From patchwork Fri Sep 8 18:13:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13377761 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 CFE1E14A9F for ; Fri, 8 Sep 2023 18:14:50 +0000 (UTC) Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BC922108 for ; Fri, 8 Sep 2023 11:14:17 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-58d9e327d3aso26441127b3.3 for ; Fri, 08 Sep 2023 11:14:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1694196841; x=1694801641; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=M0RLm5ta3TzXSRWdgzSlQ/2STQqaYv7B3pKmfp0gY38=; b=5WxpACBB0XtsyMtcRfHi/m/LsOIwxqn98h45FW5h5pyzQVA1s11rw1BPKoyCHUAiHL WncEy6xrslxfMwZzF0Uroq0tW/GaRTFrY/siCefAFqWFazkT2+iy8XX5D4ysAsx02Mgl /GecKTYp1fkbH8fy6V6oqMYMA5Xl48cwPvi/7S1uGM3boM4zVNSvIL/fLeAHvAltfmoU SlPtF2iv7JzcckVjN4FCewx8iGoe5EyZpFrHoEDHkGtjSDGt4e4ZxKCfBPKbdbfO+B1l mEkjW+1agCO3fOzK69nWLfuaqJdbfjmnmKNBMAa8J9TK4oJta/rgsA5Gw25fT1BAn2YI QjXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694196841; x=1694801641; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=M0RLm5ta3TzXSRWdgzSlQ/2STQqaYv7B3pKmfp0gY38=; b=Zdm6K5HI8Jrmv1KDVPRqUcl8E35EZe8S1sk2t4w9N+hGZqxdiaeQN0SVYH10p4oi+E 2jLXqcibIf8JP/GOL4KGJBqWKSKe714QjEGt9PZEHvddH2BYnLmQkLYKk8IyhYywcoxZ M1hWSm7A2Z5eiUmAJVRryKm6315J2fM/C4geNOCwiHtV0fzEVcprPNn13oOeAbypl3pA EGnIseR/VQubDSSeFBz8R3UFQsOc2LaoBzoJLpx+MfUukoCIPfiBfs1FgmxttfxOvtNu pj7jH6tRMNJyENmyC820OXHsCEkCS3Qx+PBOYez/f51x/mdfx+6dGnbj+xSl3wD17dqz Ygjg== X-Gm-Message-State: AOJu0Ywwqrp0CYMDuhsyWKtbcsDqoamn1k6EcOeZC0v1qLMU58cKLXcV cQZ3cOXARDFTBmJ0B9+5STBtbj3OXB5BLw== X-Google-Smtp-Source: AGHT+IG1Pd3wX0pmUNNgZb2VMQ+CTk7wGdyL8u/fDqAldhrDFagc/y1K+B7AdTyZH9PUia1yPWN12SrywMYd5g== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a25:a2c8:0:b0:d80:183c:92b9 with SMTP id c8-20020a25a2c8000000b00d80183c92b9mr70693ybn.4.1694196841090; Fri, 08 Sep 2023 11:14:01 -0700 (PDT) Date: Fri, 8 Sep 2023 18:13:59 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.42.0.283.g2d96d420d3-goog Message-ID: <20230908181359.1889304-1-edumazet@google.com> Subject: [PATCH net] xfrm: fix a data-race in xfrm_gen_index() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot , Steffen Klassert , Herbert Xu X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org xfrm_gen_index() mutual exclusion uses net->xfrm.xfrm_policy_lock. This means we must use a per-netns idx_generator variable, instead of a static one. Alternative would be to use an atomic variable. syzbot reported: BUG: KCSAN: data-race in xfrm_sk_policy_insert / xfrm_sk_policy_insert write to 0xffffffff87005938 of 4 bytes by task 29466 on cpu 0: xfrm_gen_index net/xfrm/xfrm_policy.c:1385 [inline] xfrm_sk_policy_insert+0x262/0x640 net/xfrm/xfrm_policy.c:2347 xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639 do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943 ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012 rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054 sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697 __sys_setsockopt+0x1c9/0x230 net/socket.c:2263 __do_sys_setsockopt net/socket.c:2274 [inline] __se_sys_setsockopt net/socket.c:2271 [inline] __x64_sys_setsockopt+0x66/0x80 net/socket.c:2271 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffffffff87005938 of 4 bytes by task 29460 on cpu 1: xfrm_sk_policy_insert+0x13e/0x640 xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639 do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943 ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012 rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054 sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697 __sys_setsockopt+0x1c9/0x230 net/socket.c:2263 __do_sys_setsockopt net/socket.c:2274 [inline] __se_sys_setsockopt net/socket.c:2271 [inline] __x64_sys_setsockopt+0x66/0x80 net/socket.c:2271 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x00006ad8 -> 0x00006b18 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 29460 Comm: syz-executor.1 Not tainted 6.5.0-rc5-syzkaller-00243-g9106536c1aa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Fixes: 1121994c803f ("netns xfrm: policy insertion in netns") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Steffen Klassert Cc: Herbert Xu Acked-by: Herbert Xu --- include/net/netns/xfrm.h | 1 + net/xfrm/xfrm_policy.c | 6 ++---- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h index bd7c3be4af5d7bee4c63a57a2b0bf283b81bc4bf..423b52eca908d90009889b64764fbd4008a29529 100644 --- a/include/net/netns/xfrm.h +++ b/include/net/netns/xfrm.h @@ -50,6 +50,7 @@ struct netns_xfrm { struct list_head policy_all; struct hlist_head *policy_byidx; unsigned int policy_idx_hmask; + unsigned int idx_generator; struct hlist_head policy_inexact[XFRM_POLICY_MAX]; struct xfrm_policy_hash policy_bydst[XFRM_POLICY_MAX]; unsigned int policy_count[XFRM_POLICY_MAX * 2]; diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index d6b405782b6361c4da2e06fae50befbd699aed15..a73e4b66c98f9db98d94a146bc963fa29979c592 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1372,8 +1372,6 @@ EXPORT_SYMBOL(xfrm_policy_hash_rebuild); * of an absolute inpredictability of ordering of rules. This will not pass. */ static u32 xfrm_gen_index(struct net *net, int dir, u32 index) { - static u32 idx_generator; - for (;;) { struct hlist_head *list; struct xfrm_policy *p; @@ -1381,8 +1379,8 @@ static u32 xfrm_gen_index(struct net *net, int dir, u32 index) int found; if (!index) { - idx = (idx_generator | dir); - idx_generator += 8; + idx = (net->xfrm.idx_generator | dir); + net->xfrm.idx_generator += 8; } else { idx = index; index = 0;