This selftest contains a testcase that utilizes light skeleton eBPF loaders. One version of the light skeleton is signed with the autogenerated module signing key, another is not. A test driver attempts to load the programs. With Hornet enabled, the signed version should successfully be loaded, and the unsigned version should fail.
Signed-off-by: Blaise Boscaccy bboscaccy@linux.microsoft.com --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/hornet/Makefile | 58 +++ tools/testing/selftests/hornet/fail_loader.sh | 3 + tools/testing/selftests/hornet/frozen_skel.h | 393 ++++++++++++++++++ tools/testing/selftests/hornet/loader.c | 22 + tools/testing/selftests/hornet/trivial.bpf.c | 33 ++ 6 files changed, 510 insertions(+) create mode 100644 tools/testing/selftests/hornet/Makefile create mode 100755 tools/testing/selftests/hornet/fail_loader.sh create mode 100644 tools/testing/selftests/hornet/frozen_skel.h create mode 100644 tools/testing/selftests/hornet/loader.c create mode 100644 tools/testing/selftests/hornet/trivial.bpf.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index c77c8c8e3d9b..14f5d8ede199 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -42,6 +42,7 @@ TARGETS += ftrace TARGETS += futex TARGETS += gpio TARGETS += hid +TARGETS += hornet TARGETS += intel_pstate TARGETS += iommu TARGETS += ipc diff --git a/tools/testing/selftests/hornet/Makefile b/tools/testing/selftests/hornet/Makefile new file mode 100644 index 000000000000..cd6902918564 --- /dev/null +++ b/tools/testing/selftests/hornet/Makefile @@ -0,0 +1,58 @@ +# SPDX-License-Identifier: GPL-2.0 +include ../../../build/Build.include +include ../../../scripts/Makefile.arch +include ../../../scripts/Makefile.include + +CLANG ?= clang +CFLAGS := -g -O2 -Wall +BPFTOOL ?= bpftool +SCRIPTSDIR := $(abspath ../../../../scripts/hornet) +TOOLSDIR := $(abspath ../../..) +LIBDIR := $(TOOLSDIR)/lib +BPFDIR := $(LIBDIR)/bpf +TOOLSINCDIR := $(TOOLSDIR)/include +APIDIR := $(TOOLSINCDIR)/uapi +CERTDIR := $(abspath ../../../../certs) +PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config + +TEST_GEN_PROGS_EXTENDED := loader +TEST_GEN_PROGS := signed_loader +TEST_PROGS := fail_loader.sh +TEST_GEN_FILES := vmlinux.h loader.h trivial.bin trivial.bpf.o +$(TEST_GEN_PROGS): LDLIBS += -lbpf +$(TEST_GEN_PROGS): $(TEST_GEN_FILES) + +include ../lib.mk + +BPF_CFLAGS := -target bpf \ + -D__TARGET_ARCH_$(ARCH) \ + -I/usr/include/$(shell uname -m)-linux-gnu \ + $(KHDR_INCLUDES) + +vmlinux.h: + $(BPFTOOL) btf dump file /sys/kernel/btf/vmlinux format c > vmlinux.h + +trivial.bpf.o: trivial.bpf.c vmlinux.h + $(CLANG) $(CFLAGS) $(BPF_CFLAGS) -c $< -o $@ + +loader.h: trivial.bpf.o + $(BPFTOOL) gen skeleton -L $< name trivial > $@ + +trivial.bin: loader.h + $(SCRIPTSDIR)/extract-skel.sh $< $@ + +loader: loader.c loader.h + $(CC) $(CFLAGS) -I$(LIBDIR) -I$(APIDIR) $< -o $@ -lbpf + +$(OUTPUT)/sign-ebpf: ../../../../scripts/hornet/sign-ebpf.c + $(call msg,SIGN-EBPF,,$@) + $(Q)$(CC) $(shell $(PKG_CONFIG) --cflags libcrypto 2> /dev/null) \ + $< -o $@ \ + $(shell $(PKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto) + +signed_loader: trivial.bin loader $(OUTPUT)/sign-ebpf + $(OUTPUT)/sign-ebpf sha256 $(CERTDIR)/signing_key.pem $(CERTDIR)/signing_key.x509 \ + trivial.bin loader signed_loader + chmod u+x $@ + +EXTRA_CLEAN = $(OUTPUT)/sign-ebpf diff --git a/tools/testing/selftests/hornet/fail_loader.sh b/tools/testing/selftests/hornet/fail_loader.sh new file mode 100755 index 000000000000..99314369f5de --- /dev/null +++ b/tools/testing/selftests/hornet/fail_loader.sh @@ -0,0 +1,3 @@ +#!/bin/bash + +./loader && exit 1; exit 0 diff --git a/tools/testing/selftests/hornet/frozen_skel.h b/tools/testing/selftests/hornet/frozen_skel.h new file mode 100644 index 000000000000..2e31a52f41c2 --- /dev/null +++ b/tools/testing/selftests/hornet/frozen_skel.h @@ -0,0 +1,393 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +/* Copyright (c) 2021 Facebook */ +#ifndef __SKEL_INTERNAL_H +#define __SKEL_INTERNAL_H + +#ifdef __KERNEL__ +#include <linux/fdtable.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/slab.h> +#include <linux/bpf.h> +#else +#include <unistd.h> +#include <sys/syscall.h> +#include <sys/mman.h> +#include <stdlib.h> +#include <bpf/bpf.h> +#endif + +#ifndef __NR_bpf +# if defined(__mips__) && defined(_ABIO32) +# define __NR_bpf 4355 +# elif defined(__mips__) && defined(_ABIN32) +# define __NR_bpf 6319 +# elif defined(__mips__) && defined(_ABI64) +# define __NR_bpf 5315 +# endif +#endif + +/* This file is a base header for auto-generated *.lskel.h files. + * Its contents will change and may become part of auto-generation in the future. + * + * The layout of bpf_[map|prog]_desc and bpf_loader_ctx is feature dependent + * and will change from one version of libbpf to another and features + * requested during loader program generation. + */ +struct bpf_map_desc { + /* output of the loader prog */ + int map_fd; + /* input for the loader prog */ + __u32 max_entries; + __aligned_u64 initial_value; +}; +struct bpf_prog_desc { + int prog_fd; +}; + +enum { + BPF_SKEL_KERNEL = (1ULL << 0), +}; + +struct bpf_loader_ctx { + __u32 sz; + __u32 flags; + __u32 log_level; + __u32 log_size; + __u64 log_buf; +}; + +struct bpf_load_and_run_opts { + struct bpf_loader_ctx *ctx; + const void *data; + const void *insns; + __u32 data_sz; + __u32 insns_sz; + const char *errstr; +}; + +long kern_sys_bpf(__u32 cmd, void *attr, __u32 attr_size); + +static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, + unsigned int size) +{ +#ifdef __KERNEL__ + return kern_sys_bpf(cmd, attr, size); +#else + return syscall(__NR_bpf, cmd, attr, size); +#endif +} + +#ifdef __KERNEL__ +static inline int close(int fd) +{ + return close_fd(fd); +} + +static inline void *skel_alloc(size_t size) +{ + struct bpf_loader_ctx *ctx = kzalloc(size, GFP_KERNEL); + + if (!ctx) + return NULL; + ctx->flags |= BPF_SKEL_KERNEL; + return ctx; +} + +static inline void skel_free(const void *p) +{ + kfree(p); +} + +/* skel->bss/rodata maps are populated the following way: + * + * For kernel use: + * skel_prep_map_data() allocates kernel memory that kernel module can directly access. + * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value. + * The loader program will perform probe_read_kernel() from maps.rodata.initial_value. + * skel_finalize_map_data() sets skel->rodata to point to actual value in a bpf map and + * does maps.rodata.initial_value = ~0ULL to signal skel_free_map_data() that kvfree + * is not necessary. + * + * For user space: + * skel_prep_map_data() mmaps anon memory into skel->rodata that can be accessed directly. + * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value. + * The loader program will perform copy_from_user() from maps.rodata.initial_value. + * skel_finalize_map_data() remaps bpf array map value from the kernel memory into + * skel->rodata address. + * + * The "bpftool gen skeleton -L" command generates lskel.h that is suitable for + * both kernel and user space. The generated loader program does + * either bpf_probe_read_kernel() or bpf_copy_from_user() from initial_value + * depending on bpf_loader_ctx->flags. + */ +static inline void skel_free_map_data(void *p, __u64 addr, size_t sz) +{ + if (addr != ~0ULL) + kvfree(p); + /* When addr == ~0ULL the 'p' points to + * ((struct bpf_array *)map)->value. See skel_finalize_map_data. + */ +} + +static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz) +{ + void *addr; + + addr = kvmalloc(val_sz, GFP_KERNEL); + if (!addr) + return NULL; + memcpy(addr, val, val_sz); + return addr; +} + +static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd) +{ + struct bpf_map *map; + void *addr = NULL; + + kvfree((void *) (long) *init_val); + *init_val = ~0ULL; + + /* At this point bpf_load_and_run() finished without error and + * 'fd' is a valid bpf map FD. All sanity checks below should succeed. + */ + map = bpf_map_get(fd); + if (IS_ERR(map)) + return NULL; + if (map->map_type != BPF_MAP_TYPE_ARRAY) + goto out; + addr = ((struct bpf_array *)map)->value; + /* the addr stays valid, since FD is not closed */ +out: + bpf_map_put(map); + return addr; +} + +#else + +static inline void *skel_alloc(size_t size) +{ + return calloc(1, size); +} + +static inline void skel_free(void *p) +{ + free(p); +} + +static inline void skel_free_map_data(void *p, __u64 addr, size_t sz) +{ + munmap(p, sz); +} + +static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz) +{ + void *addr; + + addr = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, -1, 0); + if (addr == (void *) -1) + return NULL; + memcpy(addr, val, val_sz); + return addr; +} + +static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd) +{ + void *addr; + + addr = mmap((void *) (long) *init_val, mmap_sz, flags, MAP_SHARED | MAP_FIXED, fd, 0); + if (addr == (void *) -1) + return NULL; + return addr; +} +#endif + +static inline int skel_closenz(int fd) +{ + if (fd > 0) + return close(fd); + return -EINVAL; +} + +#ifndef offsetofend +#define offsetofend(TYPE, MEMBER) \ + (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER))) +#endif + +static inline int skel_map_create(enum bpf_map_type map_type, + const char *map_name, + __u32 key_size, + __u32 value_size, + __u32 max_entries) +{ + const size_t attr_sz = offsetofend(union bpf_attr, map_extra); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + + attr.map_type = map_type; + strncpy(attr.map_name, map_name, sizeof(attr.map_name)); + attr.key_size = key_size; + attr.value_size = value_size; + attr.max_entries = max_entries; + + return skel_sys_bpf(BPF_MAP_CREATE, &attr, attr_sz); +} + +static inline int skel_map_update_elem(int fd, const void *key, + const void *value, __u64 flags) +{ + const size_t attr_sz = offsetofend(union bpf_attr, flags); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.map_fd = fd; + attr.key = (long) key; + attr.value = (long) value; + attr.flags = flags; + + return skel_sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz); +} + +static inline int skel_map_delete_elem(int fd, const void *key) +{ + const size_t attr_sz = offsetofend(union bpf_attr, flags); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.map_fd = fd; + attr.key = (long)key; + + return skel_sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz); +} + +static inline int skel_map_freeze(int fd) +{ + const size_t attr_sz = offsetofend(union bpf_attr, map_fd); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.map_fd = fd; + + return skel_sys_bpf(BPF_MAP_FREEZE, &attr, attr_sz); +} + +static inline int skel_map_get_fd_by_id(__u32 id) +{ + const size_t attr_sz = offsetofend(union bpf_attr, flags); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.map_id = id; + + return skel_sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz); +} + +static inline int skel_raw_tracepoint_open(const char *name, int prog_fd) +{ + const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint.prog_fd); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.raw_tracepoint.name = (long) name; + attr.raw_tracepoint.prog_fd = prog_fd; + + return skel_sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, attr_sz); +} + +static inline int skel_link_create(int prog_fd, int target_fd, + enum bpf_attach_type attach_type) +{ + const size_t attr_sz = offsetofend(union bpf_attr, link_create.iter_info_len); + union bpf_attr attr; + + memset(&attr, 0, attr_sz); + attr.link_create.prog_fd = prog_fd; + attr.link_create.target_fd = target_fd; + attr.link_create.attach_type = attach_type; + + return skel_sys_bpf(BPF_LINK_CREATE, &attr, attr_sz); +} + +#ifdef __KERNEL__ +#define set_err +#else +#define set_err err = -errno +#endif + +static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts) +{ + const size_t prog_load_attr_sz = offsetofend(union bpf_attr, fd_array); + const size_t test_run_attr_sz = offsetofend(union bpf_attr, test); + int map_fd = -1, prog_fd = -1, key = 0, err; + union bpf_attr attr; + + err = map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1); + if (map_fd < 0) { + opts->errstr = "failed to create loader map"; + set_err; + goto out; + } + + err = skel_map_update_elem(map_fd, &key, opts->data, 0); + if (err < 0) { + opts->errstr = "failed to update loader map"; + set_err; + goto out; + } + + err = skel_map_freeze(map_fd); + if (err < 0) { + opts->errstr = "failed to freeze map"; + set_err; + goto out; + } + + memset(&attr, 0, prog_load_attr_sz); + attr.prog_type = BPF_PROG_TYPE_SYSCALL; + attr.insns = (long) opts->insns; + attr.insn_cnt = opts->insns_sz / sizeof(struct bpf_insn); + attr.license = (long) "Dual BSD/GPL"; + memcpy(attr.prog_name, "__loader.prog", sizeof("__loader.prog")); + attr.fd_array = (long) &map_fd; + attr.log_level = opts->ctx->log_level; + attr.log_size = opts->ctx->log_size; + attr.log_buf = opts->ctx->log_buf; + attr.prog_flags = BPF_F_SLEEPABLE; + err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, prog_load_attr_sz); + if (prog_fd < 0) { + opts->errstr = "failed to load loader prog"; + set_err; + goto out; + } + + memset(&attr, 0, test_run_attr_sz); + attr.test.prog_fd = prog_fd; + attr.test.ctx_in = (long) opts->ctx; + attr.test.ctx_size_in = opts->ctx->sz; + err = skel_sys_bpf(BPF_PROG_RUN, &attr, test_run_attr_sz); + if (err < 0 || (int)attr.test.retval < 0) { + if (err < 0) { + opts->errstr = "failed to execute loader prog"; + set_err; + } else { + opts->errstr = "error returned by loader prog"; + err = (int)attr.test.retval; +#ifndef __KERNEL__ + errno = -err; +#endif + } + goto out; + } + err = 0; +out: + if (map_fd >= 0) + close(map_fd); + if (prog_fd >= 0) + close(prog_fd); + return err; +} + +#endif diff --git a/tools/testing/selftests/hornet/loader.c b/tools/testing/selftests/hornet/loader.c new file mode 100644 index 000000000000..548b50a0c1fe --- /dev/null +++ b/tools/testing/selftests/hornet/loader.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause + +#include <stdio.h> +#include <unistd.h> +#include <stddef.h> +#include <sys/resource.h> +#include <bpf/libbpf.h> +#include <errno.h> +#include "frozen_skel.h" +#include "loader.h" + +int main(int argc, char **argv) +{ + struct trivial *skel; + + skel = trivial__open_and_load(); + if (!skel) + return -1; + + trivial__destroy(skel); + return 0; +} diff --git a/tools/testing/selftests/hornet/trivial.bpf.c b/tools/testing/selftests/hornet/trivial.bpf.c new file mode 100644 index 000000000000..d38c5b53ff93 --- /dev/null +++ b/tools/testing/selftests/hornet/trivial.bpf.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause + +#include "vmlinux.h" + +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_core_read.h> + +char LICENSE[] SEC("license") = "Dual BSD/GPL"; + +int monitored_pid = 0; + +SEC("tracepoint/syscalls/sys_enter_unlinkat") +int handle_enter_unlink(struct trace_event_raw_sys_enter *ctx) +{ + char filename[128] = { 0 }; + struct task_struct *task; + unsigned long start_time = 0; + int pid = bpf_get_current_pid_tgid() >> 32; + char *pathname_ptr = (char *) BPF_CORE_READ(ctx, args[1]); + + bpf_probe_read_str(filename, sizeof(filename), pathname_ptr); + task = (struct task_struct *)bpf_get_current_task(); + start_time = BPF_CORE_READ(task, start_time); + + bpf_printk("BPF triggered unlinkat by PID: %d, start_time %ld. pathname = %s", + pid, start_time, filename); + + if (monitored_pid == pid) + bpf_printk("target pid found"); + + return 0; +}