From 29edd8b003db897d81d82d950785327f164650d3 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 12 Jun 2024 08:44:28 +0900 Subject: selftests/x86: Add return uprobe shadow stack test Adding return uprobe test for shadow stack and making sure it's working properly. Borrowed some of the code from bpf selftests. Link: https://lore.kernel.org/all/20240611112158.40795-5-jolsa@kernel.org/ Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- tools/testing/selftests/x86/test_shadow_stack.c | 145 ++++++++++++++++++++++++ 1 file changed, 145 insertions(+) (limited to 'tools/testing') diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c index ee909a7927f9..21af54d5f4ea 100644 --- a/tools/testing/selftests/x86/test_shadow_stack.c +++ b/tools/testing/selftests/x86/test_shadow_stack.c @@ -34,6 +34,7 @@ #include #include #include +#include /* * Define the ABI defines if needed, so people can run the tests @@ -734,6 +735,144 @@ int test_32bit(void) return !segv_triggered; } +static int parse_uint_from_file(const char *file, const char *fmt) +{ + int err, ret; + FILE *f; + + f = fopen(file, "re"); + if (!f) { + err = -errno; + printf("failed to open '%s': %d\n", file, err); + return err; + } + err = fscanf(f, fmt, &ret); + if (err != 1) { + err = err == EOF ? -EIO : -errno; + printf("failed to parse '%s': %d\n", file, err); + fclose(f); + return err; + } + fclose(f); + return ret; +} + +static int determine_uprobe_perf_type(void) +{ + const char *file = "/sys/bus/event_source/devices/uprobe/type"; + + return parse_uint_from_file(file, "%d\n"); +} + +static int determine_uprobe_retprobe_bit(void) +{ + const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe"; + + return parse_uint_from_file(file, "config:%d\n"); +} + +static ssize_t get_uprobe_offset(const void *addr) +{ + size_t start, end, base; + char buf[256]; + bool found = false; + FILE *f; + + f = fopen("/proc/self/maps", "r"); + if (!f) + return -errno; + + while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) { + if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) { + found = true; + break; + } + } + + fclose(f); + + if (!found) + return -ESRCH; + + return (uintptr_t)addr - start + base; +} + +static __attribute__((noinline)) void uretprobe_trigger(void) +{ + asm volatile (""); +} + +/* + * This test setups return uprobe, which is sensitive to shadow stack + * (crashes without extra fix). After executing the uretprobe we fail + * the test if we receive SIGSEGV, no crash means we're good. + * + * Helper functions above borrowed from bpf selftests. + */ +static int test_uretprobe(void) +{ + const size_t attr_sz = sizeof(struct perf_event_attr); + const char *file = "/proc/self/exe"; + int bit, fd = 0, type, err = 1; + struct perf_event_attr attr; + struct sigaction sa = {}; + ssize_t offset; + + type = determine_uprobe_perf_type(); + if (type < 0) { + if (type == -ENOENT) + printf("[SKIP]\tUretprobe test, uprobes are not available\n"); + return 0; + } + + offset = get_uprobe_offset(uretprobe_trigger); + if (offset < 0) + return 1; + + bit = determine_uprobe_retprobe_bit(); + if (bit < 0) + return 1; + + sa.sa_sigaction = segv_gp_handler; + sa.sa_flags = SA_SIGINFO; + if (sigaction(SIGSEGV, &sa, NULL)) + return 1; + + /* Setup return uprobe through perf event interface. */ + memset(&attr, 0, attr_sz); + attr.size = attr_sz; + attr.type = type; + attr.config = 1 << bit; + attr.config1 = (__u64) (unsigned long) file; + attr.config2 = offset; + + fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, -1 /* cpu */, + -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); + if (fd < 0) + goto out; + + if (sigsetjmp(jmp_buffer, 1)) + goto out; + + ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK); + + /* + * This either segfaults and goes through sigsetjmp above + * or succeeds and we're good. + */ + uretprobe_trigger(); + + printf("[OK]\tUretprobe test\n"); + err = 0; + +out: + ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK); + signal(SIGSEGV, SIG_DFL); + if (fd) + close(fd); + return err; +} + void segv_handler_ptrace(int signum, siginfo_t *si, void *uc) { /* The SSP adjustment caused a segfault. */ @@ -926,6 +1065,12 @@ int main(int argc, char *argv[]) goto out; } + if (test_uretprobe()) { + ret = 1; + printf("[FAIL]\turetprobe test\n"); + goto out; + } + return ret; out: -- cgit v1.2.3 From 3e8e25761a40194887336650673587191564e12c Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 12 Jun 2024 08:44:28 +0900 Subject: selftests/bpf: Add uretprobe syscall test for regs integrity Add uretprobe syscall test that compares register values before and after the uretprobe is hit. It also compares the register values seen from attached bpf program. Link: https://lore.kernel.org/all/20240611112158.40795-6-jolsa@kernel.org/ Acked-by: Andrii Nakryiko Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- tools/include/linux/compiler.h | 4 + .../selftests/bpf/prog_tests/uprobe_syscall.c | 163 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/uprobe_syscall.c | 15 ++ 3 files changed, 182 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall.c (limited to 'tools/testing') diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h index 8a63a9913495..6f7f22ac9da5 100644 --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -62,6 +62,10 @@ #define __nocf_check __attribute__((nocf_check)) #endif +#ifndef __naked +#define __naked __attribute__((__naked__)) +#endif + /* Are two types/vars the same type (ignoring qualifiers)? */ #ifndef __same_type # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c new file mode 100644 index 000000000000..311ac19d8992 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +#ifdef __x86_64__ + +#include +#include +#include +#include "uprobe_syscall.skel.h" + +__naked unsigned long uretprobe_regs_trigger(void) +{ + asm volatile ( + "movq $0xdeadbeef, %rax\n" + "ret\n" + ); +} + +__naked void uretprobe_regs(struct pt_regs *before, struct pt_regs *after) +{ + asm volatile ( + "movq %r15, 0(%rdi)\n" + "movq %r14, 8(%rdi)\n" + "movq %r13, 16(%rdi)\n" + "movq %r12, 24(%rdi)\n" + "movq %rbp, 32(%rdi)\n" + "movq %rbx, 40(%rdi)\n" + "movq %r11, 48(%rdi)\n" + "movq %r10, 56(%rdi)\n" + "movq %r9, 64(%rdi)\n" + "movq %r8, 72(%rdi)\n" + "movq %rax, 80(%rdi)\n" + "movq %rcx, 88(%rdi)\n" + "movq %rdx, 96(%rdi)\n" + "movq %rsi, 104(%rdi)\n" + "movq %rdi, 112(%rdi)\n" + "movq $0, 120(%rdi)\n" /* orig_rax */ + "movq $0, 128(%rdi)\n" /* rip */ + "movq $0, 136(%rdi)\n" /* cs */ + "pushf\n" + "pop %rax\n" + "movq %rax, 144(%rdi)\n" /* eflags */ + "movq %rsp, 152(%rdi)\n" /* rsp */ + "movq $0, 160(%rdi)\n" /* ss */ + + /* save 2nd argument */ + "pushq %rsi\n" + "call uretprobe_regs_trigger\n" + + /* save return value and load 2nd argument pointer to rax */ + "pushq %rax\n" + "movq 8(%rsp), %rax\n" + + "movq %r15, 0(%rax)\n" + "movq %r14, 8(%rax)\n" + "movq %r13, 16(%rax)\n" + "movq %r12, 24(%rax)\n" + "movq %rbp, 32(%rax)\n" + "movq %rbx, 40(%rax)\n" + "movq %r11, 48(%rax)\n" + "movq %r10, 56(%rax)\n" + "movq %r9, 64(%rax)\n" + "movq %r8, 72(%rax)\n" + "movq %rcx, 88(%rax)\n" + "movq %rdx, 96(%rax)\n" + "movq %rsi, 104(%rax)\n" + "movq %rdi, 112(%rax)\n" + "movq $0, 120(%rax)\n" /* orig_rax */ + "movq $0, 128(%rax)\n" /* rip */ + "movq $0, 136(%rax)\n" /* cs */ + + /* restore return value and 2nd argument */ + "pop %rax\n" + "pop %rsi\n" + + "movq %rax, 80(%rsi)\n" + + "pushf\n" + "pop %rax\n" + + "movq %rax, 144(%rsi)\n" /* eflags */ + "movq %rsp, 152(%rsi)\n" /* rsp */ + "movq $0, 160(%rsi)\n" /* ss */ + "ret\n" +); +} + +static void test_uretprobe_regs_equal(void) +{ + struct uprobe_syscall *skel = NULL; + struct pt_regs before = {}, after = {}; + unsigned long *pb = (unsigned long *) &before; + unsigned long *pa = (unsigned long *) &after; + unsigned long *pp; + unsigned int i, cnt; + int err; + + skel = uprobe_syscall__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uprobe_syscall__open_and_load")) + goto cleanup; + + err = uprobe_syscall__attach(skel); + if (!ASSERT_OK(err, "uprobe_syscall__attach")) + goto cleanup; + + uretprobe_regs(&before, &after); + + pp = (unsigned long *) &skel->bss->regs; + cnt = sizeof(before)/sizeof(*pb); + + for (i = 0; i < cnt; i++) { + unsigned int offset = i * sizeof(unsigned long); + + /* + * Check register before and after uretprobe_regs_trigger call + * that triggers the uretprobe. + */ + switch (offset) { + case offsetof(struct pt_regs, rax): + ASSERT_EQ(pa[i], 0xdeadbeef, "return value"); + break; + default: + if (!ASSERT_EQ(pb[i], pa[i], "register before-after value check")) + fprintf(stdout, "failed register offset %u\n", offset); + } + + /* + * Check register seen from bpf program and register after + * uretprobe_regs_trigger call + */ + switch (offset) { + /* + * These values will be different (not set in uretprobe_regs), + * we don't care. + */ + case offsetof(struct pt_regs, orig_rax): + case offsetof(struct pt_regs, rip): + case offsetof(struct pt_regs, cs): + case offsetof(struct pt_regs, rsp): + case offsetof(struct pt_regs, ss): + break; + default: + if (!ASSERT_EQ(pp[i], pa[i], "register prog-after value check")) + fprintf(stdout, "failed register offset %u\n", offset); + } + } + +cleanup: + uprobe_syscall__destroy(skel); +} +#else +static void test_uretprobe_regs_equal(void) +{ + test__skip(); +} +#endif + +void test_uprobe_syscall(void) +{ + if (test__start_subtest("uretprobe_regs_equal")) + test_uretprobe_regs_equal(); +} diff --git a/tools/testing/selftests/bpf/progs/uprobe_syscall.c b/tools/testing/selftests/bpf/progs/uprobe_syscall.c new file mode 100644 index 000000000000..8a4fa6c7ef59 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/uprobe_syscall.c @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include +#include + +struct pt_regs regs; + +char _license[] SEC("license") = "GPL"; + +SEC("uretprobe//proc/self/exe:uretprobe_regs_trigger") +int uretprobe(struct pt_regs *ctx) +{ + __builtin_memcpy(®s, ctx, sizeof(regs)); + return 0; +} -- cgit v1.2.3 From f42a58ffb8bb54e66bf9668a6be91477828c0c1b Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 12 Jun 2024 08:44:28 +0900 Subject: selftests/bpf: Add uretprobe syscall test for regs changes Adding test that creates uprobe consumer on uretprobe which changes some of the registers. Making sure the changed registers are propagated to the user space when the ureptobe syscall trampoline is used on x86_64. To be able to do this, adding support to bpf_testmod to create uprobe via new attribute file: /sys/kernel/bpf_testmod_uprobe This file is expecting file offset and creates related uprobe on current process exe file and removes existing uprobe if offset is 0. The can be only single uprobe at any time. The uprobe has specific consumer that changes registers used in ureprobe syscall trampoline and which are later checked in the test. Link: https://lore.kernel.org/all/20240611112158.40795-7-jolsa@kernel.org/ Acked-by: Andrii Nakryiko Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 123 ++++++++++++++++++++- .../selftests/bpf/prog_tests/uprobe_syscall.c | 67 +++++++++++ 2 files changed, 189 insertions(+), 1 deletion(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 2a18bd320e92..b0132a342bb5 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "bpf_testmod.h" #include "bpf_testmod_kfunc.h" @@ -358,6 +359,119 @@ static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = { .write = bpf_testmod_test_write, }; +/* bpf_testmod_uprobe sysfs attribute is so far enabled for x86_64 only, + * please see test_uretprobe_regs_change test + */ +#ifdef __x86_64__ + +static int +uprobe_ret_handler(struct uprobe_consumer *self, unsigned long func, + struct pt_regs *regs) + +{ + regs->ax = 0x12345678deadbeef; + regs->cx = 0x87654321feebdaed; + regs->r11 = (u64) -1; + return true; +} + +struct testmod_uprobe { + struct path path; + loff_t offset; + struct uprobe_consumer consumer; +}; + +static DEFINE_MUTEX(testmod_uprobe_mutex); + +static struct testmod_uprobe uprobe = { + .consumer.ret_handler = uprobe_ret_handler, +}; + +static int testmod_register_uprobe(loff_t offset) +{ + int err = -EBUSY; + + if (uprobe.offset) + return -EBUSY; + + mutex_lock(&testmod_uprobe_mutex); + + if (uprobe.offset) + goto out; + + err = kern_path("/proc/self/exe", LOOKUP_FOLLOW, &uprobe.path); + if (err) + goto out; + + err = uprobe_register_refctr(d_real_inode(uprobe.path.dentry), + offset, 0, &uprobe.consumer); + if (err) + path_put(&uprobe.path); + else + uprobe.offset = offset; + +out: + mutex_unlock(&testmod_uprobe_mutex); + return err; +} + +static void testmod_unregister_uprobe(void) +{ + mutex_lock(&testmod_uprobe_mutex); + + if (uprobe.offset) { + uprobe_unregister(d_real_inode(uprobe.path.dentry), + uprobe.offset, &uprobe.consumer); + uprobe.offset = 0; + } + + mutex_unlock(&testmod_uprobe_mutex); +} + +static ssize_t +bpf_testmod_uprobe_write(struct file *file, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t off, size_t len) +{ + unsigned long offset = 0; + int err = 0; + + if (kstrtoul(buf, 0, &offset)) + return -EINVAL; + + if (offset) + err = testmod_register_uprobe(offset); + else + testmod_unregister_uprobe(); + + return err ?: strlen(buf); +} + +static struct bin_attribute bin_attr_bpf_testmod_uprobe_file __ro_after_init = { + .attr = { .name = "bpf_testmod_uprobe", .mode = 0666, }, + .write = bpf_testmod_uprobe_write, +}; + +static int register_bpf_testmod_uprobe(void) +{ + return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_uprobe_file); +} + +static void unregister_bpf_testmod_uprobe(void) +{ + testmod_unregister_uprobe(); + sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_uprobe_file); +} + +#else +static int register_bpf_testmod_uprobe(void) +{ + return 0; +} + +static void unregister_bpf_testmod_uprobe(void) { } +#endif + BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL) @@ -912,7 +1026,13 @@ static int bpf_testmod_init(void) return -EINVAL; sock = NULL; mutex_init(&sock_lock); - return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file); + ret = sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file); + if (ret < 0) + return ret; + ret = register_bpf_testmod_uprobe(); + if (ret < 0) + return ret; + return 0; } static void bpf_testmod_exit(void) @@ -927,6 +1047,7 @@ static void bpf_testmod_exit(void) bpf_kfunc_close_sock(); sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file); + unregister_bpf_testmod_uprobe(); } module_init(bpf_testmod_init); diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c index 311ac19d8992..1a50cd35205d 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c @@ -149,15 +149,82 @@ static void test_uretprobe_regs_equal(void) cleanup: uprobe_syscall__destroy(skel); } + +#define BPF_TESTMOD_UPROBE_TEST_FILE "/sys/kernel/bpf_testmod_uprobe" + +static int write_bpf_testmod_uprobe(unsigned long offset) +{ + size_t n, ret; + char buf[30]; + int fd; + + n = sprintf(buf, "%lu", offset); + + fd = open(BPF_TESTMOD_UPROBE_TEST_FILE, O_WRONLY); + if (fd < 0) + return -errno; + + ret = write(fd, buf, n); + close(fd); + return ret != n ? (int) ret : 0; +} + +static void test_uretprobe_regs_change(void) +{ + struct pt_regs before = {}, after = {}; + unsigned long *pb = (unsigned long *) &before; + unsigned long *pa = (unsigned long *) &after; + unsigned long cnt = sizeof(before)/sizeof(*pb); + unsigned int i, err, offset; + + offset = get_uprobe_offset(uretprobe_regs_trigger); + + err = write_bpf_testmod_uprobe(offset); + if (!ASSERT_OK(err, "register_uprobe")) + return; + + uretprobe_regs(&before, &after); + + err = write_bpf_testmod_uprobe(0); + if (!ASSERT_OK(err, "unregister_uprobe")) + return; + + for (i = 0; i < cnt; i++) { + unsigned int offset = i * sizeof(unsigned long); + + switch (offset) { + case offsetof(struct pt_regs, rax): + ASSERT_EQ(pa[i], 0x12345678deadbeef, "rax"); + break; + case offsetof(struct pt_regs, rcx): + ASSERT_EQ(pa[i], 0x87654321feebdaed, "rcx"); + break; + case offsetof(struct pt_regs, r11): + ASSERT_EQ(pa[i], (__u64) -1, "r11"); + break; + default: + if (!ASSERT_EQ(pa[i], pb[i], "register before-after value check")) + fprintf(stdout, "failed register offset %u\n", offset); + } + } +} + #else static void test_uretprobe_regs_equal(void) { test__skip(); } + +static void test_uretprobe_regs_change(void) +{ + test__skip(); +} #endif void test_uprobe_syscall(void) { if (test__start_subtest("uretprobe_regs_equal")) test_uretprobe_regs_equal(); + if (test__start_subtest("uretprobe_regs_change")) + test_uretprobe_regs_change(); } -- cgit v1.2.3 From 9e7f74e64ae58688a33a6445e4f9a4e291d0824f Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 12 Jun 2024 08:44:28 +0900 Subject: selftests/bpf: Add uretprobe syscall call from user space test Adding test to verify that when called from outside of the trampoline provided by kernel, the uretprobe syscall will cause calling process to receive SIGILL signal and the attached bpf program is not executed. Link: https://lore.kernel.org/all/20240611112158.40795-8-jolsa@kernel.org/ Acked-by: Andrii Nakryiko Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- .../selftests/bpf/prog_tests/uprobe_syscall.c | 95 ++++++++++++++++++++++ .../selftests/bpf/progs/uprobe_syscall_executed.c | 17 ++++ 2 files changed, 112 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c index 1a50cd35205d..11ccd693ef73 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c @@ -7,7 +7,10 @@ #include #include #include +#include +#include #include "uprobe_syscall.skel.h" +#include "uprobe_syscall_executed.skel.h" __naked unsigned long uretprobe_regs_trigger(void) { @@ -209,6 +212,91 @@ static void test_uretprobe_regs_change(void) } } +#ifndef __NR_uretprobe +#define __NR_uretprobe 463 +#endif + +__naked unsigned long uretprobe_syscall_call_1(void) +{ + /* + * Pretend we are uretprobe trampoline to trigger the return + * probe invocation in order to verify we get SIGILL. + */ + asm volatile ( + "pushq %rax\n" + "pushq %rcx\n" + "pushq %r11\n" + "movq $" __stringify(__NR_uretprobe) ", %rax\n" + "syscall\n" + "popq %r11\n" + "popq %rcx\n" + "retq\n" + ); +} + +__naked unsigned long uretprobe_syscall_call(void) +{ + asm volatile ( + "call uretprobe_syscall_call_1\n" + "retq\n" + ); +} + +static void test_uretprobe_syscall_call(void) +{ + LIBBPF_OPTS(bpf_uprobe_multi_opts, opts, + .retprobe = true, + ); + struct uprobe_syscall_executed *skel; + int pid, status, err, go[2], c; + + if (ASSERT_OK(pipe(go), "pipe")) + return; + + skel = uprobe_syscall_executed__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load")) + goto cleanup; + + pid = fork(); + if (!ASSERT_GE(pid, 0, "fork")) + goto cleanup; + + /* child */ + if (pid == 0) { + close(go[1]); + + /* wait for parent's kick */ + err = read(go[0], &c, 1); + if (err != 1) + exit(-1); + + uretprobe_syscall_call(); + _exit(0); + } + + skel->links.test = bpf_program__attach_uprobe_multi(skel->progs.test, pid, + "/proc/self/exe", + "uretprobe_syscall_call", &opts); + if (!ASSERT_OK_PTR(skel->links.test, "bpf_program__attach_uprobe_multi")) + goto cleanup; + + /* kick the child */ + write(go[1], &c, 1); + err = waitpid(pid, &status, 0); + ASSERT_EQ(err, pid, "waitpid"); + + /* verify the child got killed with SIGILL */ + ASSERT_EQ(WIFSIGNALED(status), 1, "WIFSIGNALED"); + ASSERT_EQ(WTERMSIG(status), SIGILL, "WTERMSIG"); + + /* verify the uretprobe program wasn't called */ + ASSERT_EQ(skel->bss->executed, 0, "executed"); + +cleanup: + uprobe_syscall_executed__destroy(skel); + close(go[1]); + close(go[0]); +} #else static void test_uretprobe_regs_equal(void) { @@ -219,6 +307,11 @@ static void test_uretprobe_regs_change(void) { test__skip(); } + +static void test_uretprobe_syscall_call(void) +{ + test__skip(); +} #endif void test_uprobe_syscall(void) @@ -227,4 +320,6 @@ void test_uprobe_syscall(void) test_uretprobe_regs_equal(); if (test__start_subtest("uretprobe_regs_change")) test_uretprobe_regs_change(); + if (test__start_subtest("uretprobe_syscall_call")) + test_uretprobe_syscall_call(); } diff --git a/tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c b/tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c new file mode 100644 index 000000000000..0d7f1a7db2e2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include +#include + +struct pt_regs regs; + +char _license[] SEC("license") = "GPL"; + +int executed = 0; + +SEC("uretprobe.multi") +int test(struct pt_regs *regs) +{ + executed = 1; + return 0; +} -- cgit v1.2.3 From 30addd1dc6cc4558ec7024448f04bc77d508fe7d Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 12 Jun 2024 08:44:29 +0900 Subject: selftests/bpf: Add uretprobe shadow stack test Adding uretprobe shadow stack test that runs all existing uretprobe tests with shadow stack enabled if it's available. Link: https://lore.kernel.org/all/20240611112158.40795-9-jolsa@kernel.org/ Acked-by: Andrii Nakryiko Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- .../selftests/bpf/prog_tests/uprobe_syscall.c | 60 ++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c index 11ccd693ef73..c8517c8f5313 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c @@ -9,6 +9,9 @@ #include #include #include +#include +#include +#include #include "uprobe_syscall.skel.h" #include "uprobe_syscall_executed.skel.h" @@ -297,6 +300,56 @@ cleanup: close(go[1]); close(go[0]); } + +/* + * Borrowed from tools/testing/selftests/x86/test_shadow_stack.c. + * + * For use in inline enablement of shadow stack. + * + * The program can't return from the point where shadow stack gets enabled + * because there will be no address on the shadow stack. So it can't use + * syscall() for enablement, since it is a function. + * + * Based on code from nolibc.h. Keep a copy here because this can't pull + * in all of nolibc.h. + */ +#define ARCH_PRCTL(arg1, arg2) \ +({ \ + long _ret; \ + register long _num asm("eax") = __NR_arch_prctl; \ + register long _arg1 asm("rdi") = (long)(arg1); \ + register long _arg2 asm("rsi") = (long)(arg2); \ + \ + asm volatile ( \ + "syscall\n" \ + : "=a"(_ret) \ + : "r"(_arg1), "r"(_arg2), \ + "0"(_num) \ + : "rcx", "r11", "memory", "cc" \ + ); \ + _ret; \ +}) + +#ifndef ARCH_SHSTK_ENABLE +#define ARCH_SHSTK_ENABLE 0x5001 +#define ARCH_SHSTK_DISABLE 0x5002 +#define ARCH_SHSTK_SHSTK (1ULL << 0) +#endif + +static void test_uretprobe_shadow_stack(void) +{ + if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) { + test__skip(); + return; + } + + /* Run all of the uretprobe tests. */ + test_uretprobe_regs_equal(); + test_uretprobe_regs_change(); + test_uretprobe_syscall_call(); + + ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK); +} #else static void test_uretprobe_regs_equal(void) { @@ -312,6 +365,11 @@ static void test_uretprobe_syscall_call(void) { test__skip(); } + +static void test_uretprobe_shadow_stack(void) +{ + test__skip(); +} #endif void test_uprobe_syscall(void) @@ -322,4 +380,6 @@ void test_uprobe_syscall(void) test_uretprobe_regs_change(); if (test__start_subtest("uretprobe_syscall_call")) test_uretprobe_syscall_call(); + if (test__start_subtest("uretprobe_shadow_stack")) + test_uretprobe_shadow_stack(); } -- cgit v1.2.3 From 637c26f9b02d9c72448fcd5c9c4e3b08015404fc Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 21 May 2024 18:38:45 -0700 Subject: selftests/bpf: add test validating uprobe/uretprobe stack traces Add a set of tests to validate that stack traces captured from or in the presence of active uprobes and uretprobes are valid and complete. For this we use BPF program that are installed either on entry or exit of user function, plus deep-nested USDT. One of target funtions (target_1) is recursive to generate two different entries in the stack trace for the same uprobe/uretprobe, testing potential edge conditions. If there is no fixes, we get something like this for one of the scenarios: caller: 0x758fff - 0x7595ab target_1: 0x758fd5 - 0x758fff target_2: 0x758fca - 0x758fd5 target_3: 0x758fbf - 0x758fca target_4: 0x758fb3 - 0x758fbf ENTRY #0: 0x758fb3 (in target_4) ENTRY #1: 0x758fd3 (in target_2) ENTRY #2: 0x758ffd (in target_1) ENTRY #3: 0x7fffffffe000 ENTRY #4: 0x7fffffffe000 ENTRY #5: 0x6f8f39 ENTRY #6: 0x6fa6f0 ENTRY #7: 0x7f403f229590 Entry #3 and #4 (0x7fffffffe000) are uretprobe trampoline addresses which obscure actual target_1 and another target_1 invocations. Also note that between entry #0 and entry #1 we are missing an entry for target_3. With fixes, we get desired full stack traces: caller: 0x758fff - 0x7595ab target_1: 0x758fd5 - 0x758fff target_2: 0x758fca - 0x758fd5 target_3: 0x758fbf - 0x758fca target_4: 0x758fb3 - 0x758fbf ENTRY #0: 0x758fb7 (in target_4) ENTRY #1: 0x758fc8 (in target_3) ENTRY #2: 0x758fd3 (in target_2) ENTRY #3: 0x758ffd (in target_1) ENTRY #4: 0x758ff3 (in target_1) ENTRY #5: 0x75922c (in caller) ENTRY #6: 0x6f8f39 ENTRY #7: 0x6fa6f0 ENTRY #8: 0x7f986adc4cd0 Now there is a logical and complete sequence of function calls. Link: https://lore.kernel.org/all/20240522013845.1631305-5-andrii@kernel.org/ Signed-off-by: Andrii Nakryiko Acked-by: Jiri Olsa Signed-off-by: Masami Hiramatsu (Google) --- .../selftests/bpf/prog_tests/uretprobe_stack.c | 186 +++++++++++++++++++++ .../testing/selftests/bpf/progs/uretprobe_stack.c | 96 +++++++++++ 2 files changed, 282 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/uretprobe_stack.c create mode 100644 tools/testing/selftests/bpf/progs/uretprobe_stack.c (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/uretprobe_stack.c b/tools/testing/selftests/bpf/prog_tests/uretprobe_stack.c new file mode 100644 index 000000000000..6deb8d560ddd --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/uretprobe_stack.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ + +#include +#include "uretprobe_stack.skel.h" +#include "../sdt.h" + +/* We set up target_1() -> target_2() -> target_3() -> target_4() -> USDT() + * call chain, each being traced by our BPF program. On entry or return from + * each target_*() we are capturing user stack trace and recording it in + * global variable, so that user space part of the test can validate it. + * + * Note, we put each target function into a custom section to get those + * __start_XXX/__stop_XXX symbols, generated by linker for us, which allow us + * to know address range of those functions + */ +__attribute__((section("uprobe__target_4"))) +__weak int target_4(void) +{ + STAP_PROBE1(uretprobe_stack, target, 42); + return 42; +} + +extern const void *__start_uprobe__target_4; +extern const void *__stop_uprobe__target_4; + +__attribute__((section("uprobe__target_3"))) +__weak int target_3(void) +{ + return target_4(); +} + +extern const void *__start_uprobe__target_3; +extern const void *__stop_uprobe__target_3; + +__attribute__((section("uprobe__target_2"))) +__weak int target_2(void) +{ + return target_3(); +} + +extern const void *__start_uprobe__target_2; +extern const void *__stop_uprobe__target_2; + +__attribute__((section("uprobe__target_1"))) +__weak int target_1(int depth) +{ + if (depth < 1) + return 1 + target_1(depth + 1); + else + return target_2(); +} + +extern const void *__start_uprobe__target_1; +extern const void *__stop_uprobe__target_1; + +extern const void *__start_uretprobe_stack_sec; +extern const void *__stop_uretprobe_stack_sec; + +struct range { + long start; + long stop; +}; + +static struct range targets[] = { + {}, /* we want target_1 to map to target[1], so need 1-based indexing */ + { (long)&__start_uprobe__target_1, (long)&__stop_uprobe__target_1 }, + { (long)&__start_uprobe__target_2, (long)&__stop_uprobe__target_2 }, + { (long)&__start_uprobe__target_3, (long)&__stop_uprobe__target_3 }, + { (long)&__start_uprobe__target_4, (long)&__stop_uprobe__target_4 }, +}; + +static struct range caller = { + (long)&__start_uretprobe_stack_sec, + (long)&__stop_uretprobe_stack_sec, +}; + +static void validate_stack(__u64 *ips, int stack_len, int cnt, ...) +{ + int i, j; + va_list args; + + if (!ASSERT_GT(stack_len, 0, "stack_len")) + return; + + stack_len /= 8; + + /* check if we have enough entries to satisfy test expectations */ + if (!ASSERT_GE(stack_len, cnt, "stack_len2")) + return; + + if (env.verbosity >= VERBOSE_NORMAL) { + printf("caller: %#lx - %#lx\n", caller.start, caller.stop); + for (i = 1; i < ARRAY_SIZE(targets); i++) + printf("target_%d: %#lx - %#lx\n", i, targets[i].start, targets[i].stop); + for (i = 0; i < stack_len; i++) { + for (j = 1; j < ARRAY_SIZE(targets); j++) { + if (ips[i] >= targets[j].start && ips[i] < targets[j].stop) + break; + } + if (j < ARRAY_SIZE(targets)) { /* found target match */ + printf("ENTRY #%d: %#lx (in target_%d)\n", i, (long)ips[i], j); + } else if (ips[i] >= caller.start && ips[i] < caller.stop) { + printf("ENTRY #%d: %#lx (in caller)\n", i, (long)ips[i]); + } else { + printf("ENTRY #%d: %#lx\n", i, (long)ips[i]); + } + } + } + + va_start(args, cnt); + + for (i = cnt - 1; i >= 0; i--) { + /* most recent entry is the deepest target function */ + const struct range *t = va_arg(args, const struct range *); + + ASSERT_GE(ips[i], t->start, "addr_start"); + ASSERT_LT(ips[i], t->stop, "addr_stop"); + } + + va_end(args); +} + +/* __weak prevents inlining */ +__attribute__((section("uretprobe_stack_sec"))) +__weak void test_uretprobe_stack(void) +{ + LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts); + struct uretprobe_stack *skel; + int err; + + skel = uretprobe_stack__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + err = uretprobe_stack__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* trigger */ + ASSERT_EQ(target_1(0), 42 + 1, "trigger_return"); + + /* + * Stacks captured on ENTRY uprobes + */ + + /* (uprobe 1) target_1 in stack trace*/ + validate_stack(skel->bss->entry_stack1, skel->bss->entry1_len, + 2, &caller, &targets[1]); + /* (uprobe 1, recursed) */ + validate_stack(skel->bss->entry_stack1_recur, skel->bss->entry1_recur_len, + 3, &caller, &targets[1], &targets[1]); + /* (uprobe 2) caller -> target_1 -> target_1 -> target_2 */ + validate_stack(skel->bss->entry_stack2, skel->bss->entry2_len, + 4, &caller, &targets[1], &targets[1], &targets[2]); + /* (uprobe 3) */ + validate_stack(skel->bss->entry_stack3, skel->bss->entry3_len, + 5, &caller, &targets[1], &targets[1], &targets[2], &targets[3]); + /* (uprobe 4) caller -> target_1 -> target_1 -> target_2 -> target_3 -> target_4 */ + validate_stack(skel->bss->entry_stack4, skel->bss->entry4_len, + 6, &caller, &targets[1], &targets[1], &targets[2], &targets[3], &targets[4]); + + /* (USDT): full caller -> target_1 -> target_1 -> target_2 (uretprobed) + * -> target_3 -> target_4 (uretprobes) chain + */ + validate_stack(skel->bss->usdt_stack, skel->bss->usdt_len, + 6, &caller, &targets[1], &targets[1], &targets[2], &targets[3], &targets[4]); + + /* + * Now stacks captured on the way out in EXIT uprobes + */ + + /* (uretprobe 4) everything up to target_4, but excluding it */ + validate_stack(skel->bss->exit_stack4, skel->bss->exit4_len, + 5, &caller, &targets[1], &targets[1], &targets[2], &targets[3]); + /* we didn't install uretprobes on target_2 and target_3 */ + /* (uretprobe 1, recur) first target_1 call only */ + validate_stack(skel->bss->exit_stack1_recur, skel->bss->exit1_recur_len, + 2, &caller, &targets[1]); + /* (uretprobe 1) just a caller in the stack trace */ + validate_stack(skel->bss->exit_stack1, skel->bss->exit1_len, + 1, &caller); + +cleanup: + uretprobe_stack__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/uretprobe_stack.c b/tools/testing/selftests/bpf/progs/uretprobe_stack.c new file mode 100644 index 000000000000..9fdcf396b8f4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/uretprobe_stack.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include +#include + +char _license[] SEC("license") = "GPL"; + +__u64 entry_stack1[32], exit_stack1[32]; +__u64 entry_stack1_recur[32], exit_stack1_recur[32]; +__u64 entry_stack2[32]; +__u64 entry_stack3[32]; +__u64 entry_stack4[32], exit_stack4[32]; +__u64 usdt_stack[32]; + +int entry1_len, exit1_len; +int entry1_recur_len, exit1_recur_len; +int entry2_len, exit2_len; +int entry3_len, exit3_len; +int entry4_len, exit4_len; +int usdt_len; + +#define SZ sizeof(usdt_stack) + +SEC("uprobe//proc/self/exe:target_1") +int BPF_UPROBE(uprobe_1) +{ + /* target_1 is recursive wit depth of 2, so we capture two separate + * stack traces, depending on which occurence it is + */ + static bool recur = false; + + if (!recur) + entry1_len = bpf_get_stack(ctx, &entry_stack1, SZ, BPF_F_USER_STACK); + else + entry1_recur_len = bpf_get_stack(ctx, &entry_stack1_recur, SZ, BPF_F_USER_STACK); + + recur = true; + return 0; +} + +SEC("uretprobe//proc/self/exe:target_1") +int BPF_URETPROBE(uretprobe_1) +{ + /* see above, target_1 is recursive */ + static bool recur = false; + + /* NOTE: order of returns is reversed to order of entries */ + if (!recur) + exit1_recur_len = bpf_get_stack(ctx, &exit_stack1_recur, SZ, BPF_F_USER_STACK); + else + exit1_len = bpf_get_stack(ctx, &exit_stack1, SZ, BPF_F_USER_STACK); + + recur = true; + return 0; +} + +SEC("uprobe//proc/self/exe:target_2") +int BPF_UPROBE(uprobe_2) +{ + entry2_len = bpf_get_stack(ctx, &entry_stack2, SZ, BPF_F_USER_STACK); + return 0; +} + +/* no uretprobe for target_2 */ + +SEC("uprobe//proc/self/exe:target_3") +int BPF_UPROBE(uprobe_3) +{ + entry3_len = bpf_get_stack(ctx, &entry_stack3, SZ, BPF_F_USER_STACK); + return 0; +} + +/* no uretprobe for target_3 */ + +SEC("uprobe//proc/self/exe:target_4") +int BPF_UPROBE(uprobe_4) +{ + entry4_len = bpf_get_stack(ctx, &entry_stack4, SZ, BPF_F_USER_STACK); + return 0; +} + +SEC("uretprobe//proc/self/exe:target_4") +int BPF_URETPROBE(uretprobe_4) +{ + exit4_len = bpf_get_stack(ctx, &exit_stack4, SZ, BPF_F_USER_STACK); + return 0; +} + +SEC("usdt//proc/self/exe:uretprobe_stack:target") +int BPF_USDT(usdt_probe) +{ + usdt_len = bpf_get_stack(ctx, &usdt_stack, SZ, BPF_F_USER_STACK); + return 0; +} -- cgit v1.2.3 From 3e301b431b91e4b973dbc520e90e220acb5b91f5 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 12 Jul 2024 15:52:28 +0200 Subject: selftests/bpf: Change uretprobe syscall number in uprobe_syscall test Fixing the syscall number value. Link: https://lore.kernel.org/all/20240712135228.1619332-3-jolsa@kernel.org/ Fixes: 9e7f74e64ae5 ("selftests/bpf: Add uretprobe syscall call from user space test") Signed-off-by: Jiri Olsa Acked-by: Andrii Nakryiko Signed-off-by: Masami Hiramatsu (Google) --- tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c index c8517c8f5313..bd8c75b620c2 100644 --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c @@ -216,7 +216,7 @@ static void test_uretprobe_regs_change(void) } #ifndef __NR_uretprobe -#define __NR_uretprobe 463 +#define __NR_uretprobe 467 #endif __naked unsigned long uretprobe_syscall_call_1(void) -- cgit v1.2.3