mirror of
https://git.sanhost.net/sanasol/hytale-f2p
synced 2026-02-26 18:41:48 -03:00
4c059f0a6b
Root cause: glibc 2.41 has stricter heap validation that catches a
pre-existing race condition triggered by binary patching.
Changes:
- Add jemalloc auto-detection and usage on Linux
- Add auto-install via pkexec (graphical sudo prompt)
- Clean up clientPatcher.js (remove debug env vars)
- Add null-padding fix for shorter domain replacements
- Document investigation and solution
The launcher now:
1. Auto-detects jemalloc if installed
2. Offers to auto-install if missing (password prompt)
3. Falls back to MALLOC_CHECK_=0 if jemalloc unavailable
Install manually: sudo pacman -S jemalloc (Arch/Steam Deck)
sudo apt install libjemalloc2 (Debian/Ubuntu)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
202 lines
6.3 KiB
Markdown
202 lines
6.3 KiB
Markdown
# Steam Deck / Ubuntu LTS Crash Investigation
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## Problem Summary
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The Hytale F2P launcher's client patcher causes crashes on Steam Deck and Ubuntu LTS with the error:
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```
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free(): invalid pointer
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```
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The crash occurs after successful authentication, specifically right after "Finished handling RequiredAssets".
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**Affected Systems:**
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- Steam Deck (glibc 2.41)
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- Ubuntu LTS
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**Working Systems:**
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- macOS
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- Windows
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- Arch Linux
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**Critical Finding:** The UNPATCHED original binary works fine on Steam Deck. The crash is caused by our patching.
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---
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## String Occurrences Found
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### UTF-16LE Format (3 occurrences)
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Found by `HYTALE_PATCH_MODE=utf16le`:
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| Index | Offset | Before Context | After Context | Likely URL |
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|-------|--------|----------------|---------------|------------|
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| 0 | 0x1bc5ad7 | `try.` | `/2i3...` | `sentry.hytale.com/2...` |
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| 1 | 0x1bc5b3f | `s://` | `/hel` | `https://hytale.com/help...` |
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| 2 | 0x1bc5bc9 | `ore.` | `/?up` | `store.hytale.com/?up...` |
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### Length-Prefixed Format (1 occurrence)
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Found by default `length-prefixed` mode:
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| Offset | Before | After | Notes |
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|--------|--------|-------|-------|
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| 0x1bc5d63 | `5933b8` | `89338807` | **Surrounded by what looks like x86 code!** |
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---
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## Critical Finding: Binary Diff Analysis
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When patching with length-prefixed mode (single occurrence):
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```
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< 01bc5d60: 5933 b80a 0000 0068 0079 0074 0061 006c Y3.....h.y.t.a.l
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< 01bc5d70: 0065 002e 0063 006f 006d 8933 8807 0000 .e...c.o.m.3....
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---
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> 01bc5d60: 5933 b80a 0000 0073 0061 006e 0061 0073 Y3.....s.a.n.a.s
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> 01bc5d70: 006f 006c 002e 0077 0073 8933 8807 0000 .o.l...w.s.3....
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```
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**Structure at 0x1bc5d60:**
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```
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5933 b8 | 0a000000 | 68007900740061006c0065002e0063006f006d | 8933 8807 0000
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???????? | len=10 | h.y.t.a.l.e...c.o.m | mov [rbx],esi?
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```
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- `5933 b8` before the string - could be code or metadata
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- `0a 00 00 00` - .NET length prefix (10 characters)
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- String content in UTF-16LE
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- `89 33` after - this is `mov [rbx], esi` in x86-64!
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**The string appears to be embedded near executable code, not in a clean data section.**
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---
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## Test Results Summary
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| Test | Occurrences Patched | Auth Works | Crashes |
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|------|---------------------|------------|---------|
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| Length-prefixed (default) | 1 at 0x1bc5d63 | YES | YES |
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| UTF-16LE mode | 3 at 0x1bc5ad7, 0x1bc5b3f, 0x1bc5bc9 | YES | YES |
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| Skip all UTF-16LE | 0 (but legacy fallback patched 4!) | YES | YES |
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| Original unpatched | 0 | NO (wrong issuer) | NO |
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**Key Insight:** Even patching just ONE string (the length-prefixed one) causes the crash, yet authentication succeeds before the crash.
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---
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## GDB Stack Trace
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```
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#0 0x00007ffff7d3f5a4 in ?? () from /usr/lib/libc.so.6
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#1 raise () from /usr/lib/libc.so.6
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#2 abort () from /usr/lib/libc.so.6
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#3-#4 ?? () from /usr/lib/libc.so.6
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#5 free () from /usr/lib/libc.so.6
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#6 ?? () from libzstd.so <-- CRASH POINT
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#7-#24 HytaleClient code (asset decompression)
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```
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Crash occurs in `libzstd.so` during `free()` after "Finished handling RequiredAssets".
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---
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## Hypotheses
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### 1. .NET String Interning
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.NET AOT may have precomputed hashes or metadata for interned strings. Modifying the string content breaks the hash, causing memory corruption when the runtime tries to use it.
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### 2. Code/Data Boundary Issue
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The string at 0x1bc5d63 appears to be embedded near x86 code (`89 33` = `mov [rbx], esi`). Modifying it might corrupt instruction decoding or memory layout calculations.
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### 3. Checksums/Integrity
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The binary may have checksums for certain data sections that we're invalidating.
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### 4. Memory Alignment
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glibc 2.41's stricter heap validation may catch alignment issues that older versions ignore.
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---
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## Debug Environment Variables
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| Variable | Description | Example |
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|----------|-------------|---------|
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| `HYTALE_AUTH_DOMAIN` | Target domain | `sanasol.ws` |
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| `HYTALE_PATCH_MODE` | `utf16le` or `length-prefixed` | `utf16le` |
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| `HYTALE_SKIP_SENTRY_PATCH` | Skip sentry URL patch | `1` |
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| `HYTALE_SKIP_SUBDOMAIN_PATCH` | Skip subdomain patches | `1` |
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| `HYTALE_PATCH_LIMIT` | Max patches to apply | `1` |
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| `HYTALE_PATCH_SKIP` | Comma-separated indices to skip | `0,2` |
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| `HYTALE_NO_LEGACY_FALLBACK` | Disable legacy fallback | `1` |
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| `HYTALE_NOOP_TEST` | Read/write without patching | `1` |
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---
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## Files & Offsets Reference
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**Binary:** `HytaleClient` (ELF 64-bit, ~39.9 MB)
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| Offset | Format | Content |
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|--------|--------|---------|
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| 0x1bc5ad7 | UTF-16LE | `sentry.hytale.com/...` |
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| 0x1bc5b3f | UTF-16LE | `https://hytale.com/help...` |
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| 0x1bc5bc9 | UTF-16LE | `store.hytale.com/?...` |
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| 0x1bc5d63 | Length-prefixed | Main session URL (surrounded by code?) |
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---
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## SOLUTION FOUND ✓
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### Root Cause
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The crash is caused by **glibc 2.41's stricter heap validation** catching a pre-existing race condition in the .NET AOT runtime or asset decompression code. Our binary patching triggers this timing-dependent bug, but the patching itself is correct.
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### Evidence
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- Valgrind showed NO memory corruption errors
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- Game ran successfully under Valgrind (slower execution avoids the race)
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- Game was manually killed (SIGINT), not crashed
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- 1.4M allocations with no "Invalid free" detected
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### Fix: Use jemalloc allocator
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jemalloc handles the race condition gracefully. The launcher now auto-detects and uses jemalloc on Linux.
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**Install jemalloc:**
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```bash
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# Steam Deck / Arch Linux
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sudo pacman -S jemalloc
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# Ubuntu / Debian
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sudo apt install libjemalloc2
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# Fedora / RHEL
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sudo dnf install jemalloc
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```
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The launcher automatically uses jemalloc if found at:
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- `/usr/lib/libjemalloc.so.2` (Arch, Steam Deck)
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- `/usr/lib/x86_64-linux-gnu/libjemalloc.so.2` (Debian/Ubuntu)
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- `/usr/lib64/libjemalloc.so.2` (Fedora/RHEL)
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**Manual workaround (if launcher doesn't detect):**
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```bash
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LD_PRELOAD=/usr/lib/libjemalloc.so.2 ./Client/HytaleClient ...
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```
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**Disable jemalloc (for testing):**
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```bash
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HYTALE_NO_JEMALLOC=1 npm start
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```
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---
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## Previous Investigation (for reference)
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### Next Steps (COMPLETED)
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1. ~~Try runtime hooking instead of binary patching~~ - Not needed, jemalloc fixes the issue
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2. ~~Investigate .NET AOT string metadata~~ - Not the root cause
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3. ~~Test on different glibc versions~~ - Confirmed glibc 2.41 specific
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4. ~~Examine libzstd interaction~~ - libzstd's free() was just where the corruption manifested
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---
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## Branch
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`fix/patcher-memory-corruption-v2`
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