diff options
author | Amit Daniel Kachhap <amit.kachhap@arm.com> | 2020-10-02 17:26:30 +0530 |
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committer | Will Deacon <will@kernel.org> | 2020-10-05 18:52:17 +0100 |
commit | 4dafc08d0ba4768e8540f49ab40c3ea26e40d554 (patch) | |
tree | abd3c2e5031537bd67107a13d31e129546a39fab /tools/testing/selftests/arm64/mte/check_user_mem.c | |
parent | f981d8fa26469e19d2ce73006685ae88205e914a (diff) |
kselftest/arm64: Check mte tagged user address in kernel
Add a testcase to check that user address with valid/invalid
mte tag works in kernel mode. This test verifies that the kernel
API's __arch_copy_from_user/__arch_copy_to_user works by considering
if the user pointer has valid/invalid allocation tags.
In MTE sync mode, file memory read/write and other similar interfaces
fails if a user memory with invalid tag is accessed in kernel. In async
mode no such failure occurs.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201002115630.24683-7-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'tools/testing/selftests/arm64/mte/check_user_mem.c')
-rw-r--r-- | tools/testing/selftests/arm64/mte/check_user_mem.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c new file mode 100644 index 000000000000..594e98e76880 --- /dev/null +++ b/tools/testing/selftests/arm64/mte/check_user_mem.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2020 ARM Limited + +#define _GNU_SOURCE + +#include <errno.h> +#include <fcntl.h> +#include <signal.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <ucontext.h> +#include <unistd.h> +#include <sys/mman.h> + +#include "kselftest.h" +#include "mte_common_util.h" +#include "mte_def.h" + +static size_t page_sz; + +static int check_usermem_access_fault(int mem_type, int mode, int mapping) +{ + int fd, i, err; + char val = 'A'; + size_t len, read_len; + void *ptr, *ptr_next; + + err = KSFT_FAIL; + len = 2 * page_sz; + mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); + fd = create_temp_file(); + if (fd == -1) + return KSFT_FAIL; + for (i = 0; i < len; i++) + write(fd, &val, sizeof(val)); + lseek(fd, 0, 0); + ptr = mte_allocate_memory(len, mem_type, mapping, true); + if (check_allocated_memory(ptr, len, mem_type, true) != KSFT_PASS) { + close(fd); + return KSFT_FAIL; + } + mte_initialize_current_context(mode, (uintptr_t)ptr, len); + /* Copy from file into buffer with valid tag */ + read_len = read(fd, ptr, len); + mte_wait_after_trig(); + if (cur_mte_cxt.fault_valid || read_len < len) + goto usermem_acc_err; + /* Verify same pattern is read */ + for (i = 0; i < len; i++) + if (*(char *)(ptr + i) != val) + break; + if (i < len) + goto usermem_acc_err; + + /* Tag the next half of memory with different value */ + ptr_next = (void *)((unsigned long)ptr + page_sz); + ptr_next = mte_insert_new_tag(ptr_next); + mte_set_tag_address_range(ptr_next, page_sz); + + lseek(fd, 0, 0); + /* Copy from file into buffer with invalid tag */ + read_len = read(fd, ptr, len); + mte_wait_after_trig(); + /* + * Accessing user memory in kernel with invalid tag should fail in sync + * mode without fault but may not fail in async mode as per the + * implemented MTE userspace support in Arm64 kernel. + */ + if (mode == MTE_SYNC_ERR && + !cur_mte_cxt.fault_valid && read_len < len) { + err = KSFT_PASS; + } else if (mode == MTE_ASYNC_ERR && + !cur_mte_cxt.fault_valid && read_len == len) { + err = KSFT_PASS; + } +usermem_acc_err: + mte_free_memory((void *)ptr, len, mem_type, true); + close(fd); + return err; +} + +int main(int argc, char *argv[]) +{ + int err; + + page_sz = getpagesize(); + if (!page_sz) { + ksft_print_msg("ERR: Unable to get page size\n"); + return KSFT_FAIL; + } + err = mte_default_setup(); + if (err) + return err; + /* Register signal handlers */ + mte_register_signal(SIGSEGV, mte_default_handler); + + evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_PRIVATE), + "Check memory access from kernel in sync mode, private mapping and mmap memory\n"); + evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_SYNC_ERR, MAP_SHARED), + "Check memory access from kernel in sync mode, shared mapping and mmap memory\n"); + + evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_PRIVATE), + "Check memory access from kernel in async mode, private mapping and mmap memory\n"); + evaluate_test(check_usermem_access_fault(USE_MMAP, MTE_ASYNC_ERR, MAP_SHARED), + "Check memory access from kernel in async mode, shared mapping and mmap memory\n"); + + mte_restore_setup(); + ksft_print_cnts(); + return ksft_get_fail_cnt() == 0 ? KSFT_PASS : KSFT_FAIL; +} |