[Bug libc/15385] New: Results from "getent group" may be truncated with nss_db

["wjones at fluke dot com" <sourceware-bugzilla@sourceware.org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=15385

             Bug #: 15385
           Summary: Results from "getent group" may be truncated with
                    nss_db
           Product: glibc
           Version: 2.15
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: unassigned@sourceware.org
        ReportedBy: wjones@fluke.com
                CC: drepper.fsp@gmail.com
    Classification: Unclassified


The results from "getent group" may be truncated when using nss_db.  This will
happen when getgrent() encounters a group entry long enough to overflow the
default 1024 byte buffer.  getgrent() sets errno to ERANGE and returns NULL,
but getent fails to check errno, and truncates the results at this point.

Two things make me suspect that this failure is avoidable:

  1. Requesting a specific long group entry will return it in full, e.g.:

         getent group myverylonggroup

  2. Our local configuration in /etc/nsswitch.conf looks like this:

         group:  files db

     Long entries in group.db will cause output from "getent group" to be
truncated as described, but if I add a long entry to /etc/group, it will be
output in full, along with all subsequent entries in group.db.  It appears that
that nss_files will grow the buffer as required, and then the expanded buffer
is used by nss_db.

-- 
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.