On Tue, Feb 17, 2009 at 03:12:05PM +0100, Philipp Kolmann wrote: > Hi, > > we found some discussion about this issue here: > > http://www.velocityreviews.com/forums/t283343-shifting-bits-shift-32-bits-on-32-bit-int.html > > In post #4 it reads: > The behaviour of shifts defined only if the value of the right operand > is less than the number of bits in the left operand. So shifting a > 32-bit value by 32 or more is undefined... > > further info in #7: > > Better yet, read the first part of section 5.8 of the ISO/IEC 14882:2003 > standard: > > The behavior is undefined if the right operand is negative, > or greater than or equal to the length in bits of the > promoted left operand. > > So it seems that my patch is the proper fix in the end after all. > Attached as file, since BT distroyed the formatting. > > Thanks > Philipp
> --- IPv6addr.c_ORIG 2009-02-17 14:28:45.000000000 +0100 > +++ IPv6addr.c 2009-02-17 14:29:24.000000000 +0100 > @@ -487,7 +487,10 @@ > n = plen / 32; > memset(mask.s6_addr32 + n + 1, 0, (3 - n) * 4); > s = 32 - plen % 32; > - mask.s6_addr32[n] = 0xffffffff << s; > + if (s == 32) > + mask.s6_addr32[n] = 0x0; > + else > + mask.s6_addr32[n] = 0xffffffff << s; > mask.s6_addr32[n] = htonl(mask.s6_addr32[n]); > } > Hi Phillipp, this looks like a good fix to me, how well tested is it? I'm embarrassed to say that this problem was introduced by me the last time that I tried to fix this code [1]. http://hg.vergenet.net/linux-ha/dev/rev/774ee922abe7 -- Simon Horman VA Linux Systems Japan K.K., Sydney, Australia Satellite Office H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
