Index: sys_ptrace_common.c =================================================================== RCS file: /cvsroot/src/sys/kern/sys_ptrace_common.c,v retrieving revision 1.48 diff -u -r1.48 sys_ptrace_common.c --- sys_ptrace_common.c 26 Apr 2019 08:38:25 -0000 1.48 +++ sys_ptrace_common.c 30 Apr 2019 19:13:32 -0000 @@ -1106,6 +1106,10 @@ piod.piod_op = write ? PIOD_WRITE_D : PIOD_READ_D; if ((error = ptrace_doio(l, t, lt, &piod, addr, true)) != 0) break; + if (piod.piod_len < sizeof(tmp)) { + error = EIO; + break; + } if (!write) *retval = tmp; break; @@ -1115,6 +1119,10 @@ break; if ((error = ptrace_doio(l, t, lt, &piod, addr, false)) != 0) break; + if (piod.piod_len < 1) { + error = EIO; + break; + } error = ptm->ptm_copyout_piod(&piod, addr, data); break;