Date: Wed, 13 Jun 2012 19:32:48 +0200 From: Szabolcs Nagy <nsz@...t70.net> To: musl@...ts.openwall.com Subject: Re: FreeSec crypt() * Solar Designer <solar@...nwall.com> [2012-06-13 20:45:46 +0400]: > On Wed, Jun 13, 2012 at 10:56:03AM -0400, Rich Felker wrote: > > Well if char is signed, (char)0x80 << 1 is -256. If char is unsigned, > > (char)0x80 << 1 is 256. > > Sure, but we had: > > const char *key; > u_char *q; > *q++ = *key << 1; > > so while *key << 1 is either -256 or 256 (promoted to int or unsigned > int), those high bits get dropped on the assignment to *q anyway, > resulting in the same value there either way. No? yes the code happens to work whenever -128<<1 is -256 and i assume -256 is what most compilers will give usually in case of two's complement int representation but -128<<1 is UB and should be fixed anyway
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.