Bug 706026

Description of problem:
There is difference in environment when tests are started from shell and in beah. Normally what login does is to call initgroups(2) to initialise supplementary groups. Beah is not doing this, which make some tests failing, because kernel checks for it in several places.

One such test is ltp 20110228, namely 'chown03' tests.
I dissected the offending test and made the reproducer below.

If you run it from shell (as root) you get:
setegid(99) PASS
seteuid(99) PASS
mkdir(mydir, 0700) PASS
chown(mydir, -1, 0) PASS

If you run it from beah you get:
setegid(99) PASS
seteuid(99) PASS
mkdir(mydir, 0700) PASS
chown(mydir, -1, 0) FAILED with -1:
chown(mydir, -1, 0): Operation not permitted

Things start to go different ways at fs/attr.c:inode_change_ok(), where after uid list of supplementary groups is checked.

Reproducer:

--- cut ---
#include <errno.h>
#include <sys/types.h>

int ret;
#define TEST(func)  ret=func;                                          \
                    if (ret != 0)                                      \
                    {                                                  \
                        perror(#func);                                 \
                        printf("%s FAILED with %d:\n", #func, ret);    \
                    }                                                  \
                    else                                               \
                    {                                                  \
                        printf("%s PASS\n", #func);                    \
                    }

int main()
{
    char mydir[] = "/tmp/testgroups";

    if (geteuid() != 0)
    {
        printf("I need root.\n");
        return 1;
    }

    rmdir(mydir);

    TEST(setegid(99));
    TEST(seteuid(99));

    TEST(mkdir(mydir, 0700));
    TEST(chown(mydir, -1, 0));

    return ret;
}
--- cut ---

Actual results:
The reproducer running through beah will fail.

Expected results:
The reproducer should work in beah as it does when run from shell.

Additional info:
chown03 test in LTP was changed in the meantime to avoid hitting this problem, use reproducer above.