Merge tag 'timers-urgent-2020-02-09' of git://git.kernel.org/pub/scm/linux/kernel...

[mirror_ubuntu-hirsute-kernel.git] / security / smack / smack.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
 *
 * Author:
 *      Casey Schaufler <casey@schaufler-ca.com>
 */

#ifndef _SECURITY_SMACK_H
#define _SECURITY_SMACK_H

#include <linux/capability.h>
#include <linux/spinlock.h>
#include <linux/lsm_hooks.h>
#include <linux/in.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/in6.h>
#endif /* CONFIG_IPV6 */
#include <net/netlabel.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/lsm_audit.h>
#include <linux/msg.h>

/*
 * Use IPv6 port labeling if IPv6 is enabled and secmarks
 * are not being used.
 */
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
#define SMACK_IPV6_PORT_LABELING 1
#endif

#if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
#define SMACK_IPV6_SECMARK_LABELING 1
#endif

/*
 * Smack labels were limited to 23 characters for a long time.
 */
#define SMK_LABELLEN    24
#define SMK_LONGLABEL   256

/*
 * This is the repository for labels seen so that it is
 * not necessary to keep allocating tiny chuncks of memory
 * and so that they can be shared.
 *
 * Labels are never modified in place. Anytime a label
 * is imported (e.g. xattrset on a file) the list is checked
 * for it and it is added if it doesn't exist. The address
 * is passed out in either case. Entries are added, but
 * never deleted.
 *
 * Since labels are hanging around anyway it doesn't
 * hurt to maintain a secid for those awkward situations
 * where kernel components that ought to use LSM independent
 * interfaces don't. The secid should go away when all of
 * these components have been repaired.
 *
 * The cipso value associated with the label gets stored here, too.
 *
 * Keep the access rules for this subject label here so that
 * the entire set of rules does not need to be examined every
 * time.
 */
struct smack_known {
        struct list_head                list;
        struct hlist_node               smk_hashed;
        char                            *smk_known;
        u32                             smk_secid;
        struct netlbl_lsm_secattr       smk_netlabel;   /* on wire labels */
        struct list_head                smk_rules;      /* access rules */
        struct mutex                    smk_rules_lock; /* lock for rules */
};

/*
 * Maximum number of bytes for the levels in a CIPSO IP option.
 * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
 * bigger than can be used, and 24 is the next lower multiple
 * of 8, and there are too many issues if there isn't space set
 * aside for the terminating null byte.
 */
#define SMK_CIPSOLEN    24

struct superblock_smack {
        struct smack_known      *smk_root;
        struct smack_known      *smk_floor;
        struct smack_known      *smk_hat;
        struct smack_known      *smk_default;
        int                     smk_flags;
};

/*
 * Superblock flags
 */
#define SMK_SB_INITIALIZED      0x01
#define SMK_SB_UNTRUSTED        0x02

struct socket_smack {
        struct smack_known      *smk_out;       /* outbound label */
        struct smack_known      *smk_in;        /* inbound label */
        struct smack_known      *smk_packet;    /* TCP peer label */
};

/*
 * Inode smack data
 */
struct inode_smack {
        struct smack_known      *smk_inode;     /* label of the fso */
        struct smack_known      *smk_task;      /* label of the task */
        struct smack_known      *smk_mmap;      /* label of the mmap domain */
        struct mutex            smk_lock;       /* initialization lock */
        int                     smk_flags;      /* smack inode flags */
        struct rcu_head         smk_rcu;        /* for freeing inode_smack */
};

struct task_smack {
        struct smack_known      *smk_task;      /* label for access control */
        struct smack_known      *smk_forked;    /* label when forked */
        struct list_head        smk_rules;      /* per task access rules */
        struct mutex            smk_rules_lock; /* lock for the rules */
        struct list_head        smk_relabel;    /* transit allowed labels */
};

#define SMK_INODE_INSTANT       0x01    /* inode is instantiated */
#define SMK_INODE_TRANSMUTE     0x02    /* directory is transmuting */
#define SMK_INODE_CHANGED       0x04    /* smack was transmuted */
#define SMK_INODE_IMPURE        0x08    /* involved in an impure transaction */

/*
 * A label access rule.
 */
struct smack_rule {
        struct list_head        list;
        struct smack_known      *smk_subject;
        struct smack_known      *smk_object;
        int                     smk_access;
};

/*
 * An entry in the table identifying IPv4 hosts.
 */
struct smk_net4addr {
        struct list_head        list;
        struct in_addr          smk_host;       /* network address */
        struct in_addr          smk_mask;       /* network mask */
        int                     smk_masks;      /* mask size */
        struct smack_known      *smk_label;     /* label */
};

#if IS_ENABLED(CONFIG_IPV6)
/*
 * An entry in the table identifying IPv6 hosts.
 */
struct smk_net6addr {
        struct list_head        list;
        struct in6_addr         smk_host;       /* network address */
        struct in6_addr         smk_mask;       /* network mask */
        int                     smk_masks;      /* mask size */
        struct smack_known      *smk_label;     /* label */
};
#endif /* CONFIG_IPV6 */

#ifdef SMACK_IPV6_PORT_LABELING
/*
 * An entry in the table identifying ports.
 */
struct smk_port_label {
        struct list_head        list;
        struct sock             *smk_sock;      /* socket initialized on */
        unsigned short          smk_port;       /* the port number */
        struct smack_known      *smk_in;        /* inbound label */
        struct smack_known      *smk_out;       /* outgoing label */
        short                   smk_sock_type;  /* Socket type */
        short                   smk_can_reuse;
};
#endif /* SMACK_IPV6_PORT_LABELING */

struct smack_known_list_elem {
        struct list_head        list;
        struct smack_known      *smk_label;
};

/* Super block security struct flags for mount options */
#define FSDEFAULT_MNT   0x01
#define FSFLOOR_MNT     0x02
#define FSHAT_MNT       0x04
#define FSROOT_MNT      0x08
#define FSTRANS_MNT     0x10

#define NUM_SMK_MNT_OPTS        5

enum {
        Opt_error = -1,
        Opt_fsdefault = 0,
        Opt_fsfloor = 1,
        Opt_fshat = 2,
        Opt_fsroot = 3,
        Opt_fstransmute = 4,
};

#define SMACK_DELETE_OPTION     "-DELETE"
#define SMACK_CIPSO_OPTION      "-CIPSO"

/*
 * How communications on this socket are treated.
 * Usually it's determined by the underlying netlabel code
 * but there are certain cases, including single label hosts
 * and potentially single label interfaces for which the
 * treatment can not be known in advance.
 *
 * The possibility of additional labeling schemes being
 * introduced in the future exists as well.
 */
#define SMACK_UNLABELED_SOCKET  0
#define SMACK_CIPSO_SOCKET      1

/*
 * CIPSO defaults.
 */
#define SMACK_CIPSO_DOI_DEFAULT         3       /* Historical */
#define SMACK_CIPSO_DOI_INVALID         -1      /* Not a DOI */
#define SMACK_CIPSO_DIRECT_DEFAULT      250     /* Arbitrary */
#define SMACK_CIPSO_MAPPED_DEFAULT      251     /* Also arbitrary */
#define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
/*
 * CIPSO 2.2 standard is 239, but Smack wants to use the
 * categories in a structured way that limits the value to
 * the bits in 23 bytes, hence the unusual number.
 */
#define SMACK_CIPSO_MAXCATNUM           184     /* 23 * 8 */

/*
 * Ptrace rules
 */
#define SMACK_PTRACE_DEFAULT    0
#define SMACK_PTRACE_EXACT      1
#define SMACK_PTRACE_DRACONIAN  2
#define SMACK_PTRACE_MAX        SMACK_PTRACE_DRACONIAN

/*
 * Flags for untraditional access modes.
 * It shouldn't be necessary to avoid conflicts with definitions
 * in fs.h, but do so anyway.
 */
#define MAY_TRANSMUTE   0x00001000      /* Controls directory labeling */
#define MAY_LOCK        0x00002000      /* Locks should be writes, but ... */
#define MAY_BRINGUP     0x00004000      /* Report use of this rule */

/*
 * The policy for delivering signals is configurable.
 * It is usually "write", but can be "append".
 */
#ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
#define MAY_DELIVER     MAY_APPEND      /* Signal delivery requires append */
#else
#define MAY_DELIVER     MAY_WRITE       /* Signal delivery requires write */
#endif

#define SMACK_BRINGUP_ALLOW             1       /* Allow bringup mode */
#define SMACK_UNCONFINED_SUBJECT        2       /* Allow unconfined label */
#define SMACK_UNCONFINED_OBJECT         3       /* Allow unconfined label */

/*
 * Just to make the common cases easier to deal with
 */
#define MAY_ANYREAD     (MAY_READ | MAY_EXEC)
#define MAY_READWRITE   (MAY_READ | MAY_WRITE)
#define MAY_NOT         0

/*
 * Number of access types used by Smack (rwxatlb)
 */
#define SMK_NUM_ACCESS_TYPE 7

/* SMACK data */
struct smack_audit_data {
        const char *function;
        char *subject;
        char *object;
        char *request;
        int result;
};

/*
 * Smack audit data; is empty if CONFIG_AUDIT not set
 * to save some stack
 */
struct smk_audit_info {
#ifdef CONFIG_AUDIT
        struct common_audit_data a;
        struct smack_audit_data sad;
#endif
};

/*
 * These functions are in smack_access.c
 */
int smk_access_entry(char *, char *, struct list_head *);
int smk_access(struct smack_known *, struct smack_known *,
               int, struct smk_audit_info *);
int smk_tskacc(struct task_smack *, struct smack_known *,
               u32, struct smk_audit_info *);
int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
struct smack_known *smack_from_secid(const u32);
char *smk_parse_smack(const char *string, int len);
int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
struct smack_known *smk_import_entry(const char *, int);
void smk_insert_entry(struct smack_known *skp);
struct smack_known *smk_find_entry(const char *);
bool smack_privileged(int cap);
bool smack_privileged_cred(int cap, const struct cred *cred);
void smk_destroy_label_list(struct list_head *list);

/*
 * Shared data.
 */
extern int smack_enabled;
extern int smack_cipso_direct;
extern int smack_cipso_mapped;
extern struct smack_known *smack_net_ambient;
extern struct smack_known *smack_syslog_label;
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
extern struct smack_known *smack_unconfined;
#endif
extern int smack_ptrace_rule;
extern struct lsm_blob_sizes smack_blob_sizes;

extern struct smack_known smack_known_floor;
extern struct smack_known smack_known_hat;
extern struct smack_known smack_known_huh;
extern struct smack_known smack_known_star;
extern struct smack_known smack_known_web;

extern struct mutex     smack_known_lock;
extern struct list_head smack_known_list;
extern struct list_head smk_net4addr_list;
#if IS_ENABLED(CONFIG_IPV6)
extern struct list_head smk_net6addr_list;
#endif /* CONFIG_IPV6 */

extern struct mutex     smack_onlycap_lock;
extern struct list_head smack_onlycap_list;

#define SMACK_HASH_SLOTS 16
extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
extern struct kmem_cache *smack_rule_cache;

static inline struct task_smack *smack_cred(const struct cred *cred)
{
        return cred->security + smack_blob_sizes.lbs_cred;
}

static inline struct smack_known **smack_file(const struct file *file)
{
        return (struct smack_known **)(file->f_security +
                                       smack_blob_sizes.lbs_file);
}

static inline struct inode_smack *smack_inode(const struct inode *inode)
{
        return inode->i_security + smack_blob_sizes.lbs_inode;
}

static inline struct smack_known **smack_msg_msg(const struct msg_msg *msg)
{
        return msg->security + smack_blob_sizes.lbs_msg_msg;
}

static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
{
        return ipc->security + smack_blob_sizes.lbs_ipc;
}

/*
 * Is the directory transmuting?
 */
static inline int smk_inode_transmutable(const struct inode *isp)
{
        struct inode_smack *sip = smack_inode(isp);
        return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
}

/*
 * Present a pointer to the smack label entry in an inode blob.
 */
static inline struct smack_known *smk_of_inode(const struct inode *isp)
{
        struct inode_smack *sip = smack_inode(isp);
        return sip->smk_inode;
}

/*
 * Present a pointer to the smack label entry in an task blob.
 */
static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
{
        return tsp->smk_task;
}

static inline struct smack_known *smk_of_task_struct(
                                                const struct task_struct *t)
{
        struct smack_known *skp;
        const struct cred *cred;

        rcu_read_lock();

        cred = __task_cred(t);
        skp = smk_of_task(smack_cred(cred));

        rcu_read_unlock();

        return skp;
}

/*
 * Present a pointer to the forked smack label entry in an task blob.
 */
static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
{
        return tsp->smk_forked;
}

/*
 * Present a pointer to the smack label in the current task blob.
 */
static inline struct smack_known *smk_of_current(void)
{
        return smk_of_task(smack_cred(current_cred()));
}

/*
 * logging functions
 */
#define SMACK_AUDIT_DENIED 0x1
#define SMACK_AUDIT_ACCEPT 0x2
extern int log_policy;

void smack_log(char *subject_label, char *object_label,
                int request,
                int result, struct smk_audit_info *auditdata);

#ifdef CONFIG_AUDIT

/*
 * some inline functions to set up audit data
 * they do nothing if CONFIG_AUDIT is not set
 *
 */
static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
                               char type)
{
        memset(&a->sad, 0, sizeof(a->sad));
        a->a.type = type;
        a->a.smack_audit_data = &a->sad;
        a->a.smack_audit_data->function = func;
}

static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
                                   char type, struct lsm_network_audit *net)
{
        smk_ad_init(a, func, type);
        memset(net, 0, sizeof(*net));
        a->a.u.net = net;
}

static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
                                         struct task_struct *t)
{
        a->a.u.tsk = t;
}
static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
                                                    struct dentry *d)
{
        a->a.u.dentry = d;
}
static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
                                              struct inode *i)
{
        a->a.u.inode = i;
}
static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
                                             struct path p)
{
        a->a.u.path = p;
}
static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
                                            struct sock *sk)
{
        a->a.u.net->sk = sk;
}

#else /* no AUDIT */

static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
                               char type)
{
}
static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
                                         struct task_struct *t)
{
}
static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
                                                    struct dentry *d)
{
}
static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
                                                 struct vfsmount *m)
{
}
static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
                                              struct inode *i)
{
}
static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
                                             struct path p)
{
}
static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
                                            struct sock *sk)
{
}
#endif

#endif  /* _SECURITY_SMACK_H */