shadow-utils mailbox creation race condition CERT reported an issue with the way shadow-utils' useradd program creates the users mail spool file. The file is intially created improperly which gives it random permissions, owned by root for a short period of time. It may be possible for a local attacker to get very lucky and acquire write permissions to a world writable SUID file. The upstream fix is here: http://cvs.pld.org.pl/shadow/src/useradd.c?r1=1.50&r2=1.51 When we patch our packages, we may want to check the return value of the the fchown and fchmod calls. This issue also affects RHEL3 This issue also affects RHEL2.1
Created attachment 129979 [details] "#useradd foo" strace output I patched shadow-utils-4.0.3 from rhel4 and checked return value of fchown and fchmod. Can I commit patch to CVS and rebuild shadow-utils in rhel[2.1,3, 4]?
Feel free to apply the patch to CVS, but we won't release an update just for this issue. We've rated it as having a "low" severity, which means we wait until there is another more sever issue to fix, releasing both fixes at the same time. Thanks.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2007-0276.html