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gerrit.omnirom.org / android_bionic / 7493568ba82752d405bbb16dd7c42b3b88c67f86 / . / libc / arch-arm / krait / bionic / __strcpy_chk.S
blob: d5e1db610af253c22d0c256ebc359acb9361d8e2 [file] [log] [blame]
Christopher Ferris5f45d582013-08-07 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
34 .thumb
35 .thumb_func
36
37// Get the length of the source string first, then do a memcpy of the data
38// instead of a strcpy.
39ENTRY(__strcpy_chk)
40 .cfi_startproc
41 pld [r0, #0]
Christopher Ferrisbd7fe1d2013-08-20 11:20:48 -0700[diff] [blame]42 .save {r0, lr}
Christopher Ferris5f45d582013-08-07 13:09:51 -0700[diff] [blame]43 push {r0, lr}
44 .cfi_def_cfa_offset 8
45 .cfi_rel_offset r0, 0
46 .cfi_rel_offset lr, 4
47
48 mov lr, r2
49 mov r0, r1
50
51 ands r3, r1, #7
52 beq .L_mainloop
53
54 // Align to a double word (64 bits).
55 rsb r3, r3, #8
56 lsls ip, r3, #31
57 beq .L_align_to_32
58
59 ldrb r2, [r0], #1
60 cbz r2, .L_update_count_and_finish
61
62.L_align_to_32:
63 bcc .L_align_to_64
64 ands ip, r3, #2
65 beq .L_align_to_64
66
67 ldrb r2, [r0], #1
68 cbz r2, .L_update_count_and_finish
69 ldrb r2, [r0], #1
70 cbz r2, .L_update_count_and_finish
71
72.L_align_to_64:
73 tst r3, #4
74 beq .L_mainloop
75 ldr r3, [r0], #4
76
77 sub ip, r3, #0x01010101
78 bic ip, ip, r3
79 ands ip, ip, #0x80808080
80 bne .L_zero_in_second_register
81
82 .p2align 2
83.L_mainloop:
84 ldrd r2, r3, [r0], #8
85
86 pld [r0, #64]
87
88 sub ip, r2, #0x01010101
89 bic ip, ip, r2
90 ands ip, ip, #0x80808080
91 bne .L_zero_in_first_register
92
93 sub ip, r3, #0x01010101
94 bic ip, ip, r3
95 ands ip, ip, #0x80808080
96 bne .L_zero_in_second_register
97 b .L_mainloop
98
99.L_update_count_and_finish:
100 sub r3, r0, r1
101 sub r3, r3, #1
102 b .L_check_size
103
104.L_zero_in_first_register:
105 sub r3, r0, r1
106 lsls r2, ip, #17
107 bne .L_sub8_and_finish
108 bcs .L_sub7_and_finish
109 lsls ip, ip, #1
110 bne .L_sub6_and_finish
111
112 sub r3, r3, #5
113 b .L_check_size
114
115.L_sub8_and_finish:
116 sub r3, r3, #8
117 b .L_check_size
118
119.L_sub7_and_finish:
120 sub r3, r3, #7
121 b .L_check_size
122
123.L_sub6_and_finish:
124 sub r3, r3, #6
125 b .L_check_size
126
127.L_zero_in_second_register:
128 sub r3, r0, r1
129 lsls r2, ip, #17
130 bne .L_sub4_and_finish
131 bcs .L_sub3_and_finish
132 lsls ip, ip, #1
133 bne .L_sub2_and_finish
134
135 sub r3, r3, #1
136 b .L_check_size
137
138.L_sub4_and_finish:
139 sub r3, r3, #4
140 b .L_check_size
141
142.L_sub3_and_finish:
143 sub r3, r3, #3
144 b .L_check_size
145
146.L_sub2_and_finish:
147 sub r3, r3, #2
148
149.L_check_size:
150 pld [r1, #0]
151 pld [r1, #64]
152 ldr r0, [sp]
153 cmp r3, lr
154 bge .L_fortify_check_failed
155
156 // Add 1 for copy length to get the string terminator.
157 add r2, r3, #1
158
159 #include "memcpy_base.S"
160
161.L_fortify_check_failed:
162 ldr r0, error_message
163 ldr r1, error_code
1641:
165 add r0, pc
166 bl __fortify_chk_fail
167error_code:
168 .word BIONIC_EVENT_STRCPY_BUFFER_OVERFLOW
169error_message:
170 .word error_string-(1b+4)
171 .cfi_endproc
172END(__strcpy_chk)
173
174 .data
175error_string:
176 .string "strcpy buffer overflow"