From fa7a41a129697b6e7dce363060d2265f5fdb93a6 Mon Sep 17 00:00:00 2001
From: bg <bg@b1d182e4-1ff8-0310-901f-bddb46175740>
Date: Tue, 17 Feb 2009 14:11:49 +0000
Subject: [PATCH] bug fixed in md5-asm.S ( wrong values for
length_b%512=505..511 )
---
md5-asm.S | 38 ++++++++++++++++++++------------------
md5.c | 3 ++-
md5_sbox.h | 7 +++++--
test_src/main-md5-test.c | 21 ++++++++++++++++-----
4 files changed, 43 insertions(+), 26 deletions(-)
diff --git a/md5-asm.S b/md5-asm.S
index 469f9ab..de3b170 100644
--- a/md5-asm.S
+++ b/md5-asm.S
@@ -785,6 +785,7 @@ md5_lastBlock:
movw r16, r20 /* length_b */
movw r14, r22 /* block_ptr */
movw r12, r24 /* state_ptr */
+ ldi r18, 64
2:
cpi r17, 2 /* hi8(512) */
brlo 2f
@@ -792,7 +793,6 @@ md5_lastBlock:
movw r24, r12
movw r22, r14
rcall md5_nextBlock
- ldi r18, 64
add r14, r18
adc r15, r1
subi r17, 2
@@ -801,58 +801,59 @@ md5_lastBlock:
pop r31
pop r30
- adiw r30, 1
+ adiw r30, 1 /* adjust Z to point to buffer */
movw r26, r14
movw r24, r16
adiw r24, 7
lsr r25
ror r24
- lsr r24
+ lsr r25
+ ror r24
lsr r24 /* r24 now holds how many bytes are to copy */
- ldi r18, 64
- sub r18, r24
+ ldi r18, 64
+ sub r18, r24 /* r18 will hold the amount of used bytes in buffer */
tst r24
4:
breq 5f
ld r0, X+
- st Z+, r0
+ st Z+, r0
dec r24
- rjmp 4b
+ rjmp 4b /* Z points to the byte after msg in buffer */
5: /* append 1-bit */
mov r20, r16
+ ldi r19, 0x80
andi r20, 0x07
brne bit_fucking
- ldi r19, 0x80
st Z+, r19
- dec r18
+ dec r18 /* 'allocate' another byte in buffer */
rjmp after_bit_fucking
bit_fucking:
- ldi r19, 0x80
1:
lsr r19
dec r20
brne 1b
or r0, r19
st -Z, r0
- adiw r30, 1
+ adiw r30, 1
after_bit_fucking:
clt
cpi r18, 8
brmi 2f
- set /* store in t if the counter will also fit in this block */
+ set /* store in t if the counter will also fit in this block (1 if fit)*/
2:
tst r18
breq 2f
-1:
+1: /* fill remaning buffer with zeros */
st Z+, r1
dec r18
brne 1b
2:
sbiw r30, 63
sbiw r30, 1
- movw r14, r30
+ movw r14, r30 /* r14:r15 now points to buffer */
brts load_counter
+ /* counter does not fit, finalize this block */
movw r24, r12
movw r22, r14
rcall md5_nextBlock
@@ -864,13 +865,14 @@ after_bit_fucking:
brne 3b
load_counter:
- movw r26, r12
+ movw r26, r12 /* X points to state */
adiw r26, 16
ld r19, X+
ld r20, X+
ld r21, X+
ld r22, X+
- brts post_counter_decrement
+ brts post_counter_decrement /* do not decremen because counter fits */
+counter_decrement:
subi r19, 1
sbci r20, 0
sbci r21, 0
@@ -883,8 +885,8 @@ post_counter_decrement:
rol r21
rol r22
rol r23
- add r18, r16
- adc r19, r17
+ mov r18, r16 /* r16:r17 length_b */
+ add r19, r17
adc r20, r1
adc r21, r1
adc r22, r1
diff --git a/md5.c b/md5.c
index ddad0b9..20ec519 100644
--- a/md5.c
+++ b/md5.c
@@ -80,7 +80,8 @@ void md5_core(uint32_t* a, void* block, uint8_t as, uint8_t s, uint8_t i, uint8_
uart_hexdump(&s, 1); uart_putc(' ');
uart_hexdump(&i, 1); uart_putc(']');
#endif
- t = a[as] + funcs[fi](a[(as+1)&3], a[(as+2)&3], a[(as+3)&3]) + *((uint32_t*)block) + md5_T[i] ;
+ t = a[as] + funcs[fi](a[(as+1)&3], a[(as+2)&3], a[(as+3)&3])
+ + *((uint32_t*)block) + pgm_read_dword(md5_T+i) ;
a[as]=a[(as+1)&3] + ROTL32(t, s);
}
diff --git a/md5_sbox.h b/md5_sbox.h
index b8ab636..597b3db 100644
--- a/md5_sbox.h
+++ b/md5_sbox.h
@@ -19,7 +19,10 @@
#ifndef MD5_SBOX_H_
#define MD5_SBOX_H_
-uint32_t md5_T[]={
+#include <stdint.h>
+#include <avr/pgmspace.h>
+
+uint32_t md5_T[] PROGMEM = {
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf,
0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af,
0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e,
@@ -32,6 +35,6 @@ uint32_t md5_T[]={
0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97,
0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d,
0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
- 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391};
+ 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 };
#endif /*MD5_SBOX_H_*/
diff --git a/test_src/main-md5-test.c b/test_src/main-md5-test.c
index 1ede353..90c5971 100644
--- a/test_src/main-md5-test.c
+++ b/test_src/main-md5-test.c
@@ -93,15 +93,26 @@ void testrun_md5(void){
"abcdefghijklmnopqrstuvwxyz",
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
"12345678901234567890123456789012345678901234567890123456789012345678901234567890"};
- uint8_t i;
+ uint16_t i;
uart_putstr("\r\n=== MD5 test suit ===");
for(i=0; i<7; ++i){
- uart_putstr("\r\n MD5 (\"");
- uart_putstr(testv[i]);
- uart_putstr("\") = \r\n\t");
+ cli_putstr("\r\n MD5 (\"");
+ cli_putstr(testv[i]);
+ cli_putstr("\") = \r\n\t");
md5(&hash, testv[i], strlen(testv[i])*8);
- uart_hexdump(hash, 16);
+ cli_hexdump(hash, 16);
+ }
+ uint8_t buffer[512/8];
+ char str[5];
+ for(i=505; i<512; ++i){
+ memset(buffer, 0, 512/8);
+ cli_putstr_P(PSTR("\r\nMD5("));
+ utoa(i, str, 10);
+ cli_putstr(str);
+ cli_putstr_P(PSTR(" zero bits) = "));
+ md5(&hash, buffer, i);
+ cli_hexdump(hash, 16);
}
}
--
2.39.5