"module privilege check" breaks (cross-)compilation due to libelf dependency

"module privilege check" breaks (cross-)compilation due to libelf dependency

[Turgis, Frederic]

Hi,

Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128: Implement module privilege check in staprun." has broken my cross-compilation environment to build "staprun" tool for ARM android (I do 4 first steps on host, staprun step on target), see end of mail.
Having a deeper look, there is in fact code in staprun_funcs.c that requires libelf like find_section_in_module() and get_module_required_credentials() (Elf_Scn for example) and that is not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX

I never had libelf in my ARM filesystem, I am using --with-elfutils but configure.ac in runtime/staprun states that "We link only against the system elfutils.  Connecting to a bundled elfutils build (stap/configure --with-elfutils=PATH) is too tricky to bother with"

I have then removed some code in a very hackish way to make it work (see below, basically the analysis of section STAP_PRIVILEGE_SECTION of module) but I am not sure if this is aligned with the goal of the author.
Script executes fine on target but I am "root" so this can hide some other issue



BUILD FAILURE:
  CC     staprun-staprun_funcs.o
staprun_funcs.c:237: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
staprun_funcs.c: In function 'get_module_required_credentials':
staprun_funcs.c:587: error: 'Elf_Scn' undeclared (first use in this function)
staprun_funcs.c:587: error: (Each undeclared identifier is reported only once
staprun_funcs.c:587: error: for each function it appears in.)
staprun_funcs.c:587: error: 'scn' undeclared (first use in this function)
staprun_funcs.c:588: error: 'Elf_Data' undeclared (first use in this function)
staprun_funcs.c:588: error: 'data' undeclared (first use in this function)
staprun_funcs.c:589: error: 'GElf_Shdr' undeclared (first use in this function)
staprun_funcs.c:589: error: expected ';' before 'shdr'

Hackish patch:
diff --git a/runtime/staprun/staprun_funcs.c b/runtime/staprun/staprun_funcs.c
index 163a0ce..17265f3 100644
--- a/runtime/staprun/staprun_funcs.c
+++ b/runtime/staprun/staprun_funcs.c
@@ -233,14 +233,14 @@ find_section_in_module(const void* module_file, const __off_t st_size, const cha
        }
        return scn;
 }
-#else /* no elf */
-static Elf_Scn *
-find_section_in_module(const void* v __attribute__((unused)),
-                       const __off_t o __attribute__((unused)),
-                       const char *c __attribute__((unused)))
-{
-       return NULL;
-}
+//#else /* no elf */
+//static Elf_Scn *
+//find_section_in_module(const void* v __attribute__((unused)),
+//                       const __off_t o __attribute__((unused)),
+//                       const char *c __attribute__((unused)))
+//{
+//     return NULL;
+//}
 #endif

 int
@@ -582,6 +582,7 @@ check_uprobes_module_path (
  * Returns the required credentials if they can be determined or the default safe required
  * credentials otherwise.
  */
+#if 0
 static privilege_t get_module_required_credentials (const void* module_file, const __off_t st_size)
 {
   Elf_Scn *scn = 0;
@@ -645,7 +646,7 @@ static privilege_t get_module_required_credentials (const void* module_file, con
   /* ALl is ok. Return the extrated privilege data. */
   return privilege;
 }
-
+#endif
 /*
  * Check the user's group membership.
  *
@@ -668,8 +669,9 @@ check_groups (
   off_t module_size
 )
 {
-  privilege_t user_credentials, module_required_credentials;
-
+  privilege_t user_credentials;//, module_required_credentials;
+module_data = NULL;
+module_size = 0;
   /* Lookup the user's privilege credentials. */
   user_credentials = get_privilege_credentials ();

@@ -684,6 +686,7 @@ check_groups (
     if (pr_contains (user_credentials, pr_stapsys))
       return 1;

+#ifdef HAVE_LIBELF_H
     /* For stapusr users, we must verify that the module was compiled for that privilege level. */
     module_required_credentials = get_module_required_credentials (module_data, module_size);
     if (pr_contains (user_credentials, pr_stapusr)) {
@@ -700,8 +703,8 @@ check_groups (

     if (user_credentials == pr_none)
       return -2;
-
     return 0;
+#endif
   }

   /* Not fatal. The module could still be on a blessed path. */


Regards
Fred

Frederic Turgis
OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia


Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

Re: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Mark Wielaard]

On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128: Implement
> module privilege check in staprun." has broken my cross-compilation
> environment to build "staprun" tool for ARM android (I do 4 first steps
> on host, staprun step on target), see end of mail.
>
> Having a deeper look, there is in fact code in staprun_funcs.c that
> requires libelf like find_section_in_module() and
> get_module_required_credentials() (Elf_Scn for example) and that is
> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX

I had something similar a few days ago, though I don't remember exactly
which setup it was on. Does the following commit help in your case?

commit fa2418539b4ac2cb1352948f68da08890cec7774
Author: Mark Wielaard <mjw@redhat.com>
Date:   Sat Nov 26 02:33:01 2011 +0100

  Fix build error in staprun_funcs.c when HAVE_ELF_GETSHDRSTRNDX is not set.
  
  Mark find_section_in_module arguments unused when HAVE_ELF_GETSHDRSTRNDX
  isn't set.

Or do you need more than that?

Cheers,

Mark

RE: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Turgis, Frederic]

Hi,

After making few times the mistake to not check latest code, I ensure now to be on HEAD of master branch ;-)

My feeling is that you had an environment with libelf available but elf_getshdrstrndx() not available.

This is then not sufficient but similar. This solves the issue of unused parameters (this is a warning considered as an error) but not the issue of the use of Elf_Scn type. Systemtap only defines "typedef struct Elf_Scn Elf_Scn;", real definition would come from "elfutils-0.143/libelf/libelfP.h" in my case (but --with-elfutils is not used)



Regards
Fred

Frederic Turgis
OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia



>
Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

-----Original Message-----
>From: Mark Wielaard [mailto:mjw@redhat.com]
>Sent: Monday, December 05, 2011 2:58 PM
>To: Turgis, Frederic
>Cc: SystemTap
>Subject: Re: "module privilege check" breaks
>(cross-)compilation due to libelf dependency
>
>On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
>> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128: Implement
>> module privilege check in staprun." has broken my cross-compilation
>> environment to build "staprun" tool for ARM android (I do 4 first
>> steps on host, staprun step on target), see end of mail.
>>
>> Having a deeper look, there is in fact code in staprun_funcs.c that
>> requires libelf like find_section_in_module() and
>> get_module_required_credentials() (Elf_Scn for example) and that is
>> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX
>
>I had something similar a few days ago, though I don't
>remember exactly which setup it was on. Does the following
>commit help in your case?
>
>commit fa2418539b4ac2cb1352948f68da08890cec7774
>Author: Mark Wielaard <mjw@redhat.com>
>Date:   Sat Nov 26 02:33:01 2011 +0100
>
>  Fix build error in staprun_funcs.c when
>HAVE_ELF_GETSHDRSTRNDX is not set.
>
>  Mark find_section_in_module arguments unused when
>HAVE_ELF_GETSHDRSTRNDX
>  isn't set.
>
>Or do you need more than that?
>
>Cheers,
>
>Mark
>

Re: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Dave Brolley]

Hi,

Sorry for this. I'll re-examine the code to make sure it builds in all 
environments.

Dave

On 12/05/2011 09:09 AM, Turgis, Frederic wrote:
> Hi,
>
> After making few times the mistake to not check latest code, I ensure now to be on HEAD of master branch ;-)
>
> My feeling is that you had an environment with libelf available but elf_getshdrstrndx() not available.
>
> This is then not sufficient but similar. This solves the issue of unused parameters (this is a warning considered as an error) but not the issue of the use of Elf_Scn type. Systemtap only defines "typedef struct Elf_Scn Elf_Scn;", real definition would come from "elfutils-0.143/libelf/libelfP.h" in my case (but --with-elfutils is not used)
>
>
>
> Regards
> Fred
>
> Frederic Turgis
> OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia
>
>
>
> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>
> -----Original Message-----
>> From: Mark Wielaard [mailto:mjw@redhat.com]
>> Sent: Monday, December 05, 2011 2:58 PM
>> To: Turgis, Frederic
>> Cc: SystemTap
>> Subject: Re: "module privilege check" breaks
>> (cross-)compilation due to libelf dependency
>>
>> On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
>>> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128: Implement
>>> module privilege check in staprun." has broken my cross-compilation
>>> environment to build "staprun" tool for ARM android (I do 4 first
>>> steps on host, staprun step on target), see end of mail.
>>>
>>> Having a deeper look, there is in fact code in staprun_funcs.c that
>>> requires libelf like find_section_in_module() and
>>> get_module_required_credentials() (Elf_Scn for example) and that is
>>> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX
>> I had something similar a few days ago, though I don't
>> remember exactly which setup it was on. Does the following
>> commit help in your case?
>>
>> commit fa2418539b4ac2cb1352948f68da08890cec7774
>> Author: Mark Wielaard<mjw@redhat.com>
>> Date:   Sat Nov 26 02:33:01 2011 +0100
>>
>>   Fix build error in staprun_funcs.c when
>> HAVE_ELF_GETSHDRSTRNDX is not set.
>>
>>   Mark find_section_in_module arguments unused when
>> HAVE_ELF_GETSHDRSTRNDX
>>   isn't set.
>>
>> Or do you need more than that?
>>
>> Cheers,
>>
>> Mark
>>

RE: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Turgis, Frederic]

Thanks, my first mail points to code that broke on my environment, still I do not know all the goals of the code so could not provide more complete/clean stuff.

Regards
Fred

Frederic Turgis
OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia



>
Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

-----Original Message-----
>From: systemtap-owner@sourceware.org
>[mailto:systemtap-owner@sourceware.org] On Behalf Of Dave Brolley
>Sent: Monday, December 05, 2011 5:13 PM
>To: systemtap@sourceware.org
>Subject: Re: "module privilege check" breaks
>(cross-)compilation due to libelf dependency
>
>Hi,
>
>Sorry for this. I'll re-examine the code to make sure it
>builds in all environments.
>
>Dave
>
>On 12/05/2011 09:09 AM, Turgis, Frederic wrote:
>> Hi,
>>
>> After making few times the mistake to not check latest code,
>I ensure
>> now to be on HEAD of master branch ;-)
>>
>> My feeling is that you had an environment with libelf
>available but elf_getshdrstrndx() not available.
>>
>> This is then not sufficient but similar. This solves the issue of
>> unused parameters (this is a warning considered as an error) but not
>> the issue of the use of Elf_Scn type. Systemtap only defines
>"typedef
>> struct Elf_Scn Elf_Scn;", real definition would come from
>> "elfutils-0.143/libelf/libelfP.h" in my case (but --with-elfutils is
>> not used)
>>
>>
>>
>> Regards
>> Fred
>>
>> Frederic Turgis
>> OMAP Platform Business Unit - OMAP System Engineering - Platform
>> Enablement - System Multimedia
>>
>>
>>
>> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve
>> Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>>
>> -----Original Message-----
>>> From: Mark Wielaard [mailto:mjw@redhat.com]
>>> Sent: Monday, December 05, 2011 2:58 PM
>>> To: Turgis, Frederic
>>> Cc: SystemTap
>>> Subject: Re: "module privilege check" breaks
>(cross-)compilation due
>>> to libelf dependency
>>>
>>> On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
>>>> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128:
>Implement
>>>> module privilege check in staprun." has broken my
>cross-compilation
>>>> environment to build "staprun" tool for ARM android (I do 4 first
>>>> steps on host, staprun step on target), see end of mail.
>>>>
>>>> Having a deeper look, there is in fact code in
>staprun_funcs.c that
>>>> requires libelf like find_section_in_module() and
>>>> get_module_required_credentials() (Elf_Scn for example)
>and that is
>>>> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX
>>> I had something similar a few days ago, though I don't remember
>>> exactly which setup it was on. Does the following commit
>help in your
>>> case?
>>>
>>> commit fa2418539b4ac2cb1352948f68da08890cec7774
>>> Author: Mark Wielaard<mjw@redhat.com>
>>> Date:   Sat Nov 26 02:33:01 2011 +0100
>>>
>>>   Fix build error in staprun_funcs.c when HAVE_ELF_GETSHDRSTRNDX is
>>> not set.
>>>
>>>   Mark find_section_in_module arguments unused when
>>> HAVE_ELF_GETSHDRSTRNDX
>>>   isn't set.
>>>
>>> Or do you need more than that?
>>>
>>> Cheers,
>>>
>>> Mark
>>>
>

Re: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Dave Brolley]

Hi Fred,

Try commit 8bb4f64.

Dave

On 12/05/2011 12:42 PM, Turgis, Frederic wrote:
> Thanks, my first mail points to code that broke on my environment, still I do not know all the goals of the code so could not provide more complete/clean stuff.
>
> Regards
> Fred
>
> Frederic Turgis
> OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia
>
>
>
> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>
> -----Original Message-----
>> From: systemtap-owner@sourceware.org
>> [mailto:systemtap-owner@sourceware.org] On Behalf Of Dave Brolley
>> Sent: Monday, December 05, 2011 5:13 PM
>> To: systemtap@sourceware.org
>> Subject: Re: "module privilege check" breaks
>> (cross-)compilation due to libelf dependency
>>
>> Hi,
>>
>> Sorry for this. I'll re-examine the code to make sure it
>> builds in all environments.
>>
>> Dave
>>
>> On 12/05/2011 09:09 AM, Turgis, Frederic wrote:
>>> Hi,
>>>
>>> After making few times the mistake to not check latest code,
>> I ensure
>>> now to be on HEAD of master branch ;-)
>>>
>>> My feeling is that you had an environment with libelf
>> available but elf_getshdrstrndx() not available.
>>> This is then not sufficient but similar. This solves the issue of
>>> unused parameters (this is a warning considered as an error) but not
>>> the issue of the use of Elf_Scn type. Systemtap only defines
>> "typedef
>>> struct Elf_Scn Elf_Scn;", real definition would come from
>>> "elfutils-0.143/libelf/libelfP.h" in my case (but --with-elfutils is
>>> not used)
>>>
>>>
>>>
>>> Regards
>>> Fred
>>>
>>> Frederic Turgis
>>> OMAP Platform Business Unit - OMAP System Engineering - Platform
>>> Enablement - System Multimedia
>>>
>>>
>>>
>>> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve
>>> Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>>>
>>> -----Original Message-----
>>>> From: Mark Wielaard [mailto:mjw@redhat.com]
>>>> Sent: Monday, December 05, 2011 2:58 PM
>>>> To: Turgis, Frederic
>>>> Cc: SystemTap
>>>> Subject: Re: "module privilege check" breaks
>> (cross-)compilation due
>>>> to libelf dependency
>>>>
>>>> On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
>>>>> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128:
>> Implement
>>>>> module privilege check in staprun." has broken my
>> cross-compilation
>>>>> environment to build "staprun" tool for ARM android (I do 4 first
>>>>> steps on host, staprun step on target), see end of mail.
>>>>>
>>>>> Having a deeper look, there is in fact code in
>> staprun_funcs.c that
>>>>> requires libelf like find_section_in_module() and
>>>>> get_module_required_credentials() (Elf_Scn for example)
>> and that is
>>>>> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX
>>>> I had something similar a few days ago, though I don't remember
>>>> exactly which setup it was on. Does the following commit
>> help in your
>>>> case?
>>>>
>>>> commit fa2418539b4ac2cb1352948f68da08890cec7774
>>>> Author: Mark Wielaard<mjw@redhat.com>
>>>> Date:   Sat Nov 26 02:33:01 2011 +0100
>>>>
>>>>    Fix build error in staprun_funcs.c when HAVE_ELF_GETSHDRSTRNDX is
>>>> not set.
>>>>
>>>>    Mark find_section_in_module arguments unused when
>>>> HAVE_ELF_GETSHDRSTRNDX
>>>>    isn't set.
>>>>
>>>> Or do you need more than that?
>>>>
>>>> Cheers,
>>>>
>>>> Mark
>>>>

RE: "module privilege check" breaks (cross-)compilation due to libelf dependency

[Turgis, Frederic]

Hi,

Problem solved, thanks. Tool builds fine and host compilation/target execution of script went fine.

Regards
Fred



Frederic Turgis
OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement - System Multimedia



>
Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

-----Original Message-----
>From: systemtap-owner@sourceware.org
>[mailto:systemtap-owner@sourceware.org] On Behalf Of Dave Brolley
>Sent: Tuesday, December 06, 2011 10:37 PM
>To: Turgis, Frederic
>Cc: systemtap@sourceware.org
>Subject: Re: "module privilege check" breaks
>(cross-)compilation due to libelf dependency
>
>Hi Fred,
>
>Try commit 8bb4f64.
>
>Dave
>
>On 12/05/2011 12:42 PM, Turgis, Frederic wrote:
>> Thanks, my first mail points to code that broke on my
>environment, still I do not know all the goals of the code so
>could not provide more complete/clean stuff.
>>
>> Regards
>> Fred
>>
>> Frederic Turgis
>> OMAP Platform Business Unit - OMAP System Engineering - Platform
>> Enablement - System Multimedia
>>
>>
>>
>> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve
>> Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>>
>> -----Original Message-----
>>> From: systemtap-owner@sourceware.org
>>> [mailto:systemtap-owner@sourceware.org] On Behalf Of Dave Brolley
>>> Sent: Monday, December 05, 2011 5:13 PM
>>> To: systemtap@sourceware.org
>>> Subject: Re: "module privilege check" breaks
>(cross-)compilation due
>>> to libelf dependency
>>>
>>> Hi,
>>>
>>> Sorry for this. I'll re-examine the code to make sure it builds in
>>> all environments.
>>>
>>> Dave
>>>
>>> On 12/05/2011 09:09 AM, Turgis, Frederic wrote:
>>>> Hi,
>>>>
>>>> After making few times the mistake to not check latest code,
>>> I ensure
>>>> now to be on HEAD of master branch ;-)
>>>>
>>>> My feeling is that you had an environment with libelf
>>> available but elf_getshdrstrndx() not available.
>>>> This is then not sufficient but similar. This solves the issue of
>>>> unused parameters (this is a warning considered as an
>error) but not
>>>> the issue of the use of Elf_Scn type. Systemtap only defines
>>> "typedef
>>>> struct Elf_Scn Elf_Scn;", real definition would come from
>>>> "elfutils-0.143/libelf/libelfP.h" in my case (but
>--with-elfutils is
>>>> not used)
>>>>
>>>>
>>>>
>>>> Regards
>>>> Fred
>>>>
>>>> Frederic Turgis
>>>> OMAP Platform Business Unit - OMAP System Engineering - Platform
>>>> Enablement - System Multimedia
>>>>
>>>>
>>>>
>>>> Texas Instruments France SA, 821 Avenue Jack Kilby, 06270
>Villeneuve
>>>> Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920
>>>>
>>>> -----Original Message-----
>>>>> From: Mark Wielaard [mailto:mjw@redhat.com]
>>>>> Sent: Monday, December 05, 2011 2:58 PM
>>>>> To: Turgis, Frederic
>>>>> Cc: SystemTap
>>>>> Subject: Re: "module privilege check" breaks
>>> (cross-)compilation due
>>>>> to libelf dependency
>>>>>
>>>>> On Mon, Dec 05, 2011 at 01:36:01PM +0000, Turgis, Frederic wrote:
>>>>>> Commit "bb4470cacb3f7ce5161f9e8a1b7c37a87516a6c3 PR 13128:
>>> Implement
>>>>>> module privilege check in staprun." has broken my
>>> cross-compilation
>>>>>> environment to build "staprun" tool for ARM android (I
>do 4 first
>>>>>> steps on host, staprun step on target), see end of mail.
>>>>>>
>>>>>> Having a deeper look, there is in fact code in
>>> staprun_funcs.c that
>>>>>> requires libelf like find_section_in_module() and
>>>>>> get_module_required_credentials() (Elf_Scn for example)
>>> and that is
>>>>>> not surrounded by HAVE_LIBELF_H or HAVE_ELF_GETSHDRSTRNDX
>>>>> I had something similar a few days ago, though I don't remember
>>>>> exactly which setup it was on. Does the following commit
>>> help in your
>>>>> case?
>>>>>
>>>>> commit fa2418539b4ac2cb1352948f68da08890cec7774
>>>>> Author: Mark Wielaard<mjw@redhat.com>
>>>>> Date:   Sat Nov 26 02:33:01 2011 +0100
>>>>>
>>>>>    Fix build error in staprun_funcs.c when HAVE_ELF_GETSHDRSTRNDX
>>>>> is not set.
>>>>>
>>>>>    Mark find_section_in_module arguments unused when
>>>>> HAVE_ELF_GETSHDRSTRNDX
>>>>>    isn't set.
>>>>>
>>>>> Or do you need more than that?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Mark
>>>>>
>