Good advice. Integer arithmetic is one of the trickiest aspects of C, and dangerous in combination with the manual memory management. For more information, see

Good advice. Integer arithmetic is one of the trickiest aspects of C, and dangerous in combination with the manual memory management. For more information, see the free chapter of TAOSSA: http://pentest.cryptocity.net/files/code_analysis/Dowd_ch06.pdf‎ http://pentest.cryptocity.net/files/code_analysis/Dowd_ch06.... There are (were) a couple bugs in the example code. Here are a some guidelines that will help avoid those, and most problems with integer operations and the heap in general. First, don't mix unsigned and signed types in arithmetic; and always prefer the size_t type for variables representing the size of an object. Second, check for overflow before an operation, not after, like so: if (size > SIZE_MAX / 2) { goto error; } newsize = size * 2; Third, always double-check the arguments to memory allocation functions, especially for zero, because the result is not always well defined. if (size >= SIZE_MAX - n) { goto error; } foo = malloc(size + n); foo[size] = ...;