* [PATCH v2] checkpatch: add warning on invalid %p extensions
@ 2017-02-10 22:43 ` william.c.roberts
0 siblings, 0 replies; 4+ messages in thread
From: william.c.roberts @ 2017-02-10 22:43 UTC (permalink / raw)
To: linux-kernel, joe, apw; +Cc: keescook, kernel-hardening, William Roberts
From: William Roberts <william.c.roberts@intel.com>
The kernel supports %p extensions as documented in
Documentation/printk-formats.txt. Warn on possibly
improper use of non-extension characters.
One issue would be the usage of %pk when %pK should have
been used. This has a side-effect of appearing to work
alright, but does not respect the kptr_restrict setting
as %pK does.
Sample output:
WARNING: Invalid vsprintf pointer extension '%pk'
+ printk(KERN_INFO "Could not allocate IRQ %d for PCI Applicom device. %pk\n", dev->irq, pci_get_class); // NOT OK
WARNING: Invalid vsprintf pointer extension '%pn'
+ sprintf(buf, "%pn", x); // NOT OK
Signed-off-by: William Roberts <william.c.roberts@intel.com>
---
scripts/checkpatch.pl | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 982c52c..fa22751 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6096,6 +6096,12 @@ sub process {
"recursive locking is bad, do not use this ever.\n" . $herecurr);
}
+# check for vsprintf extension %p<foo> misuses
+ if (get_quoted_string($line, $rawline) =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
+ WARN("VSPRINTF_POINTER_EXTENSION",
+ "Invalid vsprintf pointer extension '$1'\n" . $herecurr);
+ }
+
# check for lockdep_set_novalidate_class
if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kernel-hardening] [PATCH v2] checkpatch: add warning on invalid %p extensions
@ 2017-02-10 22:43 ` william.c.roberts
0 siblings, 0 replies; 4+ messages in thread
From: william.c.roberts @ 2017-02-10 22:43 UTC (permalink / raw)
To: linux-kernel, joe, apw; +Cc: keescook, kernel-hardening, William Roberts
From: William Roberts <william.c.roberts@intel.com>
The kernel supports %p extensions as documented in
Documentation/printk-formats.txt. Warn on possibly
improper use of non-extension characters.
One issue would be the usage of %pk when %pK should have
been used. This has a side-effect of appearing to work
alright, but does not respect the kptr_restrict setting
as %pK does.
Sample output:
WARNING: Invalid vsprintf pointer extension '%pk'
+ printk(KERN_INFO "Could not allocate IRQ %d for PCI Applicom device. %pk\n", dev->irq, pci_get_class); // NOT OK
WARNING: Invalid vsprintf pointer extension '%pn'
+ sprintf(buf, "%pn", x); // NOT OK
Signed-off-by: William Roberts <william.c.roberts@intel.com>
---
scripts/checkpatch.pl | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 982c52c..fa22751 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6096,6 +6096,12 @@ sub process {
"recursive locking is bad, do not use this ever.\n" . $herecurr);
}
+# check for vsprintf extension %p<foo> misuses
+ if (get_quoted_string($line, $rawline) =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
+ WARN("VSPRINTF_POINTER_EXTENSION",
+ "Invalid vsprintf pointer extension '$1'\n" . $herecurr);
+ }
+
# check for lockdep_set_novalidate_class
if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] checkpatch: add warning on invalid %p extensions
2017-02-10 22:43 ` [kernel-hardening] " william.c.roberts
@ 2017-02-10 22:49 ` Joe Perches
-1 siblings, 0 replies; 4+ messages in thread
From: Joe Perches @ 2017-02-10 22:49 UTC (permalink / raw)
To: william.c.roberts, linux-kernel, apw; +Cc: keescook, kernel-hardening
On Fri, 2017-02-10 at 14:43 -0800, william.c.roberts@intel.com wrote:
> From: William Roberts <william.c.roberts@intel.com>
>
> The kernel supports %p extensions as documented in
> Documentation/printk-formats.txt. Warn on possibly
> improper use of non-extension characters.
>
> One issue would be the usage of %pk when %pK should have
> been used. This has a side-effect of appearing to work
> alright, but does not respect the kptr_restrict setting
> as %pK does.
>
> Sample output:
> WARNING: Invalid vsprintf pointer extension '%pk'
> + printk(KERN_INFO "Could not allocate IRQ %d for PCI Applicom device. %pk\n", dev->irq, pci_get_class); // NOT OK
>
> WARNING: Invalid vsprintf pointer extension '%pn'
> + sprintf(buf, "%pn", x); // NOT OK
>
> Signed-off-by: William Roberts <william.c.roberts@intel.com>
> ---
> scripts/checkpatch.pl | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 982c52c..fa22751 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -6096,6 +6096,12 @@ sub process {
> "recursive locking is bad, do not use this ever.\n" . $herecurr);
> }
>
> +# check for vsprintf extension %p<foo> misuses
> + if (get_quoted_string($line, $rawline) =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
> + WARN("VSPRINTF_POINTER_EXTENSION",
> + "Invalid vsprintf pointer extension '$1'\n" . $herecurr);
> + }
> +
nack.
You can't just use get_quoted_string.
You have to verify that the thing being scanned is
actually a format. There are many quoted uses of
%p like %%pil and %%pstate used by inline assembly.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [kernel-hardening] Re: [PATCH v2] checkpatch: add warning on invalid %p extensions
@ 2017-02-10 22:49 ` Joe Perches
0 siblings, 0 replies; 4+ messages in thread
From: Joe Perches @ 2017-02-10 22:49 UTC (permalink / raw)
To: william.c.roberts, linux-kernel, apw; +Cc: keescook, kernel-hardening
On Fri, 2017-02-10 at 14:43 -0800, william.c.roberts@intel.com wrote:
> From: William Roberts <william.c.roberts@intel.com>
>
> The kernel supports %p extensions as documented in
> Documentation/printk-formats.txt. Warn on possibly
> improper use of non-extension characters.
>
> One issue would be the usage of %pk when %pK should have
> been used. This has a side-effect of appearing to work
> alright, but does not respect the kptr_restrict setting
> as %pK does.
>
> Sample output:
> WARNING: Invalid vsprintf pointer extension '%pk'
> + printk(KERN_INFO "Could not allocate IRQ %d for PCI Applicom device. %pk\n", dev->irq, pci_get_class); // NOT OK
>
> WARNING: Invalid vsprintf pointer extension '%pn'
> + sprintf(buf, "%pn", x); // NOT OK
>
> Signed-off-by: William Roberts <william.c.roberts@intel.com>
> ---
> scripts/checkpatch.pl | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 982c52c..fa22751 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -6096,6 +6096,12 @@ sub process {
> "recursive locking is bad, do not use this ever.\n" . $herecurr);
> }
>
> +# check for vsprintf extension %p<foo> misuses
> + if (get_quoted_string($line, $rawline) =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
> + WARN("VSPRINTF_POINTER_EXTENSION",
> + "Invalid vsprintf pointer extension '$1'\n" . $herecurr);
> + }
> +
nack.
You can't just use get_quoted_string.
You have to verify that the thing being scanned is
actually a format. There are many quoted uses of
%p like %%pil and %%pstate used by inline assembly.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-02-10 22:49 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-02-10 22:43 [PATCH v2] checkpatch: add warning on invalid %p extensions william.c.roberts
2017-02-10 22:43 ` [kernel-hardening] " william.c.roberts
2017-02-10 22:49 ` Joe Perches
2017-02-10 22:49 ` [kernel-hardening] " Joe Perches
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