From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 49F3B52D2C4; Wed, 9 Sep 2026 10:43:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788950608; cv=none; b=Qd2fi5+vUAVMEPkurQx+jRFqB0URNM08PPeo48riVlghD0jn0UTypvEJl9/e2QRm3Nt/S71ZHmugx7h5KA5fngBgI1cMrTAFqn8E1hvQujcRPtcCEnMndt+Nk6JpnIHUteyIFjU982UbuHUsKVgtyy/Xw6glWEBXHiIGa5tpz0E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788950608; c=relaxed/simple; bh=2YnxsfrAF7HQBfWzTLMa2O/I/q1GmiD7jT9cB0DlWWk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AvTu9Ov/xgamCuHd8sSa9n2XgYwWiOiVjwcze4UM/Sr8z0mdVTBjCmnfxK4kR/XLjMMgIS1ypzxTmK9UQTcHRW2lniiE/kK9C6/OkEKIVYw1quetbJMJ8POYAWYGjE383PLwYXsL9ps5KyKHCdzQt9gJaZS9eXohyfKG5LU3GNo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oLpzQOge; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oLpzQOge" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3AE81F00A3D; Wed, 9 Sep 2026 10:43:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788950607; bh=2QGYk5eR/9VO1k3tAFlZXnTVM66BZOkvZZisq9g5IQA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=oLpzQOgefLCEmc5Kzk35bB4HXYq9vemi5qlqr8+SBZaXZb3YDpYbNNbHtj2qVYuLy 6amkiQnF2NyBOZWoaTXH+yXEXykGYZL5VhFNm5HJF4l1LH2R6JOnT5yzXYiUxYiBB0 HORQi7yWzu5BNZHz/2l1/Fm63vXtMkCtHupkA6MBosQGWocfdq0lQVvNgTEHy5uN5Q t+4E+vXL7XCzdXl/8uLdbuebVzCSdn26n/DR6QwC2eZiv/InkaYacMwu2Ii4hbqqTt NDS+zKpqa3psoktkoZvjNz2N+oarQPO7IaqVWXBOMDIQB1Id2m3sx/PrwGjB++J/Op MVkZt8YS6sIlQ== From: Christian Brauner Date: Wed, 09 Sep 2026 12:43:03 +0200 Subject: [PATCH v2 04/10] selftests/net: SO_PASSPIDFD_THREAD Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260909-work-unix-passpidfd-v2-4-7bd342abb2d1@kernel.org> References: <20260909-work-unix-passpidfd-v2-0-7bd342abb2d1@kernel.org> In-Reply-To: <20260909-work-unix-passpidfd-v2-0-7bd342abb2d1@kernel.org> To: Jakub Kicinski , Kuniyuki Iwashima , Oleg Nesterov Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Willem de Bruijn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org, Alexander Mikhalitsyn , "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=7771; i=brauner@kernel.org; h=from:subject:message-id; bh=2YnxsfrAF7HQBfWzTLMa2O/I/q1GmiD7jT9cB0DlWWk=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWQttLA+v/XnxLD2SOmre1jOmN45Zn9u47zszPt9LxkyV h+X2/n3UkcpC4MYF4OsmCKLQ7tJuNxynorNRpkaMHNYmUCGMHBxCsBEjq5m+B9kbOR0ILvSVJjh 11f/rdqieteV9poJv9qkzH6DMdxryipGhoX656cd+mrOdWoJq9dqgabtVvfTJZUqCkscNCpfvFr +mAcA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Extend the af_unix scm_pidfd selftest with SO_PASSPIDFD_THREAD tests. Signed-off-by: Christian Brauner (Amutable) --- tools/testing/selftests/net/af_unix/Makefile | 2 + tools/testing/selftests/net/af_unix/scm_pidfd.c | 269 ++++++++++++++++++++++++ 2 files changed, 271 insertions(+) diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/selftests/net/af_unix/Makefile index a66f10fb0c23..45b841758f1b 100644 --- a/tools/testing/selftests/net/af_unix/Makefile +++ b/tools/testing/selftests/net/af_unix/Makefile @@ -23,6 +23,8 @@ TEST_GEN_FILES := scm_rights_denial_lsm.bpf.o include ../../lib.mk include ../bpf.mk +$(OUTPUT)/scm_pidfd: CFLAGS += -pthread + $(OUTPUT)/scm_rights_denial_lsm: $(BPFOBJ) $(OUTPUT)/scm_rights_denial_lsm: CFLAGS += -I$(SCRATCH_DIR)/include $(OUTPUT)/scm_rights_denial_lsm: LDLIBS += -lelf -lz diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testing/selftests/net/af_unix/scm_pidfd.c index 2c18b92a2603..019c48e1cdcd 100644 --- a/tools/testing/selftests/net/af_unix/scm_pidfd.c +++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -27,6 +28,10 @@ #define SCM_PIDFD 0x04 #endif +#ifndef SO_PASSPIDFD_THREAD +#define SO_PASSPIDFD_THREAD 86 +#endif + #define CHILD_EXIT_CODE_OK 123 static void child_die() @@ -553,4 +558,268 @@ TEST_F(scm_pidfd, test) close(pfd); } +struct thread_ids { + pid_t pid; + pid_t tid; +}; + +static void *send_ids_thread(void *arg) +{ + int fd = *(int *)arg; + struct thread_ids ids = { + .pid = getpid(), + .tid = gettid(), + }; + char sync; + + if (send(fd, &ids, sizeof(ids), 0) != sizeof(ids)) + return (void *)1; + + /* stay alive until the receiver has looked at our pidfd */ + if (read(fd, &sync, 1) != 1) + return (void *)1; + + return NULL; +} + +static void *send_ids_creds_thread(void *arg) +{ + int fd = *(int *)arg; + struct thread_ids ids = { + .pid = getpid(), + .tid = gettid(), + }; + struct ucred ucred = { + .pid = getpid(), + .uid = getuid(), + .gid = getgid(), + }; + char control[CMSG_SPACE(sizeof(ucred))] = { 0 }; + struct iovec iov; + struct msghdr msg = { 0 }; + struct cmsghdr *cmsg; + char sync; + + iov.iov_base = &ids; + iov.iov_len = sizeof(ids); + + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = control; + msg.msg_controllen = sizeof(control); + + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_CREDENTIALS; + cmsg->cmsg_len = CMSG_LEN(sizeof(ucred)); + memcpy(CMSG_DATA(cmsg), &ucred, sizeof(ucred)); + + if (sendmsg(fd, &msg, 0) != sizeof(ids)) + return (void *)1; + + if (read(fd, &sync, 1) != 1) + return (void *)1; + + return NULL; +} + +static void thread_client(int fd, int syncfd, void *(*sender)(void *)) +{ + pthread_t thread; + void *ret; + char sync; + + /* wait until the receiver enabled SO_PASSPIDFD */ + if (read(syncfd, &sync, 1) != 1) + child_die(); + + if (pthread_create(&thread, NULL, sender, &fd)) + child_die(); + + if (pthread_join(thread, &ret) || ret) + child_die(); + + exit(0); +} + +static int recv_pidfd(int fd, struct thread_ids *ids) +{ + char control[CMSG_SPACE(sizeof(int))] = { 0 }; + struct iovec iov; + struct msghdr msg = { 0 }; + struct cmsghdr *cmsg; + int pidfd = -1; + + iov.iov_base = ids; + iov.iov_len = sizeof(*ids); + + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = control; + msg.msg_controllen = sizeof(control); + + if (recvmsg(fd, &msg, 0) != sizeof(*ids)) { + log_err("recvmsg"); + return -1; + } + + if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) { + log_err("recvmsg: truncated"); + return -1; + } + + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; + cmsg = CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_PIDFD) + memcpy(&pidfd, CMSG_DATA(cmsg), sizeof(pidfd)); + } + + return pidfd; +} + +static int thread_pidfd_flow(void *(*sender)(void *), int optname, + struct thread_ids *ids, struct pidfd_info *info) +{ + int sk[2]; + int syncpipe[2]; + int pidfd; + int child_status = 0; + pid_t child; + + if (socketpair(AF_UNIX, SOCK_STREAM, 0, sk)) + return -1; + + if (pipe(syncpipe)) + return -1; + + child = fork(); + if (child < 0) + return -1; + + if (child == 0) { + close(sk[0]); + close(syncpipe[1]); + thread_client(sk[1], syncpipe[0], sender); + } + close(sk[1]); + close(syncpipe[0]); + + int on = 1; + + if (setsockopt(sk[0], SOL_SOCKET, optname, &on, sizeof(on))) { + log_err("Failed to set pidfd passing option"); + return -1; + } + + if (write(syncpipe[1], "1", 1) != 1) + return -1; + close(syncpipe[1]); + + pidfd = recv_pidfd(sk[0], ids); + if (pidfd < 0) + return -1; + + info->mask = PIDFD_INFO_PID; + if (ioctl(pidfd, PIDFD_GET_INFO, info)) { + log_err("ioctl(PIDFD_GET_INFO)"); + close(pidfd); + return -1; + } + close(pidfd); + + /* release the sending thread */ + if (write(sk[0], "x", 1) != 1) + return -1; + close(sk[0]); + + waitpid(child, &child_status, 0); + if (!WIFEXITED(child_status) || WEXITSTATUS(child_status)) + return -1; + + return 0; +} + +static int sockopt_set(int fd, int optname, int val) +{ + return setsockopt(fd, SOL_SOCKET, optname, &val, sizeof(val)); +} + +static int sockopt_get(int fd, int optname) +{ + socklen_t len = sizeof(int); + int val = -1; + + if (getsockopt(fd, SOL_SOCKET, optname, &val, &len)) + return -1; + + return val; +} + +TEST(scm_pidfd_setsockopt_values) +{ + int sk[2]; + + ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, sk)); + + ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 1)); + ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD)); + ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD)); + + /* The option set last wins. */ + ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD, 1)); + ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD)); + ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD_THREAD)); + + ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 1)); + ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD)); + ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD)); + + /* Disabling one option leaves the other alone. */ + ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD, 0)); + ASSERT_EQ(1, sockopt_get(sk[0], SO_PASSPIDFD_THREAD)); + ASSERT_EQ(0, sockopt_set(sk[0], SO_PASSPIDFD_THREAD, 0)); + ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD)); + ASSERT_EQ(0, sockopt_get(sk[0], SO_PASSPIDFD_THREAD)); + + close(sk[0]); + close(sk[1]); +} + +TEST(scm_pidfd_thread) +{ + struct thread_ids ids; + struct pidfd_info info; + + ASSERT_EQ(0, thread_pidfd_flow(send_ids_thread, SO_PASSPIDFD_THREAD, + &ids, &info)); + ASSERT_NE(ids.pid, ids.tid); + EXPECT_EQ(ids.tid, info.pid); + EXPECT_EQ(ids.pid, info.tgid); +} + +TEST(scm_pidfd_thread_group) +{ + struct thread_ids ids; + struct pidfd_info info; + + ASSERT_EQ(0, thread_pidfd_flow(send_ids_thread, SO_PASSPIDFD, + &ids, &info)); + ASSERT_NE(ids.pid, ids.tid); + EXPECT_EQ(ids.pid, info.pid); + EXPECT_EQ(ids.pid, info.tgid); +} + +TEST(scm_pidfd_thread_creds) +{ + struct thread_ids ids; + struct pidfd_info info; + + ASSERT_EQ(0, thread_pidfd_flow(send_ids_creds_thread, SO_PASSPIDFD_THREAD, + &ids, &info)); + ASSERT_NE(ids.pid, ids.tid); + EXPECT_EQ(ids.tid, info.pid); + EXPECT_EQ(ids.pid, info.tgid); +} + TEST_HARNESS_MAIN -- 2.53.0