From nobody Mon Feb 9 02:52:27 2026 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (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 6CA4B1DFFB for ; Fri, 28 Jun 2024 02:10:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719540623; cv=none; b=A4gZLf9E7IZNWagIECSTua+dhMgrBBdOdRj9ItEkVnJBTbwYh5mffxMfJbReO6Yq1OxcQYFQXjofElgc3zlWL7u3WlQZ0/SebImm+rV3GqsyDlkinKnHRsElsf6kMxcUW7RwpdhkL30ptRDKaabCoKCyHNDWMjpNgqmCUFB5j4I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719540623; c=relaxed/simple; bh=WENDZcP8N/LxqpPFeFbXSpD17nZKdUoSCPD3rZP7z/4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=KWRgKlVIvJcFNuTamaezFtswx8RoOZh7F04Q2K0HU8tx+HyZE2pBYmh5wIM3Ny55J4lSJv2Wp5XTpy1bcgDGJEBefOOyFgQoLCeNT9RLCHG6gTJcUMFlIvwwtUi1Llj/UV/aJSFes8rnRcundbie8gFXw7IRW4cmIRNsWyG3yR4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--avagin.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=vjNU8hNj; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--avagin.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vjNU8hNj" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-dfa73db88dcso209172276.0 for ; Thu, 27 Jun 2024 19:10:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1719540621; x=1720145421; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=3+q5Yudne0apm40w9a/NrughomiVS9st32ZmfN+LWk8=; b=vjNU8hNjRTIwBKueXomX94VOHx4bjgLlIvCCksTjU3bVDxvmSRQ8qQ7gzMorhv+RtP ZETTW1ShQbRmh+m1UY+qA5KPEaBn2Oqc+Nw3B4wVOF6wgs9U6P+LbQPOYIcsi3I8trui 8v78Yvv957SN6F65+/UM0K6OELJAdK1pFOD/rbhGVOHVDhs3WU3iFTskNnn6/d+5R5oQ RmZWpXF5124ie9T6fUftfUkWBw+XNjc0lQqc3xzewXsPyf63uZI5vkj7HTYmAm5s+1H5 HGH6E75feblxasGbq9JAwW4Ia64IplknPk+7Mlqjxb8RnISf4wz5Uf14lRU46gx16dtU HNlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719540621; x=1720145421; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=3+q5Yudne0apm40w9a/NrughomiVS9st32ZmfN+LWk8=; b=RCZzG4gRxha5nGDHbz+i54kKlRGBRCtn5LA6r0WkIN3MecWVg7yYi+Q24eoQkeopf3 rbKhIQG0psHqzN/fLlPu7Tp2rLdsQMO7EZKTA41w+CLlxkLonf0k0TZsptlC2e0pWsyq cGjvHuUEG3nERd6mJswgXQT2I4Ek4ZHjzHiliJDrjzQAV/rEks0rLCID3wEpjp2aW3nB gvKkV2jxCUO4lkMxXMACrLViqaKS+2SZ21r0xQG1AsIUZ9Qz2dvuBHbGbqk5+YCm0qYB modHx3znCmsEYR3N7khmVnFkge63Yi8qe8rqNAxB9Wavb9xp2D3EDoi35lCdYVyvb/2j xXSg== X-Gm-Message-State: AOJu0YyJCjwprqjEeV0s5kAUtqDzzddDZgrQvFBn7aXdJ6PGhQ8uDNcq 2H7FKstR9j+LCg7cLQWExQlYaJjayB1ES4vEUIOa0SSckRlFtnkQYDn1VTrV3IM5yDB51nIPThr XUA== X-Google-Smtp-Source: AGHT+IFeZp+OKnBr03iY/sVg8Bm8WE9n5a0TRPt0/ahgfiqmGEwYv7yfgX7jncSzfInGJlJsU77XXD1DtRI= X-Received: from avagin.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:b84]) (user=avagin job=sendgmr) by 2002:a05:6902:120d:b0:dfb:fb2:ebd with SMTP id 3f1490d57ef6-e0303fdc528mr43728276.8.1719540621021; Thu, 27 Jun 2024 19:10:21 -0700 (PDT) Date: Fri, 28 Jun 2024 02:10:14 +0000 In-Reply-To: <20240628021014.231976-1-avagin@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240628021014.231976-1-avagin@google.com> X-Mailer: git-send-email 2.45.2.803.g4e1b14247a-goog Message-ID: <20240628021014.231976-5-avagin@google.com> Subject: [PATCH 4/4] selftests/seccomp: check that a zombie leader doesn't affect others From: Andrei Vagin To: Kees Cook Cc: linux-kernel@vger.kernel.org, Tycho Andersen , Andy Lutomirski , Will Drewry , Oleg Nesterov , Christian Brauner , Andrei Vagin Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Ensure that a dead thread leader doesn't prevent installing new filters with SECCOMP_FILTER_FLAG_TSYNC from other threads. Signed-off-by: Andrei Vagin --- tools/testing/selftests/seccomp/seccomp_bpf.c | 77 +++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/= selftests/seccomp/seccomp_bpf.c index 390781d7c951..e3f97f90d8db 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -4809,6 +4809,83 @@ TEST(user_notification_wait_killable_fatal) EXPECT_EQ(SIGTERM, WTERMSIG(status)); } =20 +struct tsync_vs_thread_leader_args { + pthread_t leader; +}; + +static void *tsync_vs_dead_thread_leader_sibling(void *_args) +{ + struct sock_filter allow_filter[] =3D { + BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), + }; + struct sock_fprog allow_prog =3D { + .len =3D (unsigned short)ARRAY_SIZE(allow_filter), + .filter =3D allow_filter, + }; + struct tsync_vs_thread_leader_args *args =3D _args; + void *retval; + long ret; + + ret =3D pthread_join(args->leader, &retval); + if (ret) + exit(1); + if (retval !=3D _args) + exit(2); + ret =3D seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC, &allo= w_prog); + if (ret) + exit(3); + + exit(0); +} + +/* + * Ensure that a dead thread leader doesn't prevent installing new filters= with + * SECCOMP_FILTER_FLAG_TSYNC from other threads. + */ +TEST(tsync_vs_dead_thread_leader) +{ + int status; + pid_t pid; + long ret; + + ret =3D prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + pid =3D fork(); + ASSERT_GE(pid, 0); + + if (pid =3D=3D 0) { + struct sock_filter allow_filter[] =3D { + BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), + }; + struct sock_fprog allow_prog =3D { + .len =3D (unsigned short)ARRAY_SIZE(allow_filter), + .filter =3D allow_filter, + }; + struct tsync_vs_thread_leader_args *args; + pthread_t sibling; + + args =3D malloc(sizeof(*args)); + ASSERT_NE(NULL, args); + args->leader =3D pthread_self(); + + ret =3D pthread_create(&sibling, NULL, + tsync_vs_dead_thread_leader_sibling, args); + ASSERT_EQ(0, ret); + + /* Install a new filter just to the leader thread. */ + ret =3D seccomp(SECCOMP_SET_MODE_FILTER, 0, &allow_prog); + ASSERT_EQ(0, ret); + pthread_exit(args); + exit(1); + } + + EXPECT_EQ(pid, waitpid(pid, &status, 0)); + EXPECT_EQ(0, status); +} + /* * TODO: * - expand NNP testing --=20 2.45.2.803.g4e1b14247a-goog