[PATCH] title: no lookup_page for if statement

[PATCH] title: no lookup_page for if statement

[Nicholas Krause]

This patch removes the if define statement for page_lookup in order
to remove a fix me of this not being defined as of yet.

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
---
 0001-title-no-lookup_page-for-if-statement.patch | 37 ++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 0001-title-no-lookup_page-for-if-statement.patch

diff --git a/0001-title-no-lookup_page-for-if-statement.patch b/0001-title-no-lookup_page-for-if-statement.patch
new file mode 100644
index 0000000..f11c12e
--- /dev/null
+++ b/0001-title-no-lookup_page-for-if-statement.patch
@@ -0,0 +1,37 @@
+From 23c4afac6742d5df1d083ab6335a0a69f38c76b0 Mon Sep 17 00:00:00 2001
+From: Nicholas Krause <xerofoify@gmail.com>
+Date: Mon, 14 Jul 2014 14:39:02 -0400
+Subject: [PATCH] title: no lookup_page for if statement
+
+This patch removes the if define statement for page_lookup in order
+to remove a fix me of this not being defined as of yet.
+
+Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
+---
+ arch/tile/mm/fault.c | 3 ---
+ 1 file changed, 3 deletions(-)
+
+diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
+index 6c05712..2297bf7 100644
+--- a/arch/tile/mm/fault.c
++++ b/arch/tile/mm/fault.c
+@@ -513,8 +513,6 @@ no_context:
+ 
+ 	bust_spinlocks(1);
+ 
+-	/* FIXME: no lookup_address() yet */
+-#ifdef SUPPORT_LOOKUP_ADDRESS
+ 	if (fault_num == INT_ITLB_MISS) {
+ 		pte_t *pte = lookup_address(address);
+ 
+@@ -523,7 +521,6 @@ no_context:
+ 			       " non-executable page - exploit attempt?"
+ 			       " (uid: %d)\n", current->uid);
+ 	}
+-#endif
+ 	if (address < PAGE_SIZE)
+ 		pr_alert("Unable to handle kernel NULL pointer dereference\n");
+ 	else
+-- 
+1.9.1
+
-- 
1.9.1

Re: [PATCH] title: no lookup_page for if statement

[Paul Bolle]

On Mon, 2014-07-14 at 14:49 -0400, Nicholas Krause wrote:
> This patch removes the if define statement for page_lookup in order
> to remove a fix me of this not being defined as of yet.
> 
> Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> ---
>  0001-title-no-lookup_page-for-if-statement.patch | 37 ++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
>  create mode 100644 0001-title-no-lookup_page-for-if-statement.patch
> 
> diff --git a/0001-title-no-lookup_page-for-if-statement.patch b/0001-title-no-lookup_page-for-if-statement.patch
> new file mode 100644
> index 0000000..f11c12e
> --- /dev/null
> +++ b/0001-title-no-lookup_page-for-if-statement.patch
> @@ -0,0 +1,37 @@
> +From 23c4afac6742d5df1d083ab6335a0a69f38c76b0 Mon Sep 17 00:00:00 2001
> +From: Nicholas Krause <xerofoify@gmail.com>
> +Date: Mon, 14 Jul 2014 14:39:02 -0400
> +Subject: [PATCH] title: no lookup_page for if statement
> +
> +This patch removes the if define statement for page_lookup in order
> +to remove a fix me of this not being defined as of yet.
> +
> +Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> +---
> + arch/tile/mm/fault.c | 3 ---
> + 1 file changed, 3 deletions(-)
> +
> +diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
> +index 6c05712..2297bf7 100644
> +--- a/arch/tile/mm/fault.c
> ++++ b/arch/tile/mm/fault.c
> +@@ -513,8 +513,6 @@ no_context:
> + 
> + 	bust_spinlocks(1);
> + 
> +-	/* FIXME: no lookup_address() yet */
> +-#ifdef SUPPORT_LOOKUP_ADDRESS

Nicholas, stop! Just stop.

> + 	if (fault_num == INT_ITLB_MISS) {
> + 		pte_t *pte = lookup_address(address);
> + 
> +@@ -523,7 +521,6 @@ no_context:
> + 			       " non-executable page - exploit attempt?"
> + 			       " (uid: %d)\n", current->uid);
> + 	}
> +-#endif
> + 	if (address < PAGE_SIZE)
> + 		pr_alert("Unable to handle kernel NULL pointer dereference\n");
> + 	else
> +-- 
> +1.9.1
> +

For those not yet familiar with this train wreck, please do
    git grep SUPPORT_LOOKUP_ADDRESS


Paul Bolle

Re: [PATCH] title: no lookup_page for if statement

[Nick Krause]

On Mon, Jul 14, 2014 at 2:59 PM, Paul Bolle <pebolle@tiscali.nl> wrote:
> On Mon, 2014-07-14 at 14:49 -0400, Nicholas Krause wrote:
>> This patch removes the if define statement for page_lookup in order
>> to remove a fix me of this not being defined as of yet.
>>
>> Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
>> ---
>>  0001-title-no-lookup_page-for-if-statement.patch | 37 ++++++++++++++++++++++++
>>  1 file changed, 37 insertions(+)
>>  create mode 100644 0001-title-no-lookup_page-for-if-statement.patch
>>
>> diff --git a/0001-title-no-lookup_page-for-if-statement.patch b/0001-title-no-lookup_page-for-if-statement.patch
>> new file mode 100644
>> index 0000000..f11c12e
>> --- /dev/null
>> +++ b/0001-title-no-lookup_page-for-if-statement.patch
>> @@ -0,0 +1,37 @@
>> +From 23c4afac6742d5df1d083ab6335a0a69f38c76b0 Mon Sep 17 00:00:00 2001
>> +From: Nicholas Krause <xerofoify@gmail.com>
>> +Date: Mon, 14 Jul 2014 14:39:02 -0400
>> +Subject: [PATCH] title: no lookup_page for if statement
>> +
>> +This patch removes the if define statement for page_lookup in order
>> +to remove a fix me of this not being defined as of yet.
>> +
>> +Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
>> +---
>> + arch/tile/mm/fault.c | 3 ---
>> + 1 file changed, 3 deletions(-)
>> +
>> +diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
>> +index 6c05712..2297bf7 100644
>> +--- a/arch/tile/mm/fault.c
>> ++++ b/arch/tile/mm/fault.c
>> +@@ -513,8 +513,6 @@ no_context:
>> +
>> +     bust_spinlocks(1);
>> +
>> +-    /* FIXME: no lookup_address() yet */
>> +-#ifdef SUPPORT_LOOKUP_ADDRESS
>
> Nicholas, stop! Just stop.
>
>> +     if (fault_num == INT_ITLB_MISS) {
>> +             pte_t *pte = lookup_address(address);
>> +
>> +@@ -523,7 +521,6 @@ no_context:
>> +                            " non-executable page - exploit attempt?"
>> +                            " (uid: %d)\n", current->uid);
>> +     }
>> +-#endif
>> +     if (address < PAGE_SIZE)
>> +             pr_alert("Unable to handle kernel NULL pointer dereference\n");
>> +     else
>> +--
>> +1.9.1
>> +
>
> For those not yet familiar with this train wreck, please do
>     git grep SUPPORT_LOOKUP_ADDRESS
>
>
> Paul Bolle
>

Very well , I will not work on this any longer as I seem to be just
screwing it up.
Cheers Nick

Re: [PATCH] title: no lookup_page for if statement

[Chris Metcalf]

On 7/14/2014 2:59 PM, Paul Bolle wrote:
> On Mon, 2014-07-14 at 14:49 -0400, Nicholas Krause wrote:
>> >This patch removes the if define statement for page_lookup in order
>> >to remove a fix me of this not being defined as of yet.
>> >
>> >Signed-off-by: Nicholas Krause<xerofoify@gmail.com>

Nicholas, you can't just enable this code; it will break the
build, since there is no lookup_address() symbol on tile.

I'd like to encourage you to look for more substantive kinds of
changes to submit to LKML.  This one and the last one (adding some
underscores to some obsolete symbols) both have ended up costing me
some time to look at and figure out what's actually going on, but
for no real value.  I suspect there may be "janitor" tasks that
are more useful if you are looking for small starting points
(Google for "linux kernel janitors").

That said I'm going to go ahead and check in the following change
which actually does work, now that my attention has been drawn here.

diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 6c0571216a9d..7e884001ca6a 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -513,17 +513,14 @@ no_context:

         bust_spinlocks(1);

-       /* FIXME: no lookup_address() yet */
-#ifdef SUPPORT_LOOKUP_ADDRESS
-       if (fault_num == INT_ITLB_MISS) {
-               pte_t *pte = lookup_address(address);
+       if (fault_num == INT_ITLB_MISS && address >= PAGE_OFFSET) {
+               pte_t *pte = virt_to_kpte(address);

-               if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
-                       pr_crit("kernel tried to execute"
-                              " non-executable page - exploit attempt?"
-                              " (uid: %d)\n", current->uid);
+               if (pte && pte_present(*pte) && !pte_exec(*pte))
+                       pr_crit("kernel tried to execute non-executable page"
+                               " - exploit attempt? (uid: %d)\n",
+                               from_kuid(&init_user_ns, current_uid()));
         }
-#endif
         if (address < PAGE_SIZE)
                 pr_alert("Unable to handle kernel NULL pointer dereference\n");
         else

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com

Re: [PATCH] title: no lookup_page for if statement

[Nick Krause]

On Mon, Jul 14, 2014 at 3:35 PM, Chris Metcalf <cmetcalf@tilera.com> wrote:
> On 7/14/2014 2:59 PM, Paul Bolle wrote:
>>
>> On Mon, 2014-07-14 at 14:49 -0400, Nicholas Krause wrote:
>>>
>>> >This patch removes the if define statement for page_lookup in order
>>> >to remove a fix me of this not being defined as of yet.
>>> >
>>> >Signed-off-by: Nicholas Krause<xerofoify@gmail.com>
>
>
> Nicholas, you can't just enable this code; it will break the
> build, since there is no lookup_address() symbol on tile.
>
> I'd like to encourage you to look for more substantive kinds of
> changes to submit to LKML.  This one and the last one (adding some
> underscores to some obsolete symbols) both have ended up costing me
> some time to look at and figure out what's actually going on, but
> for no real value.  I suspect there may be "janitor" tasks that
> are more useful if you are looking for small starting points
> (Google for "linux kernel janitors").
>
> That said I'm going to go ahead and check in the following change
> which actually does work, now that my attention has been drawn here.
>
> diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
> index 6c0571216a9d..7e884001ca6a 100644
> --- a/arch/tile/mm/fault.c
> +++ b/arch/tile/mm/fault.c
> @@ -513,17 +513,14 @@ no_context:
>
>         bust_spinlocks(1);
>
> -       /* FIXME: no lookup_address() yet */
> -#ifdef SUPPORT_LOOKUP_ADDRESS
> -       if (fault_num == INT_ITLB_MISS) {
> -               pte_t *pte = lookup_address(address);
> +       if (fault_num == INT_ITLB_MISS && address >= PAGE_OFFSET) {
> +               pte_t *pte = virt_to_kpte(address);
>
> -               if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
> -                       pr_crit("kernel tried to execute"
> -                              " non-executable page - exploit attempt?"
> -                              " (uid: %d)\n", current->uid);
> +               if (pte && pte_present(*pte) && !pte_exec(*pte))
> +                       pr_crit("kernel tried to execute non-executable
> page"
> +                               " - exploit attempt? (uid: %d)\n",
> +                               from_kuid(&init_user_ns, current_uid()));
>         }
> -#endif
>         if (address < PAGE_SIZE)
>                 pr_alert("Unable to handle kernel NULL pointer
> dereference\n");
>         else
>
> --
> Chris Metcalf, Tilera Corp.
> http://www.tilera.com
>
Chris,
Understood I screwed up here. I am doing other changes with build and
warning errors. Plus some
fix me issues that are simple. I will double check my patches and the
code they are relating to more
carefully. I should have asked you before writing this patch:(.
Nick