• Steve Grubb's avatar
    audit: Record fanotify access control decisions · de8cd83e
    Steve Grubb authored
    The fanotify interface allows user space daemons to make access
    control decisions. Under common criteria requirements, we need to
    optionally record decisions based on policy. This patch adds a bit mask,
    FAN_AUDIT, that a user space daemon can 'or' into the response decision
    which will tell the kernel that it made a decision and record it.
    
    It would be used something like this in user space code:
    
      response.response = FAN_DENY | FAN_AUDIT;
      write(fd, &response, sizeof(struct fanotify_response));
    
    When the syscall ends, the audit system will record the decision as a
    AUDIT_FANOTIFY auxiliary record to denote that the reason this event
    occurred is the result of an access control decision from fanotify
    rather than DAC or MAC policy.
    
    A sample event looks like this:
    
    type=PATH msg=audit(1504310584.332:290): item=0 name="./evil-ls"
    inode=1319561 dev=fc:03 mode=0100755 ouid=1000 ogid=1000 rdev=00:00
    obj=unconfined_u:object_r:user_home_t:s0 nametype=NORMAL
    type=CWD msg=audit(1504310584.332:290): cwd="/home/sgrubb"
    type=SYSCALL msg=audit(1504310584.332:290): arch=c000003e syscall=2
    success=no exit=-1 a0=32cb3fca90 a1=0 a2=43 a3=8 items=1 ppid=901
    pid=959 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000
    fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="bash"
    exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t:
    s0-s0:c0.c1023 key=(null)
    type=FANOTIFY msg=audit(1504310584.332:290): resp=2
    
    Prior to using the audit flag, the developer needs to call
    fanotify_init or'ing in FAN_ENABLE_AUDIT to ensure that the kernel
    supports auditing. The calling process must also have the CAP_AUDIT_WRITE
    capability.
    Signed-off-by: default avatarsgrubb <sgrubb@redhat.com>
    Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
    Signed-off-by: default avatarJan Kara <jack@suse.cz>
    de8cd83e
fdinfo.c 4.32 KB