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| 1 | +/* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | +/* |
| 3 | + * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args |
| 4 | + * Copyright (c) 2018 Andrew Lutomirski |
| 5 | + */ |
| 6 | + |
| 7 | +#define _GNU_SOURCE |
| 8 | + |
| 9 | +#include <stdlib.h> |
| 10 | +#include <stdio.h> |
| 11 | +#include <stdbool.h> |
| 12 | +#include <errno.h> |
| 13 | +#include <unistd.h> |
| 14 | +#include <syscall.h> |
| 15 | + |
| 16 | +static int nerrs; |
| 17 | + |
| 18 | +#define X32_BIT 0x40000000UL |
| 19 | + |
| 20 | +static void check_enosys(unsigned long nr, bool *ok) |
| 21 | +{ |
| 22 | + /* If this fails, a segfault is reasonably likely. */ |
| 23 | + fflush(stdout); |
| 24 | + |
| 25 | + long ret = syscall(nr, 0, 0, 0, 0, 0, 0); |
| 26 | + if (ret == 0) { |
| 27 | + printf("[FAIL]\tsyscall %lu succeeded, but it should have failed\n", nr); |
| 28 | + *ok = false; |
| 29 | + } else if (errno != ENOSYS) { |
| 30 | + printf("[FAIL]\tsyscall %lu had error code %d, but it should have reported ENOSYS\n", nr, errno); |
| 31 | + *ok = false; |
| 32 | + } |
| 33 | +} |
| 34 | + |
| 35 | +static void test_x32_without_x32_bit(void) |
| 36 | +{ |
| 37 | + bool ok = true; |
| 38 | + |
| 39 | + /* |
| 40 | + * Syscalls 512-547 are "x32" syscalls. They are intended to be |
| 41 | + * called with the x32 (0x40000000) bit set. Calling them without |
| 42 | + * the x32 bit set is nonsense and should not work. |
| 43 | + */ |
| 44 | + printf("[RUN]\tChecking syscalls 512-547\n"); |
| 45 | + for (int i = 512; i <= 547; i++) |
| 46 | + check_enosys(i, &ok); |
| 47 | + |
| 48 | + /* |
| 49 | + * Check that a handful of 64-bit-only syscalls are rejected if the x32 |
| 50 | + * bit is set. |
| 51 | + */ |
| 52 | + printf("[RUN]\tChecking some 64-bit syscalls in x32 range\n"); |
| 53 | + check_enosys(16 | X32_BIT, &ok); /* ioctl */ |
| 54 | + check_enosys(19 | X32_BIT, &ok); /* readv */ |
| 55 | + check_enosys(20 | X32_BIT, &ok); /* writev */ |
| 56 | + |
| 57 | + /* |
| 58 | + * Check some syscalls with high bits set. |
| 59 | + */ |
| 60 | + printf("[RUN]\tChecking numbers above 2^32-1\n"); |
| 61 | + check_enosys((1UL << 32), &ok); |
| 62 | + check_enosys(X32_BIT | (1UL << 32), &ok); |
| 63 | + |
| 64 | + if (!ok) |
| 65 | + nerrs++; |
| 66 | + else |
| 67 | + printf("[OK]\tThey all returned -ENOSYS\n"); |
| 68 | +} |
| 69 | + |
| 70 | +int main() |
| 71 | +{ |
| 72 | + /* |
| 73 | + * Anyone diagnosing a failure will want to know whether the kernel |
| 74 | + * supports x32. Tell them. |
| 75 | + */ |
| 76 | + printf("\tChecking for x32..."); |
| 77 | + fflush(stdout); |
| 78 | + if (syscall(39 | X32_BIT, 0, 0, 0, 0, 0, 0) >= 0) { |
| 79 | + printf(" supported\n"); |
| 80 | + } else if (errno == ENOSYS) { |
| 81 | + printf(" not supported\n"); |
| 82 | + } else { |
| 83 | + printf(" confused\n"); |
| 84 | + } |
| 85 | + |
| 86 | + test_x32_without_x32_bit(); |
| 87 | + |
| 88 | + return nerrs ? 1 : 0; |
| 89 | +} |
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