Linux 2.6.22.18

Linux 2.6.22.18

[Greg Kroah-Hartman]

We (the -stable team) are announcing the release of the 2.6.22.18
kernel.

It fixes one thing, CVE-2008-0600.

All users of the 2.6.22 series, with untrusted local users are strongly
encouraged to upgrade.

I'll also be replying to this message with a copy of the patch between
2.6.22.17 and 2.6.22.18

The updated 2.6.22.y git tree can be found at:
        git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-2.6.22.y.git
and can be browsed at the normal kernel.org git web browser:
        http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.22.y.git;a=summary

thanks,

greg k-h

--------

 Makefile    |    2 +-
 fs/splice.c |    3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

Summary of changes from v2.6.22.17 to v2.6.22.18
================================================

Bastian Blank (1):
      splice: fix user pointer access in get_iovec_page_array() (CVE-2008-0600)

Greg Kroah-Hartman (1):
      Linux 2.6.22.18

Re: Linux 2.6.22.18

[Greg Kroah-Hartman]

diff --git a/Makefile b/Makefile
index 6a949eb..99c5e87 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 22
-EXTRAVERSION = .17
+EXTRAVERSION = .18
 NAME = Holy Dancing Manatees, Batman!
 
 # *DOCUMENTATION*
diff --git a/fs/splice.c b/fs/splice.c
index e263d3b..dbbe267 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1182,6 +1182,9 @@ static int get_iovec_page_array(const struct iovec __user *iov,
 		if (unlikely(!base))
 			break;
 
+		if (!access_ok(VERIFY_READ, base, len))
+			break;
+
 		/*
 		 * Get this base offset and number of pages, then map
 		 * in the user pages.

Re: Linux 2.6.22.18

[Matthew Keenan]

On Sun, 2008-02-10 at 23:43 -0800, Greg Kroah-Hartman wrote:
> diff --git a/Makefile b/Makefile
> index 6a949eb..99c5e87 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1,7 +1,7 @@
>  VERSION = 2
>  PATCHLEVEL = 6
>  SUBLEVEL = 22
> -EXTRAVERSION = .17
> +EXTRAVERSION = .18
>  NAME = Holy Dancing Manatees, Batman!
>  
>  # *DOCUMENTATION*
> diff --git a/fs/splice.c b/fs/splice.c
> index e263d3b..dbbe267 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1182,6 +1182,9 @@ static int get_iovec_page_array(const struct iovec __user *iov,
>  		if (unlikely(!base))
>  			break;
>  
> +		if (!access_ok(VERIFY_READ, base, len))
> +			break;
> +
>  		/*
>  		 * Get this base offset and number of pages, then map
>  		 * in the user pages.

Maybe I'm missing something here, but is there are reason that the patch
for 2.6.22 differs from 2.6.2[34]? The "if(unlikely(!base))" is removed
in the latter.

Matt

Re: Linux 2.6.22.18

[Greg KH]

On Mon, Feb 11, 2008 at 11:31:25AM +0000, Matthew Keenan wrote:
> 
> On Sun, 2008-02-10 at 23:43 -0800, Greg Kroah-Hartman wrote:
> > diff --git a/Makefile b/Makefile
> > index 6a949eb..99c5e87 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1,7 +1,7 @@
> >  VERSION = 2
> >  PATCHLEVEL = 6
> >  SUBLEVEL = 22
> > -EXTRAVERSION = .17
> > +EXTRAVERSION = .18
> >  NAME = Holy Dancing Manatees, Batman!
> >  
> >  # *DOCUMENTATION*
> > diff --git a/fs/splice.c b/fs/splice.c
> > index e263d3b..dbbe267 100644
> > --- a/fs/splice.c
> > +++ b/fs/splice.c
> > @@ -1182,6 +1182,9 @@ static int get_iovec_page_array(const struct iovec __user *iov,
> >  		if (unlikely(!base))
> >  			break;
> >  
> > +		if (!access_ok(VERIFY_READ, base, len))
> > +			break;
> > +
> >  		/*
> >  		 * Get this base offset and number of pages, then map
> >  		 * in the user pages.
> 
> Maybe I'm missing something here, but is there are reason that the patch
> for 2.6.22 differs from 2.6.2[34]? The "if(unlikely(!base))" is removed
> in the latter.

the logic is a little different in 2.6.22 and earlier in regards to this
area of code.  This way we are safer.

thanks,

greg k-h

Re: Linux 2.6.22.18

[Linus Torvalds]

On Mon, 11 Feb 2008, Matthew Keenan wrote:
> 
> Maybe I'm missing something here, but is there are reason that the patch
> for 2.6.22 differs from 2.6.2[34]? The "if(unlikely(!base))" is removed
> in the latter.

No real reason, except that there are simply two versions of the patches 
floating around: the original (that added the "access_ok()"), and the one 
I actually applied to the development tree (in which I hand-edited the 
patch to remove the old "!base" comparison, since I thought that one was 
just wrong).

Which one you prefer is probably a matter of taste, and which one you 
ended up picking up is probably a matter of just luck. They are basically 
the same, with the only difference being whether you think NULL is special 
or not. I don't personally think it should be, and if people want to put 
data at their linear address zero, they may have reasons for it (vm86 mode 
is one such reason, things like wine might be another - basically some 
environments may have legacy reasons to think that address 0 can be 
something else than just NULL).

For any *normal* program, this should be totally immaterial, since address 
0 won't be mapped, and you'll just take an EFAULT later. And from the 
security standpoint in this particular case, address 0 is a perfectly 
normal user address, so there is nothing special about it.

[ What _is_ special about address 0 is that if the kernel forgets some 
  NULL pointer check, we'd want to see an oops, not a user space access. 

  But that's really a totally different class of bug, and quite frankly, 
  if you want to disallow people mmap'ing at offset zero, it's an mmap() 
  issue, not anything else. See the new SECURITY_DEFAULT_MMAP_MIN_ADDR 
  thing for that. ]

In this particular case, maybe some -stable person might have felt that 
they just didn't want to change semantics for the NULL pointer, or maybe 
they didn't even notice that what I committed to the development tree was 
slightly changed. It _really_ doesn't matter.

			Linus

Re: Linux 2.6.22.18

[Florian Weimer]

* Greg KH:

> the logic is a little different in 2.6.22 and earlier in regards to this
> area of code.  This way we are safer.

Your patch doesn't include the CVE-2006-0010 hunk.  Is this because
get_user() implies an access_ok() check (while __copy_from_user()
obviously does not)?

Re: Linux 2.6.22.18

[Greg KH]

On Tue, Feb 12, 2008 at 06:48:42PM +0100, Florian Weimer wrote:
> * Greg KH:
> 
> > the logic is a little different in 2.6.22 and earlier in regards to this
> > area of code.  This way we are safer.
> 
> Your patch doesn't include the CVE-2006-0010 hunk.  Is this because
> get_user() implies an access_ok() check (while __copy_from_user()
> obviously does not)?

Yes, that is exactly why.  CVE-2006-0010 and -0009 are not applicable to
kernels prior to 2.6.23.

thanks,

greg k-h