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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: bpf@vger.kernel.org, Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH bpf-next v3 03/11] selftests/bpf: Fix an endianness issue in bpf_syscall_macro test
Date: Fri,  4 Feb 2022 15:50:10 +0100	[thread overview]
Message-ID: <20220204145018.1983773-4-iii@linux.ibm.com> (raw)
In-Reply-To: <20220204145018.1983773-1-iii@linux.ibm.com>

bpf_syscall_macro reads a long argument into an int variable, which
produces a wrong value on big-endian systems. Fix by reading the
argument into an intermediate long variable first.

Fixes: 77fc0330dfe5 ("selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tools/testing/selftests/bpf/progs/bpf_syscall_macro.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
index c8e60220cda8..f5c6ef2ff6d1 100644
--- a/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
+++ b/tools/testing/selftests/bpf/progs/bpf_syscall_macro.c
@@ -28,6 +28,7 @@ int BPF_KPROBE(handle_sys_prctl)
 {
 	struct pt_regs *real_regs;
 	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+	unsigned long tmp;
 
 	if (pid != filter_pid)
 		return 0;
@@ -35,7 +36,9 @@ int BPF_KPROBE(handle_sys_prctl)
 	real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);
 
 	/* test for PT_REGS_PARM */
-	bpf_probe_read_kernel(&arg1, sizeof(arg1), &PT_REGS_PARM1_SYSCALL(real_regs));
+
+	bpf_probe_read_kernel(&tmp, sizeof(tmp), &PT_REGS_PARM1_SYSCALL(real_regs));
+	arg1 = tmp;
 	bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
 	bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
 	bpf_probe_read_kernel(&arg4_cx, sizeof(arg4_cx), &PT_REGS_PARM4(real_regs));
-- 
2.34.1


  parent reply	other threads:[~2022-02-04 14:50 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-04 14:50 [PATCH bpf-next v3 00/11] libbpf: Fix accessing syscall arguments Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 01/11] arm64/bpf: Add orig_x0 to user_pt_regs Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 02/11] s390/bpf: Add orig_gpr2 " Ilya Leoshkevich
2022-02-05  0:36   ` Heiko Carstens
2022-02-05 12:37   ` Vasily Gorbik
2022-02-04 14:50 ` Ilya Leoshkevich [this message]
2022-02-04 14:50 ` [PATCH bpf-next v3 04/11] libbpf: Add __PT_PARM1_REG_SYSCALL macro Ilya Leoshkevich
2022-02-04 16:15   ` Naveen N. Rao
2022-02-04 14:50 ` [PATCH bpf-next v3 05/11] libbpf: Add PT_REGS_SYSCALL_REGS macro Ilya Leoshkevich
2022-02-04 16:46   ` Naveen N. Rao
2022-02-04 18:15     ` Andrii Nakryiko
2022-02-05  7:04       ` Naveen N. Rao
2022-02-04 14:50 ` [PATCH bpf-next v3 06/11] selftests/bpf: Use PT_REGS_SYSCALL_REGS in bpf_syscall_macro Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 07/11] libbpf: Fix accessing the first syscall argument on arm64 Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 08/11] libbpf: Fix accessing syscall arguments on powerpc Ilya Leoshkevich
2022-02-05  7:05   ` Naveen N. Rao
2022-02-04 14:50 ` [PATCH bpf-next v3 09/11] libbpf: Fix accessing program counter on riscv Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 10/11] libbpf: Fix accessing syscall arguments " Ilya Leoshkevich
2022-02-04 14:50 ` [PATCH bpf-next v3 11/11] libbpf: Fix accessing the first syscall argument on s390 Ilya Leoshkevich
2022-02-05 20:30 ` [PATCH bpf-next v3 00/11] libbpf: Fix accessing syscall arguments patchwork-bot+netdevbpf
2022-02-07 16:10   ` Andrii Nakryiko

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