Module Name: src Committed By: bouyer Date: Tue May 17 12:12:15 UTC 2022
Modified Files: src/libexec/mail.local [netbsd-8]: mail.local.c Log Message: Pull up following revision(s) (requested by kre in ticket #1743): libexec/mail.local/mail.local.c: revision 1.29 fix local privilege escalation due to a race condition NetBSD-SA2016-006 included an incomplete fix for CVE-2016-6253, a local privilege escalation vulnerability in mail.local(8). mail.local(8) attempts to open(2) a user's existing mailbox file to append to it. If that call fails, mail.local(8) will then issue a second open(2) call to create the file (O_CREAT). An attacker had the opportunity to create the file in question (as a symlink, or link to some other file) in between these two open(2) calls. Fix this by using O_EXCL in the 2nd open call, if the file exists when that one happens, something is going wrong, so just abort. Also, only attempt that 2nd open if the reason the first failed was that the file did not exist (this doesn't fix the issue, but it potentially saves some cycles). Thanks to Jan Schaumann for bringing this to our attention. To generate a diff of this commit: cvs rdiff -u -r1.28 -r1.28.6.1 src/libexec/mail.local/mail.local.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.