Re: [PATCH 1/2] selftests/powerpc: Add ptrace tests for Protection Key registers

Ram Pai linuxram@us.ibm.com writes:

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@us.ibm.com Acked-by: Ram Pai linuxram@us.ibm.com

Ping? Can this and patch 2/2 go in v4.17?

...

Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com

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) {