Re: Secure coding in C (was Re: Administrivia #4883)

[core.lists.exploit-dev () CORE-SDI COM (Iván Arce)]

Bennett Todd wrote:

> For a specific case, is there any security hole directly implied by
> this C fragment, assuming attackers could control the contents of a
> and b?
>
>         char *a = something();
>         char *b = something_else();
>         int len = strlen(a) + strlen(b);

just being picky but what about ...
uint len = strlen(a) + strlen(b);

>         char *c = malloc(len + 1) || die("malloc");
>         (void) strcat(strcpy(c, a), b);
>
> BTW, what I ended up coding instead of that last line (as it grew
> way more complex) was equivalent to:
>
>         snprintf(c, len, "%s%s", a, b) > 0 || die "snprintf";
>
> -Bennett

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 a house from a horse by the roof on the house,
 It's nature and laws have been exhaustively expounded by Locke,
 who rode a house, and Kant, who lived in a horse." - Ambrose Bierce

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