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 4825B47DFA5; Fri, 7 Aug 2026 15:00:11 +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=1786114812; cv=none; b=FM4jxUmw+ND0LeT84az+bpQSrdYcO5P+8TUPCJBhr5xKIIBgka7Hsfr8tnhQoroF7IjII2izeG8DDNTlRA/3lebHFBBHpUbUP3AdNQx8htp2XBmq4vYZfvBycXuyTDxoPJ1eoa8Kxf8eFDU/UhwdkAS+aylvIcAbQ+f4WnL9nZE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786114812; c=relaxed/simple; bh=pF2OmjP9iu4fk6Ong5vrLe6zneMx96aZy3jVvuHbPH4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=f3fSyFgAk69Uacg9gPZIDCy7G6AGElb0+x3CPj4vUDRUYmFd3MuGU4A3Cf5w7CJarRH14XWTeHCmDC9M2/+yBhIh6mp01lWt10BgPngT/1ywRe7cprAQOuyb65aIuylc12xiWMa1yL9C5QBI/N1ghcN+fktbNURI4T+RC9PprS4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AY+llc7k; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AY+llc7k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CA121F000E9; Fri, 7 Aug 2026 15:00:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786114811; bh=+9FvQu4K39E/+0iAywqHwefDCTuNOC2t+ku4TCbr9xg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AY+llc7kJrySjdcTpsU4QT0Up2vz1LiZrbIFrrdiZcB5nHmSPNQdvrDodSo4g5U9s r+DGlaXeApBCl6EY7w/7ts6UVWG+tY1/FWs/vztRvFyjsXn32Vp+dG+yDMmY72Jf9l PhSjLh3On8YO26Bc4K6YDHLl9sIkxJ6b0CnPrahM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Sunday Adelodun , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 057/396] selftests: af_unix: Add tests for ECONNRESET and EOF semantics Date: Fri, 7 Aug 2026 16:33:37 +0200 Message-ID: <20260807143425.501025335@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143424.272339768@linuxfoundation.org> References: <20260807143424.272339768@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sunday Adelodun [ Upstream commit 45a1cd8346ca245a1ca475b26eb6ceb9d8b7c6f0 ] Add selftests to verify and document Linux’s intended behaviour for UNIX domain sockets (SOCK_STREAM and SOCK_DGRAM) when a peer closes. The tests verify that: 1. SOCK_STREAM returns EOF when the peer closes normally. 2. SOCK_STREAM returns ECONNRESET if the peer closes with unread data. 3. SOCK_SEQPACKET returns EOF when the peer closes normally. 4. SOCK_SEQPACKET returns ECONNRESET if the peer closes with unread data. 5. SOCK_DGRAM does not return ECONNRESET when the peer closes. This follows up on review feedback suggesting a selftest to clarify Linux’s semantics. Suggested-by: Kuniyuki Iwashima Signed-off-by: Sunday Adelodun Link: https://patch.msgid.link/20251113112802.44657-1-adelodunolaoluwa@yahoo.com Signed-off-by: Paolo Abeni Stable-dep-of: 7f57c650d08b ("selftests/net/af_unix: test listen() rejects wrong socket states") Signed-off-by: Sasha Levin --- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/af_unix/Makefile | 1 + .../selftests/net/af_unix/unix_connreset.c | 177 ++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 tools/testing/selftests/net/af_unix/unix_connreset.c diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index 8f9850a71f542..f627f1a2a2b8c 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -66,3 +66,4 @@ udpgso udpgso_bench_rx udpgso_bench_tx unix_connect +unix_connreset diff --git a/tools/testing/selftests/net/af_unix/Makefile b/tools/testing/selftests/net/af_unix/Makefile index 2889403e35468..4c0375e28bbee 100644 --- a/tools/testing/selftests/net/af_unix/Makefile +++ b/tools/testing/selftests/net/af_unix/Makefile @@ -13,6 +13,7 @@ TEST_GEN_PROGS := \ scm_rights \ so_peek_off \ unix_connect \ + unix_connreset \ # end of TEST_GEN_PROGS include ../../lib.mk diff --git a/tools/testing/selftests/net/af_unix/unix_connreset.c b/tools/testing/selftests/net/af_unix/unix_connreset.c new file mode 100644 index 0000000000000..bffef2b54bfd1 --- /dev/null +++ b/tools/testing/selftests/net/af_unix/unix_connreset.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Selftest for AF_UNIX socket close and ECONNRESET behaviour. + * + * This test verifies: + * 1. SOCK_STREAM returns EOF when the peer closes normally. + * 2. SOCK_STREAM returns ECONNRESET if peer closes with unread data. + * 3. SOCK_SEQPACKET returns EOF when the peer closes normally. + * 4. SOCK_SEQPACKET returns ECONNRESET if the peer closes with unread data. + * 5. SOCK_DGRAM does not return ECONNRESET when the peer closes. + * + * These tests document the intended Linux behaviour. + * + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include "../../kselftest_harness.h" + +#define SOCK_PATH "/tmp/af_unix_connreset.sock" + +static void remove_socket_file(void) +{ + unlink(SOCK_PATH); +} + +FIXTURE(unix_sock) +{ + int server; + int client; + int child; +}; + +FIXTURE_VARIANT(unix_sock) +{ + int socket_type; + const char *name; +}; + +FIXTURE_VARIANT_ADD(unix_sock, stream) { + .socket_type = SOCK_STREAM, + .name = "SOCK_STREAM", +}; + +FIXTURE_VARIANT_ADD(unix_sock, dgram) { + .socket_type = SOCK_DGRAM, + .name = "SOCK_DGRAM", +}; + +FIXTURE_VARIANT_ADD(unix_sock, seqpacket) { + .socket_type = SOCK_SEQPACKET, + .name = "SOCK_SEQPACKET", +}; + +FIXTURE_SETUP(unix_sock) +{ + struct sockaddr_un addr = {}; + int err; + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + self->server = socket(AF_UNIX, variant->socket_type, 0); + ASSERT_LT(-1, self->server); + + err = bind(self->server, (struct sockaddr *)&addr, sizeof(addr)); + ASSERT_EQ(0, err); + + if (variant->socket_type == SOCK_STREAM || + variant->socket_type == SOCK_SEQPACKET) { + err = listen(self->server, 1); + ASSERT_EQ(0, err); + } + + self->client = socket(AF_UNIX, variant->socket_type | SOCK_NONBLOCK, 0); + ASSERT_LT(-1, self->client); + + err = connect(self->client, (struct sockaddr *)&addr, sizeof(addr)); + ASSERT_EQ(0, err); +} + +FIXTURE_TEARDOWN(unix_sock) +{ + if (variant->socket_type == SOCK_STREAM || + variant->socket_type == SOCK_SEQPACKET) + close(self->child); + + close(self->client); + close(self->server); + remove_socket_file(); +} + +/* Test 1: peer closes normally */ +TEST_F(unix_sock, eof) +{ + char buf[16] = {}; + ssize_t n; + + if (variant->socket_type == SOCK_STREAM || + variant->socket_type == SOCK_SEQPACKET) { + self->child = accept(self->server, NULL, NULL); + ASSERT_LT(-1, self->child); + + close(self->child); + } else { + close(self->server); + } + + n = recv(self->client, buf, sizeof(buf), 0); + + if (variant->socket_type == SOCK_STREAM || + variant->socket_type == SOCK_SEQPACKET) { + ASSERT_EQ(0, n); + } else { + ASSERT_EQ(-1, n); + ASSERT_EQ(EAGAIN, errno); + } +} + +/* Test 2: peer closes with unread data */ +TEST_F(unix_sock, reset_unread_behavior) +{ + char buf[16] = {}; + ssize_t n; + + /* Send data that will remain unread */ + send(self->client, "hello", 5, 0); + + if (variant->socket_type == SOCK_DGRAM) { + /* No real connection, just close the server */ + close(self->server); + } else { + self->child = accept(self->server, NULL, NULL); + ASSERT_LT(-1, self->child); + + /* Peer closes before client reads */ + close(self->child); + } + + n = recv(self->client, buf, sizeof(buf), 0); + ASSERT_EQ(-1, n); + + if (variant->socket_type == SOCK_STREAM || + variant->socket_type == SOCK_SEQPACKET) { + ASSERT_EQ(ECONNRESET, errno); + } else { + ASSERT_EQ(EAGAIN, errno); + } +} + +/* Test 3: closing unaccepted (embryo) server socket should reset client. */ +TEST_F(unix_sock, reset_closed_embryo) +{ + char buf[16] = {}; + ssize_t n; + + if (variant->socket_type == SOCK_DGRAM) + SKIP(return, "This test only applies to SOCK_STREAM and SOCK_SEQPACKET"); + + /* Close server without accept()ing */ + close(self->server); + + n = recv(self->client, buf, sizeof(buf), 0); + + ASSERT_EQ(-1, n); + ASSERT_EQ(ECONNRESET, errno); +} + +TEST_HARNESS_MAIN + -- 2.53.0