Steve Grubb wrote:
> The rule matcher only uses the information readily at hand during a syscall. 

Ah, the rule matcher does not solve f_path.dentry->d_inode->i_mode etc. from
the FD argument. Then, I see that it is impossible.

> -a exit,always -w /dev/watchdog -p wa -k watchdog
> 
> It will detect the opening with write permissions, but not the individual 
> writes.

What I wanted to do is to record the timestamp of the individual writes, for
what I want to do is to determine whether watchdog NMI is raised by error or
by timeout. To determine it, I need to know when the last write syscall on
/dev/watchdog was.

> If you have to watch writes and you know with some certainty which descriptor 
> the program always uses and which selinux type it uses (assuming hpwdt_t 
> below), you might be able to do something like:
> 
> -a exit,always -F arch=b64 -S write -F a0=4 -F subj_type=hpwdt_t
> 
> If you know the buffer size used in the program, you might add -F a2=X where 
> X 
> is the buffer size to help identify writes to the correct descriptor if the 
> descriptor gets reused.

Yes, I'll try a0= and a2= conditions.

Thank you.

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