filename not audited for openat() on F28

Mon Apr 23 22:12:45 UTC 2018

On Mon, Apr 23, 2018 at 11:29 AM, Steve Grubb <sgrubb at redhat.com> wrote:
> On Monday, April 23, 2018 6:24:52 AM EDT Jiri Jaburek wrote:
>> On 04/20/18 15:37, Steve Grubb wrote:
>> > On Friday, April 20, 2018 9:20:29 AM EDT Jiri Jaburek wrote:
>> >> (Please CC me on replies.)
>> >>
>> >> Hello,
>> >> I'm trying to run the audit-test suite on Fedora 28 and am running into
>> >> it expecting a name= field in the SYSCALL entry.
>> >>
>> >> augrok --seek=697600 -m1 type==SYSCALL         syscall=openat success=no
>> >> pid=3951 auid=1000         uid=0 euid=0 suid=0 fsuid=0         gid=0
>> >> egid=0 sgid=0 fsgid=0 exit=-13
>> >> subj=staff_u:lspp_test_r:lspp_test_generic_t:SystemHigh
>> >> name=tmp.owfFtgPOjx/new
>> >>
>> >> Fedora 28:
>> >>
>> >> ----
>> >> time->Fri Apr 20 15:04:59 2018
>> >> type=PROCTITLE msg=audit(1524229499.918:366591):
>> >> proctitle=2F62696E2F62617368002E2F72756E2E62617368002D647600323734
>> >> type=PATH msg=audit(1524229499.918:366591): item=0
>> >> name="tmp.J4IQL7Buxe/" inode=1055495 dev=fd:02 mode=040700 ouid=0 ogid=0
>> >> rdev=00:00 obj=staff_u:object_r:user_tmp_t:s15:c0.c1023 nametype=PARENT
>> >> cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
>> >> type=CWD msg=audit(1524229499.918:366591):
>> >> cwd="/usr/local/eal4_testing/audit-test/syscalls"
>> >> type=SYSCALL msg=audit(1524229499.918:366591): arch=c000003e syscall=257
>> >> success=no exit=-13 a0=3 a1=7ffc02f0eaf6 a2=c0 a3=16b6010 items=1
>> >> ppid=5275 pid=5276 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0
>> >> sgid=0 fsgid=0 tty=(none) ses=2 comm="do_openat"
>> >> exe="/usr/local/eal4_testing/audit-test/utils/bin/do_openat"
>> >> subj=staff_u:lspp_test_r:lspp_test_generic_t:s15:c0.c1023 key=(null)
>> >> type=AVC msg=audit(1524229499.918:366591): avc:  denied  { create } for
>> >> pid=5276 comm="do_openat" name="new"
>> >> scontext=staff_u:lspp_test_r:lspp_test_generic_t:s15:c0.c1023
>> >> tcontext=staff_u:object_r:user_tmp_t:s0 tclass=file permissive=0
>> >> ----
>> >>
>> >> RHEL-7.5:
>> >>
>> >> ----
>> >> time->Fri Apr 20 15:06:59 2018
>> >> type=PROCTITLE msg=audit(1524229619.726:56605):
>> >> proctitle=72756E636F6E0073746166665F753A6C7370705F746573745F723A6C737070
>> >> 5F7
>> >> 46573745F67656E657269635F743A53797374656D4869676800646F5F6F70656E617400
>> >> 2F74
>> >> 6D7000746D702E30674C74574A336977622F6E6577006372656174650073746166665F7
>> >> 53A6 F626A6563745F723A757365725F746D705F743A53 type=PATH
>> >> msg=audit(1524229619.726:56605): item=1
>> >> name="tmp.0gLtWJ3iwb/new" objtype=CREATE cap_fp=0000000000000000
>> >> cap_fi=0000000000000000 cap_fe=0 cap_fver=0
>> >> type=PATH msg=audit(1524229619.726:56605): item=0 name="tmp.0gLtWJ3iwb/"
>> >> inode=1055489 dev=fd:02 mode=040700 ouid=0 ogid=0 rdev=00:00
>> >> obj=staff_u:object_r:user_tmp_t:s15:c0.c1023 objtype=PARENT
>> >> cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
>> >> type=CWD msg=audit(1524229619.726:56605):
>> >> cwd="/usr/local/eal4_testing/audit-test/syscalls"
>> >> type=SYSCALL msg=audit(1524229619.726:56605): arch=c000003e syscall=257
>> >> success=no exit=-13 a0=3 a1=7ffc1ecd6b57 a2=c0 a3=0 items=2 ppid=20750
>> >> pid=20751 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0
>> >> fsgid=0 tty=(none) ses=1595 comm="do_openat"
>> >> exe="/usr/local/eal4_testing/audit-test/utils/bin/do_openat"
>> >> subj=staff_u:lspp_test_r:lspp_test_generic_t:s15:c0.c1023 key=(null)
>> >> ----
>> >>
>> >> The key difference here is probably the absence of
>> >>
>> >> type=PATH msg=audit(1524229619.726:56605): item=1
>> >> name="tmp.0gLtWJ3iwb/new" objtype=CREATE cap_fp=0000000000000000
>> >> cap_fi=0000000000000000 cap_fe=0 cap_fver=0
>> >>
>> >> on Fedora 28, which augrok looks for.
>> >>
>> >> Is this expected?
>> >>
>> >>
>> >>
>> >> I'm seeing something similar with other syscalls like
>> >>
>> >> creat("/tmp/tmp.9EsMgMuio7/new", 0700)
>> >>
>> >> producing
>> >>
>> >> ----
>> >> type=PROCTITLE msg=audit(04/20/2018 15:15:35.547:371576) :
>> >> proctitle=runcon staff_u:lspp_test_r:lspp_test_generic_t:SystemHigh
>> >> do_creat /tmp/tmp.9EsMgMuio7/new staff_u:object_r:user_tmp_t:SystemLow
>> >> type=PATH msg=audit(04/20/2018 15:15:35.547:371576) : item=0
>> >> name=/tmp/tmp.9EsMgMuio7/ inode=1572964 dev=fd:02 mode=dir,700 ouid=root
>> >> ogid=root rdev=00:00 obj=staff_u:object_r:user_tmp_t:s15:c0.c1023
>> >> nametype=PARENT cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
>> >> type=CWD msg=audit(04/20/2018 15:15:35.547:371576) :
>> >> cwd=/usr/local/eal4_testing/audit-test/syscalls
>> >> type=SYSCALL msg=audit(04/20/2018 15:15:35.547:371576) : arch=x86_64
>> >> syscall=creat success=no exit=EACCES(Permission denied)
>> >> a0=0x7ffc41d04af9 a1=0700 a2=0x0 a3=0x0 items=1 ppid=6779 pid=6780
>> >> auid=eal uid=root gid=root euid=root suid=root fsuid=root egid=root
>> >> sgid=root fsgid=root tty=(none) ses=2 comm=do_creat
>> >> exe=/usr/local/eal4_testing/audit-test/utils/bin/do_creat
>> >> subj=staff_u:lspp_test_r:lspp_test_generic_t:s15:c0.c1023 key=(null)
>> >> type=AVC msg=audit(04/20/2018 15:15:35.547:371576) : avc:  denied  {
>> >> create } for  pid=6780 comm=do_creat name=new
>> >> scontext=staff_u:lspp_test_r:lspp_test_generic_t:s15:c0.c1023
>> >> tcontext=staff_u:object_r:user_tmp_t:s0 tclass=file permissive=0
>> >
>> > This record says you were denied create. That means it can report the
>> > parent object and its properties. But it cannot report on the object
>> > being created because it has no properties except an intended name. But
>> > it has no device, inode, owner, label, etc. If the system were in
>> > permissive mode, you will probably get the actual object and its
>> > properties.
>>
>> Thanks, however I don't know if the reply was to openat() or creat()
>
> Both have a denial AVC for the action that the syscall is performing.
>
>> and I also don't know if it's an expected change compared to RHEL-7 or if
>> I should treat it as bug.
>
> The current behavior is a change. I suspect that because the name is about
> all we have at this point, the record was dropped because it cannot be
> normalized. IOW, its missing a bunch of fields. The old behavior is nice,
> though, because you can see what was denied.
>
> I don't know if this is considered a bug. Paul or Richard might need to say
> if this is the new behavior going forward.

Richard has been playing with the PATH records most recently so I'll
let him have first crack at answering this ...

-- 
paul moore
www.paul-moore.com