPE_ATTR_PAD)) + goto nla_put_failure; + break; + } + case NLA_BITFIELD32: + type = NL_ATTR_TYPE_BITFIELD32; + if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_BITFIELD32_MASK, + pt->bitfield32_valid)) + goto nla_put_failure; + break; + case NLA_EXACT_LEN: + type = NL_ATTR_TYPE_BINARY; + if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len) || + nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH, pt->len)) + goto nla_put_failure; + break; + case NLA_STRING: + case NLA_NUL_STRING: + case NLA_BINARY: + if (pt->type == NLA_STRING) + type = NL_ATTR_TYPE_STRING; + else if (pt->type == NLA_NUL_STRING) + type = NL_ATTR_TYPE_NUL_STRING; + else + type = NL_ATTR_TYPE_BINARY; + if (pt->len && nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH, + pt->len)) + goto nla_put_failure; + break; + case NLA_MIN_LEN: + type = NL_ATTR_TYPE_BINARY; + if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len)) + goto nla_put_failure; + break; + case NLA_FLAG: + type = NL_ATTR_TYPE_FLAG; + break; + } + + if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_TYPE, type)) + goto nla_put_failure; + + /* finish and move state to next attribute */ + nla_nest_end(skb, attr); + nla_nest_end(skb, policy); + +next: + state->attr_idx += 1; + if (state->attr_idx > state->policies[state->policy_idx].maxtype) { + state->attr_idx = 0; + state->policy_idx++; + } + + if (again) { + if (netlink_policy_dump_finished(state)) + return -ENODATA; + goto send_attribute; + } + + return 0; + +nla_put_failure: + nla_nest_cancel(skb, policy); + return -ENOBUFS; +}