From patchwork Thu May 23 12:11:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 13671696 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4CD3778C8B; Thu, 23 May 2024 12:12:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716466366; cv=none; b=CsTfami6G/YNOCqBlTzkVQHYeJIlqiYUtJ6Mx2fDNG9PnFrlE0jUDMXE1mghVtMNp+Wb2W9JdlPmi+mmJ84WFcWSV3SmBhae7CGdJSb/3ySHLECs+Xoxo4AUFP7KH6CXX4YOU3FnFDWm35t9pPW3tSIJ7xGK4U7YeMZndTpR5ic= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716466366; c=relaxed/simple; bh=H7m0sHQPtyf1voojk8tll6CO+KmjIGNVI3OSqf3KuMw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aOf/OTjmkILMDzsk9WLvgza/IxV6Zoyy2CDz4RHY3aVCcAxzlc+aANEhBmIO+SXNSEV+QoIMnK/oE7X9PEEyaHV8dqq2GNYxkO+m8UMK6VKdsJuexNLtfFo7eUsiRZM5hw6CEY0zreLJ3WIlXBNPdeCKMiP2+k53jyOmPpiZ7Ik= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W1xeK4y9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="W1xeK4y9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EA04C3277B; Thu, 23 May 2024 12:12:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716466365; bh=H7m0sHQPtyf1voojk8tll6CO+KmjIGNVI3OSqf3KuMw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W1xeK4y9enoIkkkcx0IM3G13R7grhVOyon7oHBPYnKdRDWHVVkn9SeUg7XD6yDWpV nVEnKsvTe+8heAk2wJHdyIfHA//3D7PTnKc1VKYbojVc22+j5mFb0xb1PH7yMyaTy9 D6RUbfTWrXsvPaG9Tl4ie8OE7RXzNNysEBeeJB3TM108RJAy2hS7/Advdq6eqebixc sOXF4yjpFdHB1oE+9zl4Q/a9I0Qwsw0sXNPjvWd+7pETNfwxXHa5wwHxJMzKLQ1ufy 1cXcNZfkrizxi4yxJOK82jYKNNigG6Mi9BSjUM3CQvieije5wClBEyK5r5HKV6rRGj Gc5n2a8UO41RQ== From: Jiri Olsa To: Steven Rostedt , Masami Hiramatsu , Oleg Nesterov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-man@vger.kernel.org, x86@kernel.org, bpf@vger.kernel.org, Song Liu , Yonghong Song , John Fastabend , Peter Zijlstra , Thomas Gleixner , "Borislav Petkov (AMD)" , Ingo Molnar , Andy Lutomirski , "Edgecombe, Rick P" , Deepak Gupta Subject: [PATCHv7 bpf-next 4/9] selftests/x86: Add return uprobe shadow stack test Date: Thu, 23 May 2024 14:11:44 +0200 Message-ID: <20240523121149.575616-5-jolsa@kernel.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240523121149.575616-1-jolsa@kernel.org> References: <20240523121149.575616-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Adding return uprobe test for shadow stack and making sure it's working properly. Borrowed some of the code from bpf selftests. Signed-off-by: Jiri Olsa --- .../testing/selftests/x86/test_shadow_stack.c | 145 ++++++++++++++++++ 1 file changed, 145 insertions(+) diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c index 757e6527f67e..e3501b7e2ecc 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 @@ -681,6 +682,144 @@ 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. */ @@ -867,6 +1006,12 @@ int main(int argc, char *argv[]) goto out; } + if (test_uretprobe()) { + ret = 1; + printf("[FAIL]\turetprobe test\n"); + goto out; + } + return ret; out: