Make minijail respect the groups of the uid provided on the command line.

Make minijail respect the groups of the uid provided on the command line.

[Will Drewry, 2010-02-04 15:16:43]

Needs at least a entry != NULL check but otherwise it looks good.

http://codereview.chromium.org/561069/diff/1/2
File src/platform/minijail/env.cc (right):

http://codereview.chromium.org/561069/diff/1/2#newcode86
src/platform/minijail/env.cc:86: struct passwd* entry = getpwuid(uid);
There may be cases where we want to use a uid we haven't defined in /etc/passwd.
For those cases, it might be worth doing something like:

endpwent();
if (!entry) {
  LOG(INFO) << "UID is unknown. Clearing all supplemental groups";
  PLOG_IF(FATAL, setgroups(0, NULL)) 
    << "Failed to clear supplementary groups";
} else {
  PLOG_IF(FATAL, initgroups(entry->pw_name, entry->pw_gid))
    << "Failed to set supplementary groups";
}

(Next I need to figure out if a second level of Env is needed for testing these
failures... ugh. At least autotest will be useful for testing this case.)

[Chris Masone, 2010-02-04 16:40:58]

http://codereview.chromium.org/561069/diff/1/2
File src/platform/minijail/env.cc (right):

http://codereview.chromium.org/561069/diff/1/2#newcode86
src/platform/minijail/env.cc:86: struct passwd* entry = getpwuid(uid);
On 2010/02/04 15:16:44, Will Drewry wrote:
> There may be cases where we want to use a uid we haven't defined in
/etc/passwd.
> For those cases, it might be worth doing something like:
> 
> endpwent();
> if (!entry) {
>   LOG(INFO) << "UID is unknown. Clearing all supplemental groups";
>   PLOG_IF(FATAL, setgroups(0, NULL)) 
>     << "Failed to clear supplementary groups";
> } else {
>   PLOG_IF(FATAL, initgroups(entry->pw_name, entry->pw_gid))
>     << "Failed to set supplementary groups";
> }
> 
> (Next I need to figure out if a second level of Env is needed for testing
these
> failures... ugh. At least autotest will be useful for testing this case.)

Done.

[Will Drewry, 2010-02-04 17:32:52]

LGTM