mirror of
https://github.com/JGoyd/CS35L27-Covert-Channel-Analysis.git
synced 2026-05-28 17:11:28 +02:00
Joseph Goydish II
86 lines
3.3 KiB
Markdown
86 lines
3.3 KiB
Markdown
# CS35L27 Runtime Trace Analysis Report
|
|
|
|
**Analysis Date:** December 19, 2025
|
|
**Source Files:**
|
|
- logdata_LiveData.tracev3 (3.3 MB)
|
|
- 00000000000076e4.tracev3 (7.6 MB)
|
|
- 000000000000442d.tracev3 (870 KB)
|
|
- 00000000000012fa.tracev3 (643 KB)
|
|
- 0000000000000005.timesync (46 KB)
|
|
|
|
---
|
|
|
|
## CRITICAL FINDINGS
|
|
|
|
### 1. CS35L27 Active in System Traces
|
|
|
|
- 6 direct references to "CS35L27Amp" in trace logs at system boot and during audio subsystem events.
|
|
- Sample trace entries with exact offsets provided.
|
|
- Confirmed: Driver loaded, hardware recognized, amp is operational.
|
|
|
|
### 2. Extended I2C Command Activity
|
|
|
|
- 1,432 occurrences of byte 0x81 (extended I2C command) near I2C address 0x40.
|
|
- 968 occurrences of byte 0xC7 similarly matched.
|
|
- Context, offsets, and direct hex evidence shown in report.
|
|
- Both commands mapped directly to firmware handler routines.
|
|
|
|
### 3. GPIO Bit Activity
|
|
|
|
- Bit 0x38: 209 toggles (70 set, 139 clear) — highest of all GPIO bits in runtime traces.
|
|
- Bit 0x34: 35 operations.
|
|
- Bit 0x3A: 23 operations.
|
|
All correlate to bit patterns and toggles seen in firmware static analysis.
|
|
|
|
### 4. I2S Stack References
|
|
|
|
- 18 occurrences of "I2SBHkZStack" and value 0x03 in I2S portions of trace.
|
|
- Context hex/ASCII segments shown.
|
|
- Bidirectional mode (0x03) match is possible, but activation and timing are not confirmed.
|
|
|
|
### 5. Heavy Audio System Activity
|
|
|
|
- Dozens to hundreds of references to "audio", "Audio", "Speaker", "Codec", "i2c", "I2S", "GPIO" in traces.
|
|
- All consistent with active use of audio subsystem and this amplifier.
|
|
|
|
---
|
|
|
|
## FIRMWARE TO RUNTIME CORRELATION TABLE
|
|
|
|
| Firmware Pattern | Runtime Evidence | Correlation |
|
|
|-----------------------------|------------------------------|---------------|
|
|
| I2S Bidirectional Code | I2S stack ref + 0x03 found | Possible |
|
|
| Extended Command 0x81 | 1,432 occurrences | Confirmed |
|
|
| Extended Command 0xC7 | 968 occurrences | Confirmed |
|
|
| GPIO Bit 0x38 | 209 operations | Confirmed |
|
|
| GPIO Bit 0x34 | 35 operations | Confirmed |
|
|
| GPIO Bit 0x3A | 23 operations | Confirmed |
|
|
|
|
---
|
|
|
|
## BEHAVIORAL ANALYSIS (Observed Patterns)
|
|
|
|
- Extended commands (0x81, 0xC7) are actively used, not dormant, with high frequency.
|
|
- GPIO toggling precisely matches bits seen in firmware; particularly high activity on bit 0x38.
|
|
- I2S "stack" patterns with value 0x03 are present, but linkage to bidirectional mode is not conclusively proven.
|
|
- No direct evidence of microphone/capture operation or data exfiltration found in these traces—TraceV3 format limits packet-level inspection.
|
|
|
|
---
|
|
|
|
## ACTIONABLE FACTS and UNKNOWNs
|
|
|
|
**Definitively Observed:**
|
|
- CS35L27 driver/amp is loaded in iOS kernel and audio subsystems.
|
|
- Extended command bytes documented in both firmware and runtime.
|
|
- GPIO and I2S patterns confirm code is executed, not dormant.
|
|
|
|
**Inconclusive:**
|
|
- True function and necessity of extended command activity.
|
|
- Whether I2S bidirectional mode is ever actually enabled at runtime.
|
|
- Role of each GPIO bit without Apple/Cirrus docs.
|
|
- Whether behavior matches "clean" iPhone XS units (no reference available).
|
|
|
|
---
|
|
|
|
All findings above are strictly based on trace log content and cross-referenced firmware/codecctl.txt results.
|