Possible syslogd DoS ?

From: Petr Baudis (paskyat_private)
Date: Wed Oct 03 2001 - 11:09:58 PDT

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    Hello,
      I just recently came on a thought (thanks to Marek Jaros) of possible
    DoS of syslogd. It uses /dev/log for receiving log messages, which has
    mode 0666 on most linuxes. It should be ok, as many non-root applications
    should be allowed to log things etc.
      But imagine that you will send a lot of very long messages there, different
    everytime in order not to get stripped into kinda 'message repeated x times'.
    In this way, you can imho flood syslogd successfully, possibly filling whole
    partition where /var/log resides, regardless to your quota settings on
    the machine!
      Then, if /var/log is not on separate partition, the whole system can get
    into serious problems, and especially, further events won't be obviously
    logged, so you can do evil things there happily and nobody will know about it.
      Discussion? Something i didn't take into account? Possible solutions?
    
    -- 
    
    				Petr "Pasky" Baudis
    .                                                                       .
            n = ((n >>  1) & 0x55555555) | ((n <<  1) & 0xaaaaaaaa);
            n = ((n >>  2) & 0x33333333) | ((n <<  2) & 0xcccccccc);
            n = ((n >>  4) & 0x0f0f0f0f) | ((n <<  4) & 0xf0f0f0f0);
            n = ((n >>  8) & 0x00ff00ff) | ((n <<  8) & 0xff00ff00);
            n = ((n >> 16) & 0x0000ffff) | ((n << 16) & 0xffff0000);
                    -- C code which reverses the bits in a word.
    .                                                                       .
    My public PGP key is on: http://pasky.ji.cz/~pasky/pubkey.txt
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