Aborted in CWriter::MangleType at wasm2c

[Q1IQ]

Title

Aborted in CWriter::MangleType at wasm2c

Environment

OS      : Linux ubuntu 5.15.0-46-generic #49~20.04.1-Ubuntu SMP Thu Aug 4 19:15:44 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Commit  : 3054d61f703d609995798f872fc86b462617c294
Version : 1.0.29
Build   : make clang-debug-asan

Proof of concept

poc.wasm2c-2.wasm poc_wasm2c-2.wasm.zip

Stack dump

gdb /wabt/out/clang/Debug/asan/wasm2c
pwndbg> r  --enable-multi-memory ./poc.wasm2c-2.wasm
context:
 LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
─────────────────────────────────[ REGISTERS ]──────────────────────────────────
 RAX  0x0
*RBX  0x7ffff7a357c0 ◂— 0x7ffff7a357c0
*RCX  0x7ffff7a7b00b (raise+203) —▸ 0x10824848b48 ◂— 0x0
 RDX  0x0
*RDI  0x2
*RSI  0x7fffffff9a90 ◂— 0x0
 R8   0x0
*R9   0x7fffffff9a90 ◂— 0x0
*R10  0x8
*R11  0x246
*R12  0x43e420 (_start) ◂— endbr64
*R13  0x7fffffffe070 ◂— 0x3
 R14  0x0
 R15  0x0
*RBP  0x7fffffff9df0 —▸ 0x7fffffffa270 —▸ 0x7fffffffa3c0 —▸ 0x7fffffffa690 —▸ 0x7fffffffc3c0 ◂— ...
*RSP  0x7fffffff9a90 ◂— 0x0
*RIP  0x7ffff7a7b00b (raise+203) —▸ 0x10824848b48 ◂— 0x0
───────────────────────────────────[ DISASM ]───────────────────────────────────
 ► 0x7ffff7a7b00b <raise+203>    mov    rax, qword ptr [rsp + 0x108]
   0x7ffff7a7b013 <raise+211>    xor    rax, qword ptr fs:[0x28]
   0x7ffff7a7b01c <raise+220>    jne    raise+260                <raise+260>
    ↓
   0x7ffff7a7b044 <raise+260>    call   __stack_chk_fail                <__stack_chk_fail>

   0x7ffff7a7b049                nop    dword ptr [rax]
   0x7ffff7a7b050 <killpg>       endbr64
   0x7ffff7a7b054 <killpg+4>     test   edi, edi
   0x7ffff7a7b056 <killpg+6>     js     killpg+16                <killpg+16>

   0x7ffff7a7b058 <killpg+8>     neg    edi
   0x7ffff7a7b05a <killpg+10>    jmp    kill                <kill>

   0x7ffff7a7b05f <killpg+15>    nop
───────────────────────────────────[ STACK ]────────────────────────────────────
00:0000│ rsi r9 rsp 0x7fffffff9a90 ◂— 0x0
01:0008│            0x7fffffff9a98 ◂— 0xfffffffffffffffb
02:0010│            0x7fffffff9aa0 —▸ 0x757525 ◂— cli
03:0018│            0x7fffffff9aa8 ◂— 0x0
... ↓               4 skipped
─────────────────────────────────[ BACKTRACE ]──────────────────────────────────
 ► f 0   0x7ffff7a7b00b raise+203
   f 1   0x7ffff7a5a859 abort+299
   f 2         0x5074f0
   f 3         0x52cebf
   f 4         0x545a44
   f 5         0x535a2f
   f 6         0x528543
   f 7         0x51dd51
────────────────────────────────────────────────────────────────────────────────
backtrace_msg:
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007ffff7a5a859 in __GI_abort () at abort.c:79
#2  0x00000000005074f0 in wabt::(anonymous namespace)::CWriter::MangleType (type=...) at ../../../../src/c-writer.cc:427
#3  0x000000000052cebf in wabt::(anonymous namespace)::CWriter::Write (this=0x7fffffffce30, sv=...) at ../../../../src/c-writer.cc:701
#4  0x0000000000545a44 in wabt::(anonymous namespace)::CWriter::Write<wabt::(anonymous namespace)::StackVar, char const (&) [4], char const*, char const (&) [2], wabt::(anonymous namespace)::Name<2>, char const (&) [9], wabt::(anonymous namespace)::StackVar> (this=0x7fffffffce30, t=..., u=..., args=..., args=..., args=..., args=..., args=...) at ../../../../src/c-writer.cc:204
#5  0x0000000000535a2f in wabt::(anonymous namespace)::CWriter::Write (this=0x7fffffffce30, expr=warning: RTTI symbol not found for class 'wabt::LoadStoreExpr<(wabt::ExprType)47>'
...) at ../../../../src/c-writer.cc:2752
#6  0x0000000000528543 in wabt::(anonymous namespace)::CWriter::Write (this=0x7fffffffce30, exprs=...) at ../../../../src/c-writer.cc:2043
#7  0x000000000051dd51 in wabt::(anonymous namespace)::CWriter::Write<wabt::intrusive_list<wabt::Expr> const&, wabt::(anonymous namespace)::LabelDecl> (this=0x7fffffffce30, t=..., u=...) at ../../../../src/c-writer.cc:204
#8  0x000000000051bd15 in wabt::(anonymous namespace)::CWriter::Write (this=0x7fffffffce30, func=...) at ../../../../src/c-writer.cc:1423
#9  0x000000000051b647 in wabt::(anonymous namespace)::CWriter::Write<wabt::(anonymous namespace)::Newline, wabt::Func const&, wabt::(anonymous namespace)::Newline> (this=0x7fffffffce30, t=..., u=..., args=...) at ../../../../src/c-writer.cc:205
#10 0x000000000051182d in wabt::(anonymous namespace)::CWriter::WriteFuncs (this=0x7fffffffce30) at ../../../../src/c-writer.cc:1393
#11 0x0000000000500bf4 in wabt::(anonymous namespace)::CWriter::WriteCSource (this=0x7fffffffce30) at ../../../../src/c-writer.cc:2794
#12 0x00000000004ffcd7 in wabt::(anonymous namespace)::CWriter::WriteModule (this=0x7fffffffce30, module=...) at ../../../../src/c-writer.cc:2807
#13 0x00000000004ff48d in wabt::WriteC (c_stream=0x7fffffffdaa0, h_stream=0x7fffffffdaa0, header_name=0x7ccce0 <str> "wasm.h", module=0x7fffffffd2b0, options=...) at ../../../../src/c-writer.cc:2819
#14 0x00000000004f11b4 in ProgramMain (argc=3, argv=0x7fffffffe078) at ../../../../src/tools/wasm2c.cc:179
#15 0x00000000004f37f2 in main (argc=3, argv=0x7fffffffe078) at ../../../../src/tools/wasm2c.cc:190
#16 0x00007ffff7a5c083 in __libc_start_main (main=0x4f37d0 <main(int, char**)>, argc=3, argv=0x7fffffffe078, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe068) at ../csu/libc-start.c:308
#17 0x000000000043e44e in _start ()

[keithw]

wasm2c currently aborts on any SIMD instructions or types. Probably it should configure the validator to disable SIMD (or we should implement SIMD in wasm2c).

[keithw]

Will be fixed by #2021

[keithw]

Fixed by #2119

[rathann]

CVE-2023-27116 for the record.

[keithw]

This particular one is a bit silly -- a well-detected unsupported feature (in this case, it was SIMD) doesn't represent a security vulnerability, even if the program is missing a helpful error message. I suspect if wasm2c threw exceptions instead of aborting (and had a descriptive error message), nobody would have been confused here. But, MITRE didn't ask our opinion before issuing the CVE, and I imagine the reporter here was eager to have a CVE credited to them. :-/