Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 The Android Open Source Project |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * * Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * * Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in |
| 12 | * the documentation and/or other materials provided with the |
| 13 | * distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 16 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 17 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| 18 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| 19 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| 21 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| 22 | * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| 23 | * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| 24 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| 25 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 26 | * SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #include <machine/asm.h> |
| 30 | #include "libc_events.h" |
| 31 | |
| 32 | .syntax unified |
| 33 | .fpu neon |
| 34 | .thumb |
| 35 | .thumb_func |
| 36 | |
| 37 | // Get the length of src string, then get the source of the dst string. |
| 38 | // Check that the two lengths together don't exceed the threshold, then |
| 39 | // do a memcpy of the data. |
| 40 | ENTRY(__strcat_chk) |
| 41 | .cfi_startproc |
| 42 | pld [r0, #0] |
| 43 | push {r0, lr} |
Christopher Ferris | a57c9c0 | 2013-08-21 09:41:12 -0700 | [diff] [blame] | 44 | .save {r0, lr} |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 45 | .cfi_def_cfa_offset 8 |
| 46 | .cfi_rel_offset r0, 0 |
| 47 | .cfi_rel_offset lr, 4 |
| 48 | push {r4, r5} |
Christopher Ferris | a57c9c0 | 2013-08-21 09:41:12 -0700 | [diff] [blame] | 49 | .save {r4, r5} |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 50 | .cfi_adjust_cfa_offset 8 |
| 51 | .cfi_rel_offset r4, 0 |
| 52 | .cfi_rel_offset r5, 4 |
| 53 | |
| 54 | mov lr, r2 |
| 55 | |
| 56 | // Save the dst register to r5 |
| 57 | mov r5, r0 |
| 58 | |
| 59 | // Zero out r4 |
| 60 | eor r4, r4, r4 |
| 61 | |
| 62 | // r1 contains the address of the string to count. |
| 63 | .L_strlen_start: |
| 64 | mov r0, r1 |
| 65 | |
| 66 | ands r3, r0, #7 |
| 67 | bne .L_align_src |
| 68 | |
| 69 | .p2align 2 |
| 70 | .L_mainloop: |
| 71 | ldmia r1!, {r2, r3} |
| 72 | |
| 73 | pld [r1, #64] |
| 74 | |
| 75 | sub ip, r2, #0x01010101 |
| 76 | bic ip, ip, r2 |
| 77 | ands ip, ip, #0x80808080 |
| 78 | bne .L_zero_in_first_register |
| 79 | |
| 80 | sub ip, r3, #0x01010101 |
| 81 | bic ip, ip, r3 |
| 82 | ands ip, ip, #0x80808080 |
| 83 | bne .L_zero_in_second_register |
| 84 | b .L_mainloop |
| 85 | |
| 86 | .L_zero_in_first_register: |
| 87 | sub r3, r1, r0 |
| 88 | // Check for zero in byte 0. |
| 89 | lsls r2, ip, #17 |
| 90 | beq .L_check_byte1_reg1 |
| 91 | |
| 92 | sub r3, r3, #8 |
| 93 | b .L_finish |
| 94 | |
| 95 | .L_check_byte1_reg1: |
| 96 | bcc .L_check_byte2_reg1 |
| 97 | |
| 98 | sub r3, r3, #7 |
| 99 | b .L_finish |
| 100 | |
| 101 | .L_check_byte2_reg1: |
| 102 | // Check for zero in byte 2. |
| 103 | tst ip, #0x800000 |
| 104 | it ne |
| 105 | subne r3, r3, #6 |
| 106 | bne .L_finish |
| 107 | sub r3, r3, #5 |
| 108 | b .L_finish |
| 109 | |
| 110 | .L_zero_in_second_register: |
| 111 | sub r3, r1, r0 |
| 112 | // Check for zero in byte 0. |
| 113 | lsls r2, ip, #17 |
| 114 | beq .L_check_byte1_reg2 |
| 115 | |
| 116 | sub r3, r3, #4 |
| 117 | b .L_finish |
| 118 | |
| 119 | .L_check_byte1_reg2: |
| 120 | bcc .L_check_byte2_reg2 |
| 121 | |
| 122 | sub r3, r3, #3 |
| 123 | b .L_finish |
| 124 | |
| 125 | .L_check_byte2_reg2: |
| 126 | // Check for zero in byte 2. |
| 127 | tst ip, #0x800000 |
| 128 | it ne |
| 129 | subne r3, r3, #2 |
| 130 | bne .L_finish |
| 131 | sub r3, r3, #1 |
| 132 | b .L_finish |
| 133 | |
| 134 | .L_align_src: |
| 135 | // Align to a double word (64 bits). |
| 136 | rsb r3, r3, #8 |
| 137 | lsls ip, r3, #31 |
| 138 | beq .L_align_to_32 |
| 139 | |
| 140 | ldrb r2, [r1], #1 |
| 141 | cbz r2, .L_done |
| 142 | |
| 143 | .L_align_to_32: |
| 144 | bcc .L_align_to_64 |
| 145 | |
| 146 | ldrb r2, [r1], #1 |
| 147 | cbz r2, .L_done |
| 148 | ldrb r2, [r1], #1 |
| 149 | cbz r2, .L_done |
| 150 | |
| 151 | .L_align_to_64: |
| 152 | tst r3, #4 |
| 153 | beq .L_mainloop |
| 154 | ldr r2, [r1], #4 |
| 155 | |
| 156 | sub ip, r2, #0x01010101 |
| 157 | bic ip, ip, r2 |
| 158 | ands ip, ip, #0x80808080 |
| 159 | bne .L_zero_in_second_register |
| 160 | b .L_mainloop |
| 161 | |
| 162 | .L_done: |
| 163 | sub r3, r1, r0 |
| 164 | sub r3, r3, #1 |
| 165 | |
| 166 | .L_finish: |
| 167 | cmp r4, #0 |
| 168 | bne .L_strlen_done |
| 169 | |
| 170 | // Time to get the dst string length. |
| 171 | mov r1, r5 |
| 172 | |
| 173 | // Save the original source address to r5. |
| 174 | mov r5, r0 |
| 175 | |
| 176 | // Save the current length (adding 1 for the terminator). |
| 177 | add r4, r3, #1 |
| 178 | b .L_strlen_start |
| 179 | |
| 180 | // r0 holds the pointer to the dst string. |
| 181 | // r3 holds the dst string length. |
| 182 | // r4 holds the src string length + 1. |
| 183 | .L_strlen_done: |
| 184 | add r2, r3, r4 |
| 185 | cmp r2, lr |
Christopher Ferris | 16e185c | 2013-09-10 16:56:34 -0700 | [diff] [blame^] | 186 | bhi __strcat_chk_fail |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 187 | |
| 188 | // Set up the registers for the memcpy code. |
| 189 | mov r1, r5 |
| 190 | pld [r1, #64] |
| 191 | mov r2, r4 |
| 192 | add r0, r0, r3 |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 193 | pop {r4, r5} |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 194 | |
Christopher Ferris | a57c9c0 | 2013-08-21 09:41:12 -0700 | [diff] [blame] | 195 | // Fall through into the memcpy_base function. |
| 196 | .cfi_endproc |
| 197 | END(__strcat_chk) |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 198 | |
Christopher Ferris | a57c9c0 | 2013-08-21 09:41:12 -0700 | [diff] [blame] | 199 | #define MEMCPY_BASE __strcat_chk_memcpy_base |
| 200 | #define MEMCPY_BASE_ALIGNED __strcat_chk_memcpy_base_aligned |
| 201 | #include "memcpy_base.S" |
| 202 | |
| 203 | ENTRY(__strcat_chk_fail) |
| 204 | .cfi_startproc |
| 205 | |
| 206 | .save {r0, lr} |
| 207 | .save {r4, r5} |
| 208 | .cfi_def_cfa_offset 8 |
| 209 | .cfi_rel_offset r0, 0 |
| 210 | .cfi_rel_offset lr, 4 |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 211 | .cfi_adjust_cfa_offset 8 |
| 212 | .cfi_rel_offset r4, 0 |
| 213 | .cfi_rel_offset r5, 4 |
| 214 | |
| 215 | ldr r0, error_message |
| 216 | ldr r1, error_code |
| 217 | 1: |
| 218 | add r0, pc |
| 219 | bl __fortify_chk_fail |
| 220 | error_code: |
| 221 | .word BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW |
| 222 | error_message: |
| 223 | .word error_string-(1b+4) |
| 224 | |
| 225 | .cfi_endproc |
Christopher Ferris | a57c9c0 | 2013-08-21 09:41:12 -0700 | [diff] [blame] | 226 | END(__strcat_chk_fail) |
Christopher Ferris | 5f45d58 | 2013-08-07 13:09:51 -0700 | [diff] [blame] | 227 | |
| 228 | .data |
| 229 | error_string: |
| 230 | .string "strcat buffer overflow" |