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No, do not just copy code from i386 and expect it to work on amd64. There

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are several structural differences. At least two issues here: segment
registers that could fault in kernel mode with userland TLS, and a non-
canonical %eip on iret.

Not even tested, but just obvious. By the way, I believe this function is
still buggy since we don't call cpu_fsgs_reload while %fs/%gs could have
been reloaded.
This commit is contained in:
maxv 2017-02-09 08:38:25 +00:00
parent 74eedc014a
commit 929132b4a7
1 changed files with 24 additions and 6 deletions
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30
sys/arch/amd64/amd64/netbsd32_machdep.c
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@ -1,4 +1,4 @@
/* $NetBSD: netbsd32_machdep.c,v 1.101 2017/02/06 16:34:37 maxv Exp $ */ /* $NetBSD: netbsd32_machdep.c,v 1.102 2017/02/09 08:38:25 maxv Exp $ */
/* /*
* Copyright (c) 2001 Wasabi Systems, Inc. * Copyright (c) 2001 Wasabi Systems, Inc.
@ -36,7 +36,7 @@
*/ */
#include <sys/cdefs.h> #include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.101 2017/02/06 16:34:37 maxv Exp $"); __KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.102 2017/02/09 08:38:25 maxv Exp $");
#ifdef _KERNEL_OPT #ifdef _KERNEL_OPT
#include "opt_compat_netbsd.h" #include "opt_compat_netbsd.h"
@ -531,13 +531,31 @@ netbsd32_process_read_fpregs(struct lwp *l, struct fpreg32 *regs, size_t *sz)
int int
netbsd32_process_write_regs(struct lwp *l, const struct reg32 *regs) netbsd32_process_write_regs(struct lwp *l, const struct reg32 *regs)
{ {
struct trapframe *tf = l->l_md.md_regs; struct trapframe *tf;
struct pcb *pcb;
tf = l->l_md.md_regs;
pcb = lwp_getpcb(l);
/* /*
* Check for security violations. Taken from i386/process_machdep.c. * Check for security violations.
*/ */
if (((regs->r_eflags ^ tf->tf_rflags) & PSL_USERSTATIC) != 0 || if (((regs->r_eflags ^ tf->tf_rflags) & PSL_USERSTATIC) != 0)
!VALID_USER_CSEL32(regs->r_cs)) return EINVAL;
if (!VALID_USER_CSEL32(regs->r_cs))
return EINVAL;
if (regs->r_fs != 0 && !VALID_USER_DSEL32(regs->r_fs) &&
!(VALID_USER_FSEL32(regs->r_fs) && pcb->pcb_fs != 0))
return EINVAL;
if (regs->r_gs != 0 && !VALID_USER_DSEL32(regs->r_gs) &&
!(VALID_USER_GSEL32(regs->r_gs) && pcb->pcb_gs != 0))
return EINVAL;
if (regs->r_es != 0 && !VALID_USER_DSEL32(regs->r_es))
return EINVAL;
if (!VALID_USER_DSEL32(regs->r_ds) ||
!VALID_USER_DSEL32(regs->r_ss))
return EINVAL;
if (regs->r_eip >= VM_MAXUSER_ADDRESS32)
return EINVAL; return EINVAL;
tf->tf_rax = regs->r_eax; tf->tf_rax = regs->r_eax;