gnats/52: send-pr is vulnerable to symlink attacks

[phil+gnats]

>Number:         52
>Category:       gnats
>Synopsis:       send-pr is vulnerable to symlink attacks
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Mar 04 02:04:00 PST 2000
>Closed-Date:
>Last-Modified:
>Originator:     Phil Homewood
>Release:        send-pr claims v3.2; code inspection indicates 3.112 also 
>vulnerable.
>Organization:
>Environment:
FreeBSD 3.4-STABLE
>Description:
send-pr overwrites predictably named files in /tmp (unless
TMPDIR is set.)
>How-To-Repeat:
symlink /tmp/p$$ to something interesting for a range of
values of $$, run send-pr (or sit back and wait for victim
to run it if you're evil.) Observe overwritten target file.
>Fix:
Use mktemp(1) on systems that support it, else do the
usual create-temp-directory-carefully magic.
>Release-Note:
>Audit-Trail:
>Unformatted: