String Taint Ranges for Memory Overhead Reduction
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Solution Overview
Problem
Existing approaches to managing taint information for strings lack granularity, leading to high memory overhead and inefficiencies in handling taint data, especially when dealing with large strings and complex operations, as they often treat entire strings as tainted even if only parts are malicious, and require significant memory and computation resources.
Innovation Solution
Implementing character-level taint tracking using taint ranges instead of single flags or arrays, which reduces memory consumption by representing taint information with ranges and storing metadata with the string, allowing for efficient tracking and processing of tainted characters while maintaining operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If character-level taint tracking is implemented using arrays or single flags for entire strings, then taint information can be tracked, but memory overhead becomes excessively high
Solution Approach 1:
The patent segments taint tracking from character-level (fine-grained) to range-level (coarse-grained). Instead of tracking each character individually with separate flags, the system identifies contiguous ranges of tainted characters and represents them as single intervals [start, end). This segmentation reduces the number of taint representations from O(n) for n characters to O(k) for k tainted ranges, significantly decreasing memory consumption while preserving the ability to track which portions of strings are tainted.
Solution Approach 2:
The patent transitions from a one-dimensional array representation (where each index corresponds to a character position) to a two-dimensional range representation (where each element represents an interval [start, end)). This dimensional change allows the system to compress multiple contiguous tainted characters into a single range object, reducing memory overhead from linear to logarithmic or constant space depending on the number of tainted regions.
2Reliability
If entire strings are treated as tainted when containing malicious input, then security is maintained, but processing efficiency decreases due to unnecessary operations on clean portions
Solution Approach 1:
The patent applies local quality by differentiating between tainted and clean portions within the same string. Instead of uniformly treating the entire string as tainted, the system assigns different taint properties to different character ranges. This allows security-critical operations to be applied only to tainted ranges while skipping clean portions, improving processing efficiency without compromising security. For example, when concatenating strings, the system only copies or validates characters from tainted ranges rather than processing the entire string.
3Measurement precision
If fine-grained taint tracking is implemented, then precise identification of tainted data is achieved, but computational overhead increases significantly
Solution Approach 1:
The patent merges adjacent tainted character ranges into single consolidated intervals. When performing string operations such as concatenation or substring extraction, the system combines overlapping or adjacent tainted ranges into unified intervals, reducing the total number of range objects that need to be tracked and manipulated. This merging operation decreases computational overhead for subsequent taint propagation while maintaining precise identification of all tainted character positions.
Data Source
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AI summary
Disclosed herein are system, method, and computer program product embodiments for propagating taint information for strings using metadata. Taint information for a string is encoded using taint ranges. When an operation is performed on the string, the operation and any additional taint information corresponding to the operation is encoded into a delta layer of the metadata. Rather than immediately obtaining taint information for a result string when the operation is performed on the string, the delta layer stores the taint information for the operation, and any subsequent operation, until it is needed. Once the taint information is needed, then the delta layers are collapsed into base layer taint information in order to resolve taint information for a result string.