cups-lpr -- lppasswd multiple vulnerabilities

D. J. Bernstein reports that Bartlomiej Sieka has
discovered several security vulnerabilities in lppasswd,
which is part of CUPS. In the following excerpt from
Bernstein’s email, CVE names have been added for each issue:

First, lppasswd blithely ignores write errors in
fputs(line,outfile) at lines 311 and 315 of lppasswd.c,
and in fprintf(…) at line 346. An attacker who fills up
the disk at the right moment can arrange for
/usr/local/etc/cups/passwd to be truncated.
(CAN-2004-1268)
Second, if lppasswd bumps into a file-size resource limit
while writing passwd.new, it leaves passwd.new in place,
disabling all subsequent invocations of lppasswd. Any
local user can thus disable lppasswd…
(CAN-2004-1269)
Third, line 306 of lppasswd.c prints an error message to
stderr but does not exit. This is not a problem on systems
that ensure that file descriptors 0, 1, and 2 are open for
setuid programs, but it is a problem on other systems;
lppasswd does not check that passwd.new is different from
stderr, so it ends up writing a user-controlled error
message to passwd if the user closes file descriptor
2. (CAN-2004-1270)

Note: The third issue, CVE-2004-1270, does
not affect FreeBSD 4.6-RELEASE or later systems, as these
systems ensure that the file descriptors 0, 1, and 2 are
always open for set-user-ID and set-group-ID programs.