On Fri, Feb 23, 2018 at 03:33:43PM -0300, Thiago Jung Bauermann wrote:
> This test exercises read and write access to the AMR, IAMR and UAMOR.
>
Tested-by: Ram Pai <linuxram@xxxxxxxxxx>
Acked-by: Ram Pai <linuxram@xxxxxxxxxx>
> Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/powerpc/include/reg.h | 1 +
> tools/testing/selftests/powerpc/ptrace/Makefile | 5 +-
> tools/testing/selftests/powerpc/ptrace/child.h | 130 ++++++++
> .../testing/selftests/powerpc/ptrace/ptrace-pkey.c | 326 +++++++++++++++++++++
> tools/testing/selftests/powerpc/ptrace/ptrace.h | 37 +++
> 5 files changed, 498 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/powerpc/ptrace/child.h
> create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
>
> diff --git a/tools/testing/selftests/powerpc/include/reg.h b/tools/testing/selftests/powerpc/include/reg.h
> index 4afdebcce4cd..7f348c059bc2 100644
> --- a/tools/testing/selftests/powerpc/include/reg.h
> +++ b/tools/testing/selftests/powerpc/include/reg.h
> @@ -54,6 +54,7 @@
> #define SPRN_DSCR_PRIV 0x11 /* Privilege State DSCR */
> #define SPRN_DSCR 0x03 /* Data Stream Control Register */
> #define SPRN_PPR 896 /* Program Priority Register */
> +#define SPRN_AMR 13 /* Authority Mask Register - problem state */
>
> /* TEXASR register bits */
> #define TEXASR_FC 0xFE00000000000000
> diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile
> index 480305266504..707ba734faf2 100644
> --- a/tools/testing/selftests/powerpc/ptrace/Makefile
> +++ b/tools/testing/selftests/powerpc/ptrace/Makefile
> @@ -1,7 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0
> TEST_PROGS := ptrace-gpr ptrace-tm-gpr ptrace-tm-spd-gpr \
> ptrace-tar ptrace-tm-tar ptrace-tm-spd-tar ptrace-vsx ptrace-tm-vsx \
> - ptrace-tm-spd-vsx ptrace-tm-spr
> + ptrace-tm-spd-vsx ptrace-tm-spr ptrace-pkey
>
> include ../../lib.mk
>
> @@ -9,6 +9,9 @@ all: $(TEST_PROGS)
>
> CFLAGS += -m64 -I../../../../../usr/include -I../tm -mhtm -fno-pie
>
> +ptrace-pkey: ../harness.c ../utils.c ../lib/reg.S ptrace.h child.h ptrace-pkey.c
> + $(LINK.c) $^ $(LDLIBS) -pthread -o $@
> +
> $(TEST_PROGS): ../harness.c ../utils.c ../lib/reg.S ptrace.h
>
> clean:
> diff --git a/tools/testing/selftests/powerpc/ptrace/child.h b/tools/testing/selftests/powerpc/ptrace/child.h
> new file mode 100644
> index 000000000000..40c1a6d92111
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/child.h
> @@ -0,0 +1,130 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Helper functions to sync execution between parent and child processes.
> + *
> + * Copyright 2018, Thiago Jung Bauermann, IBM Corporation.
> + */
> +#include <stdio.h>
> +#include <stdbool.h>
> +#include <semaphore.h>
> +
> +/*
> + * Information in a shared memory location for synchronization between child and
> + * parent.
> + */
> +struct child_sync {
> + /* The parent waits on this semaphore. */
> + sem_t sem_parent;
> +
> + /* If true, the child should give up as well. */
> + bool parent_gave_up;
> +
> + /* The child waits on this semaphore. */
> + sem_t sem_child;
> +
> + /* If true, the parent should give up as well. */
> + bool child_gave_up;
> +};
> +
> +#define CHILD_FAIL_IF(x, sync) \
> + do { \
> + if (x) { \
> + fprintf(stderr, \
> + "[FAIL] Test FAILED on line %d\n", __LINE__); \
> + (sync)->child_gave_up = true; \
> + prod_parent(sync); \
> + return 1; \
> + } \
> + } while (0)
> +
> +#define PARENT_FAIL_IF(x, sync) \
> + do { \
> + if (x) { \
> + fprintf(stderr, \
> + "[FAIL] Test FAILED on line %d\n", __LINE__); \
> + (sync)->parent_gave_up = true; \
> + prod_child(sync); \
> + return 1; \
> + } \
> + } while (0)
> +
> +int init_child_sync(struct child_sync *sync)
> +{
> + int ret;
> +
> + ret = sem_init(&sync->sem_parent, 1, 0);
> + if (ret) {
> + perror("Semaphore initialization failed");
> + return 1;
> + }
> +
> + ret = sem_init(&sync->sem_child, 1, 0);
> + if (ret) {
> + perror("Semaphore initialization failed");
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +void destroy_child_sync(struct child_sync *sync)
> +{
> + sem_destroy(&sync->sem_parent);
> + sem_destroy(&sync->sem_child);
> +}
> +
> +int wait_child(struct child_sync *sync)
> +{
> + int ret;
> +
> + /* Wait until the child prods us. */
> + ret = sem_wait(&sync->sem_parent);
> + if (ret) {
> + perror("Error waiting for child");
> + return 1;
> + }
> +
> + return sync->child_gave_up;
> +}
> +
> +int prod_child(struct child_sync *sync)
> +{
> + int ret;
> +
> + /* Unblock the child now. */
> + ret = sem_post(&sync->sem_child);
> + if (ret) {
> + perror("Error prodding child");
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +int wait_parent(struct child_sync *sync)
> +{
> + int ret;
> +
> + /* Wait until the parent prods us. */
> + ret = sem_wait(&sync->sem_child);
> + if (ret) {
> + perror("Error waiting for parent");
> + return 1;
> + }
> +
> + return sync->parent_gave_up;
> +}
> +
> +int prod_parent(struct child_sync *sync)
> +{
> + int ret;
> +
> + /* Unblock the parent now. */
> + ret = sem_post(&sync->sem_parent);
> + if (ret) {
> + perror("Error prodding parent");
> + return 1;
> + }
> +
> + return 0;
> +}
> 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..8332b9338d39
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c
> @@ -0,0 +1,326 @@
> +// 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_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");
> +}
> diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace.h b/tools/testing/selftests/powerpc/ptrace/ptrace.h
> index 19fb825270a1..d2c9c4c2b5ee 100644
> --- a/tools/testing/selftests/powerpc/ptrace/ptrace.h
> +++ b/tools/testing/selftests/powerpc/ptrace/ptrace.h
> @@ -102,6 +102,43 @@ int cont_trace(pid_t child)
> return TEST_PASS;
> }
>
> +int ptrace_read_regs(pid_t child, unsigned long type, unsigned long regs[],
> + int n)
> +{
> + struct iovec iov;
> + long ret;
> +
> + FAIL_IF(start_trace(child));
> +
> + iov.iov_base = regs;
> + iov.iov_len = n * sizeof(unsigned long);
> +
> + ret = ptrace(PTRACE_GETREGSET, child, type, &iov);
> + FAIL_IF(ret != 0);
> +
> + FAIL_IF(stop_trace(child));
> +
> + return TEST_PASS;
> +}
> +
> +long ptrace_write_regs(pid_t child, unsigned long type, unsigned long regs[],
> + int n)
> +{
> + struct iovec iov;
> + long ret;
> +
> + FAIL_IF(start_trace(child));
> +
> + iov.iov_base = regs;
> + iov.iov_len = n * sizeof(unsigned long);
> +
> + ret = ptrace(PTRACE_SETREGSET, child, type, &iov);
> +
> + FAIL_IF(stop_trace(child));
> +
> + return ret;
> +}
> +
> /* TAR, PPR, DSCR */
> int show_tar_registers(pid_t child, unsigned long *out)
> {
--
Ram Pai
--
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