fix: add buffer-length check in network_wrapper.cpp

[orbisai0security]

Summary

Fix critical severity security issue in tools/PCKRetrievalTool/App/linux/network_wrapper.cpp.

Vulnerability

Field	Value
ID	V-001
Severity	CRITICAL
Scanner	multi_agent_ai
Rule	V-001
File	tools/PCKRetrievalTool/App/linux/network_wrapper.cpp:59
Assessment	Confirmed exploitable
CWE	CWE-120

Description: The curl write callback in network_wrapper.cpp performs memory allocation and copy operations using sizenmemb from the network response without overflow checks. At line 59, malloc(sizenmemb) is called where sizenmemb could overflow. At line 64, realloc is used to grow the buffer. At line 72, memcpy copies data using sizenmemb without verifying the destination buffer has sufficient space. If realloc fails (returns NULL) or if the multiplication overflows, a heap buffer overflow occurs.

Evidence

Exploitation scenario: A MITM attacker or compromised PCS server sends a crafted HTTP response that triggers the curl write callback with size and nmemb values whose product overflows or exceeds the allocated buffer.

Scanner confirmation: multi_agent_ai rule V-001 flagged this pattern.

Production code: This file is in the production codebase, not test-only code.

Threat Model Context

This is a local CLI tool - exploitation requires the attacker to control command-line arguments or input files.

Changes

• tools/PCKRetrievalTool/App/linux/network_wrapper.cpp

Note: The following lines in the same file use a similar pattern and may also need review: tools/PCKRetrievalTool/App/linux/network_wrapper.cpp:76

Verification

• Build passes
• Scanner re-scan confirms fix
• LLM code review passed

Security Invariant

Property: Buffer reads never exceed the declared length

Regression test

#include <gtest/gtest.h>
#include <cstdlib>
#include <cstring>
#include <climits>

// Include the actual implementation
// We need to access the write_callback function from network_wrapper.cpp
// The callback has signature: size_t write_callback(void *ptr, size_t size, size_t nmemb, void *stream)
// and uses a struct with base, size fields

// Replicate the struct used by the callback (from the source)
struct MemoryStruct {
    char *base;
    size_t size;
};

// Declare the write_callback as extern - it's defined in network_wrapper.cpp
extern "C" size_t write_callback(void *ptr, size_t size, size_t nmemb, void *stream);

class WriteCallbackSecurityTest : public ::testing::Test {
protected:
    MemoryStruct response;
    
    void SetUp() override {
        response.base = nullptr;
        response.size = 0;
    }
    
    void TearDown() override {
        if (response.base) {
            free(response.base);
            response.base = nullptr;
        }
    }
};

// Test: multiplication overflow case - size*nmemb overflows size_t
TEST_F(WriteCallbackSecurityTest, OverflowMultiplicationMustNotCauseHeapCorruption) {
    // size * nmemb would overflow: e.g., SIZE_MAX/2 + 1 * 2 = 0 (overflow)
    char dummy_data[16] = "AAAAAAAAAAAAAAAA";
    size_t big_size = (SIZE_MAX / 2) + 1;
    size_t nmemb = 2;
    // This should either return 0 (failure) or not corrupt memory
    size_t result = write_callback(dummy_data, big_size, nmemb, &response);
    // If overflow is not checked, malloc(0) may succeed and memcpy would overflow
    // The invariant: result should be 0 (rejected) OR response.size <= allocated amount
    EXPECT_TRUE(result == 0 || response.size <= big_size * nmemb);
}

// Test: realloc failure path - accumulate large chunks to exhaust growth
TEST_F(WriteCallbackSecurityTest, LargeAccumulationDoesNotOverflow) {
    // First call with valid data to initialize
    std::vector<char> payload(4096, 'B');
    size_t result1 = write_callback(payload.data(), 1, payload.size(), &response);
    ASSERT_EQ(result1, payload.size());
    ASSERT_EQ(response.size, payload.size());
    
    // Second call to trigger realloc path
    std::vector<char> payload2(8192, 'C');
    size_t result2 = write_callback(payload2.data(), 1, payload2.size(), &response);
    ASSERT_EQ(result2, payload2.size());
    // Verify total size is sum of both
    EXPECT_EQ(response.size, payload.size() + payload2.size());
    // Verify data integrity (no corruption)
    EXPECT_EQ(memcmp(response.base, payload.data(), payload.size()), 0);
    EXPECT_EQ(memcmp(response.base + payload.size(), payload2.data(), payload2.size()), 0);
}

// Test: valid small input works correctly
TEST_F(WriteCallbackSecurityTest, ValidSmallInputWorksCorrectly) {
    const char *data = "Hello";
    size_t result = write_callback((void*)data, 1, 5, &response);
    EXPECT_EQ(result, 5u);
    EXPECT_EQ(response.size, 5u);
    EXPECT_EQ(memcmp(response.base, data, 5), 0);
}

// Test: near-overflow boundary where size*nmemb is close to SIZE_MAX
TEST_F(WriteCallbackSecurityTest, BoundaryNearMaxSizeMustBeRejected) {
    char dummy_data[1] = {'X'};
    size_t result = write_callback(dummy_data, SIZE_MAX, 1, &response);
    // Allocation of SIZE_MAX bytes should fail; callback should handle gracefully
    // Either returns 0 (error) or SIZE_MAX (unlikely malloc succeeds)
    if (result != SIZE_MAX) {
        EXPECT_EQ(result, 0u);
    }
}

int main(int argc, char **argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

This test guards against regressions — it's useful independent of the code change above.

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Automated security fix by OrbisAI Security