by
Anonymous Coward
on 2010年02月19日 16時25分
(#1720894)
これを見て納得がいかなければもう一度聞いてくれ。
Prevention and Mitigations *Requirements Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
*Requirements Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
*Architecture and Design Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
*Implementation Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range. Use unsigned integers where possible. This makes it easier to perform sanity checks for integer overflows. If you must use signed integers, make sure that your range check includes minimum values as well as maximum values.
*Implementation Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how your language handles numbers that are too large or too small for its underlying representation. Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.
整数オーバフロー (スコア:1)
Re:整数オーバフロー (スコア:0)
Prevention and Mitigations
*Requirements
Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
*Requirements
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
If possible, choose a language or compiler that performs automatic bounds checking.
*Architecture and Design
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Use libraries or frameworks that make it easier to handle numbers without unexpected consequences.
Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
*Implementation
Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
Use unsigned integers where possible. This makes it easier to perform sanity checks for integer overflows. If you must use signed integers, make sure that your range check includes minimum values as well as maximum values.
*Implementation
Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how your language handles numbers that are too large or too small for its underlying representation.
Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.