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Re: Major gcc 4.1.1 and up security issue
From: Valdis.Kletnieks () vt edu
Date: Mon, 22 Jan 2007 14:50:21 -0500
On Sun, 21 Jan 2007 12:07:18 GMT, Marcin Owsiany said:
I also think that CPUs can detect internally when an overflow happens - is there a way to use that feature in C somehow, in a portable way? (Somehow I feel that the answer is that not all CPUs do that, so - no.)
The fact that some CPUs implement overflow detection in ways best described as byzantine and sometimes merely flawed or lacking entirely is why C does such hand-waving on the issue. It's generally considered performance-crippling to add inline code that does a "test condition/branch" pair after *every single* opcode that might cause an overflow - so the C paradigm is to leave them out and have the programmer code tests when actually needed. You think it's bad *now*, where you have to force-feed a 2-billion-something value in to cause an integer overflow, you obviously aren't old enough to have programmed on 16-bit machines, where numbers around 32,000 were sufficient, and even 'unsigned int' didn't suffice to let you sort 5-digit US postal ZIP codes... (And we won't mention the horrorshow that was floating point before IEEE-standard became widely used...)
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Current thread:
- Major gcc 4.1.1 and up security issue Felix von Leitner (Jan 15)
- Re: Major gcc 4.1.1 and up security issue Resident_Geek (Jan 15)
- Re: Major gcc 4.1.1 and up security issue Roflek of TK53 (Jan 15)
- Re: Major gcc 4.1.1 and up security issue Valdis . Kletnieks (Jan 16)
- Re: Major gcc 4.1.1 and up security issue Marcus Graf (Jan 17)
- Re: Major gcc 4.1.1 and up security issue Valdis . Kletnieks (Jan 17)
- Re: Major gcc 4.1.1 and up security issue Marcus Graf (Jan 17)
- Re: Major gcc 4.1.1 and up security issue Pavel Kankovsky (Jan 20)
- Re: Major gcc 4.1.1 and up security issue Marcin Owsiany (Jan 21)
- Re: Major gcc 4.1.1 and up security issue Valdis . Kletnieks (Jan 22)
- Re: Major gcc 4.1.1 and up security issue Marcin Owsiany (Jan 22)
- Re: Major gcc 4.1.1 and up security issue Valdis . Kletnieks (Jan 22)
- Re: Major gcc 4.1.1 and up security issue Marcin Owsiany (Jan 21)
- Re: Major gcc 4.1.1 and up security issue Resident_Geek (Jan 15)
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- Re: Major gcc 4.1.1 and up security issue Michele Cicciotti (Jan 21)
- <Possible follow-ups>
- Re: Major gcc 4.1.1 and up security issue Gwiasda Patrick (Jan 16)
- Re: Major gcc 4.1.1 and up security issue Glenn.Everhart (Jan 22)