On 2024-12-20 02:26, Charlie Jenkins wrote:
On Tue, Dec 03, 2024 at 01:55:07PM +0100, Andrew Jones wrote:
On Tue, Dec 03, 2024 at 05:30:05PM +0800, Celeste Liu wrote:
From: Charlie Jenkins charlie@rivosinc.com
This test checks that orig_a0 allows a syscall argument to be modified, and that changing a0 does not change the syscall argument.
Cc: stable@vger.kernel.org Co-developed-by: Quan Zhou zhouquan@iscas.ac.cn Signed-off-by: Quan Zhou zhouquan@iscas.ac.cn Co-developed-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Celeste Liu uwu@coelacanthus.name Signed-off-by: Charlie Jenkins charlie@rivosinc.com
tools/testing/selftests/riscv/abi/.gitignore | 1 + tools/testing/selftests/riscv/abi/Makefile | 5 +- tools/testing/selftests/riscv/abi/ptrace.c | 134 +++++++++++++++++++++++++++ 3 files changed, 139 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..3f74d059dfdcbce4d45d8ff618781ccea1419061 100644 --- a/tools/testing/selftests/riscv/abi/Makefile +++ b/tools/testing/selftests/riscv/abi/Makefile @@ -2,9 +2,12 @@ CFLAGS += -I$(top_srcdir)/tools/include -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..d192764b428d1f1c442f3957c6fedeb01a48d556 --- /dev/null +++ b/tools/testing/selftests/riscv/abi/ptrace.c @@ -0,0 +1,134 @@ +// 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 <asm/ptrace.h>
+#include "../../kselftest_harness.h"
+#define ORIG_A0_MODIFY 0x01 +#define A0_MODIFY 0x02 +#define A0_OLD 0x03 +#define A0_NEW 0x04
Shouldn't A0_OLD and A0_NEW set more bits, since 3 and 4 aren't very unique (we could have those values by accident)? And should we include setting bits over 31 for 64-bit targets?
+#define perr_and_exit(fmt, ...) \
- ({ \
char buf[256]; \snprintf(buf, sizeof(buf), "%s:%d:" fmt ": %m\n", \__func__, __LINE__, ##__VA_ARGS__); \perror(buf); \exit(-1); \- })
Can we use e.g. ksft_exit_fail_perror() instead? I'd prefer we try to consolidate testing/selftests/riscv/* tests on a common format for errors and exit codes and we're already using other kselftest stuff.
+static inline void resume_and_wait_tracee(pid_t pid, int flag) +{
- int status;
- if (ptrace(flag, pid, 0, 0))
perr_and_exit("failed to resume the tracee %d\n", pid);- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);+}
+static void ptrace_test(int opt, int *result) +{
- int status;
- 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),- };
- pid = fork();
- if (pid == 0) {
/* Mark oneself being traced */long val = ptrace(PTRACE_TRACEME, 0, 0, 0);if (val)perr_and_exit("failed to request for tracer to trace me: %ld\n", val);kill(getpid(), SIGSTOP);/* Perform exit syscall that will be intercepted */exit(A0_OLD);- }
- if (pid < 0)
exit(1);This unexpected error condition deserves a message, so I'd use ksft_exit_fail_perror() here.
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee %d\n", pid);- /* Stop at the entry point of the syscall */
- resume_and_wait_tracee(pid, PTRACE_SYSCALL);
- /* Check tracee regs before the syscall */
- if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov))
perr_and_exit("failed to get tracee registers\n");- if (ptrace(PTRACE_GETREGSET, pid, NT_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to get tracee registers\n");- if (orig_a0 != A0_OLD)
perr_and_exit("unexpected orig_a0: 0x%lx\n", orig_a0);- /* 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_RISCV_ORIG_A0, &a0_iov))
perr_and_exit("failed to set tracee registers\n");- /* Resume the tracee */
- ptrace(PTRACE_CONT, pid, 0, 0);
- if (waitpid(pid, &status, 0) != pid)
perr_and_exit("failed to wait for the tracee\n");- *result = WEXITSTATUS(status);
+}
+TEST(ptrace_modify_a0) +{
- int result;
- ptrace_test(A0_MODIFY, &result);
- /* The modification of a0 cannot affect the first argument of the syscall */
- EXPECT_EQ(A0_OLD, result);
What about checking that we actually set regs.a0 to A0_NEW? We'd need A0_NEW to be more unique than 4, though.
+}
+TEST(ptrace_modify_orig_a0) +{
- int result;
- ptrace_test(ORIG_A0_MODIFY, &result);
- /* Only modify orig_a0 to change the first argument of the syscall */
If we run ptrace_modify_a0 first then we've already set regs.a0 to A0_NEW and can't check with this test that we don't set it to A0_NEW. We should probably have two different test values, one for regs.a0 and one for orig_a0 and ensure on both tests that we aren't writing both.
Celeste, do you want to fix this up or are you waiting for me to?
Sorry for delay. I was busy with household affairs in the past few weeks. v3 will be sent tomorrow or the day after tomorrow.
I am deeply sorry for this.
- Charlie
- EXPECT_EQ(A0_NEW, result);
+}
+TEST_HARNESS_MAIN
-- 2.47.0
Thanks, drew