cvs commit: src/sys/i386/isa npx.c

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>]

dillon      2006/05/02 15:52:24 PDT

DragonFly src repository

  Modified files:
    sys/i386/isa         npx.c 
  Log:
  Fix an information disclosure issue on AMD cpus.  The x87 debug registers,
  in particular the last instruction and last data pointers, are not restored
  by fxrstor() if there was no pending exception.  Add some dummy FP
  instructions (about ~7ns) to 'clean' the registers so a process has no
  visibility into another process's FP state.
  
  Submitted-by: Gary <gary@xxxxxxxxxxxxxxxxxxxx>
  Taken-from: FreeBSD
  Security-Advistory: FreeBSD-SA-06:14.fpu
  
  Revision  Changes    Path
  1.31      +44 -3     src/sys/i386/isa/npx.c


http://www.dragonflybsd.org/cvsweb/src/sys/i386/isa/npx.c.diff?r1=1.30&r2=1.31&f=u