cregit-Linux how code gets into the kernel

Release 4.7 security/keys/permission.c

Directory: security/keys
/* Key permission checking
 *
 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/security.h>
#include "internal.h"

/**
 * key_task_permission - Check a key can be used
 * @key_ref: The key to check.
 * @cred: The credentials to use.
 * @perm: The permissions to check for.
 *
 * Check to see whether permission is granted to use a key in the desired way,
 * but permit the security modules to override.
 *
 * The caller must hold either a ref on cred or must hold the RCU readlock.
 *
 * Returns 0 if successful, -EACCES if access is denied based on the
 * permissions bits or the LSM check.
 */

int key_task_permission(const key_ref_t key_ref, const struct cred *cred, unsigned perm) { struct key *key; key_perm_t kperm; int ret; key = key_ref_to_ptr(key_ref); /* use the second 8-bits of permissions for keys the caller owns */ if (uid_eq(key->uid, cred->fsuid)) { kperm = key->perm >> 16; goto use_these_perms; } /* use the third 8-bits of permissions for keys the caller has a group * membership in common with */ if (gid_valid(key->gid) && key->perm & KEY_GRP_ALL) { if (gid_eq(key->gid, cred->fsgid)) { kperm = key->perm >> 8; goto use_these_perms; } ret = groups_search(cred->group_info, key->gid); if (ret) { kperm = key->perm >> 8; goto use_these_perms; } } /* otherwise use the least-significant 8-bits */ kperm = key->perm; use_these_perms: /* use the top 8-bits of permissions for keys the caller possesses * - possessor permissions are additive with other permissions */ if (is_key_possessed(key_ref)) kperm |= key->perm >> 24; kperm = kperm & perm & KEY_NEED_ALL; if (kperm != perm) return -EACCES; /* let LSM be the final arbiter */ return security_key_permission(key_ref, cred, perm); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells18094.24%685.71%
eric w. biedermaneric w. biederman115.76%114.29%
Total191100.00%7100.00%

EXPORT_SYMBOL(key_task_permission); /** * key_validate - Validate a key. * @key: The key to be validated. * * Check that a key is valid, returning 0 if the key is okay, -ENOKEY if the * key is invalidated, -EKEYREVOKED if the key's type has been removed or if * the key has been revoked or -EKEYEXPIRED if the key has expired. */
int key_validate(const struct key *key) { unsigned long flags = key->flags; if (flags & (1 << KEY_FLAG_INVALIDATED)) return -ENOKEY; /* check it's still accessible */ if (flags & ((1 << KEY_FLAG_REVOKED) | (1 << KEY_FLAG_DEAD))) return -EKEYREVOKED; /* check it hasn't expired */ if (key->expiry) { struct timespec now = current_kernel_time(); if (now.tv_sec >= key->expiry) return -EKEYEXPIRED; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells89100.00%3100.00%
Total89100.00%3100.00%

EXPORT_SYMBOL(key_validate);

Overall Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells29196.36%1090.91%
eric w. biedermaneric w. biederman113.64%19.09%
Total302100.00%11100.00%
Directory: security/keys
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