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AWK Problem
From: "Helmut Hauser" <helmut.hauser () intraplan de>
Date: Fri, 29 Aug 2003 11:01:27 +0200
We encountered a strange AWK Problem. Problematic awk script command phrase on redhat 7.3 causing a DoS resulting in a complete system crash. If the file "xyz.dat" does not exist or is locked or file permission is denied with using awk, following offending phrase causes the crash: while (getline < "xyz.dat") The correct use of awk is while ((getline < "xyz.dat") > 0) or while (0 < (getline < "xyz.dat")) This avoids an endless loop causing kernel panic., e.g. on redhat 7.3 Kernel revision is 2.4.20. Users do NOT have to have root privileges to bring the server down. Excerpt from the man page: The getline command returns 0 on end of file and -1 on an error. Upon an error, ERRNO contains a string describing the problem. I notified Redhat on 11.03.2003 and got no answer. Helmut Hauser Systemadministration EDV Intraplan Consult GmbH _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
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