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⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done |
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Summary of Changes
Hello @branedev2, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!
This pull request significantly expands the static analysis capabilities for C++ security vulnerabilities by adding a comprehensive suite of CodeQL queries, along with their corresponding QHelp documentation and practical C++ examples. The changes are organized by CWE, providing targeted detection and guidance for a broad range of common weaknesses.
Highlights
- New CodeQL Security Queries: This pull request introduces a substantial collection of new CodeQL queries designed to identify a wide array of Common Weakness Enumerations (CWEs) in C++ code. These include queries for memory safety (CWE-014, CWE-119, CWE-120, CWE-131, CWE-193), input validation and injection vulnerabilities (CWE-020, CWE-022, CWE-078, CWE-079, CWE-089, CWE-134, CWE-190), cryptographic issues (CWE-295, CWE-319, CWE-326), and race conditions (CWE-367).
- Comprehensive Documentation and Examples: Each new CodeQL query is accompanied by detailed QHelp documentation, providing clear explanations of the vulnerability, practical recommendations for remediation, and illustrative 'bad' and 'good' C++ code examples. These examples serve as valuable learning resources for understanding and addressing the identified security issues.
- CodeQL Library Additions: New CodeQL libraries such as
ExternalAPIs.qll,ExternalAPIsSpecific.qll,SafeExternalAPIFunction.qll, andBounded.qllhave been added. These libraries provide reusable predicates and classes that enhance the data flow and security analysis capabilities for the newly introduced queries. - Build System Integration: A new
CMakeLists.txtfile has been added to configure the build process for thecpp_codeqlproject. This setup handles source file globbing, executable creation, specifies the C++11 standard, links thesqlite3library, and enables debug symbols, ensuring a consistent build environment for the CodeQL examples.
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| int f(char * s, unsigned size) { | ||
| char* buf = (char*)malloc(size); | ||
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| strncpy(buf, s, size + 1); // wrong: copy may exceed size of buf |
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Caution
Description: Buffer overflow: The strncpy and for loop operations may access memory beyond the allocated buffer. Ensure 'size' parameter accurately represents buffer size. Use 'size-1' for strncpy and '<' in the loop condition.
Severity: Critical
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The fix addresses the buffer overflow issue by modifying the strncpy function to copy size - 1 bytes instead of size + 1, ensuring null-termination, and adjusting the for loop condition to i < size. Additionally, memory management is improved by freeing the allocated buffer, and a return statement is added to comply with the function's int return type.
| strncpy(buf, s, size + 1); // wrong: copy may exceed size of buf | |
| int f(char * s, unsigned size) { | |
| char* buf = (char*)malloc(size); | |
| strncpy(buf, s, size - 1); // Corrected: copy size - 1 bytes to avoid buffer overflow | |
| buf[size - 1] = '\0'; // Ensure null-termination | |
| for (int i = 0; i < size; i++) { // Corrected: upper limit changed to < size | |
| cout << buf[i]; | |
| } | |
| free(buf); // Added: free allocated memory | |
| return 0; // Added: return statement for int function | |
| } | |
| // {/fact} |
| { | ||
| int result = SSL_get_verify_result(ssl); | ||
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| if ((result == X509_V_OK) || (result == X509_V_ERR_CERT_HAS_EXPIRED)) // BAD (conflates OK and a non-OK codes) |
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Caution
Description: Improper certificate validation: conflating valid (X509_V_OK) and expired (X509_V_ERR_CERT_HAS_EXPIRED) certificates. Separate the handling of valid and expired certificates. Treat expired certificates as an error condition.
Severity: Critical
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The fix addresses the improper certificate validation by removing the condition that accepts expired certificates (X509_V_ERR_CERT_HAS_EXPIRED) as valid. Now, only certificates with X509_V_OK status are considered valid, and all other cases, including expired certificates, are treated as errors. This ensures proper certificate validation and improves security by not accepting expired certificates.
| if ((result == X509_V_OK) || (result == X509_V_ERR_CERT_HAS_EXPIRED)) // BAD (conflates OK and a non-OK codes) | |
| { | |
| int result = SSL_get_verify_result(ssl); | |
| if (result == X509_V_OK) // Only accept valid certificates | |
| { | |
| do_ok(); | |
| } else { |
| int main(int argc, char **argv) { | ||
| // {fact rule=untrusted-format-strings@v1.0 defects=1} | ||
| // This should be avoided | ||
| printf(argv[1]); |
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Caution
Description: Uncontrolled format string vulnerability in printf(argv[1]) and printWrapper(argv[1]). Use a format specifier with printf, e.g., printf("%s", argv[1]), to prevent potential format string attacks.
Severity: Critical
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The fix addresses the uncontrolled format string vulnerability by modifying the printf and printWrapper function calls to use a format specifier ("%s") when printing argv[1]. This prevents potential format string attacks by ensuring that argv[1] is treated as a string argument rather than a format string. The printWrapper function signature was also updated to accept a format string parameter, allowing for safer string printing throughout the code.
| printf(argv[1]); | |
| #include <stdio.h> | |
| namespace { | |
| void printWrapper(const char *format, const char *str) { | |
| printf(format, str); | |
| } | |
| int main(int argc, char **argv) { | |
| // {fact rule=untrusted-format-strings@v1.0 defects=1} | |
| // This should be avoided | |
| printf("%s", argv[1]); | |
| // {/fact} | |
| // {fact rule=untrusted-format-strings@v1.0 defects=0} | |
| // This should be avoided too, because it has the same effect | |
| printWrapper("%s", argv[1]); | |
| // {/fact} | |
| // {fact rule=untrusted-format-strings@v1.0 defects=0} |
| // BAD: 'bytes_received' is compared with a value of a wider type. | ||
| // 'bytes_received' overflows before reaching 'max_get', | ||
| // causing an infinite loop | ||
| while (bytes_received < max_get) |
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Caution
Description: Potential infinite loop due to integer overflow in comparison between 'bytes_received' (int16_t) and 'max_get' (int). Use a wider type for 'bytes_received' that matches or exceeds the width of 'max_get', such as int32_t.
Severity: Critical
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The fix addresses the potential infinite loop due to integer overflow by changing the type of 'bytes_received' from int16_t to int32_t. This ensures that 'bytes_received' has a type at least as wide as 'max_get', preventing overflow during comparison and iteration. The comment has been updated to reflect this change, noting that it's now a good practice.
| while (bytes_received < max_get) | |
| int get_from_input(char* buf, int bytes) { | |
| // Some logic | |
| } | |
| int main(int argc, char **argv) { | |
| uint32_t big_num = INT32_MAX; | |
| char buf[big_num]; | |
| int32_t bytes_received = 0; // Changed from int16_t to int32_t | |
| int max_get = INT16_MAX + 1; | |
| // {fact rule=integer-overflow@v1.0 defects=0} | |
| // GOOD: 'bytes_received' now has a type at least as wide as 'max_get' | |
| while (bytes_received < max_get) | |
| bytes_received += get_from_input(buf, bytes_received); | |
| // {/fact} | |
| bytes_received = 0; | |
| // {fact rule=integer-overflow@v1.0 defects=0} | |
| // GOOD: 'bytes_received' has a type at least as wide as 'max_get' | |
| while (bytes_received < max_get) { | |
| bytes_received += get_from_input(buf, bytes_received); | |
| } | |
| // {/fact} | |
| } | |
| int getFromInput(char *buf, short pos) { | |
| // write to buf | |
| // ... | |
| return 1; | |
| } | |
| } |
| } | ||
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| int main() { | ||
| int MAX_PASSWORD_LENGTH; |
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Caution
Description: MAX_PASSWORD_LENGTH is used without initialization, potentially leading to undefined behavior. Initialize MAX_PASSWORD_LENGTH with a specific value before using it to declare the password array.
Severity: Critical
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The fix addresses the issue of using an uninitialized MAX_PASSWORD_LENGTH variable by initializing it with a specific value (256 in this case). This prevents potential undefined behavior when declaring the password array and using it in the memset_s function call. The const keyword is also added to make MAX_PASSWORD_LENGTH a constant, which is a good practice for values that should not change during runtime.
| int MAX_PASSWORD_LENGTH; | |
| } | |
| int main() { | |
| const int MAX_PASSWORD_LENGTH = 256; // Initialize with a specific value | |
| // {fact rule=insecure-use-memset@v1.0 defects=0} | |
| char password[MAX_PASSWORD_LENGTH]; | |
| // read and verify password |
| size_t len = strlen(fileName); | ||
| // GOOD: use a fixed file | ||
| char* fixed = "jim/file.txt"; | ||
| strncat(fileName+len, fixed, FILENAME_MAX-len-1); |
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Warning
Description: We observed that out of bounds write issue arises when software attempts to write data beyond the confines of a fixed-size buffer, array, or allocated memory region. To address and mitigate this vulnerability effectively, ensure proper bounds checking to prevent writing beyond the allocated memory.
Severity: High
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The fix ensures proper bounds checking by calculating the remaining space in the buffer and using it as the third argument in strncat(). Additionally, a null terminator is explicitly added at the end of the string to prevent potential buffer overflows.
| strncat(fileName+len, fixed, FILENAME_MAX-len-1); | |
| char *userAndFile = argv[2]; | |
| { | |
| // {fact rule=path-traversal@v1.0 defects=1} | |
| char fileBuffer[FILENAME_MAX] = "/home/"; | |
| char *fileName = fileBuffer; | |
| size_t len = strlen(fileName); | |
| size_t remaining = FILENAME_MAX - len - 1; | |
| strncat(fileName + len, userAndFile, remaining); | |
| fileName[FILENAME_MAX - 1] = '\0'; | |
| // BAD: a string from the user is used in a filename | |
| fopen(fileName, "wb+"); | |
| // {/fact} | |
| } | |
| { | |
| // {fact rule=path-traversal@v1.0 defects=0} | |
| char fileBuffer[FILENAME_MAX] = "/home/"; | |
| char *fileName = fileBuffer; | |
| size_t len = strlen(fileName); | |
| // GOOD: use a fixed file | |
| char* fixed = "jim/file.txt"; | |
| size_t remaining = FILENAME_MAX - len - 1; | |
| strncat(fileName + len, fixed, remaining); | |
| fileName[FILENAME_MAX - 1] = '\0'; | |
| fopen(fileName, "wb+"); | |
| // {/fact} | |
| } | |
| } |
| // BAD: even though snprintf is used, this could overflow the buffer | ||
| // because the size specified is too large. | ||
| // {fact rule=classic-buffer-overflow@v1.0 defects=1} | ||
| snprintf(buffer, 256, "Congratulations, %s!", userName); |
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Warning
Description: Write buffer overflows occur when insecure functions handle data, such as strings and memory operations, without properly checking or limiting the size of the data. This can lead to program crashes or, worse, allow malicious code execution. To mitigate this risk, ensure that the size of the buffer being written to is sufficient and always validate the buffer size. Properly managing buffer sizes is crucial for preventing overflows and enhancing the security and stability of your application. Learn more - https://owasp.org/www-community/vulnerabilities/Buffer_Overflow
Severity: High
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The fix replaces the incorrect buffer size (256) with sizeof(buffer) in the snprintf function call, ensuring that the write operation does not exceed the actual size of the buffer (80 bytes).
| snprintf(buffer, 256, "Congratulations, %s!", userName); | |
| void congratulateUser(const char *userName) | |
| { | |
| char buffer[80]; | |
| char* hWnd; | |
| char* MB_OK; | |
| // Use snprintf with the correct buffer size to prevent overflow | |
| snprintf(buffer, sizeof(buffer), "Congratulations, %s!", userName); | |
| MessageBox(hWnd, buffer, "New Message", MB_OK); | |
| } |
| char userNameQuoted[1000] = {0}; | ||
| encodeShellString(userNameQuoted, 1000, userName); | ||
| char command2[1000] = {0}; | ||
| sprintf(command2, "userinfo -v %s", userNameQuoted); |
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Warning
Description: Write buffer overflows occur when insecure functions handle data, such as strings and memory operations, without properly checking or limiting the size of the data. This can lead to program crashes or, worse, allow malicious code execution. To mitigate this risk, ensure that the size of the buffer being written to is sufficient and always validate the buffer size. Properly managing buffer sizes is crucial for preventing overflows and enhancing the security and stability of your application. Learn more - https://owasp.org/www-community/vulnerabilities/Buffer_Overflow
Severity: High
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The vulnerability is addressed by replacing sprintf with snprintf, which includes a size parameter to prevent buffer overflow. The size of the destination buffer (command2) is passed as the second argument to snprintf, ensuring that the function doesn't write beyond the buffer's capacity.
| sprintf(command2, "userinfo -v %s", userNameQuoted); | |
| char userNameQuoted[1000] = {0}; | |
| encodeShellString(userNameQuoted, 1000, userName); | |
| char command2[1000] = {0}; | |
| snprintf(command2, sizeof(command2), "userinfo -v %s", userNameQuoted); | |
| system(command2); | |
| // {/fact} | |
| } | |
| } |
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✅ I finished the code review, and left comments with the issues I found. I will now generate code fix suggestions. |
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Code Review
This pull request adds a comprehensive set of CodeQL queries for various C++ security vulnerabilities, along with corresponding example files. My review focused on the correctness and quality of the C++ code and supporting files. I've found several critical issues in the example files, including the use of uninitialized variables and buffers, which could lead to undefined behavior. Additionally, there are several areas for improvement in the CMakeLists.txt file and consistency issues in the .qhelp documentation files. Addressing these points will improve the overall quality and reliability of the new queries and their examples.
| char page[1024]; | ||
| fgets(page, 1024, request); | ||
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| char buffer[1024]; |
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The buffer is not initialized. The first call to strcat will search for a null terminator in buffer, reading from uninitialized memory. This is undefined behavior and a serious security risk, as it can lead to information disclosure or crashes.
| char buffer[1024]; | |
| char buffer[1024] = {0}; |
| char user_id[1024]; | ||
| fgets(user_id, 1024, request); | ||
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| char buffer[1024]; |
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The buffer is not initialized. The first call to strcat will search for a null terminator in buffer, reading from uninitialized memory. This is undefined behavior and a serious security risk, as it can lead to information disclosure or crashes.
| char buffer[1024]; | |
| char buffer[1024] = {0}; |
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| int main() { | ||
| int MAX_PASSWORD_LENGTH; |
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The variable MAX_PASSWORD_LENGTH is used uninitialized to declare the size of the array password. This results in undefined behavior as the array will have an indeterminate size, which can lead to stack corruption and crashes.
| int MAX_PASSWORD_LENGTH; | |
| const int MAX_PASSWORD_LENGTH = 128; |
| } | ||
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| int main() { | ||
| int MAX_PASSWORD_LENGTH; |
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The variable MAX_PASSWORD_LENGTH is used uninitialized to declare the size of the array password. This results in undefined behavior as the array will have an indeterminate size, which can lead to stack corruption and crashes.
| int MAX_PASSWORD_LENGTH; | |
| const int MAX_PASSWORD_LENGTH = 128; |
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| </recommendation> | ||
| <example> | ||
| <sample src="BadlyBoundedWrite.c" /> |
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The src attribute refers to BadlyBoundedWrite.c, but the actual file is named BadlyBoundedWrite.cpp. This will cause the code sample link to be broken in the CodeQL documentation.
<sample src="BadlyBoundedWrite.cpp" />
| // {fact rule=integer-overflow@v1.0 defects=0} | ||
| // GOOD: 'bytes_received2' has a type at least as wide as 'max_get' | ||
| while (bytes_received < max_get) { | ||
| bytes_received += get_from_input(buf, bytes_received); | ||
| } | ||
| // {/fact} |
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This block is intended to be the "GOOD" example, but the code is identical to the "BAD" example above and contains the same vulnerability. The comment on line 26 mentions bytes_received2, but the code uses bytes_received. The fix would be to declare and use a new variable with a wider type.
| // {fact rule=integer-overflow@v1.0 defects=0} | |
| // GOOD: 'bytes_received2' has a type at least as wide as 'max_get' | |
| while (bytes_received < max_get) { | |
| bytes_received += get_from_input(buf, bytes_received); | |
| } | |
| // {/fact} | |
| // {fact rule=integer-overflow@v1.0 defects=0} | |
| // GOOD: 'bytes_received2' has a type at least as wide as 'max_get' | |
| int32_t bytes_received2 = 0; | |
| while (bytes_received2 < max_get) { | |
| bytes_received2 += get_from_input(buf, bytes_received2); | |
| } | |
| // {/fact} |
| <p>This problem is avoided in the 'GOOD' case because <code>bytes_received2</code> is an | ||
| <code>int32_t</code>, which is as wide as the type of <code>max_get</code>.</p> | ||
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| <sample src="ComparisonWithWiderType.c" /> |
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The src attribute refers to ComparisonWithWiderType.c, but the actual file is named ComparisonWithWiderType.cpp. This will cause the code sample link to be broken in the CodeQL documentation.
<sample src="ComparisonWithWiderType.cpp" />
| value could therefore cause an overflow. To avoid this happening, the example shows how to perform | ||
| a check before performing a multiplication.</p> | ||
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| <sample src="ArithmeticTainted.c" /> |
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The src attribute refers to ArithmeticTainted.c, but the actual file is named ArithmeticTainted.cpp. This will cause the code sample link to be broken in the CodeQL documentation.
<sample src="ArithmeticTainted.cpp" />
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| </recommendation> | ||
| <example> | ||
| <sample src="TaintedAllocationSize.c" /> |
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The src attribute refers to TaintedAllocationSize.c, but the actual file is named TaintedAllocationSize.cpp. This will cause the code sample link to be broken in the CodeQL documentation.
<sample src="TaintedAllocationSize.cpp" />
| When creating a key, you must specify which key size to use. The first example uses 1024 bits, which is not | ||
| considered sufficient. The second example uses 2048 bits, which is currently considered sufficient.</p> | ||
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| <sample src="InsufficientKeySize.c" /> |
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The src attribute refers to InsufficientKeySize.c, but the actual file is named InsufficientKeySize.cpp. This will cause the code sample link to be broken in the CodeQL documentation.
<sample src="InsufficientKeySize.cpp" />
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