1 files changed, 327 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
new file mode 100644
index 000000000000..5cf631f792cc
--- /dev/null
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Ptrace test for Memory Protection Key registers
+ *
+ * Copyright (C) 2015 Anshuman Khandual, IBM Corporation.
+ * Copyright (C) 2018 IBM Corporation.
+ */
+#include "ptrace.h"
+#include "child.h"
+
+#ifndef __NR_pkey_alloc
+#define __NR_pkey_alloc		384
+#endif
+
+#ifndef __NR_pkey_free
+#define __NR_pkey_free		385
+#endif
+
+#ifndef NT_PPC_PKEY
+#define NT_PPC_PKEY		0x110
+#endif
+
+#ifndef PKEY_DISABLE_EXECUTE
+#define PKEY_DISABLE_EXECUTE	0x4
+#endif
+
+#define AMR_BITS_PER_PKEY 2
+#define PKEY_REG_BITS (sizeof(u64) * 8)
+#define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey + 1) * AMR_BITS_PER_PKEY))
+
+static const char user_read[] = "[User Read (Running)]";
+static const char user_write[] = "[User Write (Running)]";
+static const char ptrace_read_running[] = "[Ptrace Read (Running)]";
+static const char ptrace_write_running[] = "[Ptrace Write (Running)]";
+
+/* Information shared between the parent and the child. */
+struct shared_info {
+	struct child_sync child_sync;
+
+	/* AMR value the parent expects to read from the child. */
+	unsigned long amr1;
+
+	/* AMR value the parent is expected to write to the child. */
+	unsigned long amr2;
+
+	/* AMR value that ptrace should refuse to write to the child. */
+	unsigned long amr3;
+
+	/* IAMR value the parent expects to read from the child. */
+	unsigned long expected_iamr;
+
+	/* UAMOR value the parent expects to read from the child. */
+	unsigned long expected_uamor;
+
+	/*
+	 * IAMR and UAMOR values that ptrace should refuse to write to the child
+	 * (even though they're valid ones) because userspace doesn't have
+	 * access to those registers.
+	 */
+	unsigned long new_iamr;
+	unsigned long new_uamor;
+};
+
+static int sys_pkey_alloc(unsigned long flags, unsigned long init_access_rights)
+{
+	return syscall(__NR_pkey_alloc, flags, init_access_rights);
+}
+
+static int sys_pkey_free(int pkey)
+{
+	return syscall(__NR_pkey_free, pkey);
+}
+
+static int child(struct shared_info *info)
+{
+	unsigned long reg;
+	bool disable_execute = true;
+	int pkey1, pkey2, pkey3;
+	int ret;
+
+	/* Wait until parent fills out the initial register values. */
+	ret = wait_parent(&info->child_sync);
+	if (ret)
+		return ret;
+
+	/* Get some pkeys so that we can change their bits in the AMR. */
+	pkey1 = sys_pkey_alloc(0, PKEY_DISABLE_EXECUTE);
+	if (pkey1 < 0) {
+		pkey1 = sys_pkey_alloc(0, 0);
+		CHILD_FAIL_IF(pkey1 < 0, &info->child_sync);
+
+		disable_execute = false;
+	}
+
+	pkey2 = sys_pkey_alloc(0, 0);
+	CHILD_FAIL_IF(pkey2 < 0, &info->child_sync);
+
+	pkey3 = sys_pkey_alloc(0, 0);
+	CHILD_FAIL_IF(pkey3 < 0, &info->child_sync);
+
+	info->amr1 |= 3ul << pkeyshift(pkey1);
+	info->amr2 |= 3ul << pkeyshift(pkey2);
+	info->amr3 |= info->amr2 | 3ul << pkeyshift(pkey3);
+
+	if (disable_execute)
+		info->expected_iamr |= 1ul << pkeyshift(pkey1);
+
+	info->expected_uamor |= 3ul << pkeyshift(pkey1) |
+				3ul << pkeyshift(pkey2);
+	info->new_iamr |= 1ul << pkeyshift(pkey1) | 1ul << pkeyshift(pkey2);
+	info->new_uamor |= 3ul << pkeyshift(pkey1);
+
+	/*
+	 * We won't use pkey3. We just want a plausible but invalid key to test
+	 * whether ptrace will let us write to AMR bits we are not supposed to.
+	 *
+	 * This also tests whether the kernel restores the UAMOR permissions
+	 * after a key is freed.
+	 */
+	sys_pkey_free(pkey3);
+
+	printf("%-30s AMR: %016lx pkey1: %d pkey2: %d pkey3: %d\n",
+	       user_write, info->amr1, pkey1, pkey2, pkey3);
+
+	mtspr(SPRN_AMR, info->amr1);
+
+	/* Wait for parent to read our AMR value and write a new one. */
+	ret = prod_parent(&info->child_sync);
+	CHILD_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_parent(&info->child_sync);
+	if (ret)
+		return ret;
+
+	reg = mfspr(SPRN_AMR);
+
+	printf("%-30s AMR: %016lx\n", user_read, reg);
+
+	CHILD_FAIL_IF(reg != info->amr2, &info->child_sync);
+
+	/*
+	 * Wait for parent to try to write an invalid AMR value.
+	 */
+	ret = prod_parent(&info->child_sync);
+	CHILD_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_parent(&info->child_sync);
+	if (ret)
+		return ret;
+
+	reg = mfspr(SPRN_AMR);
+
+	printf("%-30s AMR: %016lx\n", user_read, reg);
+
+	CHILD_FAIL_IF(reg != info->amr2, &info->child_sync);
+
+	/*
+	 * Wait for parent to try to write an IAMR and a UAMOR value. We can't
+	 * verify them, but we can verify that the AMR didn't change.
+	 */
+	ret = prod_parent(&info->child_sync);
+	CHILD_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_parent(&info->child_sync);
+	if (ret)
+		return ret;
+
+	reg = mfspr(SPRN_AMR);
+
+	printf("%-30s AMR: %016lx\n", user_read, reg);
+
+	CHILD_FAIL_IF(reg != info->amr2, &info->child_sync);
+
+	/* Now let parent now that we are finished. */
+
+	ret = prod_parent(&info->child_sync);
+	CHILD_FAIL_IF(ret, &info->child_sync);
+
+	return TEST_PASS;
+}
+
+static int parent(struct shared_info *info, pid_t pid)
+{
+	unsigned long regs[3];
+	int ret, status;
+
+	/*
+	 * Get the initial values for AMR, IAMR and UAMOR and communicate them
+	 * to the child.
+	 */
+	ret = ptrace_read_regs(pid, NT_PPC_PKEY, regs, 3);
+	PARENT_SKIP_IF_UNSUPPORTED(ret, &info->child_sync);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	info->amr1 = info->amr2 = info->amr3 = regs[0];
+	info->expected_iamr = info->new_iamr = regs[1];
+	info->expected_uamor = info->new_uamor = regs[2];
+
+	/* Wake up child so that it can set itself up. */
+	ret = prod_child(&info->child_sync);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_child(&info->child_sync);
+	if (ret)
+		return ret;
+
+	/* Verify that we can read the pkey registers from the child. */
+	ret = ptrace_read_regs(pid, NT_PPC_PKEY, regs, 3);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx IAMR: %016lx UAMOR: %016lx\n",
+	       ptrace_read_running, regs[0], regs[1], regs[2]);
+
+	PARENT_FAIL_IF(regs[0] != info->amr1, &info->child_sync);
+	PARENT_FAIL_IF(regs[1] != info->expected_iamr, &info->child_sync);
+	PARENT_FAIL_IF(regs[2] != info->expected_uamor, &info->child_sync);
+
+	/* Write valid AMR value in child. */
+	ret = ptrace_write_regs(pid, NT_PPC_PKEY, &info->amr2, 1);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx\n", ptrace_write_running, info->amr2);
+
+	/* Wake up child so that it can verify it changed. */
+	ret = prod_child(&info->child_sync);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_child(&info->child_sync);
+	if (ret)
+		return ret;
+
+	/* Write invalid AMR value in child. */
+	ret = ptrace_write_regs(pid, NT_PPC_PKEY, &info->amr3, 1);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx\n", ptrace_write_running, info->amr3);
+
+	/* Wake up child so that it can verify it didn't change. */
+	ret = prod_child(&info->child_sync);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait_child(&info->child_sync);
+	if (ret)
+		return ret;
+
+	/* Try to write to IAMR. */
+	regs[0] = info->amr1;
+	regs[1] = info->new_iamr;
+	ret = ptrace_write_regs(pid, NT_PPC_PKEY, regs, 2);
+	PARENT_FAIL_IF(!ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx IAMR: %016lx\n",
+	       ptrace_write_running, regs[0], regs[1]);
+
+	/* Try to write to IAMR and UAMOR. */
+	regs[2] = info->new_uamor;
+	ret = ptrace_write_regs(pid, NT_PPC_PKEY, regs, 3);
+	PARENT_FAIL_IF(!ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx IAMR: %016lx UAMOR: %016lx\n",
+	       ptrace_write_running, regs[0], regs[1], regs[2]);
+
+	/* Verify that all registers still have their expected values. */
+	ret = ptrace_read_regs(pid, NT_PPC_PKEY, regs, 3);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	printf("%-30s AMR: %016lx IAMR: %016lx UAMOR: %016lx\n",
+	       ptrace_read_running, regs[0], regs[1], regs[2]);
+
+	PARENT_FAIL_IF(regs[0] != info->amr2, &info->child_sync);
+	PARENT_FAIL_IF(regs[1] != info->expected_iamr, &info->child_sync);
+	PARENT_FAIL_IF(regs[2] != info->expected_uamor, &info->child_sync);
+
+	/* Wake up child so that it can verify AMR didn't change and wrap up. */
+	ret = prod_child(&info->child_sync);
+	PARENT_FAIL_IF(ret, &info->child_sync);
+
+	ret = wait(&status);
+	if (ret != pid) {
+		printf("Child's exit status not captured\n");
+		ret = TEST_PASS;
+	} else if (!WIFEXITED(status)) {
+		printf("Child exited abnormally\n");
+		ret = TEST_FAIL;
+	} else
+		ret = WEXITSTATUS(status) ? TEST_FAIL : TEST_PASS;
+
+	return ret;
+}
+
+static int ptrace_pkey(void)
+{
+	struct shared_info *info;
+	int shm_id;
+	int ret;
+	pid_t pid;
+
+	shm_id = shmget(IPC_PRIVATE, sizeof(*info), 0777 | IPC_CREAT);
+	info = shmat(shm_id, NULL, 0);
+
+	ret = init_child_sync(&info->child_sync);
+	if (ret)
+		return ret;
+
+	pid = fork();
+	if (pid < 0) {
+		perror("fork() failed");
+		ret = TEST_FAIL;
+	} else if (pid == 0)
+		ret = child(info);
+	else
+		ret = parent(info, pid);
+
+	shmdt(info);
+
+	if (pid) {
+		destroy_child_sync(&info->child_sync);
+		shmctl(shm_id, IPC_RMID, NULL);
+	}
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(ptrace_pkey, "ptrace_pkey");
+}