diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c index df91a41a5bab..b6166a5f37d6 100644 --- a/tools/testing/selftests/x86/lam.c +++ b/tools/testing/selftests/x86/lam.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include @@ -43,7 +44,15 @@ #define FUNC_INHERITE 0x20 #define FUNC_PASID 0x40 +/* get_user() pointer test cases */ +#define GET_USER_USER 0 +#define GET_USER_KERNEL_TOP 1 +#define GET_USER_KERNEL_BOT 2 +#define GET_USER_KERNEL 3 + #define TEST_MASK 0x7f +#define L5_SIGN_EXT_MASK (0xFFUL << 56) +#define L4_SIGN_EXT_MASK (0x1FFFFUL << 47) #define LOW_ADDR (0x1UL << 30) #define HIGH_ADDR (0x3UL << 48) @@ -389,6 +398,78 @@ static int handle_syscall(struct testcases *test) return ret; } +static int get_user_syscall(struct testcases *test) +{ + uint64_t ptr_address, bitmask; + int fd, ret = 0; + void *ptr; + + if (la57_enabled()) { + bitmask = L5_SIGN_EXT_MASK; + ptr_address = HIGH_ADDR; + } else { + bitmask = L4_SIGN_EXT_MASK; + ptr_address = LOW_ADDR; + } + + ptr = mmap((void *)ptr_address, PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); + + if (ptr == MAP_FAILED) { + perror("failed to map byte to pass into get_user"); + return 1; + } + + if (set_lam(test->lam) != 0) { + ret = 2; + goto error; + } + + fd = memfd_create("lam_ioctl", 0); + if (fd == -1) { + munmap(ptr, PAGE_SIZE); + exit(EXIT_FAILURE); + } + + switch (test->later) { + case GET_USER_USER: + /* Control group - properly tagged user pointer */ + ptr = (void *)set_metadata((uint64_t)ptr, test->lam); + break; + case GET_USER_KERNEL_TOP: + /* Kernel address with top bit cleared */ + bitmask &= (bitmask >> 1); + ptr = (void *)((uint64_t)ptr | bitmask); + break; + case GET_USER_KERNEL_BOT: + /* Kernel address with bottom sign-extension bit cleared */ + bitmask &= (bitmask << 1); + ptr = (void *)((uint64_t)ptr | bitmask); + break; + case GET_USER_KERNEL: + /* Try to pass a kernel address */ + ptr = (void *)((uint64_t)ptr | bitmask); + break; + default: + printf("Invalid test case value passed!\n"); + break; + } + + /* + * Use FIOASYNC ioctl because it utilizes get_user() internally and is + * very non-invasive to the system. Pass differently tagged pointers to + * get_user() in order to verify that valid user pointers are going + * through and invalid kernel/non-canonical pointers are not. + */ + if (ioctl(fd, FIOASYNC, ptr) != 0) + ret = 1; + + close(fd); +error: + munmap(ptr, PAGE_SIZE); + return ret; +} + int sys_uring_setup(unsigned int entries, struct io_uring_params *p) { return (int)syscall(__NR_io_uring_setup, entries, p); @@ -902,6 +983,33 @@ static struct testcases syscall_cases[] = { .test_func = handle_syscall, .msg = "SYSCALL:[Negative] Disable LAM. Dereferencing pointer with metadata.\n", }, + { + .later = GET_USER_USER, + .lam = LAM_U57_BITS, + .test_func = get_user_syscall, + .msg = "GET_USER: get_user() and pass a properly tagged user pointer.\n", + }, + { + .later = GET_USER_KERNEL_TOP, + .expected = 1, + .lam = LAM_U57_BITS, + .test_func = get_user_syscall, + .msg = "GET_USER:[Negative] get_user() with a kernel pointer and the top bit cleared.\n", + }, + { + .later = GET_USER_KERNEL_BOT, + .expected = 1, + .lam = LAM_U57_BITS, + .test_func = get_user_syscall, + .msg = "GET_USER:[Negative] get_user() with a kernel pointer and the bottom sign-extension bit cleared.\n", + }, + { + .later = GET_USER_KERNEL, + .expected = 1, + .lam = LAM_U57_BITS, + .test_func = get_user_syscall, + .msg = "GET_USER:[Negative] get_user() and pass a kernel pointer.\n", + }, }; static struct testcases mmap_cases[] = {