Thread (19 messages) 19 messages, 5 authors, 2024-06-11

Re: [PATCHv7 bpf-next 8/9] selftests/bpf: Add uretprobe shadow stack test

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date: 2024-06-10 22:02:19
Also in: bpf, linux-api, linux-man, lkml

On Thu, 23 May 2024 14:11:48 +0200
Jiri Olsa [off-list ref] wrote:
Adding uretprobe shadow stack test that runs all existing
uretprobe tests with shadow stack enabled if it's available.
According to the document and sample code, this looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,
quoted hunk ↗ jump to hunk
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 3ef324c2db50..fda456401284 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 <linux/compiler.h>
 #include <linux/stringify.h>
 #include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/prctl.h>
+#include <asm/prctl.h>
 #include "uprobe_syscall.skel.h"
 #include "uprobe_syscall_executed.skel.h"
 
@@ -297,6 +300,56 @@ static void test_uretprobe_syscall_call(void)
 	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();
 }
-- 
2.45.1

-- 
Masami Hiramatsu (Google) [off-list ref]
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help