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![Paul Moore](/assets/img/avatar_default.png)
The security_task_getsecid_subj() LSM hook invites misuse by allowing callers to specify a task even though the hook is only safe when the current task is referenced. Fix this by removing the task_struct argument to the hook, requiring LSM implementations to use the current task. While we are changing the hook declaration we also rename the function to security_current_getsecid_subj() in an effort to reinforce that the hook captures the subjective credentials of the current task and not an arbitrary task on the system. Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
513 lines
13 KiB
C
513 lines
13 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
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*
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* Author:
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* Casey Schaufler <casey@schaufler-ca.com>
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*/
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#ifndef _SECURITY_SMACK_H
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#define _SECURITY_SMACK_H
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#include <linux/capability.h>
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#include <linux/spinlock.h>
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#include <linux/lsm_hooks.h>
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#include <linux/in.h>
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#if IS_ENABLED(CONFIG_IPV6)
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#include <linux/in6.h>
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#endif /* CONFIG_IPV6 */
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#include <net/netlabel.h>
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#include <linux/list.h>
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#include <linux/rculist.h>
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#include <linux/lsm_audit.h>
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#include <linux/msg.h>
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/*
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* Use IPv6 port labeling if IPv6 is enabled and secmarks
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* are not being used.
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*/
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#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
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#define SMACK_IPV6_PORT_LABELING 1
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#endif
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#if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
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#define SMACK_IPV6_SECMARK_LABELING 1
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#endif
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/*
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* Smack labels were limited to 23 characters for a long time.
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*/
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#define SMK_LABELLEN 24
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#define SMK_LONGLABEL 256
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/*
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* This is the repository for labels seen so that it is
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* not necessary to keep allocating tiny chuncks of memory
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* and so that they can be shared.
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*
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* Labels are never modified in place. Anytime a label
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* is imported (e.g. xattrset on a file) the list is checked
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* for it and it is added if it doesn't exist. The address
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* is passed out in either case. Entries are added, but
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* never deleted.
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*
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* Since labels are hanging around anyway it doesn't
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* hurt to maintain a secid for those awkward situations
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* where kernel components that ought to use LSM independent
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* interfaces don't. The secid should go away when all of
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* these components have been repaired.
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*
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* The cipso value associated with the label gets stored here, too.
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*
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* Keep the access rules for this subject label here so that
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* the entire set of rules does not need to be examined every
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* time.
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*/
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struct smack_known {
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struct list_head list;
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struct hlist_node smk_hashed;
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char *smk_known;
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u32 smk_secid;
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struct netlbl_lsm_secattr smk_netlabel; /* on wire labels */
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struct list_head smk_rules; /* access rules */
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struct mutex smk_rules_lock; /* lock for rules */
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};
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/*
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* Maximum number of bytes for the levels in a CIPSO IP option.
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* Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
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* bigger than can be used, and 24 is the next lower multiple
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* of 8, and there are too many issues if there isn't space set
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* aside for the terminating null byte.
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*/
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#define SMK_CIPSOLEN 24
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struct superblock_smack {
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struct smack_known *smk_root;
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struct smack_known *smk_floor;
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struct smack_known *smk_hat;
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struct smack_known *smk_default;
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int smk_flags;
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};
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/*
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* Superblock flags
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*/
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#define SMK_SB_INITIALIZED 0x01
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#define SMK_SB_UNTRUSTED 0x02
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struct socket_smack {
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struct smack_known *smk_out; /* outbound label */
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struct smack_known *smk_in; /* inbound label */
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struct smack_known *smk_packet; /* TCP peer label */
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int smk_state; /* netlabel socket states */
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};
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#define SMK_NETLBL_UNSET 0
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#define SMK_NETLBL_UNLABELED 1
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#define SMK_NETLBL_LABELED 2
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#define SMK_NETLBL_REQSKB 3
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/*
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* Inode smack data
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*/
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struct inode_smack {
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struct smack_known *smk_inode; /* label of the fso */
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struct smack_known *smk_task; /* label of the task */
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struct smack_known *smk_mmap; /* label of the mmap domain */
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int smk_flags; /* smack inode flags */
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};
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struct task_smack {
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struct smack_known *smk_task; /* label for access control */
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struct smack_known *smk_forked; /* label when forked */
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struct list_head smk_rules; /* per task access rules */
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struct mutex smk_rules_lock; /* lock for the rules */
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struct list_head smk_relabel; /* transit allowed labels */
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};
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#define SMK_INODE_INSTANT 0x01 /* inode is instantiated */
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#define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */
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#define SMK_INODE_CHANGED 0x04 /* smack was transmuted */
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#define SMK_INODE_IMPURE 0x08 /* involved in an impure transaction */
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/*
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* A label access rule.
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*/
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struct smack_rule {
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struct list_head list;
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struct smack_known *smk_subject;
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struct smack_known *smk_object;
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int smk_access;
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};
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/*
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* An entry in the table identifying IPv4 hosts.
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*/
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struct smk_net4addr {
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struct list_head list;
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struct in_addr smk_host; /* network address */
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struct in_addr smk_mask; /* network mask */
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int smk_masks; /* mask size */
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struct smack_known *smk_label; /* label */
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};
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/*
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* An entry in the table identifying IPv6 hosts.
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*/
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struct smk_net6addr {
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struct list_head list;
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struct in6_addr smk_host; /* network address */
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struct in6_addr smk_mask; /* network mask */
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int smk_masks; /* mask size */
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struct smack_known *smk_label; /* label */
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};
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/*
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* An entry in the table identifying ports.
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*/
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struct smk_port_label {
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struct list_head list;
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struct sock *smk_sock; /* socket initialized on */
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unsigned short smk_port; /* the port number */
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struct smack_known *smk_in; /* inbound label */
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struct smack_known *smk_out; /* outgoing label */
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short smk_sock_type; /* Socket type */
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short smk_can_reuse;
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};
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struct smack_known_list_elem {
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struct list_head list;
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struct smack_known *smk_label;
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};
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/* Super block security struct flags for mount options */
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#define FSDEFAULT_MNT 0x01
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#define FSFLOOR_MNT 0x02
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#define FSHAT_MNT 0x04
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#define FSROOT_MNT 0x08
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#define FSTRANS_MNT 0x10
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#define NUM_SMK_MNT_OPTS 5
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enum {
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Opt_error = -1,
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Opt_fsdefault = 0,
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Opt_fsfloor = 1,
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Opt_fshat = 2,
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Opt_fsroot = 3,
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Opt_fstransmute = 4,
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};
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#define SMACK_DELETE_OPTION "-DELETE"
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#define SMACK_CIPSO_OPTION "-CIPSO"
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/*
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* CIPSO defaults.
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*/
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#define SMACK_CIPSO_DOI_DEFAULT 3 /* Historical */
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#define SMACK_CIPSO_DOI_INVALID -1 /* Not a DOI */
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#define SMACK_CIPSO_DIRECT_DEFAULT 250 /* Arbitrary */
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#define SMACK_CIPSO_MAPPED_DEFAULT 251 /* Also arbitrary */
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#define SMACK_CIPSO_MAXLEVEL 255 /* CIPSO 2.2 standard */
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/*
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* CIPSO 2.2 standard is 239, but Smack wants to use the
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* categories in a structured way that limits the value to
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* the bits in 23 bytes, hence the unusual number.
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*/
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#define SMACK_CIPSO_MAXCATNUM 184 /* 23 * 8 */
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/*
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* Ptrace rules
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*/
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#define SMACK_PTRACE_DEFAULT 0
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#define SMACK_PTRACE_EXACT 1
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#define SMACK_PTRACE_DRACONIAN 2
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#define SMACK_PTRACE_MAX SMACK_PTRACE_DRACONIAN
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/*
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* Flags for untraditional access modes.
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* It shouldn't be necessary to avoid conflicts with definitions
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* in fs.h, but do so anyway.
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*/
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#define MAY_TRANSMUTE 0x00001000 /* Controls directory labeling */
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#define MAY_LOCK 0x00002000 /* Locks should be writes, but ... */
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#define MAY_BRINGUP 0x00004000 /* Report use of this rule */
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/*
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* The policy for delivering signals is configurable.
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* It is usually "write", but can be "append".
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*/
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#ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
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#define MAY_DELIVER MAY_APPEND /* Signal delivery requires append */
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#else
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#define MAY_DELIVER MAY_WRITE /* Signal delivery requires write */
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#endif
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#define SMACK_BRINGUP_ALLOW 1 /* Allow bringup mode */
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#define SMACK_UNCONFINED_SUBJECT 2 /* Allow unconfined label */
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#define SMACK_UNCONFINED_OBJECT 3 /* Allow unconfined label */
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/*
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* Just to make the common cases easier to deal with
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*/
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#define MAY_ANYREAD (MAY_READ | MAY_EXEC)
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#define MAY_READWRITE (MAY_READ | MAY_WRITE)
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#define MAY_NOT 0
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/*
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* Number of access types used by Smack (rwxatlb)
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*/
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#define SMK_NUM_ACCESS_TYPE 7
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/* SMACK data */
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struct smack_audit_data {
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const char *function;
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char *subject;
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char *object;
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char *request;
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int result;
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};
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/*
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* Smack audit data; is empty if CONFIG_AUDIT not set
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* to save some stack
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*/
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struct smk_audit_info {
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#ifdef CONFIG_AUDIT
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struct common_audit_data a;
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struct smack_audit_data sad;
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#endif
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};
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/*
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* These functions are in smack_access.c
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*/
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int smk_access_entry(char *, char *, struct list_head *);
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int smk_access(struct smack_known *, struct smack_known *,
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int, struct smk_audit_info *);
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int smk_tskacc(struct task_smack *, struct smack_known *,
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u32, struct smk_audit_info *);
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int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
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struct smack_known *smack_from_secid(const u32);
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char *smk_parse_smack(const char *string, int len);
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int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
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struct smack_known *smk_import_entry(const char *, int);
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void smk_insert_entry(struct smack_known *skp);
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struct smack_known *smk_find_entry(const char *);
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bool smack_privileged(int cap);
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bool smack_privileged_cred(int cap, const struct cred *cred);
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void smk_destroy_label_list(struct list_head *list);
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int smack_populate_secattr(struct smack_known *skp);
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/*
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* Shared data.
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*/
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extern int smack_enabled __initdata;
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extern int smack_cipso_direct;
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extern int smack_cipso_mapped;
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extern struct smack_known *smack_net_ambient;
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extern struct smack_known *smack_syslog_label;
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#ifdef CONFIG_SECURITY_SMACK_BRINGUP
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extern struct smack_known *smack_unconfined;
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#endif
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extern int smack_ptrace_rule;
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extern struct lsm_blob_sizes smack_blob_sizes;
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extern struct smack_known smack_known_floor;
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extern struct smack_known smack_known_hat;
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extern struct smack_known smack_known_huh;
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extern struct smack_known smack_known_star;
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extern struct smack_known smack_known_web;
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extern struct mutex smack_known_lock;
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extern struct list_head smack_known_list;
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extern struct list_head smk_net4addr_list;
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extern struct list_head smk_net6addr_list;
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extern struct mutex smack_onlycap_lock;
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extern struct list_head smack_onlycap_list;
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#define SMACK_HASH_SLOTS 16
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extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
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extern struct kmem_cache *smack_rule_cache;
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static inline struct task_smack *smack_cred(const struct cred *cred)
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{
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return cred->security + smack_blob_sizes.lbs_cred;
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}
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static inline struct smack_known **smack_file(const struct file *file)
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{
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return (struct smack_known **)(file->f_security +
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smack_blob_sizes.lbs_file);
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}
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static inline struct inode_smack *smack_inode(const struct inode *inode)
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{
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return inode->i_security + smack_blob_sizes.lbs_inode;
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}
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static inline struct smack_known **smack_msg_msg(const struct msg_msg *msg)
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{
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return msg->security + smack_blob_sizes.lbs_msg_msg;
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}
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static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
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{
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return ipc->security + smack_blob_sizes.lbs_ipc;
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}
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static inline struct superblock_smack *smack_superblock(
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const struct super_block *superblock)
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{
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return superblock->s_security + smack_blob_sizes.lbs_superblock;
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}
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/*
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* Is the directory transmuting?
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*/
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static inline int smk_inode_transmutable(const struct inode *isp)
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{
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struct inode_smack *sip = smack_inode(isp);
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return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
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}
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/*
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* Present a pointer to the smack label entry in an inode blob.
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*/
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static inline struct smack_known *smk_of_inode(const struct inode *isp)
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{
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struct inode_smack *sip = smack_inode(isp);
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return sip->smk_inode;
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}
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/*
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* Present a pointer to the smack label entry in an task blob.
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*/
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static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
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{
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return tsp->smk_task;
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}
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static inline struct smack_known *smk_of_task_struct_obj(
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const struct task_struct *t)
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{
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struct smack_known *skp;
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const struct cred *cred;
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rcu_read_lock();
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cred = __task_cred(t);
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skp = smk_of_task(smack_cred(cred));
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rcu_read_unlock();
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return skp;
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}
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/*
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* Present a pointer to the forked smack label entry in an task blob.
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*/
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static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
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{
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return tsp->smk_forked;
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}
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/*
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* Present a pointer to the smack label in the current task blob.
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*/
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static inline struct smack_known *smk_of_current(void)
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{
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return smk_of_task(smack_cred(current_cred()));
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}
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/*
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* logging functions
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*/
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#define SMACK_AUDIT_DENIED 0x1
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#define SMACK_AUDIT_ACCEPT 0x2
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extern int log_policy;
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void smack_log(char *subject_label, char *object_label,
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int request,
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int result, struct smk_audit_info *auditdata);
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#ifdef CONFIG_AUDIT
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/*
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* some inline functions to set up audit data
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* they do nothing if CONFIG_AUDIT is not set
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*
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*/
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static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
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char type)
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{
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memset(&a->sad, 0, sizeof(a->sad));
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a->a.type = type;
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a->a.smack_audit_data = &a->sad;
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a->a.smack_audit_data->function = func;
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}
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static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
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char type, struct lsm_network_audit *net)
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{
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smk_ad_init(a, func, type);
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memset(net, 0, sizeof(*net));
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a->a.u.net = net;
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}
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static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
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struct task_struct *t)
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{
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a->a.u.tsk = t;
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}
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static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
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struct dentry *d)
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{
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a->a.u.dentry = d;
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}
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static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
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struct inode *i)
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{
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a->a.u.inode = i;
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}
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static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
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struct path p)
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{
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a->a.u.path = p;
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}
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static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
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struct sock *sk)
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{
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a->a.u.net->sk = sk;
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}
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#else /* no AUDIT */
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static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
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char type)
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{
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}
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static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
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struct task_struct *t)
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{
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}
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static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
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|
struct dentry *d)
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{
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|
}
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static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
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|
struct inode *i)
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|
{
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|
}
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static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
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|
struct path p)
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|
{
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}
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static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
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|
struct sock *sk)
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|
{
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|
}
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#endif
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#endif /* _SECURITY_SMACK_H */
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