fix: cap fs_read_bytes allocation and __hl_sleep duration - #33
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Signed-off-by: danbugs <danilochiarlone@gmail.com>
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Pull request overview
Adds upper bounds to two guest-controlled resource operations to prevent host resource exhaustion: a 16 MiB cap on fs_read_bytes allocations and a 60-second cap on __hl_sleep durations.
Changes:
- Introduce
MAX_FS_READ(16 MiB) andMAX_SLEEP_NS(60 s) constants and apply them via.min()in the three relevant handlers (FsSandbox::register,FsRouter::register,register_internal_tools). - Add unit tests
test_fs_read_bytes_cappedandtest_sleep_capped.
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Linux Benchmarks
Details
| Benchmark suite | Current: e6e011c | Previous: 79b32ae | Ratio |
|---|---|---|---|
hello_world (median) |
20 ms |
20 ms |
1 |
pandas (median) |
110 ms |
100 ms |
1.10 |
density (per VM) |
7 MB |
7 MB |
1 |
snapshot (disk) |
385 MiB |
385 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
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Windows Benchmarks
Details
| Benchmark suite | Current: e6e011c | Previous: 79b32ae | Ratio |
|---|---|---|---|
hello_world (median) |
213 ms |
234 ms |
0.91 |
pandas (median) |
626 ms |
708 ms |
0.88 |
density (per VM) |
6 MB |
6 MB |
1 |
snapshot (disk) |
393 MiB |
393 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
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Summary
Two guest-controlled resource exhaustion vectors:
fs_read_bytesallocatedvec![0u8; len]with no upper bound — a guestsending
len: 999999999999would attempt a ~1 TB host allocation. Now cappedat 16 MiB (
MAX_FS_READ), matching the patternnet_recvalready uses.__hl_sleepcalledthread::sleep(Duration::from_nanos(ns))with no cap — aguest could block the host thread for up to 584 years. Now capped at 60 seconds
(
MAX_SLEEP_NS).Both caps applied in FsSandbox::register and FsRouter::register (fs) and
register_internal_tools (sleep).
Test plan
test_fs_read_bytes_capped— request 1 TiB read on 5-byte file, completes without OOMtest_sleep_capped— cap constant verified, handler dispatches successfully