diff options
Diffstat (limited to 'pkg/sentry/arch/arch_x86.go')
| -rw-r--r-- | pkg/sentry/arch/arch_x86.go | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/pkg/sentry/arch/arch_x86.go b/pkg/sentry/arch/arch_x86.go index 59bf89d99..e50a76083 100644 --- a/pkg/sentry/arch/arch_x86.go +++ b/pkg/sentry/arch/arch_x86.go @@ -353,10 +353,10 @@ func (s *State) PtraceSetRegs(src io.Reader) (int, error) { if !isUserSegmentSelector(regs.Ss) { return 0, syscall.EIO } - if regs.Fs_base >= uint64(maxAddr64) { + if !isValidSegmentBase(regs.Fs_base) { return 0, syscall.EIO } - if regs.Gs_base >= uint64(maxAddr64) { + if !isValidSegmentBase(regs.Gs_base) { return 0, syscall.EIO } // CS and SS are validated, but changes to them are otherwise silently @@ -389,6 +389,12 @@ func isUserSegmentSelector(reg uint64) bool { return reg&3 == 3 } +// isValidSegmentBase returns true if the given segment base specifies a +// canonical user address. +func isValidSegmentBase(reg uint64) bool { + return reg < uint64(maxAddr64) +} + // ptraceFPRegsSize is the size in bytes of Linux's user_i387_struct, the type // manipulated by PTRACE_GETFPREGS and PTRACE_SETFPREGS on x86. Equivalently, // ptraceFPRegsSize is the size in bytes of the x86 FXSAVE area. |