Re: audit not catching accept call from a 64bit sshd

On Tuesday, January 13, 2015 03:16:25 PM hsultan(a)thefroid.net wrote: > Hi, > > So I'm a bit dumbfounded by what I'm seeing on my Ubuntu 14.04 > Server > LTS : > > ubuntu@ip-172-31-37-137:~/test$ sudo netstat -anop |grep sshd > tcp 0 0 0.0.0.0:22 0.0.0.0:* > LISTEN 1406/sshd off (0.00/0/0) > > Using file I verified that it's a 64bit process : > > ubuntu@ip-172-31-37-137:~/test$ file /usr/sbin/sshd > /usr/sbin/sshd: ELF 64-bit LSB shared object, x86-64, version 1 > (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, > BuildID[sha1]=00e04495db18849d9fa69d05f3626e66c6a6d4e1, stripped > > I then ran strace on it, and launched a telnet to 127.0.0.1 : 22 > > ubuntu@ip-172-31-37-137:~/test$ sudo strace -p 1406 > Process 1406 attached > select(7, [3 4], NULL, NULL, NULL) = 1 (in [3]) > accept(3, {sa_family=AF_INET, sin_port=htons(58853), > sin_addr=inet_addr("127.0.0.1")}, [16]) = 5 > fcntl(5, F_GETFL) = 0x2 (flags O_RDWR) > pipe([6, 7]) = 0 > socketpair(PF_LOCAL, SOCK_STREAM, 0, [8, 9]) = 0 > clone(child_stack=0, > flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, > child_tidptr=0x7f95cba7db10) = 6224 > > Clearly it is calling the accept system call. > > Next I look at the audit infrastructure to see what it gives me : > ubuntu@ip-172-31-37-137:~/test$ sudo auditctl -l > LIST_RULES: exit,always arch=3221225534 (0xc000003e) > syscall=accept,accept4 > > Then I use my own tool to catch every msg from the netlink (using > audit_get_reply) port and display each and every msg that has a > struct > audit_reply->len > 0 , as well as audit msgs from > netfilter/conntrack. > Just to make sure that my audit code/settings are correct, I launch > a > telnet to port 22, and another one to port 631 (cups), and here's > what I > see : > > audit(1421190014.387:45784): audit_enabled=1 old=1 auid=1000 ses=16 > res=1 > [NEW] tcp 6 120 SYN_SENT src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 [UNREPLIED] src=127.0.0.1 dst=127.0.0.1 > sport=22 > dport=58860 > [UPDATE] tcp 6 60 SYN_RECV src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 src=127.0.0.1 dst=127.0.0.1 sport=22 > dport=58860 > [UPDATE] tcp 6 432000 ESTABLISHED src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 src=127.0.0.1 dst=127.0.0.1 sport=22 > dport=58860 > [ASSURED] > [UPDATE] tcp 6 120 FIN_WAIT src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 src=127.0.0.1 dst=127.0.0.1 sport=22 > dport=58860 > [ASSURED] > [UPDATE] tcp 6 30 LAST_ACK src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 src=127.0.0.1 dst=127.0.0.1 sport=22 > dport=58860 > [ASSURED] > [UPDATE] tcp 6 120 TIME_WAIT src=127.0.0.1 dst=127.0.0.1 > sport=58860 dport=22 src=127.0.0.1 dst=127.0.0.1 sport=22 > dport=58860 > [ASSURED] > [NEW] tcp 6 120 SYN_SENT src=127.0.0.1 dst=127.0.0.1 > sport=40478 dport=6031 [UNREPLIED] src=127.0.0.1 dst=127.0.0.1 > sport=6031 dport=40478 > [DESTROY] tcp 6 src=127.0.0.1 dst=127.0.0.1 sport=40478 > dport=6031 > [UNREPLIED] src=127.0.0.1 dst=127.0.0.1 sport=6031 dport=40478 > [NEW] tcp 6 120 SYN_SENT src=127.0.0.1 dst=127.0.0.1 > sport=36764 dport=631 [UNREPLIED] src=127.0.0.1 dst=127.0.0.1 > sport=631 > dport=36764 > [UPDATE] tcp 6 60 SYN_RECV src=127.0.0.1 dst=127.0.0.1 > sport=36764 dport=631 src=127.0.0.1 dst=127.0.0.1 sport=631 > dport=36764 > [UPDATE] tcp 6 432000 ESTABLISHED src=127.0.0.1 dst=127.0.0.1 > sport=36764 dport=631 src=127.0.0.1 dst=127.0.0.1 sport=631 > dport=36764 > [ASSURED] > audit(1421190031.663:45785): arch=c000003e syscall=43 success=yes > exit=15 a0=b a1=7f84aee66f7c a2=7fff960572fc a3=7f84ad2b67b8 items=0 > ppid=1 pid=22048 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 > egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="cupsd" > exe="/usr/sbin/cupsd" key=(null) > audit(1421190031.663:45785): saddr=02008F9C7F0000010000000000000000 > audit(1421190031.663:45785): > > I never see the accept call for sshd ... even though connection is > established, but I see the one for cups. The machine is pretty much > idle, so there should be no msgs dropped. > > Any idea what could be the reason ? I just can't see what I could be > doing wrong here. Make sure you have both a 32 and 64 bit rule. That's all I can think of. Also, check to see if you have audit=1 on your kernel boot parameters. There is a chance that sshd is starting before auditd and then its marked inauditable. But, it works fine on my system.