Detecting loading of libraries

Detecting loading of libraries

[hsultan]

Hi,

I'm wondering if there's a good way of detecting the loading of 
libraries by processes (I am specifically NOT talking about the uselib 
syscall).

strace shows me apps do open(...)/mmap/mprotect
I'm currently intercepting mmap calls, however no additional context 
records are given to provide the name of the library, and the file 
descriptor is the 5th parameter, so I can't get that either to match it 
to an open(...)

Is there a way to do this that I'm missing ?

Thanks,

Hassan

Re: Detecting loading of libraries

[hsultan]

Ok, I now see the file descriptor in a context record for mmap 
*sometimes*

1300 - audit(1421886600.839:25623): arch=c000003e syscall=9 success=yes 
exit=140564293636096 a0=0 a1=1000 a2=3 a3=22 items=0 ppid=23505 
pid=24942 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 
fsgid=0 tty=pts5 ses=2 comm="sudo" exe="/usr/bin/sudo" key=(null)
1300 - audit(1421886600.839:25624): arch=c000003e syscall=9 success=yes 
exit=140564293636096 a0=0 a1=1000 a2=3 a3=22 items=0 ppid=23505 
pid=24942 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 
fsgid=0 tty=pts5 ses=2 comm="sudo" exe="/usr/bin/sudo" key=(null)
1300 - audit(1421886600.839:25625): arch=c000003e syscall=9 success=yes 
exit=140564239544320 a0=0 a1=2020f0 a2=5 a3=802 items=0 ppid=23505 
pid=24942 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 
fsgid=0 tty=pts5 ses=2 comm="sudo" exe="/usr/bin/sudo" key=(null)
1323 - audit(1421886600.839:25625): fd=10 flags=0x802
1300 - audit(1421886600.839:25626): arch=c000003e syscall=9 success=yes 
exit=140564241645568 a0=7fd7a9b10000 a1=2000 a2=3 a3=812 items=0 
ppid=23505 pid=24942 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 
sgid=0 fsgid=0 tty=pts5 ses=2 comm="sudo" exe="/usr/bin/sudo" key=(null)
1323 - audit(1421886600.839:25626): fd=10 flags=0x812
1300 - audit(1421886600.839:25627): arch=c000003e syscall=9 success=yes 
exit=140564293640192 a0=0 a1=1000 a2=3 a3=22 items=0 ppid=23505 
pid=24942 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 
fsgid=0 tty=pts5 ses=2 comm="sudo" exe="/usr/bin/sudo" key=(null)

Any idea why the 1323 shows up sometimes and not each time an mmap call 
is made ? Is the record generated only on the 1st mmap call for a 
library ?

Thanks,

Hassan

On 2015-01-21 16:01, hsultan@thefroid.net wrote:
> Hi,
>
> I'm wondering if there's a good way of detecting the loading of
> libraries by processes (I am specifically NOT talking about the 
> uselib
> syscall).
>
> strace shows me apps do open(...)/mmap/mprotect
> I'm currently intercepting mmap calls, however no additional context
> records are given to provide the name of the library, and the file
> descriptor is the 5th parameter, so I can't get that either to match
> it to an open(...)
>
> Is there a way to do this that I'm missing ?
>
> Thanks,
>
> Hassan
>
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit

Re: Detecting loading of libraries

[Steve Grubb]

On Wednesday, January 21, 2015 04:01:59 PM hsultan@thefroid.net wrote:
> I'm wondering if there's a good way of detecting the loading of
> libraries by processes (I am specifically NOT talking about the uselib
> syscall).

This has never been a problem people needed a solution for. Its always been 
assumed that the runtime linker does the right thing.

> strace shows me apps do open(...)/mmap/mprotect
> I'm currently intercepting mmap calls, however no additional context
> records are given to provide the name of the library, and the file
> descriptor is the 5th parameter, so I can't get that either to match it
> to an open(...)
> 
> Is there a way to do this that I'm missing ?

I'd almost thing you'd want to patch ld.so to provide this...but then its not 
running as a privileged process. So, it can't do it. Ld is the thing that 
knows the _intent_ behind the open and mmap and mprot. Nothing else does.

-Steve