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Don't allow access to illegal addresses in /dev/kmem to panic kernel

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(eg: above 0xffc00000).  Programs using /dev/kmem are implicitly racing
the kernel, and can get right up high in memory.  I've been running
these for some time now, but with printfs.  It's saved two panics at
least that I can remember.
This commit is contained in:
Peter Wemm 1997-05-07 20:32:41 +00:00
parent 1f8745a9c3
commit d021fc112b
2 changed files with 14 additions and 4 deletions
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7
sys/amd64/amd64/mem.c
View File

@ -38,7 +38,7 @@
*
* from: Utah $Hdr: mem.c 1.13 89/10/08$
* from: @(#)mem.c 7.2 (Berkeley) 5/9/91
* $Id: mem.c,v 1.42 1997/04/14 15:54:26 bde Exp $
* $Id: mem.c,v 1.43 1997/05/07 20:02:37 peter Exp $
*/
/*
@ -239,6 +239,11 @@ mmrw(dev, uio, flags)
*/
addr = trunc_page(uio->uio_offset);
eaddr = round_page(uio->uio_offset + c);
if (addr < (vm_offset_t)VADDR(PTDPTDI, 0))
return EFAULT;
if (eaddr >= (vm_offset_t)VADDR(APTDPTDI, 0))
return EFAULT;
for (; addr < eaddr; addr += PAGE_SIZE)
if (pmap_extract(kernel_pmap, addr) == 0)
return EFAULT;

7
sys/i386/i386/mem.c
View File

@ -38,7 +38,7 @@
*
* from: Utah $Hdr: mem.c 1.13 89/10/08$
* from: @(#)mem.c 7.2 (Berkeley) 5/9/91
* $Id: mem.c,v 1.42 1997/04/14 15:54:26 bde Exp $
* $Id: mem.c,v 1.43 1997/05/07 20:02:37 peter Exp $
*/
/*
@ -239,6 +239,11 @@ mmrw(dev, uio, flags)
*/
addr = trunc_page(uio->uio_offset);
eaddr = round_page(uio->uio_offset + c);
if (addr < (vm_offset_t)VADDR(PTDPTDI, 0))
return EFAULT;
if (eaddr >= (vm_offset_t)VADDR(APTDPTDI, 0))
return EFAULT;
for (; addr < eaddr; addr += PAGE_SIZE)
if (pmap_extract(kernel_pmap, addr) == 0)
return EFAULT;