Commit bc72742b authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
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selftests/bpf: Validate arch-specific argument registers limits 



Update uprobe_autoattach selftest to validate architecture-specific
argument passing through registers. Use new BPF_UPROBE and
BPF_URETPROBE, and construct both BPF-side and user-space side in such
a way that for different architectures we are fetching and checking
different number of arguments, matching architecture-specific limit of
how many registers are available for argument passing.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Tested-by: Alan Maguire <alan.maguire@oracle.com> # arm64
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> # s390x
Link: https://lore.kernel.org/bpf/20230120200914.3008030-12-andrii@kernel.org
parent ac4afd6e

tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c

+28 −5
Original line number Diff line number Diff line
@@ -3,18 +3,21 @@ 


#include <test_progs.h>

#include "test_uprobe_autoattach.skel.h"

#include "progs/bpf_misc.h"



/* uprobe attach point */

static noinline int autoattach_trigger_func(int arg)

static noinline int autoattach_trigger_func(int arg1, int arg2, int arg3,

					    int arg4, int arg5, int arg6,

					    int arg7, int arg8)

{

	asm volatile ("");

	return arg + 1;

	return arg1 + arg2 + arg3 + arg4 + arg5 + arg6 + arg7 + arg8 + 1;

}



void test_uprobe_autoattach(void)

{

	struct test_uprobe_autoattach *skel;

	int trigger_val = 100, trigger_ret;

	int trigger_ret;

	size_t malloc_sz = 1;

	char *mem;
@@ -28,22 +31,42 @@ void test_uprobe_autoattach(void) 
	skel->bss->test_pid = getpid();



	/* trigger & validate uprobe & uretprobe */

	trigger_ret = autoattach_trigger_func(trigger_val);

	trigger_ret = autoattach_trigger_func(1, 2, 3, 4, 5, 6, 7, 8);



	skel->bss->test_pid = getpid();



	/* trigger & validate shared library u[ret]probes attached by name */

	mem = malloc(malloc_sz);



	ASSERT_EQ(skel->bss->uprobe_byname_parm1, trigger_val, "check_uprobe_byname_parm1");

	ASSERT_EQ(skel->bss->uprobe_byname_parm1, 1, "check_uprobe_byname_parm1");

	ASSERT_EQ(skel->bss->uprobe_byname_ran, 1, "check_uprobe_byname_ran");

	ASSERT_EQ(skel->bss->uretprobe_byname_rc, trigger_ret, "check_uretprobe_byname_rc");

	ASSERT_EQ(skel->bss->uretprobe_byname_ret, trigger_ret, "check_uretprobe_byname_ret");

	ASSERT_EQ(skel->bss->uretprobe_byname_ran, 2, "check_uretprobe_byname_ran");

	ASSERT_EQ(skel->bss->uprobe_byname2_parm1, malloc_sz, "check_uprobe_byname2_parm1");

	ASSERT_EQ(skel->bss->uprobe_byname2_ran, 3, "check_uprobe_byname2_ran");

	ASSERT_EQ(skel->bss->uretprobe_byname2_rc, mem, "check_uretprobe_byname2_rc");

	ASSERT_EQ(skel->bss->uretprobe_byname2_ran, 4, "check_uretprobe_byname2_ran");



	ASSERT_EQ(skel->bss->a[0], 1, "arg1");

	ASSERT_EQ(skel->bss->a[1], 2, "arg2");

	ASSERT_EQ(skel->bss->a[2], 3, "arg3");

#if FUNC_REG_ARG_CNT > 3

	ASSERT_EQ(skel->bss->a[3], 4, "arg4");

#endif

#if FUNC_REG_ARG_CNT > 4

	ASSERT_EQ(skel->bss->a[4], 5, "arg5");

#endif

#if FUNC_REG_ARG_CNT > 5

	ASSERT_EQ(skel->bss->a[5], 6, "arg6");

#endif

#if FUNC_REG_ARG_CNT > 6

	ASSERT_EQ(skel->bss->a[6], 7, "arg7");

#endif

#if FUNC_REG_ARG_CNT > 7

	ASSERT_EQ(skel->bss->a[7], 8, "arg8");

#endif



	free(mem);

cleanup:

	test_uprobe_autoattach__destroy(skel);

tools/testing/selftests/bpf/progs/bpf_misc.h

+25 −0
Original line number Diff line number Diff line
@@ -28,4 +28,29 @@ 
#define SYS_PREFIX "__se_"

#endif



/* How many arguments are passed to function in register */

#if defined(__TARGET_ARCH_x86) || defined(__x86_64__)

#define FUNC_REG_ARG_CNT 6

#elif defined(__i386__)

#define FUNC_REG_ARG_CNT 3

#elif defined(__TARGET_ARCH_s390) || defined(__s390x__)

#define FUNC_REG_ARG_CNT 5

#elif defined(__TARGET_ARCH_arm) || defined(__arm__)

#define FUNC_REG_ARG_CNT 4

#elif defined(__TARGET_ARCH_arm64) || defined(__aarch64__)

#define FUNC_REG_ARG_CNT 8

#elif defined(__TARGET_ARCH_mips) || defined(__mips__)

#define FUNC_REG_ARG_CNT 8

#elif defined(__TARGET_ARCH_powerpc) || defined(__powerpc__) || defined(__powerpc64__)

#define FUNC_REG_ARG_CNT 8

#elif defined(__TARGET_ARCH_sparc) || defined(__sparc__)

#define FUNC_REG_ARG_CNT 6

#elif defined(__TARGET_ARCH_riscv) || defined(__riscv__)

#define FUNC_REG_ARG_CNT 8

#else

/* default to 5 for others */

#define FUNC_REG_ARG_CNT 5

#endif





#endif

tools/testing/selftests/bpf/progs/test_uprobe_autoattach.c

+46 −2
Original line number Diff line number Diff line
@@ -6,10 +6,12 @@ 
#include <bpf/bpf_core_read.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"



int uprobe_byname_parm1 = 0;

int uprobe_byname_ran = 0;

int uretprobe_byname_rc = 0;

int uretprobe_byname_ret = 0;

int uretprobe_byname_ran = 0;

size_t uprobe_byname2_parm1 = 0;

int uprobe_byname2_ran = 0;
@@ -18,6 +20,8 @@ int uretprobe_byname2_ran = 0; 


int test_pid;



int a[8];



/* This program cannot auto-attach, but that should not stop other

 * programs from attaching.

 */
@@ -28,18 +32,58 @@ int handle_uprobe_noautoattach(struct pt_regs *ctx) 
}



SEC("uprobe//proc/self/exe:autoattach_trigger_func")

int handle_uprobe_byname(struct pt_regs *ctx)

int BPF_UPROBE(handle_uprobe_byname

	       , int arg1

	       , int arg2

	       , int arg3

#if FUNC_REG_ARG_CNT > 3

	       , int arg4

#endif

#if FUNC_REG_ARG_CNT > 4

	       , int arg5

#endif

#if FUNC_REG_ARG_CNT > 5

	       , int arg6

#endif

#if FUNC_REG_ARG_CNT > 6

	       , int arg7

#endif

#if FUNC_REG_ARG_CNT > 7

	       , int arg8

#endif

)

{

	uprobe_byname_parm1 = PT_REGS_PARM1_CORE(ctx);

	uprobe_byname_ran = 1;



	a[0] = arg1;

	a[1] = arg2;

	a[2] = arg3;

#if FUNC_REG_ARG_CNT > 3

	a[3] = arg4;

#endif

#if FUNC_REG_ARG_CNT > 4

	a[4] = arg5;

#endif

#if FUNC_REG_ARG_CNT > 5

	a[5] = arg6;

#endif

#if FUNC_REG_ARG_CNT > 6

	a[6] = arg7;

#endif

#if FUNC_REG_ARG_CNT > 7

	a[7] = arg8;

#endif

	return 0;

}



SEC("uretprobe//proc/self/exe:autoattach_trigger_func")

int handle_uretprobe_byname(struct pt_regs *ctx)

int BPF_URETPROBE(handle_uretprobe_byname, int ret)

{

	uretprobe_byname_rc = PT_REGS_RC_CORE(ctx);

	uretprobe_byname_ret = ret;

	uretprobe_byname_ran = 2;



	return 0;

}