Because the local variable of st_int_ioctl function, such as long ltmp be assigned by arg. I think we should limit the parameter arg of st_int_ioctl function to the range of 24-bit signed integer. Yong Jianxu, please update your patch. 2013/12/18 "Kai Mäkisara (Kolumbus)" <kai.makisara@xxxxxxxxxxx>: > On 17.12.2013, at 16.43, Yongjian Xu xuyongjiande@xxxxxxxxx wrote: > >> From: Yongjian Xu <xuyongjiande@xxxxxxxxx> >> >> mtc.mt_count comes from user-space. >> int overflow may occur: >> mtc.mt_count++; >> mtc.mt_count—; > > I agree that this is a problem. However, it seems that there is also another problem: the SPACE command uses a 24-bit count field and this overflows far below INT_MAX. Should the count in MTFSF etc. be limited to (2<<24-2)? This would make the checks you suggest unnecessary. (-2 so that the behavior does not depend on whether we are at file mark or not.) > > I am a bit hesitant with this suggestion because someone may use count INT_MAX to space to the end of the tape. This probably succeeds now but after the fix it would return an error. > > Thanks, > Kai > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Best Regards ============================================== Yu Chen Ph.D. Associate Professor System Software&Software Engineering Group, Dept. of Computer Science and Technology Tsinghua University, Beijing 100084, P.R. China E-Mail: mailto:yuchen@xxxxxxxxxxxxxxx chyyuu@xxxxxxxxx ============================================== -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
