lkml.org 
[lkml]   [2012]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC v2 4/7] modsig: add integrity_module_check hook
From
On Thu, Aug 16, 2012 at 12:13 AM, Kasatkin, Dmitry
<dmitry.kasatkin@intel.com> wrote:
> On Wed, Aug 15, 2012 at 11:16 PM, Serge Hallyn
> <serge.hallyn@canonical.com> wrote:
>> Quoting Dmitry Kasatkin (dmitry.kasatkin@intel.com):
>>> IMA measures/appraises modules when modprobe or insmod opens and read them.
>>> Unfortunately, there are no guarantees between what is read by userspace and
>>> what is passed to the kernel via load_module system call. This patch adds a
>>> hook called integrity_module_check() to verify the integrity of the module
>>> being loaded.
>>>
>>> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
>>> ---
>>> include/linux/integrity.h | 10 ++++++++++
>>> kernel/module.c | 9 +++++++++
>>> 2 files changed, 19 insertions(+)
>>>
>>> diff --git a/include/linux/integrity.h b/include/linux/integrity.h
>>> index 66c5fe9..a80ec06 100644
>>> --- a/include/linux/integrity.h
>>> +++ b/include/linux/integrity.h
>>> @@ -37,4 +37,14 @@ static inline void integrity_inode_free(struct inode *inode)
>>> return;
>>> }
>>> #endif /* CONFIG_INTEGRITY_H */
>>> +
>>> +#ifdef CONFIG_INTEGRITY_MODULES
>>> +int integrity_module_check(const void *hdr, const unsigned long len);
>>
>> sadly not bisect-safe, since integrity_module_check() is defined in
>> the next patch.
>>
>
> Ok.. Hooks come after implementation...
> Will swap.
>

Hi Serge.

Actually Kconfig option is defined in following implementation patch,
so CONFIG_INTEGRITY_MODULES is not defined and it will compile inline
empty function.

Why is it not bisect-safe?

- Dmitry

> Thanks.
>
>>> +#else
>>> +static inline int integrity_module_check(const void *buf, unsigned long len)
>>> +{
>>> + return 0;
>>> +}
>>> +#endif
>>> +
>>> #endif /* _LINUX_INTEGRITY_H */
>>> diff --git a/kernel/module.c b/kernel/module.c
>>> index 4edbd9c..791da47 100644
>>> --- a/kernel/module.c
>>> +++ b/kernel/module.c
>>> @@ -58,6 +58,7 @@
>>> #include <linux/jump_label.h>
>>> #include <linux/pfn.h>
>>> #include <linux/bsearch.h>
>>> +#include <linux/integrity.h>
>>>
>>> #define CREATE_TRACE_POINTS
>>> #include <trace/events/module.h>
>>> @@ -2437,6 +2438,14 @@ static int copy_and_check(struct load_info *info,
>>>
>>> info->hdr = hdr;
>>> info->len = len;
>>> +
>>> + err = integrity_module_check(hdr, len);
>>> + if (err < 0)
>>> + goto free_hdr;
>>> +
>>> + /* cut signature tail */
>>> + info->len = err;
>>> +
>>> return 0;
>>>
>>> free_hdr:
>>> --
>>> 1.7.9.5
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html


\
 
 \ /
  Last update: 2012-08-17 08:21    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site