Deleted directory path not recorded when running rmdir with slash at directory path end

[Lenny Bruzenak]

On 3/4/21 9:09 PM, Alan Evangelista wrote:

> If I run the rmdir command with a directory path with a slash at its
> end, Audit doesn't record the deleted directory path. 
>
> Audit rule:
> -a always,exit -F dir=/sasdata -F arch=b64 -S creat -S open -S openat
> -S unlink -S unlinkat -S symlink -S symlinkat -S link -S linkat -S
> rename -S renameat -S chmod -S fchmod -S fchmodat -S chown -S fchown
> -S fchownat -S mkdir -S mkdirat -S rmdir -S setxattr -S lsetxattr -S
> fsetxattr -S removexattr -S lremovexattr -S fremovexattr -k filesystem_op
>
> Test command: 
> rmdir /sasdata/testdir
>
> Audit output:
>
> type=SYSCALL msg=audit(1614912311.117:4136): arch=c000003e syscall=84
> success=yes exit=0 a0=7ffcf6e5c757 a1=2 a2=7f200050f280
> a3=7ffcf6e5b660 items=3 ppid=17590 pid=22579 auid=201327714 uid=0
> gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts1 ses=269
> comm=\"rmdir\" exe=\"/usr/bin/rmdir\" key=\"filesystem_op\"","type=CWD
> msg=audit(1614912311.117:4136):  cwd=\"/home/aevangelista\""
>
> type=PATH msg=audit(1614912311.117:4136): item=0 name=\"/sasdata/\"
> inode=100916940 dev=08:04 mode=040775 ouid=0 ogid=201327708 rdev=00:00
> objtype=PARENT cap_fp=0000000000000000 cap_fi=0000000000000000
> cap_fe=0 cap_fver=0
>
> type=PATH msg=audit(1614912311.117:4136): item=1 name=(null)
> inode=100916940 dev=08:04 mode=040775 ouid=0 ogid=201327708 rdev=00:00
> objtype=PARENT cap_fp=0000000000000000 cap_fi=0000000000000000
> cap_fe=0 cap_fver=0
>
> type=PATH msg=audit(1614912311.117:4136): item=2 name=(null)
> inode=1181650 dev=08:04 mode=040755 ouid=0 ogid=0 rdev=00:00
> objtype=DELETE cap_fp=0000000000000000 cap_fi=0000000000000000
> cap_fe=0 cap_fver=0
>
> type=PROCTITLE msg=audit(1614912311.117:4136):
> proctitle=726D646972002F736173646174612F746573746469722F
>
> Shouldn't the directory path be recorded somewhere, regardless if
> there is a slash at the end of the directory path?
>
> I found this issue while using Auditbeat, a collector of Linux Audit
> events used for integration with Elasticsearch. Related
> discussion: https://discuss.elastic.co/t/rmdir-syscall-event-and-file-path/266015/3
> <https://discuss.elastic.co/t/rmdir-syscall-event-and-file-path/266015/3>


I tested this on a 3.10.0 kernel with userspace 2.8.5 and it works as
advertised.

The "proctitle" event in my search was the first one and I used the "-i"
interpret flag. I could decode the raw ascii above but I suspect it
would say "rmdir /sasdata/testdir/", since "72" is "r", "6D" is "m" and
"2F", the last char, is "/" .


LCB

-- 
Lenny Bruzenak
MagitekLTD