illumos-gate: Stack buffer overflow in illumos reparsed nfs-basic plugin allows local users to crash the daemon

A stack-based buffer overflow in the illumos reparse point daemon (reparsed) allows a local user to crash the daemon. get_fs_locations() in usr/src/cmd/fs.d/nfs/rp_basic/libnfs_basic.c, part of the nfs-basic reparse plugin, copies the host and path components of a reparse string into a fixed 1024-byte stack buffer without checking their length. The reparsed door at /var/run/reparsed_door is readable by all users and the door server does not check the caller's credentials, so an unprivileged local user can send an nfs-basic request with an overlong host or path component to overflow the buffer. On systems built with stack protection, which is the default, this causes reparsed to abort; repeated requests place the svc:/system/filesystem/reparse service into maintenance. The service is disabled by default. The flaw has existed since 2009 (illumos-gate commit 2f172c55), and affects any illumos distribution prior to illumos-gate commit 6a2df4aa.