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  1. 10 4月, 2013 2 次提交
  3. 13 3月, 2013 1 次提交
  5. 11 3月, 2013 1 次提交
  7. 07 3月, 2013 3 次提交
  9. 05 3月, 2013 3 次提交
    • H
      s390/mm: fix flush_tlb_kernel_range() · f6a70a07
      由 Heiko Carstens 提交于 
      Our flush_tlb_kernel_range() implementation calls __tlb_flush_mm() with
&init_mm as argument. __tlb_flush_mm() however will only flush tlbs
for the passed in mm if its mm_cpumask is not empty.

For the init_mm however its mm_cpumask has never any bits set. Which in
turn means that our flush_tlb_kernel_range() implementation doesn't
work at all.

This can be easily verified with a vmalloc/vfree loop which allocates
a page, writes to it and then frees the page again. A crash will follow
almost instantly.

To fix this remove the cpumask_empty() check in __tlb_flush_mm() since
there shouldn't be too many mms with a zero mm_cpumask, besides the
init_mm of course.

Cc: stable@vger.kernel.org
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      f6a70a07
    • H
      s390/mm: fix vmemmap size calculation · a7bb1ae7
      由 Heiko Carstens 提交于 
      The size of the vmemmap must be a multiple of PAGES_PER_SECTION, since the
common code always initializes the vmemmap in such pieces.
So we must round up in order to not have a too small vmemmap.

Fixes an IPL crash on 31 bit with more than 1920MB.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      a7bb1ae7
    • M
      s390: critical section cleanup vs. machine checks · 6551fbdf
      由 Martin Schwidefsky 提交于 
      The current machine check code uses the registers stored by the machine
in the lowcore at __LC_GPREGS_SAVE_AREA as the registers of the interrupted
context. The registers 0-7 of a user process can get clobbered if a machine
checks interrupts the execution of a critical section in entry[64].S.

The reason is that the critical section cleanup code may need to modify
the PSW and the registers for the previous context to get to the end of a
critical section. If registers 0-7 have to be replaced the relevant copy
will be in the registers, which invalidates the copy in the lowcore. The
machine check handler needs to explicitly store registers 0-7 to the stack.

Cc: stable@vger.kernel.org
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      6551fbdf
  11. 04 3月, 2013 1 次提交
    • E
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      由 Eric W. Biederman 提交于 
      Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  13. 28 2月, 2013 12 次提交
  15. 26 2月, 2013 1 次提交
  17. 25 2月, 2013 1 次提交
  19. 24 2月, 2013 3 次提交
  21. 23 2月, 2013 1 次提交
  23. 14 2月, 2013 11 次提交