This test verifies that the AMR, IAMR and UAMOR are being written to a process' core file.
Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com --- tools/testing/selftests/powerpc/ptrace/Makefile | 5 +- tools/testing/selftests/powerpc/ptrace/core-pkey.c | 460 +++++++++++++++++++++ 2 files changed, 464 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/powerpc/ptrace/core-pkey.c
diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile index 707ba734faf2..a10916c3f3e1 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-pkey + ptrace-tm-spd-vsx ptrace-tm-spr ptrace-pkey core-pkey
include ../../lib.mk
@@ -12,6 +12,9 @@ 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 $@
+core-pkey: ../harness.c ../utils.c ../lib/reg.S ptrace.h child.h core-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/core-pkey.c b/tools/testing/selftests/powerpc/ptrace/core-pkey.c new file mode 100644 index 000000000000..ddbe0f2caf70 --- /dev/null +++ b/tools/testing/selftests/powerpc/ptrace/core-pkey.c @@ -0,0 +1,460 @@ +// 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 <limits.h> +#include <linux/kernel.h> +#include <sys/mman.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/resource.h> +#include <fcntl.h> +#include <unistd.h> +#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)) + +#define CORE_FILE_LIMIT (5 * 1024 * 1024) /* 5 MB should be enough */ + +static const char core_pattern_file[] = "/proc/sys/kernel/core_pattern"; + +static const char user_write[] = "[User Write (Running)]"; +static const char core_read_running[] = "[Core Read (Running)]"; + +/* Information shared between the parent and the child. */ +struct shared_info { + struct child_sync child_sync; + + /* AMR value the parent expects to read in the core file. */ + unsigned long amr; + + /* IAMR value the parent expects to read in the core file. */ + unsigned long iamr; + + /* UAMOR value the parent expects to read in the core file. */ + unsigned long uamor; + + /* When the child crashed. */ + time_t core_time; +}; + +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 increase_core_file_limit(void) +{ + struct rlimit rlim; + int ret; + + ret = getrlimit(RLIMIT_CORE, &rlim); + FAIL_IF(ret); + + if (rlim.rlim_cur != RLIM_INFINITY && rlim.rlim_cur < CORE_FILE_LIMIT) { + rlim.rlim_cur = CORE_FILE_LIMIT; + + if (rlim.rlim_max != RLIM_INFINITY && + rlim.rlim_max < CORE_FILE_LIMIT) + rlim.rlim_max = CORE_FILE_LIMIT; + + ret = setrlimit(RLIMIT_CORE, &rlim); + FAIL_IF(ret); + } + + ret = getrlimit(RLIMIT_FSIZE, &rlim); + FAIL_IF(ret); + + if (rlim.rlim_cur != RLIM_INFINITY && rlim.rlim_cur < CORE_FILE_LIMIT) { + rlim.rlim_cur = CORE_FILE_LIMIT; + + if (rlim.rlim_max != RLIM_INFINITY && + rlim.rlim_max < CORE_FILE_LIMIT) + rlim.rlim_max = CORE_FILE_LIMIT; + + ret = setrlimit(RLIMIT_FSIZE, &rlim); + FAIL_IF(ret); + } + + return TEST_PASS; +} + +static int child(struct shared_info *info) +{ + bool disable_execute = true; + int pkey1, pkey2, pkey3; + int *ptr, ret; + + /* Wait until parent fills out the initial register values. */ + ret = wait_parent(&info->child_sync); + if (ret) + return ret; + + ret = increase_core_file_limit(); + FAIL_IF(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); + FAIL_IF(pkey1 < 0); + + disable_execute = false; + } + + pkey2 = sys_pkey_alloc(0, 0); + FAIL_IF(pkey2 < 0); + + pkey3 = sys_pkey_alloc(0, 0); + FAIL_IF(pkey3 < 0); + + info->amr |= 3ul << pkeyshift(pkey1) | 2ul << pkeyshift(pkey2); + + if (disable_execute) + info->iamr |= 1ul << pkeyshift(pkey1); + + info->uamor |= 3ul << pkeyshift(pkey1) | 3ul << pkeyshift(pkey2); + + printf("%-30s AMR: %016lx pkey1: %d pkey2: %d pkey3: %d\n", + user_write, info->amr, pkey1, pkey2, pkey3); + + mtspr(SPRN_AMR, info->amr); + + /* + * We won't use pkey3. This tests whether the kernel restores the UAMOR + * permissions after a key is freed. + */ + sys_pkey_free(pkey3); + + info->core_time = time(NULL); + + /* Crash. */ + ptr = 0; + *ptr = 1; + + /* Shouldn't get here. */ + FAIL_IF(true); + + return TEST_FAIL; +} + +/* Return file size if filename exists and pass sanity check, or zero if not. */ +static off_t try_core_file(const char *filename, struct shared_info *info, + pid_t pid) +{ + struct stat buf; + int ret; + + ret = stat(filename, &buf); + if (ret == -1) + return TEST_FAIL; + + /* Make sure we're not using a stale core file. */ + return buf.st_mtime >= info->core_time ? buf.st_size : TEST_FAIL; +} + +static Elf64_Nhdr *next_note(Elf64_Nhdr *nhdr) +{ + return (void *) nhdr + sizeof(*nhdr) + + __ALIGN_KERNEL(nhdr->n_namesz, 4) + + __ALIGN_KERNEL(nhdr->n_descsz, 4); +} + +static int check_core_file(struct shared_info *info, Elf64_Ehdr *ehdr, + off_t core_size) +{ + unsigned long *regs; + Elf64_Phdr *phdr; + Elf64_Nhdr *nhdr; + size_t phdr_size; + void *p = ehdr, *note; + int ret; + + ret = memcmp(ehdr->e_ident, ELFMAG, SELFMAG); + FAIL_IF(ret); + + FAIL_IF(ehdr->e_type != ET_CORE); + FAIL_IF(ehdr->e_machine != EM_PPC64); + FAIL_IF(ehdr->e_phoff == 0 || ehdr->e_phnum == 0); + + /* + * e_phnum is at most 65535 so calculating the size of the + * program header cannot overflow. + */ + phdr_size = sizeof(*phdr) * ehdr->e_phnum; + + /* Sanity check the program header table location. */ + FAIL_IF(ehdr->e_phoff + phdr_size < ehdr->e_phoff); + FAIL_IF(ehdr->e_phoff + phdr_size > core_size); + + /* Find the PT_NOTE segment. */ + for (phdr = p + ehdr->e_phoff; + (void *) phdr < p + ehdr->e_phoff + phdr_size; + phdr += ehdr->e_phentsize) + if (phdr->p_type == PT_NOTE) + break; + + FAIL_IF((void *) phdr >= p + ehdr->e_phoff + phdr_size); + + /* Find the NT_PPC_PKEY note. */ + for (nhdr = p + phdr->p_offset; + (void *) nhdr < p + phdr->p_offset + phdr->p_filesz; + nhdr = next_note(nhdr)) + if (nhdr->n_type == NT_PPC_PKEY) + break; + + FAIL_IF((void *) nhdr >= p + phdr->p_offset + phdr->p_filesz); + FAIL_IF(nhdr->n_descsz == 0); + + p = nhdr; + note = p + sizeof(*nhdr) + __ALIGN_KERNEL(nhdr->n_namesz, 4); + + regs = (unsigned long *) note; + + printf("%-30s AMR: %016lx IAMR: %016lx UAMOR: %016lx\n", + core_read_running, regs[0], regs[1], regs[2]); + + FAIL_IF(regs[0] != info->amr); + FAIL_IF(regs[1] != info->iamr); + FAIL_IF(regs[2] != info->uamor); + + return TEST_PASS; +} + +static int parent(struct shared_info *info, pid_t pid) +{ + char *filenames, *filename[3]; + int fd, i, ret, status; + unsigned long regs[3]; + off_t core_size; + void *core; + + /* + * 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->amr = regs[0]; + info->iamr = regs[1]; + info->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(&status); + if (ret != pid) { + printf("Child's exit status not captured\n"); + return TEST_FAIL; + } else if (!WIFSIGNALED(status) || !WCOREDUMP(status)) { + printf("Child didn't dump core\n"); + return TEST_FAIL; + } + + /* Construct array of core file names to try. */ + + filename[0] = filenames = malloc(PATH_MAX); + if (!filenames) { + perror("Error allocating memory"); + return TEST_FAIL; + } + + ret = snprintf(filename[0], PATH_MAX, "core-pkey.%d", pid); + if (ret < 0 || ret >= PATH_MAX) { + ret = TEST_FAIL; + goto out; + } + + filename[1] = filename[0] + ret + 1; + ret = snprintf(filename[1], PATH_MAX - ret - 1, "core.%d", pid); + if (ret < 0 || ret >= PATH_MAX - ret - 1) { + ret = TEST_FAIL; + goto out; + } + filename[2] = "core"; + + for (i = 0; i < 3; i++) { + core_size = try_core_file(filename[i], info, pid); + if (core_size != TEST_FAIL) + break; + } + + if (i == 3) { + printf("Couldn't find core file\n"); + ret = TEST_FAIL; + goto out; + } + + fd = open(filename[i], O_RDONLY); + if (fd == -1) { + perror("Error opening core file"); + ret = TEST_FAIL; + goto out; + } + + core = mmap(NULL, core_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (core == (void *) -1) { + perror("Error mmaping core file"); + ret = TEST_FAIL; + goto out; + } + + ret = check_core_file(info, core, core_size); + + munmap(core, core_size); + close(fd); + unlink(filename[i]); + + out: + free(filenames); + + return ret; +} + +static int write_core_pattern(const char *core_pattern) +{ + size_t len = strlen(core_pattern), ret; + FILE *f; + + f = fopen(core_pattern_file, "w"); + if (!f) { + perror("Error writing to core_pattern file"); + return TEST_FAIL; + } + + ret = fwrite(core_pattern, 1, len, f); + fclose(f); + if (ret != len) { + perror("Error writing to core_pattern file"); + return TEST_FAIL; + } + + return TEST_PASS; +} + +static int setup_core_pattern(char **core_pattern_, bool *changed_) +{ + FILE *f; + char *core_pattern; + int ret; + + core_pattern = malloc(PATH_MAX); + if (!core_pattern) { + perror("Error allocating memory"); + return TEST_FAIL; + } + + f = fopen(core_pattern_file, "r"); + if (!f) { + perror("Error opening core_pattern file"); + ret = TEST_FAIL; + goto out; + } + + ret = fread(core_pattern, 1, PATH_MAX, f); + fclose(f); + if (!ret) { + perror("Error reading core_pattern file"); + ret = TEST_FAIL; + goto out; + } + + /* Check whether we can predict the name of the core file. */ + if (!strcmp(core_pattern, "core") || !strcmp(core_pattern, "core.%p")) + *changed_ = false; + else { + ret = write_core_pattern("core-pkey.%p"); + if (ret) + goto out; + + *changed_ = true; + } + + *core_pattern_ = core_pattern; + ret = TEST_PASS; + + out: + if (ret) + free(core_pattern); + + return ret; +} + +static int core_pkey(void) +{ + char *core_pattern; + bool changed_core_pattern; + struct shared_info *info; + int shm_id; + int ret; + pid_t pid; + + ret = setup_core_pattern(&core_pattern, &changed_core_pattern); + if (ret) + return ret; + + 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); + + if (changed_core_pattern) + write_core_pattern(core_pattern); + } + + free(core_pattern); + + return ret; +} + +int main(int argc, char *argv[]) +{ + return test_harness(core_pkey, "core_pkey"); +}
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