Test user.* extended attribute operations on sockfs sockets. Sockets created via socket() have their inodes in sockfs, which now supports user.* xattrs with per-inode limits. Tests fsetxattr/fgetxattr/flistxattr/fremovexattr operations including set/get, listing (verifies system.sockprotoname presence), remove, update, XATTR_CREATE/XATTR_REPLACE flags, empty values, size queries, and buffer-too-small errors. Also tests per-inode limit enforcement: maximum 128 xattrs, maximum 128KB total value size, limit recovery after removal, and independent limits across different sockets. Signed-off-by: Christian Brauner --- .../testing/selftests/filesystems/xattr/.gitignore | 1 + tools/testing/selftests/filesystems/xattr/Makefile | 2 +- .../filesystems/xattr/xattr_sockfs_test.c | 363 +++++++++++++++++++++ 3 files changed, 365 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/xattr/.gitignore b/tools/testing/selftests/filesystems/xattr/.gitignore index 5fd015d2257a..00a59c89efab 100644 --- a/tools/testing/selftests/filesystems/xattr/.gitignore +++ b/tools/testing/selftests/filesystems/xattr/.gitignore @@ -1 +1,2 @@ xattr_socket_test +xattr_sockfs_test diff --git a/tools/testing/selftests/filesystems/xattr/Makefile b/tools/testing/selftests/filesystems/xattr/Makefile index e3d8dca80faa..2cd722dba47b 100644 --- a/tools/testing/selftests/filesystems/xattr/Makefile +++ b/tools/testing/selftests/filesystems/xattr/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 CFLAGS += $(KHDR_INCLUDES) -TEST_GEN_PROGS := xattr_socket_test +TEST_GEN_PROGS := xattr_socket_test xattr_sockfs_test include ../../lib.mk diff --git a/tools/testing/selftests/filesystems/xattr/xattr_sockfs_test.c b/tools/testing/selftests/filesystems/xattr/xattr_sockfs_test.c new file mode 100644 index 000000000000..b4824b01a86d --- /dev/null +++ b/tools/testing/selftests/filesystems/xattr/xattr_sockfs_test.c @@ -0,0 +1,363 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2026 Christian Brauner +/* + * Test extended attributes on sockfs sockets. + * + * Sockets created via socket() have their inodes in sockfs, which supports + * user.* xattrs with per-inode limits: up to 128 xattrs and 128KB total + * value size. These tests verify xattr operations via fsetxattr/fgetxattr/ + * flistxattr/fremovexattr on the socket fd, as well as limit enforcement. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../../kselftest_harness.h" + +#define TEST_XATTR_NAME "user.testattr" +#define TEST_XATTR_VALUE "testvalue" +#define TEST_XATTR_VALUE2 "newvalue" + +/* Per-inode limits for user.* xattrs on sockfs (from include/linux/xattr.h) */ +#define SIMPLE_XATTR_MAX_NR 128 +#define SIMPLE_XATTR_MAX_SIZE (128 << 10) /* 128 KB */ + +#ifndef XATTR_SIZE_MAX +#define XATTR_SIZE_MAX 65536 +#endif + +/* + * Fixture for sockfs socket xattr tests. + * Creates an AF_UNIX socket (lives in sockfs, not bound to any path). + */ +FIXTURE(xattr_sockfs) +{ + int sockfd; +}; + +FIXTURE_SETUP(xattr_sockfs) +{ + self->sockfd = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(self->sockfd, 0) { + TH_LOG("Failed to create socket: %s", strerror(errno)); + } +} + +FIXTURE_TEARDOWN(xattr_sockfs) +{ + if (self->sockfd >= 0) + close(self->sockfd); +} + +TEST_F(xattr_sockfs, set_get_user_xattr) +{ + char buf[256]; + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0) { + TH_LOG("fsetxattr failed: %s", strerror(errno)); + } + + memset(buf, 0, sizeof(buf)); + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, (ssize_t)strlen(TEST_XATTR_VALUE)) { + TH_LOG("fgetxattr returned %zd: %s", ret, strerror(errno)); + } + ASSERT_STREQ(buf, TEST_XATTR_VALUE); +} + +/* + * Test listing xattrs on a sockfs socket. + * Should include user.* xattrs and system.sockprotoname. + */ +TEST_F(xattr_sockfs, list_user_xattr) +{ + char list[4096]; + ssize_t ret; + char *ptr; + bool found_user = false; + bool found_proto = false; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0) { + TH_LOG("fsetxattr failed: %s", strerror(errno)); + } + + memset(list, 0, sizeof(list)); + ret = flistxattr(self->sockfd, list, sizeof(list)); + ASSERT_GT(ret, 0) { + TH_LOG("flistxattr failed: %s", strerror(errno)); + } + + for (ptr = list; ptr < list + ret; ptr += strlen(ptr) + 1) { + if (strcmp(ptr, TEST_XATTR_NAME) == 0) + found_user = true; + if (strcmp(ptr, "system.sockprotoname") == 0) + found_proto = true; + } + ASSERT_TRUE(found_user) { + TH_LOG("user xattr not found in list"); + } + ASSERT_TRUE(found_proto) { + TH_LOG("system.sockprotoname not found in list"); + } +} + +TEST_F(xattr_sockfs, remove_user_xattr) +{ + char buf[256]; + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + ret = fremovexattr(self->sockfd, TEST_XATTR_NAME); + ASSERT_EQ(ret, 0) { + TH_LOG("fremovexattr failed: %s", strerror(errno)); + } + + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENODATA); +} + +TEST_F(xattr_sockfs, update_user_xattr) +{ + char buf[256]; + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE2, strlen(TEST_XATTR_VALUE2), 0); + ASSERT_EQ(ret, 0); + + memset(buf, 0, sizeof(buf)); + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, (ssize_t)strlen(TEST_XATTR_VALUE2)); + ASSERT_STREQ(buf, TEST_XATTR_VALUE2); +} + +TEST_F(xattr_sockfs, xattr_create_flag) +{ + int ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE2, strlen(TEST_XATTR_VALUE2), + XATTR_CREATE); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EEXIST); +} + +TEST_F(xattr_sockfs, xattr_replace_flag) +{ + int ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), + XATTR_REPLACE); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENODATA); +} + +TEST_F(xattr_sockfs, get_nonexistent) +{ + char buf[256]; + ssize_t ret; + + ret = fgetxattr(self->sockfd, "user.nonexistent", buf, sizeof(buf)); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENODATA); +} + +TEST_F(xattr_sockfs, empty_value) +{ + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, "", 0, 0); + ASSERT_EQ(ret, 0); + + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, NULL, 0); + ASSERT_EQ(ret, 0); +} + +TEST_F(xattr_sockfs, get_size) +{ + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, NULL, 0); + ASSERT_EQ(ret, (ssize_t)strlen(TEST_XATTR_VALUE)); +} + +TEST_F(xattr_sockfs, buffer_too_small) +{ + char buf[2]; + ssize_t ret; + + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ERANGE); +} + +/* + * Test maximum number of user.* xattrs per socket. + * The kernel enforces SIMPLE_XATTR_MAX_NR (128), so the 129th should + * fail with ENOSPC. + */ +TEST_F(xattr_sockfs, max_nr_xattrs) +{ + char name[32]; + int i, ret; + + for (i = 0; i < SIMPLE_XATTR_MAX_NR; i++) { + snprintf(name, sizeof(name), "user.test%03d", i); + ret = fsetxattr(self->sockfd, name, "v", 1, 0); + ASSERT_EQ(ret, 0) { + TH_LOG("fsetxattr %s failed at i=%d: %s", + name, i, strerror(errno)); + } + } + + ret = fsetxattr(self->sockfd, "user.overflow", "v", 1, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENOSPC) { + TH_LOG("Expected ENOSPC for xattr %d, got %s", + SIMPLE_XATTR_MAX_NR + 1, strerror(errno)); + } +} + +/* + * Test maximum total value size for user.* xattrs. + * The kernel enforces SIMPLE_XATTR_MAX_SIZE (128KB). Individual xattr + * values are limited to XATTR_SIZE_MAX (64KB) by the VFS, so we need + * at least two xattrs to hit the total limit. + */ +TEST_F(xattr_sockfs, max_xattr_size) +{ + char *value; + int ret; + + value = malloc(XATTR_SIZE_MAX); + ASSERT_NE(value, NULL); + memset(value, 'A', XATTR_SIZE_MAX); + + /* First 64KB xattr - total = 64KB */ + ret = fsetxattr(self->sockfd, "user.big1", value, XATTR_SIZE_MAX, 0); + ASSERT_EQ(ret, 0) { + TH_LOG("first large xattr failed: %s", strerror(errno)); + } + + /* Second 64KB xattr - total = 128KB (exactly at limit) */ + ret = fsetxattr(self->sockfd, "user.big2", value, XATTR_SIZE_MAX, 0); + free(value); + ASSERT_EQ(ret, 0) { + TH_LOG("second large xattr failed: %s", strerror(errno)); + } + + /* Third xattr with 1 byte - total > 128KB, should fail */ + ret = fsetxattr(self->sockfd, "user.big3", "v", 1, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENOSPC) { + TH_LOG("Expected ENOSPC when exceeding size limit, got %s", + strerror(errno)); + } +} + +/* + * Test that removing an xattr frees limit space, allowing re-addition. + */ +TEST_F(xattr_sockfs, limit_remove_readd) +{ + char name[32]; + int i, ret; + + /* Fill up to the maximum count */ + for (i = 0; i < SIMPLE_XATTR_MAX_NR; i++) { + snprintf(name, sizeof(name), "user.test%03d", i); + ret = fsetxattr(self->sockfd, name, "v", 1, 0); + ASSERT_EQ(ret, 0); + } + + /* Verify we're at the limit */ + ret = fsetxattr(self->sockfd, "user.overflow", "v", 1, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENOSPC); + + /* Remove one xattr */ + ret = fremovexattr(self->sockfd, "user.test000"); + ASSERT_EQ(ret, 0); + + /* Now we should be able to add one more */ + ret = fsetxattr(self->sockfd, "user.newattr", "v", 1, 0); + ASSERT_EQ(ret, 0) { + TH_LOG("re-add after remove failed: %s", strerror(errno)); + } +} + +/* + * Test that two different sockets have independent xattr limits. + */ +TEST_F(xattr_sockfs, limits_per_inode) +{ + char buf[256]; + int sock2; + ssize_t ret; + + sock2 = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(sock2, 0); + + /* Set xattr on first socket */ + ret = fsetxattr(self->sockfd, TEST_XATTR_NAME, + TEST_XATTR_VALUE, strlen(TEST_XATTR_VALUE), 0); + ASSERT_EQ(ret, 0); + + /* First socket's xattr should not be visible on second socket */ + ret = fgetxattr(sock2, TEST_XATTR_NAME, NULL, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ENODATA); + + /* Second socket should independently accept xattrs */ + ret = fsetxattr(sock2, TEST_XATTR_NAME, + TEST_XATTR_VALUE2, strlen(TEST_XATTR_VALUE2), 0); + ASSERT_EQ(ret, 0); + + /* Verify each socket has its own value */ + memset(buf, 0, sizeof(buf)); + ret = fgetxattr(self->sockfd, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, (ssize_t)strlen(TEST_XATTR_VALUE)); + ASSERT_STREQ(buf, TEST_XATTR_VALUE); + + memset(buf, 0, sizeof(buf)); + ret = fgetxattr(sock2, TEST_XATTR_NAME, buf, sizeof(buf)); + ASSERT_EQ(ret, (ssize_t)strlen(TEST_XATTR_VALUE2)); + ASSERT_STREQ(buf, TEST_XATTR_VALUE2); + + close(sock2); +} + +TEST_HARNESS_MAIN -- 2.47.3