Re: [PATCH 0/2] vsprintf: ignore %n again

[George Spelvin]

> +#define printk(fmt, ...) do {				  \
> +	compiletime_assert(__builtin_constant_p(fmt),     \
> +			   "Non-constant format string"); \
> +	printk(fmt, ##__VA_ARGS__);			  \
> +} while (0)

May I recommend __builtin_constant_p(*fmt).  Since:

char buf[OVERFLOW_VULNERABILITY];
strcpy(buf, malicious_format);
printk(buf, args)

has __builtin_constant_p(buf), but it's not a constant format string.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/