Oops, sorry! That is a very nice warning (apparently in gcc newer than 4.2).
-----Original Message----- From: Ian Lance Taylor [mailto:[EMAIL PROTECTED] Sent: Monday, April 07, 2008 4:40 PM To: Tom Truscott Cc: gcc@gcc.gnu.org Subject: Re: US-CERT Vulnerability Note VU#162289 Tom Truscott <[EMAIL PROTECTED]> writes: > Here is an unintended bug I encountered recently, hopefully the "cert" > warning will catch this one too. > > int okay_to_increment (int i) > { > if (i + 1 < i) > return 0; /* adding 1 would cause overflow */ > return 1; /* adding 1 is safe */ > } > > Any sort of bug can cause a security vulnerability, so I recommend that gcc > developers work harder on warning messages. I can't tell whether you are joking or not, but as it happens we already warn about this case with -Wall: foo.c: In function ‘okay_to_increment’: foo.c:3: warning: assuming signed overflow does not occur when assuming that (X + c) < X is always false Ian
