[PATCH 2/2] LSM: SafeSetID: Add setgroups() security policy handling

[kernel test robot]

Hi Micah,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on jmorris-security/next-testing kees/for-next/pstore v5.19-rc2 next-20220610]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Micah-Morton/security-Add-LSM-hook-to-setgroups-syscall/20220614-050341
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3
config: x86_64-randconfig-a001-20220613 (https://download.01.org/0day-ci/archive/20220614/202206141555.zswTLROZ-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c97436f8b6e2718286e8496faf53a2c800e281cf)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/248aa1aeef5c49d4af78b9c3d09e896413258c76
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Micah-Morton/security-Add-LSM-hook-to-setgroups-syscall/20220614-050341
        git checkout 248aa1aeef5c49d4af78b9c3d09e896413258c76
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp at intel.com>

All errors (new ones prefixed by >>):

>> security/safesetid/lsm.c:248:50: error: use of undeclared identifier 'group_info'
                   if (!id_permitted_for_cred(old, (kid_t){.gid = group_info->gid[i]}, GID)) {
                                                                  ^
   1 error generated.


vim +/group_info +248 security/safesetid/lsm.c

   237	
   238	static int safesetid_task_fix_setgroups(struct cred *new, const struct cred *old)
   239	{
   240		int i;
   241	
   242		/* Do nothing if there are no setgid restrictions for our old RGID. */
   243		if (setid_policy_lookup((kid_t){.gid = old->gid}, INVALID_ID, GID) == SIDPOL_DEFAULT)
   244			return 0;
   245	
   246		get_group_info(new->group_info);
   247		for (i = 0; i < new->group_info->ngroups; i++) {
 > 248			if (!id_permitted_for_cred(old, (kid_t){.gid = group_info->gid[i]}, GID)) {
   249				put_group_info(new->group_info);
   250				/*
   251				 * Kill this process to avoid potential security vulnerabilities
   252				 * that could arise from a missing allowlist entry preventing a
   253				 * privileged process from dropping to a lesser-privileged one.
   254				 */
   255				force_sig(SIGKILL);
   256				return -EACCES;
   257			}
   258		}
   259	
   260		put_group_info(new->group_info);
   261		return 0;
   262	}
   263	

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