iovisor / ubpf / 21459857185

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Commit Message

Add bounds checking to x86_64 JIT compiler for load/store operations (#721)

* Implement bounds checking for load/store operations in x86-64 JIT compiler

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Add bounds checking for x86_64 JIT compiler - initial implementation

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix register offset calculations in bounds check, verify basic JIT works

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix stack base calculation for BasicJitMode and error path stack cleanup

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix all 5 review comments: remove unused function, fix register loading, use patchable jumps, fix stack cleanup, reserve parameter storage

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix 5 new review comments: use R11 for address, fix stack alignment, clean up comments, fix error return, fix type signatures

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix 6 new review comments: use R10 for address, add atomic bounds checks, fix formatting, add error patterns to tests

Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

* Fix JIT bounds checking register save/restore order and disable by default

The JIT bounds checking implementation had issues with register corruption:
1. Registers were being computed into before being saved
2. R10 (mapped to BPF_REG_1 on Windows) was not being properly restored
3. Stack offsets for accessing saved registers were incorrect

Fixed by:
- Save all volatile registers BEFORE computing the effective address
- Load saved register values from stack if addr_reg was pushed
- Fix stack layout comments and offsets for both Windows and Linux
- Properly restore R10 by popping instead of discarding

Since the JIT bounds checking is still not fully working (tests... (continued)

Run Details

21 of 141 new or added lines in 2 files covered. (14.89%)

32 existing lines in 2 files now uncovered.

6334 of 8268 relevant lines covered (76.61%)

533328.55 hits per line