186201 - unix_rand.c: RNG_SystemInfoForRNG should handle a null 'environ' pointer.

Status: RESOLVED FIXED

(NSS :: Libraries, defect, P1)

Description

[Wan-Teh Chang]

It was reported that on Solaris if the main executable
is built in a certain way and loads the NSS shared
library dynamically (with dlopen), NSS may see the
global 'environ' variable as a null pointer.  Here is
the description I received on how this can happen:

    The scenario is we have a primary executable and
    several optional "plug-ins" (dynamic libraries).
    To avoid name collisions, we changed the build to
    link the primary [executable] with the RTLD_GROUP
    flag.  After we made this change, the [plug-ins
    that use environ] started to crash because [they]
    couldn't locate environ, [...]

I haven't done an experiment to confirm this, but
since the fix for this crash is simple, I think we
should just fix it.

By the way, I did an experiment to fork and exec a
process passing NULL as the 'envp' (third) argument
to execve().  The child process got a non-NULL
'environ' array whose first element is a null pointer.

Comment 1

[Wan-Teh Chang]

Attachment: Proposed patch

Comment 2

[Wan-Teh Chang]

Fix checked into the tip of NSS.