selftests/seccomp: Allow syscall nr and ret value to be set separately (bef71f86) · Commits · 戴 / test

tools/testing/selftests/seccomp/seccomp_bpf.c

+47 −12

Original line number	Diff line number	Diff line
		@@ -1888,27 +1888,47 @@ int get_syscall(struct __test_metadata *_metadata, pid_t tracee)
		}

		/* Architecture-specific syscall changing routine. */
		void change_syscall(struct __test_metadata *_metadata,
		pid_t tracee, int syscall, int result)
		void __change_syscall(struct __test_metadata *_metadata,
		pid_t tracee, long syscall, long ret)
		{
		ARCH_REGS orig, regs;

		/* Do not get/set registers if we have nothing to do. */
		if (!syscall && !ret)
		return;

		EXPECT_EQ(0, ARCH_GETREGS(regs)) {
		return;
		}
		orig = regs;

		SYSCALL_NUM_SET(regs, syscall);
		if (syscall)
		SYSCALL_NUM_SET(regs, *syscall);

		/* If syscall is skipped, change return value. */
		if (syscall == -1)
		SYSCALL_RET_SET(regs, result);
		if (ret)
		SYSCALL_RET_SET(regs, *ret);

		/* Flush any register changes made. */
		if (memcmp(&orig, &regs, sizeof(orig)) != 0)
		EXPECT_EQ(0, ARCH_SETREGS(regs));
		}

		/* Change only syscall number. */
		void change_syscall_nr(struct __test_metadata *_metadata,
		pid_t tracee, long syscall)
		{
		__change_syscall(_metadata, tracee, &syscall, NULL);
		}

		/* Change syscall return value (and set syscall number to -1). */
		void change_syscall_ret(struct __test_metadata *_metadata,
		pid_t tracee, long ret)
		{
		long syscall = -1;

		__change_syscall(_metadata, tracee, &syscall, &ret);
		}

		void tracer_seccomp(struct __test_metadata *_metadata, pid_t tracee,
		int status, void *args)
		{
		@@ -1924,17 +1944,17 @@ void tracer_seccomp(struct __test_metadata *_metadata, pid_t tracee,
		case 0x1002:
		/* change getpid to getppid. */
		EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee));
		change_syscall(_metadata, tracee, __NR_getppid, 0);
		change_syscall_nr(_metadata, tracee, __NR_getppid);
		break;
		case 0x1003:
		/* skip gettid with valid return code. */
		EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee));
		change_syscall(_metadata, tracee, -1, 45000);
		change_syscall_ret(_metadata, tracee, 45000);
		break;
		case 0x1004:
		/* skip openat with error. */
		EXPECT_EQ(__NR_openat, get_syscall(_metadata, tracee));
		change_syscall(_metadata, tracee, -1, -ESRCH);
		change_syscall_ret(_metadata, tracee, -ESRCH);
		break;
		case 0x1005:
		/* do nothing (allow getppid) */
		@@ -1961,6 +1981,8 @@ void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee,
		int ret;
		unsigned long msg;
		static bool entry;
		long syscall_nr_val, syscall_ret_val;
		long syscall_nr = NULL, syscall_ret = NULL;
		FIXTURE_DATA(TRACE_syscall) *self = args;

		/*
		@@ -1987,17 +2009,30 @@ void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee,
		else
		return;

		syscall_nr = &syscall_nr_val;
		syscall_ret = &syscall_ret_val;

		/* Now handle the actual rewriting cases. */
		switch (self->syscall_nr) {
		case __NR_getpid:
		change_syscall(_metadata, tracee, __NR_getppid, 0);
		syscall_nr_val = __NR_getppid;
		/* Never change syscall return for this case. */
		syscall_ret = NULL;
		break;
		case __NR_gettid:
		change_syscall(_metadata, tracee, -1, 45000);
		syscall_nr_val = -1;
		syscall_ret_val = 45000;
		break;
		case __NR_openat:
		change_syscall(_metadata, tracee, -1, -ESRCH);
		syscall_nr_val = -1;
		syscall_ret_val = -ESRCH;
		break;
		default:
		/* Unhandled, do nothing. */
		return;
		}

		__change_syscall(_metadata, tracee, syscall_nr, syscall_ret);
		}

		FIXTURE_VARIANT(TRACE_syscall) {

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