diff options
| author | Root THC | 2026-02-24 12:42:47 +0000 |
|---|---|---|
| committer | Root THC | 2026-02-24 12:42:47 +0000 |
| commit | c9cbeced5b3f2bdd7407e29c0811e65954132540 (patch) | |
| tree | aefc355416b561111819de159ccbd86c3004cf88 /other/wrez/tmp | |
| parent | 073fe4bf9fca6bf40cef2886d75df832ef4b6fca (diff) | |
initial
Diffstat (limited to 'other/wrez/tmp')
| -rw-r--r-- | other/wrez/tmp/call.c | 106 | ||||
| -rw-r--r-- | other/wrez/tmp/call.c.backup | 137 | ||||
| -rw-r--r-- | other/wrez/tmp/elf-runtime-fixup.txt | 324 | ||||
| -rw-r--r-- | other/wrez/tmp/foo.c | 11 | ||||
| -rw-r--r-- | other/wrez/tmp/memdump.c | 249 | ||||
| -rw-r--r-- | other/wrez/tmp/ptrace-legit.c | 143 | ||||
| -rw-r--r-- | other/wrez/tmp/str.c | 30 |
7 files changed, 1000 insertions, 0 deletions
diff --git a/other/wrez/tmp/call.c b/other/wrez/tmp/call.c new file mode 100644 index 0000000..d81f072 --- /dev/null +++ b/other/wrez/tmp/call.c | |||
| @@ -0,0 +1,106 @@ | |||
| 1 | /* use ht on the 'call' executeable to set the first PT_LOAD rwx | ||
| 2 | * else it will segfault | ||
| 3 | */ | ||
| 4 | |||
| 5 | #include <stdio.h> | ||
| 6 | |||
| 7 | int foofunc (void); | ||
| 8 | |||
| 9 | |||
| 10 | #define FUNCPTR(dst,functionname) \ | ||
| 11 | { \ | ||
| 12 | register unsigned int fptr; \ | ||
| 13 | \ | ||
| 14 | __asm__ __volatile__ ( \ | ||
| 15 | " call l0_%=\n" \ | ||
| 16 | "l0_%=: movl $"##functionname", %%eax\n" \ | ||
| 17 | " subl $l0_%=, %%eax\n" \ | ||
| 18 | " popl %%edx\n" \ | ||
| 19 | " addl %%edx, %%eax\n" \ | ||
| 20 | : "=a" (fptr) : : "edx"); \ | ||
| 21 | \ | ||
| 22 | (dst) = (void *) fptr; \ | ||
| 23 | } | ||
| 24 | |||
| 25 | #define PTRINSTALL(hook,chain) \ | ||
| 26 | { \ | ||
| 27 | __asm__ __volatile__ ( \ | ||
| 28 | " call l0_%=\n" \ | ||
| 29 | "lr_%=: jmp lo_%=\n" \ | ||
| 30 | "l0_%=: pushl %%edx\n" \ | ||
| 31 | " pushl $0x64466226\n" \ | ||
| 32 | " jmpl *%%eax\n" \ | ||
| 33 | "lo_%=:\n" \ | ||
| 34 | : : "a" (hook), "d" (chain)); \ | ||
| 35 | } | ||
| 36 | |||
| 37 | #define PTRCONTROL(chain) \ | ||
| 38 | { \ | ||
| 39 | __asm__ __volatile__ ( \ | ||
| 40 | " jmp l0_%=\n" \ | ||
| 41 | "lp_%=: .byte 0x0\n" \ | ||
| 42 | " .byte 0x0\n" \ | ||
| 43 | " .byte 0x0\n" \ | ||
| 44 | " .byte 0x0\n" \ | ||
| 45 | "\n" \ | ||
| 46 | "l0_%=: call l1_%=\n" \ | ||
| 47 | "l1_%=: popl %%edx\n" \ | ||
| 48 | " addl $lp_%=, %%edx\n" \ | ||
| 49 | " subl $l1_%=, %%edx\n" \ | ||
| 50 | "\n" \ | ||
| 51 | " movl 0x4(%%ebp), %%eax\n" \ | ||
| 52 | " cmpl $0x64466226, %%eax\n" \ | ||
| 53 | " jne lo_%=\n" \ | ||
| 54 | "\n" \ | ||
| 55 | " movl 0x8(%%ebp), %%eax\n" \ | ||
| 56 | " movl %%eax, (%%edx)\n" \ | ||
| 57 | "\n" \ | ||
| 58 | " movl %%ebp, %%esp\n" \ | ||
| 59 | " popl %%ebp\n" \ | ||
| 60 | " addl $0x8, %%esp\n" \ | ||
| 61 | " ret\n" \ | ||
| 62 | "\n" \ | ||
| 63 | "lo_%=: movl (%%edx), %%eax\n" \ | ||
| 64 | : "=a" (chain) : : "edx"); \ | ||
| 65 | } | ||
| 66 | |||
| 67 | |||
| 68 | int | ||
| 69 | main (int argc, char *argv[]) | ||
| 70 | { | ||
| 71 | void (* addr)(void); | ||
| 72 | |||
| 73 | #if 0 | ||
| 74 | __asm__ __volatile__ (" | ||
| 75 | call l1_%= | ||
| 76 | l1_%=: movl $foofunc, %%eax | ||
| 77 | subl $l1_%=, %%eax | ||
| 78 | popl %%edx | ||
| 79 | addl %%edx, %%eax | ||
| 80 | pusha | ||
| 81 | call *%%eax | ||
| 82 | popa" | ||
| 83 | : "=a" (addrdiff) : : "edx"); | ||
| 84 | #endif | ||
| 85 | FUNCPTR (addr, "foofunc"); | ||
| 86 | |||
| 87 | printf ("0x%08lx\n", (unsigned long int) addr); | ||
| 88 | |||
| 89 | PTRINSTALL (addr, 0x42424242); | ||
| 90 | |||
| 91 | foofunc (); | ||
| 92 | } | ||
| 93 | |||
| 94 | |||
| 95 | int | ||
| 96 | foofunc (void) | ||
| 97 | { | ||
| 98 | void * chain; | ||
| 99 | |||
| 100 | PTRCONTROL (chain); | ||
| 101 | |||
| 102 | printf ("0x%08lx\n", chain); | ||
| 103 | } | ||
| 104 | |||
| 105 | |||
| 106 | |||
diff --git a/other/wrez/tmp/call.c.backup b/other/wrez/tmp/call.c.backup new file mode 100644 index 0000000..13d3565 --- /dev/null +++ b/other/wrez/tmp/call.c.backup | |||
| @@ -0,0 +1,137 @@ | |||
| 1 | /* use ht on the 'call' executeable to set the first PT_LOAD rwx | ||
| 2 | * else it will segfault | ||
| 3 | */ | ||
| 4 | |||
| 5 | #include <stdio.h> | ||
| 6 | |||
| 7 | int foofunc (void); | ||
| 8 | |||
| 9 | |||
| 10 | #define FUNCPTR(dst,functionname) \ | ||
| 11 | { \ | ||
| 12 | register unsigned int fptr; \ | ||
| 13 | \ | ||
| 14 | __asm__ __volatile__ ( \ | ||
| 15 | " call l0_%=\n" \ | ||
| 16 | "l0_%=: movl $"##functionname", %%eax\n" \ | ||
| 17 | " subl $l0_%=, %%eax\n" \ | ||
| 18 | " popl %%edx\n" \ | ||
| 19 | " addl %%edx, %%eax\n" \ | ||
| 20 | : "=a" (fptr) : : "edx"); \ | ||
| 21 | \ | ||
| 22 | (dst) = (void *) fptr; \ | ||
| 23 | } | ||
| 24 | |||
| 25 | #define PTRINSTALL(hook,chain) \ | ||
| 26 | { \ | ||
| 27 | __asm__ __volatile__ ( \ | ||
| 28 | " call l0_%=\n" \ | ||
| 29 | "lr_%=: jmp lo_%=\n" \ | ||
| 30 | "l0_%=: pushl %%edx\n" \ | ||
| 31 | " pushl $0x64466226\n" \ | ||
| 32 | " jmpl *%%eax\n" \ | ||
| 33 | "lo_%=:\n" \ | ||
| 34 | : : "a" (hook), "d" (chain)); \ | ||
| 35 | } | ||
| 36 | |||
| 37 | #define PTRCONTROL(chain) \ | ||
| 38 | { \ | ||
| 39 | __asm__ __volatile__ ( \ | ||
| 40 | " jmp l0_%=\n" \ | ||
| 41 | "lp_%=: .byte 0x0\n" \ | ||
| 42 | " .byte 0x0\n" \ | ||
| 43 | " .byte 0x0\n" \ | ||
| 44 | " .byte 0x0\n" \ | ||
| 45 | "\n" \ | ||
| 46 | "l0_%=: call l1_%=\n" \ | ||
| 47 | "l1_%=: popl %%edx\n" \ | ||
| 48 | " addl $lp_%=, %%edx\n" \ | ||
| 49 | " subl $l1_%=, %%edx\n" \ | ||
| 50 | "\n" \ | ||
| 51 | " movl 0x4(%%ebp), %%eax\n" \ | ||
| 52 | " cmpl $0x64466226, %%eax\n" \ | ||
| 53 | " jne lo_%=\n" \ | ||
| 54 | "\n" \ | ||
| 55 | " movl 0x8(%%ebp), %%eax\n" \ | ||
| 56 | " movl %%eax, (%%edx)\n" \ | ||
| 57 | "\n" \ | ||
| 58 | " movl %%ebp, %%esp\n" \ | ||
| 59 | " popl %%ebp\n" \ | ||
| 60 | " addl $0x8, %%esp\n" \ | ||
| 61 | " ret\n" \ | ||
| 62 | "\n" \ | ||
| 63 | "lo_%=: movl (%%edx), %%eax\n" \ | ||
| 64 | : "=a" (chain) : : "edx"); \ | ||
| 65 | } | ||
| 66 | |||
| 67 | int | ||
| 68 | main (int argc, char *argv[]) | ||
| 69 | { | ||
| 70 | void (* addr)(void); | ||
| 71 | |||
| 72 | #if 0 | ||
| 73 | __asm__ __volatile__ (" | ||
| 74 | call l1_%= | ||
| 75 | l1_%=: movl $foofunc, %%eax | ||
| 76 | subl $l1_%=, %%eax | ||
| 77 | popl %%edx | ||
| 78 | addl %%edx, %%eax | ||
| 79 | pusha | ||
| 80 | call *%%eax | ||
| 81 | popa" | ||
| 82 | : "=a" (addrdiff) : : "edx"); | ||
| 83 | #endif | ||
| 84 | FUNCPTR (addr, "foofunc"); | ||
| 85 | |||
| 86 | printf ("0x%08lx\n", (unsigned long int) addr); | ||
| 87 | |||
| 88 | __asm__ __volatile__ (" | ||
| 89 | call l0_%= | ||
| 90 | lr_%=: jmp lo_%= | ||
| 91 | l0_%=: pushl %%edx | ||
| 92 | pushl $0x64466226 | ||
| 93 | jmpl *%%eax | ||
| 94 | lo_%=: | ||
| 95 | " : : "a" (addr), "d" (0x42424242)); | ||
| 96 | |||
| 97 | foofunc (); | ||
| 98 | } | ||
| 99 | |||
| 100 | |||
| 101 | int | ||
| 102 | foofunc (void) | ||
| 103 | { | ||
| 104 | void * chain; | ||
| 105 | |||
| 106 | __asm__ __volatile__ (" | ||
| 107 | ls1_%=: jmp l0_%= | ||
| 108 | ptr_%=: .byte 0x0 | ||
| 109 | .byte 0x0 | ||
| 110 | .byte 0x0 | ||
| 111 | .byte 0x0 | ||
| 112 | |||
| 113 | l0_%=: call l1_%= | ||
| 114 | l1_%=: popl %%edx | ||
| 115 | addl $ptr_%=, %%edx | ||
| 116 | subl $l1_%=, %%edx | ||
| 117 | |||
| 118 | movl 0x4(%%ebp), %%eax | ||
| 119 | cmpl $0x64466226, %%eax | ||
| 120 | jne lo_%= | ||
| 121 | |||
| 122 | movl 0x8(%%ebp), %%eax | ||
| 123 | movl %%eax, (%%edx) | ||
| 124 | |||
| 125 | movl %%ebp, %%esp | ||
| 126 | popl %%ebp | ||
| 127 | addl $0x8, %%esp | ||
| 128 | ret | ||
| 129 | |||
| 130 | lo_%=: movl (%%edx), %%eax | ||
| 131 | " : "=a" (chain) : : "edx"); | ||
| 132 | |||
| 133 | printf ("0x%08lx\n", chain); | ||
| 134 | } | ||
| 135 | |||
| 136 | |||
| 137 | |||
diff --git a/other/wrez/tmp/elf-runtime-fixup.txt b/other/wrez/tmp/elf-runtime-fixup.txt new file mode 100644 index 0000000..a594cdd --- /dev/null +++ b/other/wrez/tmp/elf-runtime-fixup.txt | |||
| @@ -0,0 +1,324 @@ | |||
| 1 | |||
| 2 | ************************************************************************** | ||
| 3 | |||
| 4 | Reversing the ELF | ||
| 5 | |||
| 6 | Stepping with GDB during PLT uses and .GOT fixup | ||
| 7 | |||
| 8 | mayhem (mayhem@hert.org) | ||
| 9 | |||
| 10 | ************************************************************************** | ||
| 11 | |||
| 12 | |||
| 13 | This text is a GDB tutorial about runtime process fixup using the Procedure | ||
| 14 | Linkage Table section (.plt) and the Global Offset Table section (.got) . | ||
| 15 | If you dont know what is ELF, you should read the ELF ultimate documentation | ||
| 16 | you can find here : | ||
| 17 | |||
| 18 | http://www.devhell.org/~mayhem/stuffs/ELF.pdf | ||
| 19 | |||
| 20 | Some basic ASM knowledge may be requested . | ||
| 21 | |||
| 22 | This text has not been written for ELF specialists . This tutorial is an | ||
| 23 | alternative , interactive way to understand the PLT mechanisms . | ||
| 24 | |||
| 25 | When the executable is mapped into memory, the core code segment _start | ||
| 26 | fonction the executable file is called as soon as the _dl_start function | ||
| 27 | of the dynamic linker has returned . I will go step by step in the | ||
| 28 | process structures initialization mechanims using objdump, gdb and gcc ; | ||
| 29 | |||
| 30 | |||
| 31 | |||
| 32 | |||
| 33 | bash-2.03$ cat test.c | ||
| 34 | int called() | ||
| 35 | { | ||
| 36 | puts("toto"); | ||
| 37 | } | ||
| 38 | |||
| 39 | int main() | ||
| 40 | { | ||
| 41 | called(); | ||
| 42 | } | ||
| 43 | bash-2.03$ cc test.c && objdump -D ./a.out | less | ||
| 44 | |||
| 45 | <...> | ||
| 46 | |||
| 47 | 08048318 <_start>: | ||
| 48 | 8048318: 31 ed xor %ebp,%ebp | ||
| 49 | 804831a: 5e pop %esi | ||
| 50 | 804831b: 89 e1 mov %esp,%ecx | ||
| 51 | 804831d: 83 e4 f8 and $0xfffffff8,%esp | ||
| 52 | 8048320: 50 push %eax | ||
| 53 | 8048321: 54 push %esp | ||
| 54 | 8048322: 52 push %edx | ||
| 55 | 8048323: 68 04 84 04 08 push $0x8048404 | ||
| 56 | 8048328: 68 98 82 04 08 push $0x8048298 | ||
| 57 | 804832d: 51 push %ecx | ||
| 58 | 804832e: 56 push %esi | ||
| 59 | 804832f: 68 c8 83 04 08 push $0x80483c8 | ||
| 60 | 8048334: e8 cf ff ff ff call 8048308 <_init+0x70> <=== | ||
| 61 | 8048339: f4 hlt | ||
| 62 | 804833a: 90 nop | ||
| 63 | 804833b: 90 nop | ||
| 64 | |||
| 65 | |||
| 66 | <...> | ||
| 67 | |||
| 68 | |||
| 69 | |||
| 70 | |||
| 71 | Even if the dynamic linker creates some basic stuffs before everything, | ||
| 72 | he first core function called is _start . | ||
| 73 | |||
| 74 | We can see that this function initialize the stack . Some things we have | ||
| 75 | to notice : | ||
| 76 | |||
| 77 | $0x8048404 : _fini() function offset in the .fini section | ||
| 78 | $0x8048298 : _init() function offset in the .init section | ||
| 79 | $0x80483c8 : main() function offset in the .text section | ||
| 80 | |||
| 81 | |||
| 82 | This information is pushed because it's used in the libc in the | ||
| 83 | __libc_start_main function . This libc function has to : | ||
| 84 | |||
| 85 | - call the constructors . | ||
| 86 | - call the main . | ||
| 87 | - call the destructors . | ||
| 88 | |||
| 89 | |||
| 90 | The call to the offset 0x8048308 points in the Procedure Linkage Table | ||
| 91 | (.plt section) . This section provides a way to transfert inter-object | ||
| 92 | calls . Remember we're trying to call the __libc_start_main function . | ||
| 93 | |||
| 94 | The PLT code for this entry is : | ||
| 95 | |||
| 96 | |||
| 97 | 080482c8 <.plt>: | ||
| 98 | 80482c8: ff 35 54 94 04 08 pushl 0x8049454 | ||
| 99 | 80482ce: ff 25 58 94 04 08 jmp *0x8049458 | ||
| 100 | 80482d4: 00 00 add %al,(%eax) | ||
| 101 | 80482d6: 00 00 add %al,(%eax) | ||
| 102 | 80482d8: ff 25 5c 94 04 08 jmp *0x804945c | ||
| 103 | 80482de: 68 00 00 00 00 push $0x0 | ||
| 104 | 80482e3: e9 e0 ff ff ff jmp 80482c8 <_init+0x30> | ||
| 105 | 80482e8: ff 25 60 94 04 08 jmp *0x8049460 | ||
| 106 | 80482ee: 68 08 00 00 00 push $0x8 | ||
| 107 | 80482f3: e9 d0 ff ff ff jmp 80482c8 <_init+0x30> | ||
| 108 | 80482f8: ff 25 64 94 04 08 jmp *0x8049464 | ||
| 109 | 80482fe: 68 10 00 00 00 push $0x10 | ||
| 110 | 8048303: e9 c0 ff ff ff jmp 80482c8 <_init+0x30> | ||
| 111 | 8048308: ff 25 68 94 04 08 jmp *0x8049468 *YOU ARE HERE* | ||
| 112 | 804830e: 68 18 00 00 00 push $0x18 | ||
| 113 | 8048313: e9 b0 ff ff ff jmp 80482c8 <_init+0x30> | ||
| 114 | |||
| 115 | |||
| 116 | |||
| 117 | We can see that our call in the PLT is followed by a JMP : | ||
| 118 | |||
| 119 | jmp *0x8049468 | ||
| 120 | |||
| 121 | The 0x8049468 offset is in the Global Offset Table (.got section) . The | ||
| 122 | stars means (for non x86 att syntax experts readers) that we are using | ||
| 123 | the four byte pointer at 0x8049468 as an offset . This offset in actually | ||
| 124 | retreivable from the Global Offset Table (GOT) . | ||
| 125 | |||
| 126 | In the beginning, the GOT offsets points on the following push (offset | ||
| 127 | 0x804830e : look at the objdump trace above) . At the moment , the GOT | ||
| 128 | in our process is said to be "empty", and is going to be filled as long | ||
| 129 | as the process calls remote functions (one entry is updated each time the | ||
| 130 | program calls this remote function *for the first time*) . | ||
| 131 | |||
| 132 | |||
| 133 | |||
| 134 | .got : | ||
| 135 | |||
| 136 | [00] 0x8049470 [01] (nil) | ||
| 137 | [02] (nil) [03] 0x80482de | ||
| 138 | [04] 0x80482ee [05] 0x80482fe | ||
| 139 | [06] 0x804830e [07] (nil) | ||
| 140 | |||
| 141 | |||
| 142 | The GOT is empty : every offsets point on a push instruction in | ||
| 143 | the procedure linkage table (.plt) . | ||
| 144 | |||
| 145 | |||
| 146 | |||
| 147 | We can see that the third first entries in the GOT have special values : | ||
| 148 | |||
| 149 | - The [0] entry contains the offset for the .dynamic section of | ||
| 150 | this object, it's used by the dynamic linker to know some | ||
| 151 | preferences and some very useful informations . Look at the | ||
| 152 | ELF reference for further details . Some stuff are also explained | ||
| 153 | in the dynamic linking related chapter of this tfile . | ||
| 154 | |||
| 155 | - The [1] one is the link_map structure offset associated with | ||
| 156 | this object, it's an internal structure in ld.so describing | ||
| 157 | a lot of interresting stuffs, I wont go in depth with it in this | ||
| 158 | paper . | ||
| 159 | |||
| 160 | - The [2] entry contains the runtime process fixup function offset | ||
| 161 | (pointing in the dynamic linking code zone). This pointer is used by | ||
| 162 | the first entry of the plt which is called when you want to launch | ||
| 163 | a remote (undefined) function for the first time . | ||
| 164 | |||
| 165 | |||
| 166 | The 2nd and 3rd entries are set to NULL at the beginning and are filled by | ||
| 167 | the dynamic linker before the process code segment starting function takes | ||
| 168 | control . These are filled in elf_machine_runtime_setup() in | ||
| 169 | sysdeps/i386/dl-machine.h . | ||
| 170 | |||
| 171 | With that mechanism, we have to execute three call instructions (if the | ||
| 172 | corresponding GOT entry has not been updated yet), or two call instructions | ||
| 173 | (if the GOT has been filled) . Remember that the GOT has been filled during | ||
| 174 | the first call on the corresponding function . Only external functions need | ||
| 175 | that mechanism, since only in-core code segment functions offsets are known | ||
| 176 | before the process start (the executable object base address is known) . | ||
| 177 | |||
| 178 | |||
| 179 | Get back to our code, we can see that this entry jumps to the 3rd offset of | ||
| 180 | the GOT entry, it means that the code calls the dynamic linker's resolution | ||
| 181 | function dl-resolve() . Some other papers have been describing useful | ||
| 182 | information gathering with it (check Nergal's phrack 58 or grugq's subversive | ||
| 183 | dynamic linking paper) | ||
| 184 | |||
| 185 | |||
| 186 | We can note that these 2 offsets are pushed each time a call is done via | ||
| 187 | the PLT : | ||
| 188 | |||
| 189 | - The first is an offset (in octets) in the .rel.plt section of the | ||
| 190 | program binary . It's used to identify the corresponding symbol for | ||
| 191 | the function we are trying to get the real absolute address . | ||
| 192 | - The second one is the offset contained in the 2nd GOT entry | ||
| 193 | (it's 0x8049454 in our code) . | ||
| 194 | |||
| 195 | This information allows us to identify the symbol for which we want to do | ||
| 196 | a relocation . Let's discover the runtime .got fixup offset with gdb and | ||
| 197 | the procfs : | ||
| 198 | |||
| 199 | |||
| 200 | bash-2.03$ gdb a.out | ||
| 201 | |||
| 202 | (gdb) b called | ||
| 203 | Breakpoint 1 at 0x80483b7 | ||
| 204 | |||
| 205 | (gdb) r | ||
| 206 | Starting program: /home/mayhem/a.out | ||
| 207 | Breakpoint 1, 0x80483b7 in called () | ||
| 208 | |||
| 209 | (gdb) disassemble called | ||
| 210 | Dump of assembler code for function called: | ||
| 211 | 0x80483b4 <called>: push %ebp | ||
| 212 | 0x80483b5 <called+1>: mov %esp,%ebp | ||
| 213 | 0x80483b7 <called+3>: push $0x8048428 | ||
| 214 | 0x80483bc <called+8>: call 0x80482e8 <puts> <======== LOOK HERE ! | ||
| 215 | 0x80483c1 <called+13>: add $0x4,%esp | ||
| 216 | 0x80483c4 <called+16>: leave | ||
| 217 | 0x80483c5 <called+17>: ret | ||
| 218 | 0x80483c6 <called+18>: mov %esi,%esi | ||
| 219 | End of assembler dump. | ||
| 220 | |||
| 221 | |||
| 222 | What is this routine ? | ||
| 223 | |||
| 224 | |||
| 225 | |||
| 226 | (gdb) x/3i 0x80482e8 | ||
| 227 | 0x80482e8 <puts>: jmp *0x8049460 | ||
| 228 | 0x80482ee <puts+6>: push $0x8 | ||
| 229 | 0x80482f3 <puts+11>: jmp 0x80482c8 <_init+48> | ||
| 230 | |||
| 231 | |||
| 232 | It's the procedure linkage table entry for this function, it uses offset | ||
| 233 | in the GOT . As the GOT is not yet filled, the offset is the 32 bits address | ||
| 234 | of the following push ("push $0x8") . This entry is going to be modified | ||
| 235 | by the dynamic linker as soon as the symbol resolution is done ( see | ||
| 236 | chapter 2) . | ||
| 237 | |||
| 238 | |||
| 239 | |||
| 240 | (gdb) x/1x 0x8049460 | ||
| 241 | 0x8049460 <_GLOBAL_OFFSET_TABLE_+16>: 0x080482ee | ||
| 242 | |||
| 243 | |||
| 244 | Each first time you call a remote function, the PLT first entry code | ||
| 245 | is executed : | ||
| 246 | |||
| 247 | |||
| 248 | (gdb) x/3i 0x80482c8 | ||
| 249 | 0x80482c8 <_init+48>: pushl 0x8049454 | ||
| 250 | 0x80482ce <_init+54>: jmp *0x8049458 | ||
| 251 | 0x80482d4 <_init+60>: add %al,(%eax) | ||
| 252 | |||
| 253 | |||
| 254 | This first entry uses the third entry of the GOT , then the dynamic | ||
| 255 | linker takes control : | ||
| 256 | |||
| 257 | |||
| 258 | (gdb) x/1x 0x8049458 | ||
| 259 | 0x8049458 <_GLOBAL_OFFSET_TABLE_+8>: 0x40009a10 | ||
| 260 | |||
| 261 | (gdb) | ||
| 262 | |||
| 263 | |||
| 264 | Let's see what is the library containing this function at the offset | ||
| 265 | 0x40009a10 . | ||
| 266 | |||
| 267 | |||
| 268 | bash-2.04$ pidof a.out | ||
| 269 | 7905 | ||
| 270 | bash-2.04$ cat /proc/7905/maps | ||
| 271 | 08048000-08049000 r-xp 00000000 03:01 135375 /home/mayhem/a.out | ||
| 272 | 08049000-0804a000 rw-p 00000000 03:01 135375 /home/mayhem/a.out | ||
| 273 | 40000000-40012000 r-xp 00000000 03:01 229408 /lib/ld-2.1.2.so <== *GOOD* | ||
| 274 | 40012000-40013000 rw-p 00011000 03:01 229408 /lib/ld-2.1.2.so | ||
| 275 | 40013000-40014000 rw-p 00000000 00:00 0 | ||
| 276 | 4001a000-400fb000 r-xp 00000000 03:01 229410 /lib/libc-2.1.2.so | ||
| 277 | 400fb000-400ff000 rw-p 000e0000 03:01 229410 /lib/libc-2.1.2.so | ||
| 278 | 400ff000-40102000 rw-p 00000000 00:00 0 | ||
| 279 | bfffe000-c0000000 rwxp fffff000 00:00 0 | ||
| 280 | bash-2.04$ | ||
| 281 | |||
| 282 | |||
| 283 | The wanted function is in the dynamic linker code segment, more precisely | ||
| 284 | in the _dl_runtime_fixup() function, in the sysdeps/i386/dl-machine.h | ||
| 285 | file . To be honest, i had difficulties to find it , because I could not | ||
| 286 | deduce the symbol giving its virtual address, and this for 2 reasons : | ||
| 287 | |||
| 288 | - The libc and the dynamic linker are stripped (the symbol table | ||
| 289 | and the debug information has been removed) . As a consequence, | ||
| 290 | I could get the function name from the symbol table . | ||
| 291 | |||
| 292 | - In a shared library, offsets are relative (actually it's | ||
| 293 | calculated from the beginning of the file, so you can't retreive | ||
| 294 | the absolute function addresses from the ld.so symbol table) . | ||
| 295 | You can do a "objdump -D /lib/libc.so.6" to see it by yourself . | ||
| 296 | |||
| 297 | Even if I had a symbol table, I could not have got the good offset . | ||
| 298 | I could have compare the first bytes of the function in the debugged | ||
| 299 | process and the library (ld.so) code segment to find some hexadecimal | ||
| 300 | sequences matching, but I prefered to read the sources . ;) | ||
| 301 | |||
| 302 | The solution is to calculate the relocation ourself, most of the | ||
| 303 | time we have : base_addr + symbol_value = runtime address . You | ||
| 304 | can get the base address from the procfs (if you have read access, | ||
| 305 | this is okay by default) and you can check the symbol's value | ||
| 306 | from the library's .dynsym section (list of exported symbols). | ||
| 307 | Note that you can retreive it from the symbol table (.symtab) | ||
| 308 | but this section may be removed from the shared library using | ||
| 309 | known basic tools like strip(3) . | ||
| 310 | |||
| 311 | |||
| 312 | Shoutouts to silvio and grugq ! | ||
| 313 | |||
| 314 | |||
| 315 | *EOF* | ||
| 316 | |||
| 317 | |||
| 318 | |||
| 319 | |||
| 320 | |||
| 321 | |||
| 322 | |||
| 323 | |||
| 324 | |||
diff --git a/other/wrez/tmp/foo.c b/other/wrez/tmp/foo.c new file mode 100644 index 0000000..51d4bd2 --- /dev/null +++ b/other/wrez/tmp/foo.c | |||
| @@ -0,0 +1,11 @@ | |||
| 1 | |||
| 2 | #include <stdio.h> | ||
| 3 | |||
| 4 | int | ||
| 5 | main (int argc, char *argv[]) | ||
| 6 | { | ||
| 7 | printf ("my home is my castle\n"); | ||
| 8 | printf ("my castle is my home\n"); | ||
| 9 | } | ||
| 10 | |||
| 11 | |||
diff --git a/other/wrez/tmp/memdump.c b/other/wrez/tmp/memdump.c new file mode 100644 index 0000000..3215d20 --- /dev/null +++ b/other/wrez/tmp/memdump.c | |||
| @@ -0,0 +1,249 @@ | |||
| 1 | /* memory dump utility | ||
| 2 | * -scut | ||
| 3 | */ | ||
| 4 | |||
| 5 | #include <sys/types.h> | ||
| 6 | #include <sys/ptrace.h> | ||
| 7 | #include <sys/wait.h> | ||
| 8 | #include <sys/user.h> | ||
| 9 | #include <errno.h> | ||
| 10 | #include <unistd.h> | ||
| 11 | #include <stdlib.h> | ||
| 12 | #include <stdio.h> | ||
| 13 | #include <libgen.h> /* basename */ | ||
| 14 | |||
| 15 | |||
| 16 | void | ||
| 17 | hexdump (unsigned char *data, unsigned int amount); | ||
| 18 | |||
| 19 | |||
| 20 | int | ||
| 21 | main (int argc, char *argv[]) | ||
| 22 | { | ||
| 23 | pid_t fpid; /* child pid, gets ptraced */ | ||
| 24 | char * argv0; | ||
| 25 | struct user regs; /* PTRACE pulled registers */ | ||
| 26 | unsigned long int addr, /* segment start address */ | ||
| 27 | addr_end, /* segment end address */ | ||
| 28 | len; /* length of segment */ | ||
| 29 | unsigned long int addr_walker, /* walker to dump memory */ | ||
| 30 | eip; /* current childs eip */ | ||
| 31 | |||
| 32 | /* array to temporarily store data into */ | ||
| 33 | unsigned char data_saved[sizeof (unsigned long int)]; | ||
| 34 | |||
| 35 | /* file to read mapping information */ | ||
| 36 | FILE * map_f; /* /proc/<pid>/maps stream */ | ||
| 37 | unsigned char map_line[256]; /* one line each from map */ | ||
| 38 | |||
| 39 | /* data for the dump files */ | ||
| 40 | FILE * dump_f; /* stream */ | ||
| 41 | char dump_name[64]; /* filename buffer */ | ||
| 42 | |||
| 43 | |||
| 44 | if (argc < 3 || sscanf (argv[1], "0x%lx", &eip) != 1) { | ||
| 45 | printf ("usage: %s <eip> <argv0 [argv1 [...]]>\n\n", argv[0]); | ||
| 46 | printf ("will run 'argv0' as program with given arguments, " | ||
| 47 | "until 'eip' is reached, then\n" | ||
| 48 | "dumping 'len' bytes from 'addr'.\n\n" | ||
| 49 | "example: %s 0x08049014 0x08048000 0x100 /bin/ls " | ||
| 50 | "-l\n\n", argv[0]); | ||
| 51 | |||
| 52 | exit (EXIT_FAILURE); | ||
| 53 | } | ||
| 54 | |||
| 55 | argv0 = argv[2]; | ||
| 56 | |||
| 57 | fpid = fork (); | ||
| 58 | if (fpid < 0) { | ||
| 59 | perror ("fork"); | ||
| 60 | exit (EXIT_FAILURE); | ||
| 61 | } | ||
| 62 | if (fpid == 0) { /* child */ | ||
| 63 | if (ptrace (PTRACE_TRACEME, 0, NULL, NULL) != 0) { | ||
| 64 | perror ("ptrace PTRACE_TRACEME"); | ||
| 65 | exit (EXIT_FAILURE); | ||
| 66 | } | ||
| 67 | fprintf (stderr, " child: TRACEME set\n"); | ||
| 68 | |||
| 69 | fprintf (stderr, " child: executing: %s\n", argv[2]); | ||
| 70 | close (1); | ||
| 71 | dup2 (2, 1); | ||
| 72 | execve (argv[2], &argv[2], NULL); | ||
| 73 | |||
| 74 | /* failed ? */ | ||
| 75 | perror ("execve"); | ||
| 76 | exit (EXIT_FAILURE); | ||
| 77 | } | ||
| 78 | |||
| 79 | wait (NULL); | ||
| 80 | |||
| 81 | memset (®s, 0, sizeof (regs)); | ||
| 82 | |||
| 83 | if (ptrace (PTRACE_GETREGS, fpid, NULL, ®s) < 0) { | ||
| 84 | perror ("ptrace PTRACE_GETREGS"); | ||
| 85 | exit (EXIT_FAILURE); | ||
| 86 | } | ||
| 87 | fprintf (stderr, "[0x%08lx] first stop\n", regs.regs.eip); | ||
| 88 | |||
| 89 | /* now single step until given eip is reached */ | ||
| 90 | do { | ||
| 91 | if (ptrace (PTRACE_SINGLESTEP, fpid, NULL, NULL) < 0) { | ||
| 92 | perror ("ptrace PTRACE_SINGLESTEP"); | ||
| 93 | exit (EXIT_FAILURE); | ||
| 94 | } | ||
| 95 | wait (NULL); | ||
| 96 | |||
| 97 | memset (®s, 0, sizeof (regs)); | ||
| 98 | if (ptrace (PTRACE_GETREGS, fpid, NULL, ®s) < 0) { | ||
| 99 | perror ("ptrace PTRACE_GETREGS"); | ||
| 100 | exit (EXIT_FAILURE); | ||
| 101 | } | ||
| 102 | } while (regs.regs.eip != eip); | ||
| 103 | |||
| 104 | fprintf (stderr, "MEMDUMP: eip @ 0x%08lx, dumping...\n", eip); | ||
| 105 | |||
| 106 | snprintf (dump_name, sizeof (dump_name), "%s.regs", | ||
| 107 | basename (argv0)); | ||
| 108 | dump_name[sizeof (dump_name) - 1] = '\0'; | ||
| 109 | dump_f = fopen (dump_name, "w"); | ||
| 110 | if (dump_f == NULL) { | ||
| 111 | perror ("fopen dumpfile regs"); | ||
| 112 | exit (EXIT_FAILURE); | ||
| 113 | } | ||
| 114 | fprintf (dump_f, "eax = 0x%08lx\n", regs.regs.eax); | ||
| 115 | fprintf (dump_f, "ebx = 0x%08lx\n", regs.regs.ebx); | ||
| 116 | fprintf (dump_f, "ecx = 0x%08lx\n", regs.regs.ecx); | ||
| 117 | fprintf (dump_f, "edx = 0x%08lx\n", regs.regs.edx); | ||
| 118 | fprintf (dump_f, "esi = 0x%08lx\n", regs.regs.esi); | ||
| 119 | fprintf (dump_f, "edi = 0x%08lx\n", regs.regs.edi); | ||
| 120 | fprintf (dump_f, "ebp = 0x%08lx\n", regs.regs.ebp); | ||
| 121 | fprintf (dump_f, "esp = 0x%08lx\n", regs.regs.esp); | ||
| 122 | fprintf (dump_f, "eflags = 0x%08lx\n", regs.regs.eflags); | ||
| 123 | fprintf (dump_f, "xcs = 0x%08lx\n", regs.regs.xcs); | ||
| 124 | fprintf (dump_f, "xds = 0x%08lx\n", regs.regs.xds); | ||
| 125 | fprintf (dump_f, "xes = 0x%08lx\n", regs.regs.xes); | ||
| 126 | fprintf (dump_f, "xss = 0x%08lx\n", regs.regs.xss); | ||
| 127 | fclose (dump_f); | ||
| 128 | |||
| 129 | snprintf (map_line, sizeof (map_line), "/proc/%d/maps", fpid); | ||
| 130 | map_line[sizeof (map_line) - 1] = '\0'; | ||
| 131 | map_f = fopen (map_line, "r"); | ||
| 132 | if (map_f == NULL) { | ||
| 133 | perror ("fopen map-file"); | ||
| 134 | |||
| 135 | exit (EXIT_FAILURE); | ||
| 136 | } | ||
| 137 | |||
| 138 | while (fgets (map_line, sizeof (map_line), map_f) != NULL) { | ||
| 139 | char map_perm[8]; | ||
| 140 | |||
| 141 | if (sscanf (map_line, "%08lx-%08lx %7[rwxp-] ", | ||
| 142 | &addr, &addr_end, map_perm) != 3) | ||
| 143 | { | ||
| 144 | perror ("invalid map-line"); | ||
| 145 | |||
| 146 | exit (EXIT_FAILURE); | ||
| 147 | } | ||
| 148 | if (addr_end < addr) { | ||
| 149 | fprintf (stderr, "sanity required, not so: " | ||
| 150 | "addr = 0x%08lx, addr_end = 0x%08lx", | ||
| 151 | addr, addr_end); | ||
| 152 | |||
| 153 | exit (EXIT_FAILURE); | ||
| 154 | } | ||
| 155 | len = addr_end - addr; | ||
| 156 | map_perm[sizeof (map_perm) - 1] = '\0'; /* ;-) */ | ||
| 157 | |||
| 158 | fprintf (stderr, "MEMDUMP: -> 0x%08lx (0x%08lx bytes, " | ||
| 159 | "perm %s)\n", addr, len, map_perm); | ||
| 160 | |||
| 161 | snprintf (dump_name, sizeof (dump_name), | ||
| 162 | "%s.0x%08lx.0x%08lx.%s", | ||
| 163 | basename (argv0), addr, len, map_perm); | ||
| 164 | dump_name[sizeof (dump_name) - 1] = '\0'; | ||
| 165 | dump_f = fopen (dump_name, "wb"); | ||
| 166 | if (dump_f == NULL) { | ||
| 167 | perror ("fopen dumpfile"); | ||
| 168 | |||
| 169 | exit (EXIT_FAILURE); | ||
| 170 | } | ||
| 171 | |||
| 172 | /* save data, assuming addr is page aligned */ | ||
| 173 | for (addr_walker = 0 ; addr_walker < len ; | ||
| 174 | addr_walker += sizeof (data_saved)) | ||
| 175 | { | ||
| 176 | errno = 0; | ||
| 177 | |||
| 178 | *((unsigned long int *) &data_saved[0]) = | ||
| 179 | ptrace (PTRACE_PEEKDATA, fpid, | ||
| 180 | addr + addr_walker, NULL); | ||
| 181 | |||
| 182 | if (errno == 0 && fwrite (&data_saved[0], 1, 4, | ||
| 183 | dump_f) != 4) | ||
| 184 | { | ||
| 185 | perror ("fwrite dumpfile"); | ||
| 186 | |||
| 187 | exit (EXIT_FAILURE); | ||
| 188 | } else if (errno != 0) { | ||
| 189 | fprintf (stderr, | ||
| 190 | "[0x%08lx] invalid PTRACE_PEEKDATA\n", | ||
| 191 | addr + addr_walker); | ||
| 192 | |||
| 193 | exit (EXIT_FAILURE); | ||
| 194 | } | ||
| 195 | } | ||
| 196 | |||
| 197 | fclose (dump_f); | ||
| 198 | } | ||
| 199 | fclose (map_f); | ||
| 200 | |||
| 201 | if (ptrace (PTRACE_DETACH, fpid, NULL, NULL) < 0) { | ||
| 202 | perror ("ptrace PTRACE_DETACH"); | ||
| 203 | exit (EXIT_FAILURE); | ||
| 204 | } | ||
| 205 | |||
| 206 | fprintf (stderr, "MEMDUMP: success. terminating.\n"); | ||
| 207 | exit (EXIT_SUCCESS); | ||
| 208 | } | ||
| 209 | |||
| 210 | |||
| 211 | |||
| 212 | void | ||
| 213 | hexdump (unsigned char *data, unsigned int amount) | ||
| 214 | { | ||
| 215 | unsigned int dp, p; /* data pointer */ | ||
| 216 | const char trans[] = | ||
| 217 | "................................ !\"#$%&'()*+,-./0123456789" | ||
| 218 | ":;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklm" | ||
| 219 | "nopqrstuvwxyz{|}~...................................." | ||
| 220 | "....................................................." | ||
| 221 | "........................................"; | ||
| 222 | |||
| 223 | for (dp = 1; dp <= amount; dp++) { | ||
| 224 | printf ("%02x ", data[dp-1]); | ||
| 225 | if ((dp % 8) == 0) | ||
| 226 | printf (" "); | ||
| 227 | if ((dp % 16) == 0) { | ||
| 228 | printf ("| "); | ||
| 229 | p = dp; | ||
| 230 | for (dp -= 16; dp < p; dp++) | ||
| 231 | printf ("%c", trans[data[dp]]); | ||
| 232 | printf ("\n"); | ||
| 233 | } | ||
| 234 | } | ||
| 235 | if ((amount % 16) != 0) { | ||
| 236 | p = dp = 16 - (amount % 16); | ||
| 237 | for (dp = p; dp > 0; dp--) { | ||
| 238 | printf (" "); | ||
| 239 | if (((dp % 8) == 0) && (p != 8)) | ||
| 240 | printf (" "); | ||
| 241 | } | ||
| 242 | printf (" | "); | ||
| 243 | for (dp = (amount - (16 - p)); dp < amount; dp++) | ||
| 244 | printf ("%c", trans[data[dp]]); | ||
| 245 | } | ||
| 246 | printf ("\n"); | ||
| 247 | |||
| 248 | return; | ||
| 249 | } | ||
diff --git a/other/wrez/tmp/ptrace-legit.c b/other/wrez/tmp/ptrace-legit.c new file mode 100644 index 0000000..a6c53d7 --- /dev/null +++ b/other/wrez/tmp/ptrace-legit.c | |||
| @@ -0,0 +1,143 @@ | |||
| 1 | /* -scutstyle */ | ||
| 2 | |||
| 3 | #include <sys/types.h> | ||
| 4 | #include <sys/ptrace.h> | ||
| 5 | #include <sys/wait.h> | ||
| 6 | #include <sys/user.h> | ||
| 7 | #include <unistd.h> | ||
| 8 | #include <stdlib.h> | ||
| 9 | #include <stdio.h> | ||
| 10 | |||
| 11 | void | ||
| 12 | hexdump (unsigned char *data, unsigned int amount); | ||
| 13 | |||
| 14 | unsigned char shellcode[] = "\x90\x90\xcc\x73"; | ||
| 15 | |||
| 16 | int | ||
| 17 | main (int argc, char *argv[]) | ||
| 18 | { | ||
| 19 | pid_t cpid; | ||
| 20 | struct user regs; | ||
| 21 | unsigned long int safed_eip; | ||
| 22 | unsigned long int addr, | ||
| 23 | addr_walker; | ||
| 24 | unsigned char data_saved[256]; | ||
| 25 | |||
| 26 | |||
| 27 | #if 1 | ||
| 28 | if (argc != 2 || sscanf (argv[1], "%d", &cpid) != 1) { | ||
| 29 | printf ("usage: %s <pid>\n", argv[0]); | ||
| 30 | exit (EXIT_FAILURE); | ||
| 31 | } | ||
| 32 | #else | ||
| 33 | cpid = getppid(); | ||
| 34 | #endif | ||
| 35 | |||
| 36 | printf ("pid = %d\n", cpid); | ||
| 37 | |||
| 38 | printf ("exploiting\n\n"); | ||
| 39 | |||
| 40 | if (ptrace (PTRACE_ATTACH, cpid, NULL, NULL) < 0) { | ||
| 41 | perror ("ptrace"); | ||
| 42 | exit (EXIT_FAILURE); | ||
| 43 | } | ||
| 44 | |||
| 45 | /* save data */ | ||
| 46 | addr = 0xbffff010; | ||
| 47 | for (addr_walker = 0 ; addr_walker < 256 ; ++addr_walker) { | ||
| 48 | data_saved[addr_walker] = ptrace (PTRACE_PEEKDATA, cpid, | ||
| 49 | addr + addr_walker, NULL); | ||
| 50 | } | ||
| 51 | hexdump (data_saved, sizeof (data_saved)); | ||
| 52 | |||
| 53 | /* write */ | ||
| 54 | for (addr_walker = 0 ; addr_walker < sizeof (shellcode) ; | ||
| 55 | ++addr_walker) | ||
| 56 | { | ||
| 57 | ptrace (PTRACE_POKEDATA, cpid, addr + addr_walker, | ||
| 58 | shellcode[addr_walker] & 0xff); | ||
| 59 | } | ||
| 60 | |||
| 61 | /* redirect eip */ | ||
| 62 | memset (®s, 0, sizeof (regs)); | ||
| 63 | if (ptrace (PTRACE_GETREGS, cpid, NULL, ®s) < 0) { | ||
| 64 | perror ("ptrace PTRACE_GETREGS"); | ||
| 65 | exit (EXIT_FAILURE); | ||
| 66 | } | ||
| 67 | // write eip */ | ||
| 68 | safed_eip = regs.regs.eip; | ||
| 69 | regs.regs.eip = 0xbffff010; | ||
| 70 | if (ptrace (PTRACE_SETREGS, cpid, NULL, ®s) < 0) { | ||
| 71 | perror ("ptrace PTRACE_GETREGS"); | ||
| 72 | exit (EXIT_FAILURE); | ||
| 73 | } | ||
| 74 | |||
| 75 | if (ptrace (PTRACE_CONT, cpid, NULL, NULL) < 0) { | ||
| 76 | perror ("ptrace PTRACE_CONT"); | ||
| 77 | exit (EXIT_FAILURE); | ||
| 78 | } | ||
| 79 | |||
| 80 | wait (NULL); | ||
| 81 | printf ("detrap\n"); | ||
| 82 | |||
| 83 | /* restore */ | ||
| 84 | for (addr_walker = 0 ; addr_walker < 256 ; ++addr_walker) { | ||
| 85 | ptrace (PTRACE_POKEDATA, cpid, addr + addr_walker, | ||
| 86 | data_saved[addr_walker] & 0xff); | ||
| 87 | } | ||
| 88 | |||
| 89 | /* restore regs */ | ||
| 90 | regs.regs.eip = safed_eip; | ||
| 91 | if (ptrace (PTRACE_SETREGS, cpid, NULL, ®s) < 0) { | ||
| 92 | perror ("ptrace PTRACE_GETREGS"); | ||
| 93 | exit (EXIT_FAILURE); | ||
| 94 | } | ||
| 95 | |||
| 96 | if (ptrace (PTRACE_DETACH, cpid, NULL, NULL) < 0) { | ||
| 97 | perror ("ptrace PTRACE_DETACH"); | ||
| 98 | exit (EXIT_FAILURE); | ||
| 99 | } | ||
| 100 | |||
| 101 | exit (EXIT_SUCCESS); | ||
| 102 | } | ||
| 103 | |||
| 104 | |||
| 105 | |||
| 106 | void | ||
| 107 | hexdump (unsigned char *data, unsigned int amount) | ||
| 108 | { | ||
| 109 | unsigned int dp, p; /* data pointer */ | ||
| 110 | const char trans[] = | ||
| 111 | "................................ !\"#$%&'()*+,-./0123456789" | ||
| 112 | ":;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklm" | ||
| 113 | "nopqrstuvwxyz{|}~...................................." | ||
| 114 | "....................................................." | ||
| 115 | "........................................"; | ||
| 116 | |||
| 117 | for (dp = 1; dp <= amount; dp++) { | ||
| 118 | printf ("%02x ", data[dp-1]); | ||
| 119 | if ((dp % 8) == 0) | ||
| 120 | printf (" "); | ||
| 121 | if ((dp % 16) == 0) { | ||
| 122 | printf ("| "); | ||
| 123 | p = dp; | ||
| 124 | for (dp -= 16; dp < p; dp++) | ||
| 125 | printf ("%c", trans[data[dp]]); | ||
| 126 | printf ("\n"); | ||
| 127 | } | ||
| 128 | } | ||
| 129 | if ((amount % 16) != 0) { | ||
| 130 | p = dp = 16 - (amount % 16); | ||
| 131 | for (dp = p; dp > 0; dp--) { | ||
| 132 | printf (" "); | ||
| 133 | if (((dp % 8) == 0) && (p != 8)) | ||
| 134 | printf (" "); | ||
| 135 | } | ||
| 136 | printf (" | "); | ||
| 137 | for (dp = (amount - (16 - p)); dp < amount; dp++) | ||
| 138 | printf ("%c", trans[data[dp]]); | ||
| 139 | } | ||
| 140 | printf ("\n"); | ||
| 141 | |||
| 142 | return; | ||
| 143 | } | ||
diff --git a/other/wrez/tmp/str.c b/other/wrez/tmp/str.c new file mode 100644 index 0000000..d822f20 --- /dev/null +++ b/other/wrez/tmp/str.c | |||
| @@ -0,0 +1,30 @@ | |||
| 1 | |||
| 2 | #include <stdio.h> | ||
| 3 | |||
| 4 | #define STRINGPTR(dst,string) \ | ||
| 5 | { \ | ||
| 6 | register unsigned char * regtmp; \ | ||
| 7 | \ | ||
| 8 | __asm__ __volatile__ ( \ | ||
| 9 | " call l0_%=\n\t" \ | ||
| 10 | " .ascii \""##string"\"\n\t" \ | ||
| 11 | " .byte 0x00\n\t" \ | ||
| 12 | "l0_%=: popl %%eax\n\t" \ | ||
| 13 | : "=a" (regtmp)); \ | ||
| 14 | \ | ||
| 15 | (dst) = regtmp; \ | ||
| 16 | } | ||
| 17 | |||
| 18 | |||
| 19 | int | ||
| 20 | main (int argc, char *argv[]) | ||
| 21 | { | ||
| 22 | char * foo; | ||
| 23 | |||
| 24 | |||
| 25 | STRINGPTR(foo,"foobarcow"); | ||
| 26 | |||
| 27 | printf ("%s\n", foo); | ||
| 28 | } | ||
| 29 | |||
| 30 | |||
