This test exercises read and write access to the AMR, IAMR and UAMOR.

Signed-off-by: Thiago Jung Bauermann bauerman@linux.ibm.com --- tools/testing/selftests/powerpc/include/reg.h | 1 + tools/testing/selftests/powerpc/ptrace/Makefile | 5 +- tools/testing/selftests/powerpc/ptrace/child.h | 139 +++++++++ .../testing/selftests/powerpc/ptrace/ptrace-pkey.c | 327 +++++++++++++++++++++ tools/testing/selftests/powerpc/ptrace/ptrace.h | 38 +++ 5 files changed, 509 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/powerpc/ptrace/child.h create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c

Changes in v2: - Added PARENT_SKIP_IF_UNSUPPORTED macro in child.h and use it in first call to ptrace_read_regs(NT_PPC_PKEY). (Suggested by Michael Ellerman) - Changed ptrace_read_regs() to simply return the ptrace error value in case of error and avoid calling fprintf() so that errno is preserved.

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..d7275b7b33dc --- /dev/null +++ b/tools/testing/selftests/powerpc/ptrace/child.h @@ -0,0 +1,139 @@ +// 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) + +#define PARENT_SKIP_IF_UNSUPPORTED(x, sync) \ + do { \ + if ((x) == -1 && (errno == ENODEV || errno == EINVAL)) { \ + (sync)->parent_gave_up = true; \ + prod_child(sync); \ + SKIP_IF(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..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"); +} diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace.h b/tools/testing/selftests/powerpc/ptrace/ptrace.h index 19fb825270a1..34201cfa8335 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace.h +++ b/tools/testing/selftests/powerpc/ptrace/ptrace.h @@ -102,6 +102,44 @@ 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); + if (ret) + return ret; + + 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) {

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