On Wed, Jan 15, 2025 at 07:13:29PM +0800, Celeste Liu wrote:
> This test checks that orig_a0 and a0 can be modified and accessed
> independently.
>
> Co-developed-by: Quan Zhou <zhouq...@iscas.ac.cn>
> Signed-off-by: Quan Zhou <zhouq...@iscas.ac.cn>
> Co-developed-by: Charlie Jenkins <char...@rivosinc.com>
> Signed-off-by: Charlie Jenkins <char...@rivosinc.com>
> Reviewed-by: Björn Töpel <bj...@rivosinc.com>
> Signed-off-by: Celeste Liu <u...@coelacanthus.name>
> ---
> tools/testing/selftests/riscv/abi/.gitignore | 1 +
> tools/testing/selftests/riscv/abi/Makefile | 6 +-
> tools/testing/selftests/riscv/abi/ptrace.c | 193
> +++++++++++++++++++++++++++
> 3 files changed, 199 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/riscv/abi/.gitignore
> b/tools/testing/selftests/riscv/abi/.gitignore
> index
> b38358f91c4d2240ae64892871d9ca98bda1ae58..378c605919a3b3d58eec2701eb7af430cfe315d6
> 100644
> --- a/tools/testing/selftests/riscv/abi/.gitignore
> +++ b/tools/testing/selftests/riscv/abi/.gitignore
> @@ -1 +1,2 @@
> pointer_masking
> +ptrace
> diff --git a/tools/testing/selftests/riscv/abi/Makefile
> b/tools/testing/selftests/riscv/abi/Makefile
> index
> ed82ff9c664e7eb3f760cbab81fb957ff72579c5..359a082c88a401883fb3776b35e4dacf69beaaaa
> 100644
> --- a/tools/testing/selftests/riscv/abi/Makefile
> +++ b/tools/testing/selftests/riscv/abi/Makefile
> @@ -1,10 +1,14 @@
> # SPDX-License-Identifier: GPL-2.0
>
> CFLAGS += -I$(top_srcdir)/tools/include
> +CFLAGS += $(KHDR_INCLUDES)
>
> -TEST_GEN_PROGS := pointer_masking
> +TEST_GEN_PROGS := pointer_masking ptrace
>
> include ../../lib.mk
>
> $(OUTPUT)/pointer_masking: pointer_masking.c
> $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
> +
> +$(OUTPUT)/ptrace: ptrace.c
> + $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
> diff --git a/tools/testing/selftests/riscv/abi/ptrace.c
> b/tools/testing/selftests/riscv/abi/ptrace.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..cbd60462021165ca2bcc38be24b8423c96047b93
> --- /dev/null
> +++ b/tools/testing/selftests/riscv/abi/ptrace.c
> @@ -0,0 +1,193 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <errno.h>
> +#include <sys/types.h>
> +#include <sys/ptrace.h>
> +#include <sys/stat.h>
> +#include <sys/user.h>
> +#include <sys/wait.h>
> +#include <sys/uio.h>
> +#include <linux/elf.h>
> +#include <linux/unistd.h>
> +#include <linux/ptrace.h>
> +#include <linux/stddef.h>
> +#include <asm/ptrace.h>
> +
> +#include "../../kselftest_harness.h"
> +
> +#define ORIG_A0_MODIFY 0x01
> +#define A0_MODIFY 0x02
> +#define A0_OLD 0xbadbeefbeeff
> +#define A0_NEW 0xffeebfeebdab
> +
> +
> +struct a0_regs {
> + __s64 orig_a0;
> + __u64 a0;
> +};
> +
> +#define perr_and_exit(fmt, ...)
> \
> + ({ \
> + char buf[256]; \
> + snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \
> + __func__, __LINE__, ##__VA_ARGS__); \
> + ksft_exit_fail_perror(buf); \
> + })
> +
> +static void ptrace_test(int opt, struct a0_regs result[])
> +{
> + int status;
> + long rc;
> + pid_t pid;
> + struct user_regs_struct regs;
> + struct iovec iov = {
> + .iov_base = ®s,
> + .iov_len = sizeof(regs),
> + };
> +
> + unsigned long orig_a0;
> + struct iovec a0_iov = {
> + .iov_base = &orig_a0,
> + .iov_len = sizeof(orig_a0),
> + };
> + struct ptrace_syscall_info syscall_info = {
> + .op = 0xff,
> + };
> + const unsigned int expected_sci_entry_size =
> + offsetofend(struct ptrace_syscall_info, entry.args);
> + const unsigned int expected_sci_exit_size =
> + offsetofend(struct ptrace_syscall_info, exit.is_error);
> +
> + pid = fork();
> + if (pid == 0) {
> + /* Mark oneself being traced */
> + long val = ptrace(PTRACE_TRACEME, 0, 0, 0);
> +
> + if (val < 0)
> + perr_and_exit("failed to request for tracer to trace
> me: %ld", val);
> +
> + kill(getpid(), SIGSTOP);
> +
> + /* Perform chdir syscall that will be intercepted */
> + syscall(__NR_chdir, A0_OLD);
> +
> + exit(0);
> + }
> +
> + if (pid < 0)
> + ksft_exit_fail_perror("failed to fork");
> +
> + for (int i = 0; i < 3; i++) {
> + if (waitpid(pid, &status, 0) != pid)
> + perr_and_exit("failed to wait for the tracee %d", pid);
> + if (WIFSTOPPED(status)) {
> + switch (WSTOPSIG(status)) {
> + case SIGSTOP:
> + if (ptrace(PTRACE_SETOPTIONS, pid, 0,
> PTRACE_O_TRACESYSGOOD) < 0)
> + perr_and_exit("failed to set
> PTRACE_O_TRACESYSGOOD");
> + break;
> + case SIGTRAP|0x80:
> + /* Modify twice so GET_SYSCALL_INFO get
> modified a0 and orig_a0 */
> + if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS,
> &iov))
> + perr_and_exit("failed to get tracee
> registers");
> + if (ptrace(PTRACE_GETREGSET, pid,
> NT_RISCV_ORIG_A0, &a0_iov))
> + perr_and_exit("failed to get tracee
> registers");
> +
> + /* Modify a0/orig_a0 for the syscall */
> + switch (opt) {
> + case A0_MODIFY:
> + regs.a0 = A0_NEW;
> + break;
> + case ORIG_A0_MODIFY:
> + orig_a0 = A0_NEW;
> + break;
> + }
> +
> + if (ptrace(PTRACE_SETREGSET, pid, NT_PRSTATUS,
> &iov))
> + perr_and_exit("failed to set tracee
> registers");
> + if (ptrace(PTRACE_SETREGSET, pid,
> NT_RISCV_ORIG_A0, &a0_iov))
> + perr_and_exit("failed to set tracee
> registers");
> + switch (i) {
> + case 1:
> + /* Stop at the beginning of syscall */
> + rc = ptrace(PTRACE_GET_SYSCALL_INFO,
> pid,
> + sizeof(syscall_info),
> &syscall_info);
> + if (rc < 0)
> + perr_and_exit("failed to get
> syscall info of entry");
> + if (rc < expected_sci_entry_size
> + || syscall_info.op !=
> PTRACE_SYSCALL_INFO_ENTRY)
> + perr_and_exit("stop position of
> entry mismatched");
> + result[0].orig_a0 =
> syscall_info.entry.args[0];
> + break;
> +
> + case 2:
> + /* Stop at the end of syscall */
> + rc = ptrace(PTRACE_GET_SYSCALL_INFO,
> pid,
> + sizeof(syscall_info),
> &syscall_info);
> + if (rc < 0)
> + perr_and_exit("failed to get
> syscall info of entry");
> + if (rc < expected_sci_exit_size
> + || syscall_info.op !=
> PTRACE_SYSCALL_INFO_EXIT)
> + perr_and_exit("stop position of
> exit mismatched");
> + result[0].a0 = syscall_info.exit.rval;
> +
> + if (ptrace(PTRACE_GETREGSET, pid,
> NT_PRSTATUS, &iov))
> + perr_and_exit("failed to get
> tracee registers");
> + result[1].a0 = regs.a0;
> + if (ptrace(PTRACE_GETREGSET, pid,
> NT_RISCV_ORIG_A0,
> + &a0_iov))
> + perr_and_exit("failed to get
> tracee registers");
> + result[1].orig_a0 = orig_a0;
> + }
> + }
> + if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
> + perr_and_exit("failed to resume tracee");
> + }
> + }
> +
> + /* Resume the tracee */
> + ptrace(PTRACE_CONT, pid, 0, 0);
> + if (waitpid(pid, &status, 0) != pid)
> + perr_and_exit("failed to wait for the tracee");
> +
> +}
> +
> +TEST(ptrace_access_a0)
> +{
> + struct a0_regs result[2];
> +
> + ptrace_test(A0_MODIFY, result);
> +
> + /* Verify PTRACE_SETREGSET */
> + /* The modification of a0 cannot affect the first argument of the
> syscall */
> + EXPECT_EQ(A0_OLD, result[0].orig_a0);
> + EXPECT_EQ(A0_NEW, result[0].a0);
> +
> + /* Verify PTRACE_GETREGSET */
> + EXPECT_EQ(result[1].orig_a0, result[0].orig_a0);
> + EXPECT_EQ(result[1].a0, result[0].a0);
> +}
> +
> +TEST(ptrace_access_orig_a0)
> +{
> + struct a0_regs result[2];
> +
> + ptrace_test(ORIG_A0_MODIFY, result);
> +
> + /* Verify PTRACE_SETREGSET */
> + /* Only modify orig_a0 to change the first argument of the syscall */
> + EXPECT_EQ(A0_NEW, result[0].orig_a0);
> + /* a0 will not be affected */
> + EXPECT_NE(A0_NEW, result[0].a0);
> +
> + /* Verify PTRACE_GETREGSET */
> + EXPECT_EQ(result[1].orig_a0, result[0].orig_a0);
> + EXPECT_EQ(result[1].a0, result[0].a0);
> +}
> +
> +TEST_HARNESS_MAIN
>
> --
> 2.48.0
>
Reviewed-by: Andrew Jones <ajo...@ventanamicro.com>
