CERT (R) C Coding Standard, Second Edition, The
98 Rules for Developing Safe, Reliable, and Secure Systems
2nd Edition
Published on 25. April 2014
576 pages
978-0-13-380529-1 (ISBN)
Description
"At Cisco, we have adopted the CERT C Coding Standard as the internal secure coding standard for all C developers. It is a core component of our secure development lifecycle. The coding standard described in this book breaks down complex software security topics into easy-to-follow rules with excellent real-world examples. It is an essential reference for any developer who wishes to write secure and resilient software in C and C++."
-Edward D. Paradise, vice president, engineering, threat response, intelligence, and development, Cisco Systems
Secure programming in C can be more difficult than even many experienced programmers realize. To help programmers write more secure code, The CERT (R) C Coding Standard, Second Edition, fully documents the second official release of the CERT standard for secure coding in C. The rules laid forth in this new edition will help ensure that programmers' code fully complies with the new C11 standard; it also addresses earlier versions, including C99.
The new standard itemizes those coding errors that are the root causes of current software vulnerabilities in C, prioritizing them by severity, likelihood of exploitation, and remediation costs. Each of the text's 98 guidelines includes examples of insecure code as well as secure, C11-conforming, alternative implementations. If uniformly applied, these guidelines will eliminate critical coding errors that lead to buffer overflows, format-string vulnerabilities, integer overflow, and other common vulnerabilities.
This book reflects numerous experts' contributions to the open development and review of the rules and recommendations that comprise this standard.
Coverage includes
Preprocessor
Declarations and Initialization
Expressions
Integers
Floating Point
Arrays
Characters and Strings
Memory Management
Input/Output
Environment
Signals
Error Handling
Concurrency
Miscellaneous Issues
-Edward D. Paradise, vice president, engineering, threat response, intelligence, and development, Cisco Systems
Secure programming in C can be more difficult than even many experienced programmers realize. To help programmers write more secure code, The CERT (R) C Coding Standard, Second Edition, fully documents the second official release of the CERT standard for secure coding in C. The rules laid forth in this new edition will help ensure that programmers' code fully complies with the new C11 standard; it also addresses earlier versions, including C99.
The new standard itemizes those coding errors that are the root causes of current software vulnerabilities in C, prioritizing them by severity, likelihood of exploitation, and remediation costs. Each of the text's 98 guidelines includes examples of insecure code as well as secure, C11-conforming, alternative implementations. If uniformly applied, these guidelines will eliminate critical coding errors that lead to buffer overflows, format-string vulnerabilities, integer overflow, and other common vulnerabilities.
This book reflects numerous experts' contributions to the open development and review of the rules and recommendations that comprise this standard.
Coverage includes
Preprocessor
Declarations and Initialization
Expressions
Integers
Floating Point
Arrays
Characters and Strings
Memory Management
Input/Output
Environment
Signals
Error Handling
Concurrency
Miscellaneous Issues
More details
Series
Edition
2nd edition
Language
English
Place of publication
Boston
United States
Publishing group
Pearson Education (US)
Target group
College/higher education
File size
33,62 MB
ISBN-13
978-0-13-380529-1 (9780133805291)
Copyright in bibliographic data and cover images is held by Nielsen Book Services Limited or by the publishers or by their respective licensors: all rights reserved.
Schweitzer Classification
Other editions
Additional editions
Robert Seacord
CERT (R) C Coding Standard, Second Edition, The
98 Rules for Developing Safe, Reliable, and Secure Systems
Book
04/2014
2nd Edition
Addison Wesley
€55.07
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Person
Robert C. Seacord is a computer security specialist and writer. He is the author of books on computer security, legacy system modernization, and component-based software engineering.
Robert C. Seacord manages the Secure Coding Initiative in the CERT Division of Carnegie Mellon's Software Engineering Institute (SEI) in Pittsburgh, PA. CERT, among other security related activities, regularly analyzes software vulnerability reports and assesses the risk to the Internet and other critical infrastructure. Robert is an adjunct professor in the Carnegie Mellon University School of Computer Science and in the Information Networking Institute. He represents CMU at PL22.11 (ANSI "C") and is a technical expert for the JTC1/SC22/WG14 international standardization working group for the C programming language.
Robert started programming professionally for IBM in 1982, working in communications and operating system software, processor development, and software engineering. Robert also has worked at the X Consortium, where he developed and maintained code for the Common Desktop Environment and the X Window System.
Robert has a B.A. in computer science from Rensselaer Polytechnic Institute.
Robert C. Seacord manages the Secure Coding Initiative in the CERT Division of Carnegie Mellon's Software Engineering Institute (SEI) in Pittsburgh, PA. CERT, among other security related activities, regularly analyzes software vulnerability reports and assesses the risk to the Internet and other critical infrastructure. Robert is an adjunct professor in the Carnegie Mellon University School of Computer Science and in the Information Networking Institute. He represents CMU at PL22.11 (ANSI "C") and is a technical expert for the JTC1/SC22/WG14 international standardization working group for the C programming language.
Robert started programming professionally for IBM in 1982, working in communications and operating system software, processor development, and software engineering. Robert also has worked at the X Consortium, where he developed and maintained code for the Common Desktop Environment and the X Window System.
Robert has a B.A. in computer science from Rensselaer Polytechnic Institute.
Content
Preface xiii
Acknowledgments xxxvii
Contributors xxxix
About the Author xliii
Chapter 1: Preprocessor (PRE) 1
PRE30-C. Do not create a universal character name through concatenation 2
PRE31-C. Avoid side effects in arguments to unsafe macros 3
PRE32-C. Do not use preprocessor directives in invocations of function-like macros 8
Chapter 2: Declarations and Initialization (DCL) 11
DCL30-C. Declare objects with appropriate storage durations 12
DCL31-C. Declare identifiers before using them 16
DCL36-C. Do not declare an identifier with conflicting linkage classifications 20
DCL37-C. Do not declare or define a reserved identifier 23
DCL38-C. Use the correct syntax when declaring a flexible array member 29
DCL39-C. Avoid information leakage in structure padding 32
DCL40-C. Do not create incompatible declarations of the same function or object 37
DCL41-C. Do not declare variables inside a switch statement before the first case label 43
Chapter 3: Expressions (EXP) 47
EXP30-C. Do not depend on the order of evaluation for side effects 48
EXP32-C. Do not access a volatile object through a nonvolatile reference 54
EXP33-C. Do not read uninitialized memory 56
EXP34-C. Do not dereference null pointers 65
EXP35-C. Do not modify objects with temporary lifetime 70
EXP36-C. Do not cast pointers into more strictly aligned pointer types 73
EXP37-C. Call functions with the correct number and type of arguments 77
EXP39-C. Do not access a variable through a pointer of an incompatible type 83
EXP40-C. Do not modify constant objects 89
EXP42-C. Do not compare padding data 91
EXP43-C. Avoid undefined behavior when using restrict-qualified pointers 93
EXP44-C. Do not rely on side effects in operands to sizeof, _Alignof, or _Generic 102
EXP45-C. Do not perform assignments in selection statements 105
Chapter 4: Integers (INT) 111
INT30-C. Ensure that unsigned integer operations do not wrap 112
INT31-C. Ensure that integer conversions do not result in lost or misinterpreted data 118
INT32-C. Ensure that operations on signed integers do not result in overflow 126
INT33-C. Ensure that division and remainder operations do not result in divide-by-zero errors 135
INT34-C. Do not shift an expression by a negative number of bits or by greater than or equal to the number of bits that exist in the operand 138
INT35-C. Use correct integer precisions 143
INT36-C. Converting a pointer to integer or integer to pointer 145
Chapter 5: Floating Point (FLP) 151
FLP30-C. Do not use floating-point variables as loop counters 152
FLP32-C. Prevent or detect domain and range errors in math functions 154
FLP34-C. Ensure that floating-point conversions are within range of the new type 163
FLP36-C. Preserve precision when converting integral values to floating-point type 166
Chapter 6: Arrays (ARR) 169
ARR30-C. Do not form or use out-of-bounds pointers or array subscripts 170
ARR32-C. Ensure size arguments for variable length arrays are in a valid range 180
ARR36-C. Do not subtract or compare two pointers that do not refer to the same array 182
ARR37-C. Do not add or subtract an integer to a pointer to a non-array object 184
ARR38-C. Guarantee that library functions do not form invalid pointers 187
ARR39-C. Do not add or subtract a scaled integer to a pointer 196
Chapter 7: Characters and Strings (STR) 201
STR30-C. Do not attempt to modify string literals 202
STR31-C. Guarantee that storage for strings has sufficient space for character data and the null terminator 205
STR32-C. Do not pass a non-null-terminated character sequence to a library function that expects a string 218
STR34-C. Cast characters to unsigned char before converting to larger integer sizes 223
STR37-C. Arguments to character handling functions must be representable as an unsigned char 227
STR38-C. Do not confuse narrow and wide character strings and functions 229
Chapter 8: Memory Management (MEM) 233
MEM30-C. Do not access freed memory 234
MEM31-C. Free dynamically allocated memory when no longer needed 239
MEM33-C. Allocate and copy structures containing a flexible array member dynamically 241
MEM34-C. Only free memory allocated dynamically 246
MEM35-C. Allocate sufficient memory for an object 250
MEM36-C. Do not modify the alignment of objects by calling realloc() 253
Chapter 9: Input/Output (FIO) 257
FIO30-C. Exclude user input from format strings 258
FIO31-C. Do not open a file that is already open 263
FIO32-C. Do not perform operations on devices that are only appropriate for files 265
FIO34-C. Distinguish between characters read from a file and EOF or WEOF 272
FIO37-C. Do not assume that fgets() or fgetws() returns a nonempty string when successful 277
FIO38-C. Do not copy a FILE object 279
FIO39-C. Do not alternately input and output from a stream without an intervening flush or positioning call 280
FIO40-C. Reset strings on fgets() or fgetws() failure 283
FIO41-C. Do not call getc(), putc(), getwc(), or putwc() with a stream argument that has side effects 284
FIO42-C. Close files when they are no longer needed 288
FIO44-C. Only use values for fsetpos() that are returned from fgetpos() 292
FIO45-C. Avoid TOCTOU race conditions while accessing files 294
FIO46-C. Do not access a closed file 298
FIO47-C. Use valid format strings 299
Chapter 10: Environment (ENV) 305
ENV30-C. Do not modify the object referenced by the return value of certain functions 306
ENV31-C. Do not rely on an environment pointer following an operation that may invalidate it 311
ENV32-C. All exit handlers must return normally 315
ENV33-C. Do not call system() 319
ENV34-C. Do not store pointers returned by certain functions 325
Chapter 11: Signals (SIG) 333
SIG30-C. Call only asynchronous-safe functions within signal handlers 334
SIG31-C. Do not access shared objects in signal handlers 342
SIG34-C. Do not call signal() from within interruptible signal handlers 345
SIG35-C. Do not return from a computational exception signal handler 349
Chapter 12: Error Handling (ERR) 353
ERR30-C. Set errno to zero before calling a library function known to set errno, and check errno only after the function returns a value indicating failure 354
ERR32-C. Do not rely on indeterminate values of errno 361
ERR33-C. Detect and handle standard library errors 365
Chapter 13: Concurrency (CON) 383
CON30-C. Clean up thread-specific storage 384
CON31-C. Do not destroy a mutex while it is locked 388
CON32-C. Prevent data races when accessing bit-fields from multiple threads 391
CON33-C. Avoid race conditions when using library functions 394
CON34-C. Declare objects shared between threads with appropriate storage durations 398
CON35-C. Avoid deadlock by locking in a predefined order 406
CON36-C. Wrap functions that can spuriously wake up in a loop 411
CON37-C. Do not call signal() in a multithreaded program 414
CON38-C. Preserve thread-safety and liveness when using condition variables 416
CON39-C. Do not join or detach a thread that was previously joined or detached 424
CON40-C. Do not refer to an atomic variable twice in an expression 426
CON41-C. Wrap functions that can fail spuriously in a loop 430
Chapter 14: Miscellaneous (MSC) 435
MSC30-C. Do not use the rand() function for generating pseudorandom numbers 436
MSC32-C. Properly seed pseudorandom number generators 439
MSC33-C. Do not pass invalid data to the asctime() function 443
MSC37-C. Ensure that control never reaches the end of a non-void function 446
MSC38-C. Do not treat a predefined identifier as an object if it might only be implemented as a macro 449
MSC39-C. Do not call va_arg() on a va_list that has an indeterminate value 451
MSC40-C. Do not violate constraints 453
Appendix A: Glossary 459
Appendix B: Undefined Behavior 465
Appendix C: Unspecified Behavior 481
Bibliography 487
Index 495
Acknowledgments xxxvii
Contributors xxxix
About the Author xliii
Chapter 1: Preprocessor (PRE) 1
PRE30-C. Do not create a universal character name through concatenation 2
PRE31-C. Avoid side effects in arguments to unsafe macros 3
PRE32-C. Do not use preprocessor directives in invocations of function-like macros 8
Chapter 2: Declarations and Initialization (DCL) 11
DCL30-C. Declare objects with appropriate storage durations 12
DCL31-C. Declare identifiers before using them 16
DCL36-C. Do not declare an identifier with conflicting linkage classifications 20
DCL37-C. Do not declare or define a reserved identifier 23
DCL38-C. Use the correct syntax when declaring a flexible array member 29
DCL39-C. Avoid information leakage in structure padding 32
DCL40-C. Do not create incompatible declarations of the same function or object 37
DCL41-C. Do not declare variables inside a switch statement before the first case label 43
Chapter 3: Expressions (EXP) 47
EXP30-C. Do not depend on the order of evaluation for side effects 48
EXP32-C. Do not access a volatile object through a nonvolatile reference 54
EXP33-C. Do not read uninitialized memory 56
EXP34-C. Do not dereference null pointers 65
EXP35-C. Do not modify objects with temporary lifetime 70
EXP36-C. Do not cast pointers into more strictly aligned pointer types 73
EXP37-C. Call functions with the correct number and type of arguments 77
EXP39-C. Do not access a variable through a pointer of an incompatible type 83
EXP40-C. Do not modify constant objects 89
EXP42-C. Do not compare padding data 91
EXP43-C. Avoid undefined behavior when using restrict-qualified pointers 93
EXP44-C. Do not rely on side effects in operands to sizeof, _Alignof, or _Generic 102
EXP45-C. Do not perform assignments in selection statements 105
Chapter 4: Integers (INT) 111
INT30-C. Ensure that unsigned integer operations do not wrap 112
INT31-C. Ensure that integer conversions do not result in lost or misinterpreted data 118
INT32-C. Ensure that operations on signed integers do not result in overflow 126
INT33-C. Ensure that division and remainder operations do not result in divide-by-zero errors 135
INT34-C. Do not shift an expression by a negative number of bits or by greater than or equal to the number of bits that exist in the operand 138
INT35-C. Use correct integer precisions 143
INT36-C. Converting a pointer to integer or integer to pointer 145
Chapter 5: Floating Point (FLP) 151
FLP30-C. Do not use floating-point variables as loop counters 152
FLP32-C. Prevent or detect domain and range errors in math functions 154
FLP34-C. Ensure that floating-point conversions are within range of the new type 163
FLP36-C. Preserve precision when converting integral values to floating-point type 166
Chapter 6: Arrays (ARR) 169
ARR30-C. Do not form or use out-of-bounds pointers or array subscripts 170
ARR32-C. Ensure size arguments for variable length arrays are in a valid range 180
ARR36-C. Do not subtract or compare two pointers that do not refer to the same array 182
ARR37-C. Do not add or subtract an integer to a pointer to a non-array object 184
ARR38-C. Guarantee that library functions do not form invalid pointers 187
ARR39-C. Do not add or subtract a scaled integer to a pointer 196
Chapter 7: Characters and Strings (STR) 201
STR30-C. Do not attempt to modify string literals 202
STR31-C. Guarantee that storage for strings has sufficient space for character data and the null terminator 205
STR32-C. Do not pass a non-null-terminated character sequence to a library function that expects a string 218
STR34-C. Cast characters to unsigned char before converting to larger integer sizes 223
STR37-C. Arguments to character handling functions must be representable as an unsigned char 227
STR38-C. Do not confuse narrow and wide character strings and functions 229
Chapter 8: Memory Management (MEM) 233
MEM30-C. Do not access freed memory 234
MEM31-C. Free dynamically allocated memory when no longer needed 239
MEM33-C. Allocate and copy structures containing a flexible array member dynamically 241
MEM34-C. Only free memory allocated dynamically 246
MEM35-C. Allocate sufficient memory for an object 250
MEM36-C. Do not modify the alignment of objects by calling realloc() 253
Chapter 9: Input/Output (FIO) 257
FIO30-C. Exclude user input from format strings 258
FIO31-C. Do not open a file that is already open 263
FIO32-C. Do not perform operations on devices that are only appropriate for files 265
FIO34-C. Distinguish between characters read from a file and EOF or WEOF 272
FIO37-C. Do not assume that fgets() or fgetws() returns a nonempty string when successful 277
FIO38-C. Do not copy a FILE object 279
FIO39-C. Do not alternately input and output from a stream without an intervening flush or positioning call 280
FIO40-C. Reset strings on fgets() or fgetws() failure 283
FIO41-C. Do not call getc(), putc(), getwc(), or putwc() with a stream argument that has side effects 284
FIO42-C. Close files when they are no longer needed 288
FIO44-C. Only use values for fsetpos() that are returned from fgetpos() 292
FIO45-C. Avoid TOCTOU race conditions while accessing files 294
FIO46-C. Do not access a closed file 298
FIO47-C. Use valid format strings 299
Chapter 10: Environment (ENV) 305
ENV30-C. Do not modify the object referenced by the return value of certain functions 306
ENV31-C. Do not rely on an environment pointer following an operation that may invalidate it 311
ENV32-C. All exit handlers must return normally 315
ENV33-C. Do not call system() 319
ENV34-C. Do not store pointers returned by certain functions 325
Chapter 11: Signals (SIG) 333
SIG30-C. Call only asynchronous-safe functions within signal handlers 334
SIG31-C. Do not access shared objects in signal handlers 342
SIG34-C. Do not call signal() from within interruptible signal handlers 345
SIG35-C. Do not return from a computational exception signal handler 349
Chapter 12: Error Handling (ERR) 353
ERR30-C. Set errno to zero before calling a library function known to set errno, and check errno only after the function returns a value indicating failure 354
ERR32-C. Do not rely on indeterminate values of errno 361
ERR33-C. Detect and handle standard library errors 365
Chapter 13: Concurrency (CON) 383
CON30-C. Clean up thread-specific storage 384
CON31-C. Do not destroy a mutex while it is locked 388
CON32-C. Prevent data races when accessing bit-fields from multiple threads 391
CON33-C. Avoid race conditions when using library functions 394
CON34-C. Declare objects shared between threads with appropriate storage durations 398
CON35-C. Avoid deadlock by locking in a predefined order 406
CON36-C. Wrap functions that can spuriously wake up in a loop 411
CON37-C. Do not call signal() in a multithreaded program 414
CON38-C. Preserve thread-safety and liveness when using condition variables 416
CON39-C. Do not join or detach a thread that was previously joined or detached 424
CON40-C. Do not refer to an atomic variable twice in an expression 426
CON41-C. Wrap functions that can fail spuriously in a loop 430
Chapter 14: Miscellaneous (MSC) 435
MSC30-C. Do not use the rand() function for generating pseudorandom numbers 436
MSC32-C. Properly seed pseudorandom number generators 439
MSC33-C. Do not pass invalid data to the asctime() function 443
MSC37-C. Ensure that control never reaches the end of a non-void function 446
MSC38-C. Do not treat a predefined identifier as an object if it might only be implemented as a macro 449
MSC39-C. Do not call va_arg() on a va_list that has an indeterminate value 451
MSC40-C. Do not violate constraints 453
Appendix A: Glossary 459
Appendix B: Undefined Behavior 465
Appendix C: Unspecified Behavior 481
Bibliography 487
Index 495
