cregit-Linux how code gets into the kernel

Release 4.11 fs/cachefiles/security.c

Directory: fs/cachefiles
/* CacheFiles security management
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.

#include <linux/fs.h>
#include <linux/cred.h>
#include "internal.h"

 * determine the security context within which we access the cache from within
 * the kernel

int cachefiles_get_security_ID(struct cachefiles_cache *cache) { struct cred *new; int ret; _enter("{%s}", cache->secctx); new = prepare_kernel_cred(current); if (!new) { ret = -ENOMEM; goto error; } if (cache->secctx) { ret = set_security_override_from_ctx(new, cache->secctx); if (ret < 0) { put_cred(new); pr_err("Security denies permission to nominate security context: error %d\n", ret); goto error; } } cache->cache_cred = new; ret = 0; error: _leave(" = %d", ret); return ret; }


David Howells11198.23%133.33%
Fabian Frederick21.77%266.67%

/* * see if mkdir and create can be performed in the root directory */
static int cachefiles_check_cache_dir(struct cachefiles_cache *cache, struct dentry *root) { int ret; ret = security_inode_mkdir(d_backing_inode(root), root, 0); if (ret < 0) { pr_err("Security denies permission to make dirs: error %d", ret); return ret; } ret = security_inode_create(d_backing_inode(root), root, 0); if (ret < 0) pr_err("Security denies permission to create files: error %d", ret); return ret; }


David Howells7795.06%250.00%
Fabian Frederick44.94%250.00%

/* * check the security details of the on-disk cache * - must be called with security override in force * - must return with a security override in force - even in the case of an * error */
int cachefiles_determine_cache_security(struct cachefiles_cache *cache, struct dentry *root, const struct cred **_saved_cred) { struct cred *new; int ret; _enter(""); /* duplicate the cache creds for COW (the override is currently in * force, so we can use prepare_creds() to do this) */ new = prepare_creds(); if (!new) return -ENOMEM; cachefiles_end_secure(cache, *_saved_cred); /* use the cache root dir's security context as the basis with * which create files */ ret = set_create_files_as(new, d_backing_inode(root)); if (ret < 0) { abort_creds(new); cachefiles_begin_secure(cache, _saved_cred); _leave(" = %d [cfa]", ret); return ret; } put_cred(cache->cache_cred); cache->cache_cred = new; cachefiles_begin_secure(cache, _saved_cred); ret = cachefiles_check_cache_dir(cache, root); if (ret == -EOPNOTSUPP) ret = 0; _leave(" = %d", ret); return ret; }


David Howells151100.00%3100.00%

Overall Contributors

David Howells35298.32%360.00%
Fabian Frederick61.68%240.00%
Directory: fs/cachefiles
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