* [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64
@ 2022-01-24 14:16 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 1/3] libbpf: Extract syscall wrapper Kenta Tada
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Kenta Tada @ 2022-01-24 14:16 UTC (permalink / raw)
To: andrii, bpf
Cc: ast, daniel, kafai, songliubraving, yhs, john.fastabend, kpsingh,
Kenta Tada
Currently, rcx is read as the fourth parameter of syscall on x86_64.
But x86_64 Linux System Call convention uses r10 actually.
This commit adds the wrapper for users who want to access to
syscall params to analyze the user space.
Changelog:
----------
v1 -> v2:
- Rebase to current bpf-next
https://lore.kernel.org/bpf/20211222213924.1869758-1-andrii@kernel.org/
v2 -> v3:
- Modify the definition of SYSCALL macros for only targeted archs.
- Define __BPF_TARGET_MISSING variants for completeness.
- Remove CORE variants. These macros will not be used.
- Add a selftest.
v3 -> v4:
- Modify a selftest not to use serial tests.
- Modify a selftest to use ASSERT_EQ().
- Extract syscall wrapper for all the other tests.
- Add CORE variants.
v4 -> v5:
- Modify the CORE variant macro not to read memory directly.
- Remove the unnecessary comment.
- Add a selftest for the CORE variant.
Kenta Tada (3):
libbpf: Extract syscall wrapper
libbpf: Fix the incorrect register read for syscalls on x86_64
libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL
tools/lib/bpf/bpf_tracing.h | 34 ++++++++++
.../bpf/prog_tests/test_bpf_syscall_macro.c | 63 ++++++++++++++++++
tools/testing/selftests/bpf/progs/bpf_misc.h | 19 ++++++
.../selftests/bpf/progs/bpf_syscall_macro.c | 64 +++++++++++++++++++
.../selftests/bpf/progs/test_probe_user.c | 15 +----
5 files changed, 181 insertions(+), 14 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
create mode 100644 tools/testing/selftests/bpf/progs/bpf_misc.h
create mode 100644 tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
--
2.32.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v5 1/3] libbpf: Extract syscall wrapper
2022-01-24 14:16 [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64 Kenta Tada
@ 2022-01-24 14:16 ` Kenta Tada
2022-01-24 14:16 ` [PATCH v5 2/3] libbpf: Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL Kenta Tada
2 siblings, 0 replies; 7+ messages in thread
From: Kenta Tada @ 2022-01-24 14:16 UTC (permalink / raw)
To: andrii, bpf
Cc: ast, daniel, kafai, songliubraving, yhs, john.fastabend, kpsingh,
Kenta Tada
Extract the helper to set up SYS_PREFIX for fentry and kprobe selftests
that use __x86_sys_* attach functions.
Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/testing/selftests/bpf/progs/bpf_misc.h | 19 +++++++++++++++++++
.../selftests/bpf/progs/test_probe_user.c | 15 +--------------
2 files changed, 20 insertions(+), 14 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/bpf_misc.h
diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h
new file mode 100644
index 000000000000..0b78bc9b1b4c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_misc.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __BPF_MISC_H__
+#define __BPF_MISC_H__
+
+#if defined(__TARGET_ARCH_x86)
+#define SYSCALL_WRAPPER 1
+#define SYS_PREFIX "__x64_"
+#elif defined(__TARGET_ARCH_s390)
+#define SYSCALL_WRAPPER 1
+#define SYS_PREFIX "__s390x_"
+#elif defined(__TARGET_ARCH_arm64)
+#define SYSCALL_WRAPPER 1
+#define SYS_PREFIX "__arm64_"
+#else
+#define SYSCALL_WRAPPER 0
+#define SYS_PREFIX ""
+#endif
+
+#endif
diff --git a/tools/testing/selftests/bpf/progs/test_probe_user.c b/tools/testing/selftests/bpf/progs/test_probe_user.c
index 8812a90da4eb..702578a5e496 100644
--- a/tools/testing/selftests/bpf/progs/test_probe_user.c
+++ b/tools/testing/selftests/bpf/progs/test_probe_user.c
@@ -7,20 +7,7 @@
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
-
-#if defined(__TARGET_ARCH_x86)
-#define SYSCALL_WRAPPER 1
-#define SYS_PREFIX "__x64_"
-#elif defined(__TARGET_ARCH_s390)
-#define SYSCALL_WRAPPER 1
-#define SYS_PREFIX "__s390x_"
-#elif defined(__TARGET_ARCH_arm64)
-#define SYSCALL_WRAPPER 1
-#define SYS_PREFIX "__arm64_"
-#else
-#define SYSCALL_WRAPPER 0
-#define SYS_PREFIX ""
-#endif
+#include "bpf_misc.h"
static struct sockaddr_in old;
--
2.32.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v5 2/3] libbpf: Fix the incorrect register read for syscalls on x86_64
2022-01-24 14:16 [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 1/3] libbpf: Extract syscall wrapper Kenta Tada
@ 2022-01-24 14:16 ` Kenta Tada
2022-01-24 14:16 ` [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL Kenta Tada
2 siblings, 0 replies; 7+ messages in thread
From: Kenta Tada @ 2022-01-24 14:16 UTC (permalink / raw)
To: andrii, bpf
Cc: ast, daniel, kafai, songliubraving, yhs, john.fastabend, kpsingh,
Kenta Tada
Currently, rcx is read as the fourth parameter of syscall on x86_64.
But x86_64 Linux System Call convention uses r10 actually.
This commit adds the wrapper for users who want to access to
syscall params to analyze the user space.
Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
---
tools/lib/bpf/bpf_tracing.h | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 90f56b0f585f..032ba809f3e5 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -70,6 +70,7 @@
#define __PT_PARM2_REG si
#define __PT_PARM3_REG dx
#define __PT_PARM4_REG cx
+#define __PT_PARM4_REG_SYSCALL r10 /* syscall uses r10 */
#define __PT_PARM5_REG r8
#define __PT_RET_REG sp
#define __PT_FP_REG bp
@@ -99,6 +100,7 @@
#define __PT_PARM2_REG rsi
#define __PT_PARM3_REG rdx
#define __PT_PARM4_REG rcx
+#define __PT_PARM4_REG_SYSCALL r10 /* syscall uses r10 */
#define __PT_PARM5_REG r8
#define __PT_RET_REG rsp
#define __PT_FP_REG rbp
@@ -263,6 +265,26 @@ struct pt_regs;
#endif
+#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1(x)
+#define PT_REGS_PARM2_SYSCALL(x) PT_REGS_PARM2(x)
+#define PT_REGS_PARM3_SYSCALL(x) PT_REGS_PARM3(x)
+#ifdef __PT_PARM4_REG_SYSCALL
+#define PT_REGS_PARM4_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM4_REG_SYSCALL)
+#else /* __PT_PARM4_REG_SYSCALL */
+#define PT_REGS_PARM4_SYSCALL(x) PT_REGS_PARM4(x)
+#endif
+#define PT_REGS_PARM5_SYSCALL(x) PT_REGS_PARM5(x)
+
+#define PT_REGS_PARM1_CORE_SYSCALL(x) PT_REGS_PARM1_CORE(x)
+#define PT_REGS_PARM2_CORE_SYSCALL(x) PT_REGS_PARM2_CORE(x)
+#define PT_REGS_PARM3_CORE_SYSCALL(x) PT_REGS_PARM3_CORE(x)
+#ifdef __PT_PARM4_REG_SYSCALL
+#define PT_REGS_PARM4_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM4_REG_SYSCALL)
+#else /* __PT_PARM4_REG_SYSCALL */
+#define PT_REGS_PARM4_CORE_SYSCALL(x) PT_REGS_PARM4_CORE(x)
+#endif
+#define PT_REGS_PARM5_CORE_SYSCALL(x) PT_REGS_PARM5_CORE(x)
+
#else /* defined(bpf_target_defined) */
#define PT_REGS_PARM1(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
@@ -290,6 +312,18 @@ struct pt_regs;
#define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
#define BPF_KRETPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM1_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define PT_REGS_PARM1_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
#endif /* defined(bpf_target_defined) */
#ifndef ___bpf_concat
--
2.32.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL
2022-01-24 14:16 [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 1/3] libbpf: Extract syscall wrapper Kenta Tada
2022-01-24 14:16 ` [PATCH v5 2/3] libbpf: Fix the incorrect register read for syscalls on x86_64 Kenta Tada
@ 2022-01-24 14:16 ` Kenta Tada
2022-01-25 5:05 ` Andrii Nakryiko
2 siblings, 1 reply; 7+ messages in thread
From: Kenta Tada @ 2022-01-24 14:16 UTC (permalink / raw)
To: andrii, bpf
Cc: ast, daniel, kafai, songliubraving, yhs, john.fastabend, kpsingh,
Kenta Tada
Add a selftest to verify the behavior of PT_REGS_xxx
and the CORE variant.
Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
---
.../bpf/prog_tests/test_bpf_syscall_macro.c | 63 ++++++++++++++++++
.../selftests/bpf/progs/bpf_syscall_macro.c | 64 +++++++++++++++++++
2 files changed, 127 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
create mode 100644 tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c b/tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
new file mode 100644
index 000000000000..f5f4c8adf539
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2022 Sony Group Corporation */
+#include <sys/prctl.h>
+#include <test_progs.h>
+#include "bpf_syscall_macro.skel.h"
+
+void test_bpf_syscall_macro(void)
+{
+ struct bpf_syscall_macro *skel = NULL;
+ int err;
+ int exp_arg1 = 1001;
+ unsigned long exp_arg2 = 12;
+ unsigned long exp_arg3 = 13;
+ unsigned long exp_arg4 = 14;
+ unsigned long exp_arg5 = 15;
+
+ /* check whether it can open program */
+ skel = bpf_syscall_macro__open();
+ if (!ASSERT_OK_PTR(skel, "bpf_syscall_macro__open"))
+ return;
+
+ skel->rodata->filter_pid = getpid();
+
+ /* check whether it can load program */
+ err = bpf_syscall_macro__load(skel);
+ if (!ASSERT_OK(err, "bpf_syscall_macro__load"))
+ goto cleanup;
+
+ /* check whether it can attach kprobe */
+ err = bpf_syscall_macro__attach(skel);
+ if (!ASSERT_OK(err, "bpf_syscall_macro__attach"))
+ goto cleanup;
+
+ /* check whether args of syscall are copied correctly */
+ prctl(exp_arg1, exp_arg2, exp_arg3, exp_arg4, exp_arg5);
+ ASSERT_EQ(skel->bss->arg1, exp_arg1, "syscall_arg1");
+ ASSERT_EQ(skel->bss->arg2, exp_arg2, "syscall_arg2");
+ ASSERT_EQ(skel->bss->arg3, exp_arg3, "syscall_arg3");
+ /* it cannot copy arg4 when uses PT_REGS_PARM4 on x86_64 */
+#ifdef __x86_64__
+ ASSERT_NEQ(skel->bss->arg4_cx, exp_arg4, "syscall_arg4_from_cx");
+#else
+ ASSERT_EQ(skel->bss->arg4_cx, exp_arg4, "syscall_arg4_from_cx");
+#endif
+ ASSERT_EQ(skel->bss->arg4, exp_arg4, "syscall_arg4");
+ ASSERT_EQ(skel->bss->arg5, exp_arg5, "syscall_arg5");
+
+ /* check whether args of syscall are copied correctly for CORE variants */
+ ASSERT_EQ(skel->bss->arg1_core, exp_arg1, "syscall_arg1_core_variant");
+ ASSERT_EQ(skel->bss->arg2_core, exp_arg2, "syscall_arg2_core_variant");
+ ASSERT_EQ(skel->bss->arg3_core, exp_arg3, "syscall_arg3_core_variant");
+ /* it cannot copy arg4 when uses PT_REGS_PARM4_CORE on x86_64 */
+#ifdef __x86_64__
+ ASSERT_NEQ(skel->bss->arg4_core_cx, exp_arg4, "syscall_arg4_from_cx_core_variant");
+#else
+ ASSERT_EQ(skel->bss->arg4_core_cx, exp_arg4, "syscall_arg4_from_cx_core_variant");
+#endif
+ ASSERT_EQ(skel->bss->arg4_core, exp_arg4, "syscall_arg4_core_variant");
+ ASSERT_EQ(skel->bss->arg5_core, exp_arg5, "syscall_arg5_core_variant");
+
+cleanup:
+ bpf_syscall_macro__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
new file mode 100644
index 000000000000..cfeccd85f40e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2022 Sony Group Corporation */
+#include <vmlinux.h>
+
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+
+int arg1 = 0;
+unsigned long arg2 = 0;
+unsigned long arg3 = 0;
+unsigned long arg4_cx = 0;
+unsigned long arg4 = 0;
+unsigned long arg5 = 0;
+
+int arg1_core = 0;
+unsigned long arg2_core = 0;
+unsigned long arg3_core = 0;
+unsigned long arg4_core_cx = 0;
+unsigned long arg4_core = 0;
+unsigned long arg5_core = 0;
+
+const volatile pid_t filter_pid = 0;
+
+SEC("kprobe/" SYS_PREFIX "sys_prctl")
+int BPF_KPROBE(handle_sys_prctl)
+{
+ struct pt_regs *real_regs;
+ int orig_arg1;
+ unsigned long orig_arg2, orig_arg3, orig_arg4_cx, orig_arg4, orig_arg5;
+ pid_t pid = bpf_get_current_pid_tgid() >> 32;
+
+ if (pid != filter_pid)
+ return 0;
+
+ /* test for PT_REGS_PARM */
+ real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
+ bpf_probe_read_kernel(&orig_arg1, sizeof(orig_arg1), &PT_REGS_PARM1_SYSCALL(real_regs));
+ bpf_probe_read_kernel(&orig_arg2, sizeof(orig_arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
+ bpf_probe_read_kernel(&orig_arg3, sizeof(orig_arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
+ bpf_probe_read_kernel(&orig_arg4_cx, sizeof(orig_arg4_cx), &PT_REGS_PARM4(real_regs));
+ bpf_probe_read_kernel(&orig_arg4, sizeof(orig_arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
+ bpf_probe_read_kernel(&orig_arg5, sizeof(orig_arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
+ /* copy all actual args and the wrong arg4 on x86_64 */
+ arg1 = orig_arg1;
+ arg2 = orig_arg2;
+ arg3 = orig_arg3;
+ arg4_cx = orig_arg4_cx;
+ arg4 = orig_arg4;
+ arg5 = orig_arg5;
+
+ /* test for the CORE variant of PT_REGS_PARM */
+ arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
+ arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
+ arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
+ arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
+ arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
+ arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.32.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL
2022-01-24 14:16 ` [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL Kenta Tada
@ 2022-01-25 5:05 ` Andrii Nakryiko
2022-02-01 19:36 ` Andrii Nakryiko
0 siblings, 1 reply; 7+ messages in thread
From: Andrii Nakryiko @ 2022-01-25 5:05 UTC (permalink / raw)
To: Kenta Tada, Hengqi Chen
Cc: Andrii Nakryiko, bpf, Alexei Starovoitov, Daniel Borkmann,
Martin Lau, Song Liu, Yonghong Song, john fastabend, KP Singh
+cc Hengqi
On Mon, Jan 24, 2022 at 6:20 AM Kenta Tada <Kenta.Tada@sony.com> wrote:
>
> Add a selftest to verify the behavior of PT_REGS_xxx
> and the CORE variant.
>
> Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
> ---
> .../bpf/prog_tests/test_bpf_syscall_macro.c | 63 ++++++++++++++++++
> .../selftests/bpf/progs/bpf_syscall_macro.c | 64 +++++++++++++++++++
> 2 files changed, 127 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
> create mode 100644 tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
>
[...]
> diff --git a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> new file mode 100644
> index 000000000000..cfeccd85f40e
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> @@ -0,0 +1,64 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright 2022 Sony Group Corporation */
> +#include <vmlinux.h>
> +
> +#include <bpf/bpf_core_read.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +#include "bpf_misc.h"
> +
> +int arg1 = 0;
> +unsigned long arg2 = 0;
> +unsigned long arg3 = 0;
> +unsigned long arg4_cx = 0;
> +unsigned long arg4 = 0;
> +unsigned long arg5 = 0;
> +
> +int arg1_core = 0;
> +unsigned long arg2_core = 0;
> +unsigned long arg3_core = 0;
> +unsigned long arg4_core_cx = 0;
> +unsigned long arg4_core = 0;
> +unsigned long arg5_core = 0;
> +
> +const volatile pid_t filter_pid = 0;
> +
> +SEC("kprobe/" SYS_PREFIX "sys_prctl")
> +int BPF_KPROBE(handle_sys_prctl)
> +{
> + struct pt_regs *real_regs;
> + int orig_arg1;
> + unsigned long orig_arg2, orig_arg3, orig_arg4_cx, orig_arg4, orig_arg5;
> + pid_t pid = bpf_get_current_pid_tgid() >> 32;
> +
> + if (pid != filter_pid)
> + return 0;
> +
> + /* test for PT_REGS_PARM */
> + real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
> + bpf_probe_read_kernel(&orig_arg1, sizeof(orig_arg1), &PT_REGS_PARM1_SYSCALL(real_regs));
> + bpf_probe_read_kernel(&orig_arg2, sizeof(orig_arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
> + bpf_probe_read_kernel(&orig_arg3, sizeof(orig_arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
> + bpf_probe_read_kernel(&orig_arg4_cx, sizeof(orig_arg4_cx), &PT_REGS_PARM4(real_regs));
> + bpf_probe_read_kernel(&orig_arg4, sizeof(orig_arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
> + bpf_probe_read_kernel(&orig_arg5, sizeof(orig_arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
> + /* copy all actual args and the wrong arg4 on x86_64 */
> + arg1 = orig_arg1;
> + arg2 = orig_arg2;
> + arg3 = orig_arg3;
> + arg4_cx = orig_arg4_cx;
> + arg4 = orig_arg4;
> + arg5 = orig_arg5;
I don't get why you needed orig_argX variables and then copying them
into argX variables. I changed this to read directly into argX. I
suspect arg1 handling might break on big-endian arches due to int vs
long differences, please check that and send a follow up fix.
Also keep in mind that selftest changes should come with
"selftests/bpf:" subject prefix, not "libbpf:". Fixed that up as well.
Applied to bpf-next, thanks.
Hopefully Hengqi will build his SYSCALL prog wrapper macros on top of
this as a follow up as well.
> +
> + /* test for the CORE variant of PT_REGS_PARM */
> + arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
> + arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
> + arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
> + arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
> + arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
> + arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
> +
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> --
> 2.32.0
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL
2022-01-25 5:05 ` Andrii Nakryiko
@ 2022-02-01 19:36 ` Andrii Nakryiko
2022-02-01 21:01 ` Ilya Leoshkevich
0 siblings, 1 reply; 7+ messages in thread
From: Andrii Nakryiko @ 2022-02-01 19:36 UTC (permalink / raw)
To: Kenta Tada, Hengqi Chen, Ilya Leoshkevich
Cc: Andrii Nakryiko, bpf, Alexei Starovoitov, Daniel Borkmann,
Martin Lau, Song Liu, Yonghong Song, john fastabend, KP Singh
+cc Ilya
On Mon, Jan 24, 2022 at 9:05 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> +cc Hengqi
>
> On Mon, Jan 24, 2022 at 6:20 AM Kenta Tada <Kenta.Tada@sony.com> wrote:
> >
> > Add a selftest to verify the behavior of PT_REGS_xxx
> > and the CORE variant.
> >
> > Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
> > ---
> > .../bpf/prog_tests/test_bpf_syscall_macro.c | 63 ++++++++++++++++++
> > .../selftests/bpf/progs/bpf_syscall_macro.c | 64 +++++++++++++++++++
> > 2 files changed, 127 insertions(+)
> > create mode 100644 tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
> > create mode 100644 tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> >
>
> [...]
>
> > diff --git a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > new file mode 100644
> > index 000000000000..cfeccd85f40e
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > @@ -0,0 +1,64 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright 2022 Sony Group Corporation */
> > +#include <vmlinux.h>
> > +
> > +#include <bpf/bpf_core_read.h>
> > +#include <bpf/bpf_helpers.h>
> > +#include <bpf/bpf_tracing.h>
> > +#include "bpf_misc.h"
> > +
> > +int arg1 = 0;
> > +unsigned long arg2 = 0;
> > +unsigned long arg3 = 0;
> > +unsigned long arg4_cx = 0;
> > +unsigned long arg4 = 0;
> > +unsigned long arg5 = 0;
> > +
> > +int arg1_core = 0;
> > +unsigned long arg2_core = 0;
> > +unsigned long arg3_core = 0;
> > +unsigned long arg4_core_cx = 0;
> > +unsigned long arg4_core = 0;
> > +unsigned long arg5_core = 0;
> > +
> > +const volatile pid_t filter_pid = 0;
> > +
> > +SEC("kprobe/" SYS_PREFIX "sys_prctl")
> > +int BPF_KPROBE(handle_sys_prctl)
> > +{
> > + struct pt_regs *real_regs;
> > + int orig_arg1;
> > + unsigned long orig_arg2, orig_arg3, orig_arg4_cx, orig_arg4, orig_arg5;
> > + pid_t pid = bpf_get_current_pid_tgid() >> 32;
> > +
> > + if (pid != filter_pid)
> > + return 0;
> > +
> > + /* test for PT_REGS_PARM */
> > + real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
> > + bpf_probe_read_kernel(&orig_arg1, sizeof(orig_arg1), &PT_REGS_PARM1_SYSCALL(real_regs));
> > + bpf_probe_read_kernel(&orig_arg2, sizeof(orig_arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
> > + bpf_probe_read_kernel(&orig_arg3, sizeof(orig_arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
> > + bpf_probe_read_kernel(&orig_arg4_cx, sizeof(orig_arg4_cx), &PT_REGS_PARM4(real_regs));
> > + bpf_probe_read_kernel(&orig_arg4, sizeof(orig_arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
> > + bpf_probe_read_kernel(&orig_arg5, sizeof(orig_arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
> > + /* copy all actual args and the wrong arg4 on x86_64 */
> > + arg1 = orig_arg1;
> > + arg2 = orig_arg2;
> > + arg3 = orig_arg3;
> > + arg4_cx = orig_arg4_cx;
> > + arg4 = orig_arg4;
> > + arg5 = orig_arg5;
>
> I don't get why you needed orig_argX variables and then copying them
> into argX variables. I changed this to read directly into argX. I
> suspect arg1 handling might break on big-endian arches due to int vs
> long differences, please check that and send a follow up fix.
>
> Also keep in mind that selftest changes should come with
> "selftests/bpf:" subject prefix, not "libbpf:". Fixed that up as well.
>
> Applied to bpf-next, thanks.
This selftest is failing on s390x (see [0]). Ilya, do you know if
something special needs to be done for s390x for this case?
Here are the two failures:
test_bpf_syscall_macro:FAIL:syscall_arg1 unexpected syscall_arg1:
actual -1 != expected 1001
test_bpf_syscall_macro:FAIL:syscall_arg1_core_variant unexpected
syscall_arg1_core_variant: actual -38 != expected 1001
[0] https://github.com/libbpf/libbpf/runs/5025905587?check_suite_focus=true
>
> Hopefully Hengqi will build his SYSCALL prog wrapper macros on top of
> this as a follow up as well.
>
> > +
> > + /* test for the CORE variant of PT_REGS_PARM */
> > + arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
> > + arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
> > + arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
> > + arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
> > + arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
> > + arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
> > +
> > + return 0;
> > +}
> > +
> > +char _license[] SEC("license") = "GPL";
> > --
> > 2.32.0
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL
2022-02-01 19:36 ` Andrii Nakryiko
@ 2022-02-01 21:01 ` Ilya Leoshkevich
0 siblings, 0 replies; 7+ messages in thread
From: Ilya Leoshkevich @ 2022-02-01 21:01 UTC (permalink / raw)
To: Andrii Nakryiko, Kenta Tada, Hengqi Chen
Cc: Andrii Nakryiko, bpf, Alexei Starovoitov, Daniel Borkmann,
Martin Lau, Song Liu, Yonghong Song, john fastabend, KP Singh
On Tue, 2022-02-01 at 11:36 -0800, Andrii Nakryiko wrote:
> +cc Ilya
>
>
> On Mon, Jan 24, 2022 at 9:05 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > +cc Hengqi
> >
> > On Mon, Jan 24, 2022 at 6:20 AM Kenta Tada <Kenta.Tada@sony.com>
> > wrote:
> > >
> > > Add a selftest to verify the behavior of PT_REGS_xxx
> > > and the CORE variant.
> > >
> > > Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
> > > ---
> > > .../bpf/prog_tests/test_bpf_syscall_macro.c | 63
> > > ++++++++++++++++++
> > > .../selftests/bpf/progs/bpf_syscall_macro.c | 64
> > > +++++++++++++++++++
> > > 2 files changed, 127 insertions(+)
> > > create mode 100644
> > > tools/testing/selftests/bpf/prog_tests/test_bpf_syscall_macro.c
> > > create mode 100644
> > > tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > >
> >
> > [...]
> >
> > > diff --git
> > > a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > > b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > > new file mode 100644
> > > index 000000000000..cfeccd85f40e
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
> > > @@ -0,0 +1,64 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/* Copyright 2022 Sony Group Corporation */
> > > +#include <vmlinux.h>
> > > +
> > > +#include <bpf/bpf_core_read.h>
> > > +#include <bpf/bpf_helpers.h>
> > > +#include <bpf/bpf_tracing.h>
> > > +#include "bpf_misc.h"
> > > +
> > > +int arg1 = 0;
> > > +unsigned long arg2 = 0;
> > > +unsigned long arg3 = 0;
> > > +unsigned long arg4_cx = 0;
> > > +unsigned long arg4 = 0;
> > > +unsigned long arg5 = 0;
> > > +
> > > +int arg1_core = 0;
> > > +unsigned long arg2_core = 0;
> > > +unsigned long arg3_core = 0;
> > > +unsigned long arg4_core_cx = 0;
> > > +unsigned long arg4_core = 0;
> > > +unsigned long arg5_core = 0;
> > > +
> > > +const volatile pid_t filter_pid = 0;
> > > +
> > > +SEC("kprobe/" SYS_PREFIX "sys_prctl")
> > > +int BPF_KPROBE(handle_sys_prctl)
> > > +{
> > > + struct pt_regs *real_regs;
> > > + int orig_arg1;
> > > + unsigned long orig_arg2, orig_arg3, orig_arg4_cx,
> > > orig_arg4, orig_arg5;
> > > + pid_t pid = bpf_get_current_pid_tgid() >> 32;
> > > +
> > > + if (pid != filter_pid)
> > > + return 0;
> > > +
> > > + /* test for PT_REGS_PARM */
> > > + real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
> > > + bpf_probe_read_kernel(&orig_arg1, sizeof(orig_arg1),
> > > &PT_REGS_PARM1_SYSCALL(real_regs));
> > > + bpf_probe_read_kernel(&orig_arg2, sizeof(orig_arg2),
> > > &PT_REGS_PARM2_SYSCALL(real_regs));
> > > + bpf_probe_read_kernel(&orig_arg3, sizeof(orig_arg3),
> > > &PT_REGS_PARM3_SYSCALL(real_regs));
> > > + bpf_probe_read_kernel(&orig_arg4_cx,
> > > sizeof(orig_arg4_cx), &PT_REGS_PARM4(real_regs));
> > > + bpf_probe_read_kernel(&orig_arg4, sizeof(orig_arg4),
> > > &PT_REGS_PARM4_SYSCALL(real_regs));
> > > + bpf_probe_read_kernel(&orig_arg5, sizeof(orig_arg5),
> > > &PT_REGS_PARM5_SYSCALL(real_regs));
> > > + /* copy all actual args and the wrong arg4 on x86_64 */
> > > + arg1 = orig_arg1;
> > > + arg2 = orig_arg2;
> > > + arg3 = orig_arg3;
> > > + arg4_cx = orig_arg4_cx;
> > > + arg4 = orig_arg4;
> > > + arg5 = orig_arg5;
> >
> > I don't get why you needed orig_argX variables and then copying
> > them
> > into argX variables. I changed this to read directly into argX. I
> > suspect arg1 handling might break on big-endian arches due to int
> > vs
> > long differences, please check that and send a follow up fix.
> >
> > Also keep in mind that selftest changes should come with
> > "selftests/bpf:" subject prefix, not "libbpf:". Fixed that up as
> > well.
> >
> > Applied to bpf-next, thanks.
>
> This selftest is failing on s390x (see [0]). Ilya, do you know if
> something special needs to be done for s390x for this case?
>
> Here are the two failures:
>
> test_bpf_syscall_macro:FAIL:syscall_arg1 unexpected syscall_arg1:
> actual -1 != expected 1001
> test_bpf_syscall_macro:FAIL:syscall_arg1_core_variant unexpected
> syscall_arg1_core_variant: actual -38 != expected 1001
>
> [0]
> https://github.com/libbpf/libbpf/runs/5025905587?check_suite_focus=true
>
I think we need to use orig_gpr2 for the first syscall argument
(see arch/s390/include/asm/syscall.h). I'll test it and send a patch.
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-02-01 21:01 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-01-24 14:16 [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 1/3] libbpf: Extract syscall wrapper Kenta Tada
2022-01-24 14:16 ` [PATCH v5 2/3] libbpf: Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL Kenta Tada
2022-01-25 5:05 ` Andrii Nakryiko
2022-02-01 19:36 ` Andrii Nakryiko
2022-02-01 21:01 ` Ilya Leoshkevich
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