Cfn Parameterized Queries

#!/​bin/​bash

CFN Parameterized Queries - Secure SQL Query Execution

Security Level: CRITICAL - Prevents SQL injection attacks

Status: Production Ready

set -euo pipefail

Security Functions

validate_sql_identifier() { local identifier="$1" local identifier_type="${2:-identifier}"

# Remove control characters and null bytes
identifier=$(sanitize_value "$identifier")

# Strict validation: alphanumeric + underscore, optional dot notation
if [[ ! "$identifier" =~ ^[a-zA-Z_][a-zA-Z0-9_]*(\.[a-zA-Z_][a-zA-Z0-9_]*)*$ ]]; then
    echo "ERROR: Invalid $identifier_type '$identifier' - must match ^[a-zA-Z_][a-zA-Z0-9_]*(\.[a-zA-Z_][a-zA-Z0-9_]*)*$" >&2
    return 1
fi

# Reasonable length limit (128 chars per part)
for part in ${identifier//./ }; do
    if [[ ${#part} -gt 128 ]]; then
        echo "ERROR: $identifier_type part too long (max 128 chars): '$part'" >&2
        return 1
    fi
done

return 0

}

validate_table_name() { validate_sql_identifier "$1" "table name" }

validate_column_name() { validate_sql_identifier "$1" "column name" }

sanitize_value() { local value="$1" # Remove null bytes and control characters except newline and tab echo "$value" | tr -d '\000' | tr -cd '\011\012\015\040-\176' }

Core Query Functions

execute_select_one() { local db_path="$1" local query="$2" shift 2 local params=("$@")

[[ -f "$db_path" ]] || {
    echo "ERROR: Database not found: $db_path" >&2
    return 1
}

# Build parameter file for secure binding
local param_file
param_file=$(mktemp)
trap "rm -f '$param_file'" RETURN

{
    echo ".param init"
    for i in "${!params[@]}"; do
        local param_index=$((i + 1))
        echo ".param set @p$param_index '${params[$i]}'"
    done
    echo "$query"
} > "$param_file"

sqlite3 "$db_path" < "$param_file"

}

execute_select_many() { local db_path="$1" local query="$2" shift 2 local params=("$@")

[[ -f "$db_path" ]] || {
    echo "ERROR: Database not found: $db_path" >&2
    return 1
}

# Build parameter file for secure binding
local param_file
param_file=$(mktemp)
trap "rm -f '$param_file'" RETURN

{
    echo ".param init"
    for i in "${!params[@]}"; do
        local param_index=$((i + 1))
        echo ".param set @p$param_index '${params[$i]}'"
    done
    echo "$query"
} > "$param_file"

sqlite3 -line "$db_path" < "$param_file"

}

execute_insert() { local db_path="$1" local table="$2" shift 2

validate_table_name "$table" || return 1

local columns=""
local values=()

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        --columns)
            shift
            columns="$1"
            # Validate each column name
            for col in $(echo "$columns" | tr ',' ' '); do
                validate_column_name "$col" || return 1
            done
            ;;
        --values)
            shift
            while [[ $# -gt 0 && ! "$1" =~ ^-- ]]; do
                values+=("$(sanitize_value "$1")")
                shift
            done
            ;;
        *)
            echo "ERROR: Unknown option: $1" >&2
            return 1
            ;;
    esac
    shift
done

[[ -n "$columns" ]] || {
    echo "ERROR: --columns required" >&2
    return 1
}

[[ ${#values[@]} -gt 0 ]] || {
    echo "ERROR: --values required" >&2
    return 1
}

# Build placeholders
local placeholders
placeholders=$(printf "?,%.0s" "${values[@]}" | sed 's/,$//')

# Execute parameterized insert
local param_file
param_file=$(mktemp)
trap "rm -f '$param_file'" RETURN

{
    echo ".param init"
    for i in "${!values[@]}"; do
        local param_index=$((i + 1))
        echo ".param set @p$param_index '${values[$i]}'"
    done
    echo "INSERT INTO $table ($columns) VALUES ($placeholders);"
} > "$param_file"

sqlite3 "$db_path" < "$param_file"

}

execute_update() { local db_path="$1" local table="$2" local set_column="$3" local set_value="$4" local where_column="$5" local where_value="$6"

validate_table_name "$table" || return 1
validate_column_name "$set_column" || return 1
validate_column_name "$where_column" || return 1

set_value=$(sanitize_value "$set_value")
where_value=$(sanitize_value "$where_value")

sqlite3 "$db_path" <<EOF

.param init .param set @set_value '$set_value' .param set @where_value '$where_value' UPDATE $table SET $set_column = @set_value WHERE $where_column = @where_value; EOF }

execute_delete() { local db_path="$1" local table="$2" local where_column="$3" local where_value="$4"

validate_table_name "$table" || return 1
validate_column_name "$where_column" || return 1

where_value=$(sanitize_value "$where_value")

sqlite3 "$db_path" <<EOF

.param init .param set @where_value '$where_value' DELETE FROM $table WHERE $where_column = @where_value; EOF }

Utility Functions

execute_exists() { local db_path="$1" local table="$2" local column="$3" local value="$4"

validate_table_name "$table" || return 1
validate_column_name "$column" || return 1
value=$(sanitize_value "$value")

local count
count=$(sqlite3 "$db_path" <<EOF

.param init .param set @value '$value' SELECT COUNT(*) FROM $table WHERE $column = @value; EOF )

[[ "$count" -gt 0 ]]

}

get_by_id() { local db_path="$1" local table="$2" local id="$3"

validate_table_name "$table" || return 1
id=$(sanitize_value "$id")

sqlite3 "$db_path" <<EOF

.param init .param set @id '$id' SELECT * FROM $table WHERE id = @id LIMIT 1; EOF }

count_records() { local db_path="$1" local table="$2" local where_clause="${3:-}"

validate_table_name "$table" || return 1

local query="SELECT COUNT(*) FROM $table"
[[ -n "$where_clause" ]] && query+=" WHERE $where_clause"
query+=";"

sqlite3 "$db_path" "$query"

}

Transaction Support

begin_transaction() { local db_path="$1" [[ -f "$db_path" ]] || { echo "ERROR: Database not found: $db_path" >&2 return 1 } sqlite3 "$db_path" "BEGIN TRANSACTION;" }

commit_transaction() { local db_path="$1" sqlite3 "$db_path" "COMMIT;" }

rollback_transaction() { local db_path="$1" sqlite3 "$db_path" "ROLLBACK;" }

Legacy compatibility functions

select_single_value() { execute_select_one "$@" }

multiple_row_select() { execute_select_many "$@" }

insert_record() { local db_path="$1" local table="$2" local columns="$3" shift 3 local values=("$@")

execute_insert "$db_path" "$table" --columns "$columns" --values "${values[@]}"

}

update_record() { local db_path="$1" local table="$2" local set_clause="$3" local where_clause="$4" shift 4 local params=("$@")

echo "WARNING: update_record is deprecated. Use execute_update instead." >&2

# Parse set and where clauses for simple cases
if [[ "$set_clause" =~ ^([a-zA-Z_][a-zA-Z0-9_]*)=\?$ ]]; then
    local set_col="${BASH_REMATCH[1]}"
else
    echo "ERROR: Complex SET clause not supported in legacy function" >&2
    return 1
fi

if [[ "$where_clause" =~ ^([a-zA-Z_][a-zA-Z0-9_]*)=\?$ ]]; then
    local where_col="${BASH_REMATCH[1]}"
else
    echo "ERROR: Complex WHERE clause not supported in legacy function" >&2
    return 1
fi

execute_update "$db_path" "$table" "$set_col" "${params[0]}" "$where_col" "${params[1]}"

}

delete_record() { execute_delete "$@" }

execute_parameterized() { execute_select_many "$@" }

load_skill_secure() { local db_path="$1" local skill_name="$2" local cache_dir="${3:-./​.skill-cache}"

[[ -f "$db_path" ]] || {
    echo "ERROR: Database not found: $db_path" >&2
    return 1
}

skill_name=$(sanitize_value "$skill_name")
mkdir -p "$cache_dir"
local cache_file="${cache_dir}/​${skill_name}.md"

local skill_content
skill_content=$(sqlite3 "$db_path" <<EOF

.param init .param set @skill_name '$skill_name' SELECT content FROM skills WHERE name = @skill_name; EOF )

[[ -n "$skill_content" ]] || {
    echo "ERROR: Skill not found: $skill_name" >&2
    return 1
}

echo "$skill_content" > "$cache_file"
echo "$cache_file"

}