From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f12.google.com (mail-pj2-f12.google.com [74.125.227.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41BEA4FDA4F for ; Thu, 17 Sep 2026 17:08:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.140 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789664914; cv=none; b=rQQnv6MAL+dZWfxrN9TGA4PK5eq8rMH55UiadaJ208feuDh4dwXsap0l0WKpp+h9bYykJr3W1hMljjXITyac6n94cx8Ktz7+/nKX6uqqD0sKwkmuAxkHVm1P0YlMXkSK+iOEsWuH5TIdNnZtw0KR4wtJEuN8JrP0qH0vU0hkmrs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789664914; c=relaxed/simple; bh=KjkJcTuJHjrmVijk9slNWWr20w469I1INEteAa7loK4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KxZnAyhY/lpujc7XBpDFFkGmn+tvj8Zer7DqYyf48s15ZFNd2tuxbnJ5Bu210MLZl29t1VwIqCaO1bkXWX+rzhbWCpxgT5MKDr8SM/KmNT9A0Bs+kd/Yx2qSeoVo8UljIJY4O/CKppv1xCE7mowfUPa498NkQt3ax4j3a7jRFmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=aJEN40iW; arc=none smtp.client-ip=74.125.227.140 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aJEN40iW" Received: by mail-pj2-f12.google.com with SMTP id d9443c01a7336-2d747f05ffdso9357195ad.1 for ; Thu, 17 Sep 2026 10:08:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789664913; x=1790269713; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=auzHkbE4quU1N/0aznjpHRbsdXF6x1Ysfc7XFJa0Adc=; b=aJEN40iWObrn4NGRol15JdsMxzLsRAqzSngnypsStrfECUHFee0WkAoww46Nj9r8wI ezmsemgCVcm7756NdNvOkT5R7Kg2kqcg7OLl45HdHf6QHuxkv3Wmuukm0pO+y1rVzPjw +aBSjDMYEMwSnPKwdXC6/5cct73rLDhH35MENN//lfiTcJlGR/8oXEGckLEyCM/qmwM2 bieoqZfrXjkSrmFpfiLhBNUmchiq/+oVJcURdFh/7v2TuhsGgUYUOVWlYbKOf5oCQdQD 4wFqAxE+jaxl8LO/Ac5GfPJqFOZcWehW3zEV2P57AxokPbcUYk0OK/pQ+tt6Yem3XqVT Hg/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789664913; x=1790269713; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=auzHkbE4quU1N/0aznjpHRbsdXF6x1Ysfc7XFJa0Adc=; b=QKQcf2mcC7bCHid1NmRHPUuikdjbS5D2POU5U9MAJvzUF+PEEnzovHv3x/fKjAotIt b9TE8i5RRlpXMGsmEgWG0Af4KJlLmLmWnrPVSiwhFPWYRov84KEdMVzupCfP8VgNUA+n uyBHIwH+CsRDKPNjU7nUwDDoWzPkd+4GEcFnyeU5G+PiVzoc+6Hrtu8m28G4OdNWK4bP /CS7Wx8CmN9hc3T1JIoI/S5/NbbtUTZLj+BcJBF73eXlyd/DWN8Z7F9NDzlIpiimlOmF bTTw8r83rhJyNI4KVO0FKYd+n908vT3k++Zo2/N5BNxRgeNcjg8l4FPWmEShPcXJeCDb kgMw== X-Forwarded-Encrypted: i=1; AKwUvBw/XWJ4MOvq0Iw+2QnJaGDonw2WyOpOG8hPm4MCIe79CO1chxuzUkJZ0+LxiKme9WIE3ku8W2LZTPxOKg==@lists.linux.dev X-Gm-Message-State: AFuF++lpouMYxRUuM5xvOS4IRD8im1gATYWc516+XYw7EZ7WTUSvZ6Xr 3iPHpXfXLB0iUZWzgUCXZ0C09Hde0K79tGFlkpCuNzjJvQi2QVETlvs6 X-Gm-Gg: AYBFou2T+iZnDsE9/4hCjM+7erBfOHPd6k/FSEwTRzj7NLKTTnlt/Swb/FVEIe6w5Jx CwK/cGRO0wdT9n51wjmrv38hvzucTHRSVouzb6GgX5vlUmtIjiF/lDf4f95OxLuxmq48cmXr5oW 4poOFsnod/Xc2SNX5g4vbg7oDHDUJDg5sdK5UBfWH6hcPxTEmLbpmz8Ohk0cKLIiNQW0T/vIWo6 ftIL6n6h2Q+W5m71sraz4+oOX8rDHP5Ilwl4MXMgVzUuyszLeS1loY1q9ANYMPeH2wqVEd2v11t IcOCwXuTwWv/37MnpLPxIMdbUUfQioeMapslY21mxDLFuFhW2/9uuxPERdh/F/EOvvxOiIeacuU hmIVtou4smMnwrzEzrrIQJPepX+hqrTpiOl98JN6+iTeh72pvhTP3otIKWKjjUc9QgslDa7Lgd0 sst2KLMULcZ6r3W4ljsij2oDx9JO6Px88QkcQ0Q+AOBtZHd5eKK90WWScozmdsnmM8Yul5pOh+s EeLNoCdvb90 X-Received: by 2002:a17:902:ed45:b0:2dd:ad74:ac2c with SMTP id d9443c01a7336-2ddad74ade4mr14163785ad.30.1789664912433; Thu, 17 Sep 2026 10:08:32 -0700 (PDT) Received: from archlinux ([2402:e280:411b:ec:aa93:b1ec:5a6b:5fce]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2dd89d8fe2esm30438215ad.6.2026.09.17.10.08.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Sep 2026 10:08:31 -0700 (PDT) From: Adarsh Das To: gregkh@linuxfoundation.org Cc: rafael@kernel.org, dakr@kernel.org, driver-core@lists.linux.dev, stable@vger.kernel.org, linux-kernel@vger.kernel.org, Adarsh Das , syzbot Subject: [PATCH v2] kobject: fix uevent socket use-after-free on net namespace delete Date: Thu, 17 Sep 2026 22:38:26 +0530 Message-ID: <20260917170826.102362-1-adarshdas950@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917144206.85836-1-adarshdas950@gmail.com> References: <20260917144206.85836-1-adarshdas950@gmail.com> Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When a network namespace is deleted, we free its uevent socket. But sometimes a device in that namespace is still being removed and tries to send a uevent through that socket. The socket is already freed, so KASAN reports a use-after-free. This patch attempts the fix of taking a lock around both the send path and the free path, and clear the pointer before freeing so nobody uses it after free. Reported-by: syzbot Link: https://syzkaller.appspot.com/bug?extid=4393dfdddf166f2de2b0 Tested-by: syzbot Tested-by: Adarsh Das Assisted-by: Cursor AI Signed-off-by: Adarsh Das --- lib/kobject_uevent.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index ddbc4d7482d2..ecba33abb6b1 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -411,9 +411,15 @@ static int kobject_uevent_net_broadcast(struct kobject *kobj, devpath); else { const struct net *net = container_of(ns, struct net, ns); + struct uevent_sock *ue_sk; - ret = uevent_net_broadcast_tagged(net->uevent_sock->sk, env, - action_string, devpath); + mutex_lock(&uevent_sock_mutex); + ue_sk = net->uevent_sock; + if (ue_sk && ue_sk->sk) + ret = uevent_net_broadcast_tagged(ue_sk->sk, env, + action_string, + devpath); + mutex_unlock(&uevent_sock_mutex); } #endif @@ -804,13 +810,17 @@ static int uevent_net_init(struct net *net) static void uevent_net_exit(struct net *net) { - struct uevent_sock *ue_sk = net->uevent_sock; + struct uevent_sock *ue_sk; - if (sock_net(ue_sk->sk)->user_ns == &init_user_ns) { - mutex_lock(&uevent_sock_mutex); + mutex_lock(&uevent_sock_mutex); + ue_sk = net->uevent_sock; + net->uevent_sock = NULL; + if (ue_sk && sock_net(ue_sk->sk)->user_ns == &init_user_ns) list_del(&ue_sk->list); - mutex_unlock(&uevent_sock_mutex); - } + mutex_unlock(&uevent_sock_mutex); + + if (!ue_sk) + return; netlink_kernel_release(ue_sk->sk); kfree(ue_sk); -- 2.55.0