libsemanage: genhomedircon - improve handling large groups

getgrnam_r() uses a preallocated buffer to store a structure containing
the broken-out fields of the record in the group database. The size of
this buffer is usually sysconf(_SC_GETGR_R_SIZE_MAX) == 1024 and it is
not enough for groups with a large number of users.  In these cases,
getgrnam_r() returns -1 and sets errno to ERANGE and the caller can
retry with a larger buffer.

Fixes:
$ semanage login -a -s user_u -r s0-s0:c1.c2 '%largegroup'
libsemanage.semanage_direct_commit: semanage_genhomedircon returned error code -1. (Numerical result out of range).
OSError: Numerical result out of range

Signed-off-by: Petr Lautrbach <[email protected]>
1 file changed