Safety Validation

caro includes a comprehensive safety validation system to prevent dangerous command execution.

Risk Levels

Commands are categorized into four risk levels:

Level	Color	Description	Examples
Safe	Green	Normal read operations	ls, cat, find, grep
Moderate	Yellow	File modifications	mv, cp, chmod (non-system)
High	Orange	System-level changes	sudo, chown, system paths
Critical	Red	Blocked - dangerous	rm -rf /, fork bombs

Dangerous Pattern Detection

Filesystem Destruction

# These patterns are BLOCKED:
rm -rf /
rm -rf ~
rm -rf /*
rm -rf /home
rm -rf /usr
rm -rf /bin
rm -rf /etc

Disk Operations

# These patterns are BLOCKED:
dd if=/dev/zero of=/dev/sda
mkfs.ext4 /dev/sda
> /dev/sda
shred /dev/sda

Fork Bombs

# These patterns are BLOCKED:
:(){ :|:& };:
bomb() { bomb | bomb & }; bomb
while true; do $0 & done

Privilege Escalation

# These patterns are flagged HIGH risk:
sudo su -
sudo bash
chmod 777 /
chmod -R 777 /etc

System Path Modifications

# Operations on these paths are flagged HIGH risk:
/bin/
/sbin/
/usr/bin/
/usr/sbin/
/etc/
/var/
/boot/

Validation Pipeline

┌─────────────┐     ┌───────────────┐     ┌──────────────┐
│  Generated  │────▶│   Pattern     │────▶│   Path       │
│   Command   │     │   Matching    │     │  Validation  │
└─────────────┘     └───────────────┘     └──────────────┘
                                                 │
                                                 ▼
                    ┌───────────────┐     ┌──────────────┐
                    │   Risk Level  │◀────│   POSIX      │
                    │   Assignment  │     │  Compliance  │
                    └───────────────┘     └──────────────┘

POSIX Compliance

caro validates commands for POSIX compliance:

Allowed Utilities

Standard POSIX utilities are preferred:

# File operations
ls, find, cp, mv, rm, mkdir, rmdir

# Text processing
cat, head, tail, grep, sed, awk, sort, uniq, wc

# System info
ps, df, du, who, date, uname

# Network
ping, curl, wget (where available)

Bash-Specific Avoidance

When possible, bash-specific features are avoided for portability:

# Avoid:
[[ condition ]]    # Use [ condition ] instead
$((arithmetic))    # Use expr instead where possible
{a..z}             # Use seq or explicit lists

Path Quoting

caro automatically quotes paths with special characters:

# Input: file with spaces.txt
# Output: "file with spaces.txt"

# Input: file's name.txt
# Output: "file's name.txt"

# Input: file$var.txt
# Output: 'file$var.txt'

Override Safety (Not Recommended)

For advanced users who understand the risks:

# Skip safety validation (DANGEROUS)
caro --unsafe "dangerous command"

# Acknowledge specific risk level
caro --allow-high-risk "system command"

These flags require explicit confirmation and are logged.

Configuration

Customize safety behavior in config.toml:

[safety]
# Enable safety warnings (default: true)
warnings = true

# Require confirmation for moderate risk (default: true)
confirm_moderate = true

# Require confirmation for high risk (default: true)
confirm_high = true

# Block critical commands (default: true)
block_critical = true

# Custom blocked patterns
blocked_patterns = [
    "custom-dangerous-command",
]

# Custom allowed patterns (override blocks)
allowed_patterns = [
    "rm -rf ./node_modules",  # Allow specific cleanup
]

Reporting Security Issues

If you find a way to bypass safety validation:

1. Do not disclose publicly
2. Email security@caro.sh with details
3. Include the command that bypassed validation
4. Wait for confirmation before public disclosure

We take security seriously and will respond within 48 hours.