kernel_optimize_test/security/selinux/include/security.h
Ondrej Mosnacek 19c9967e49 selinux: fix variable scope issue in live sidtab conversion
commit 6406887a12ee5dcdaffff1a8508d91113d545559 upstream.

Commit 02a52c5c8c ("selinux: move policy commit after updating
selinuxfs") moved the selinux_policy_commit() call out of
security_load_policy() into sel_write_load(), which caused a subtle yet
rather serious bug.

The problem is that security_load_policy() passes a reference to the
convert_params local variable to sidtab_convert(), which stores it in
the sidtab, where it may be accessed until the policy is swapped over
and RCU synchronized. Before 02a52c5c8c, selinux_policy_commit() was
called directly from security_load_policy(), so the convert_params
pointer remained valid all the way until the old sidtab was destroyed,
but now that's no longer the case and calls to sidtab_context_to_sid()
on the old sidtab after security_load_policy() returns may cause invalid
memory accesses.

This can be easily triggered using the stress test from commit
ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve
performance"):
```
function rand_cat() {
	echo $(( $RANDOM % 1024 ))
}

function do_work() {
	while true; do
		echo -n "system_u:system_r:kernel_t:s0:c$(rand_cat),c$(rand_cat)" \
			>/sys/fs/selinux/context 2>/dev/null || true
	done
}

do_work >/dev/null &
do_work >/dev/null &
do_work >/dev/null &

while load_policy; do echo -n .; sleep 0.1; done

kill %1
kill %2
kill %3
```

Fix this by allocating the temporary sidtab convert structures
dynamically and passing them among the
selinux_policy_{load,cancel,commit} functions.

Fixes: 02a52c5c8c ("selinux: move policy commit after updating selinuxfs")
Cc: stable@vger.kernel.org
Tested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: merge fuzz in security.h and services.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-30 14:31:53 +02:00

457 lines
13 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Security server interface.
*
* Author : Stephen Smalley, <sds@tycho.nsa.gov>
*
*/
#ifndef _SELINUX_SECURITY_H_
#define _SELINUX_SECURITY_H_
#include <linux/compiler.h>
#include <linux/dcache.h>
#include <linux/magic.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include "flask.h"
#include "policycap.h"
#define SECSID_NULL 0x00000000 /* unspecified SID */
#define SECSID_WILD 0xffffffff /* wildcard SID */
#define SECCLASS_NULL 0x0000 /* no class */
/* Identify specific policy version changes */
#define POLICYDB_VERSION_BASE 15
#define POLICYDB_VERSION_BOOL 16
#define POLICYDB_VERSION_IPV6 17
#define POLICYDB_VERSION_NLCLASS 18
#define POLICYDB_VERSION_VALIDATETRANS 19
#define POLICYDB_VERSION_MLS 19
#define POLICYDB_VERSION_AVTAB 20
#define POLICYDB_VERSION_RANGETRANS 21
#define POLICYDB_VERSION_POLCAP 22
#define POLICYDB_VERSION_PERMISSIVE 23
#define POLICYDB_VERSION_BOUNDARY 24
#define POLICYDB_VERSION_FILENAME_TRANS 25
#define POLICYDB_VERSION_ROLETRANS 26
#define POLICYDB_VERSION_NEW_OBJECT_DEFAULTS 27
#define POLICYDB_VERSION_DEFAULT_TYPE 28
#define POLICYDB_VERSION_CONSTRAINT_NAMES 29
#define POLICYDB_VERSION_XPERMS_IOCTL 30
#define POLICYDB_VERSION_INFINIBAND 31
#define POLICYDB_VERSION_GLBLUB 32
#define POLICYDB_VERSION_COMP_FTRANS 33 /* compressed filename transitions */
/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_COMP_FTRANS
/* Mask for just the mount related flags */
#define SE_MNTMASK 0x0f
/* Super block security struct flags for mount options */
/* BE CAREFUL, these need to be the low order bits for selinux_get_mnt_opts */
#define CONTEXT_MNT 0x01
#define FSCONTEXT_MNT 0x02
#define ROOTCONTEXT_MNT 0x04
#define DEFCONTEXT_MNT 0x08
#define SBLABEL_MNT 0x10
/* Non-mount related flags */
#define SE_SBINITIALIZED 0x0100
#define SE_SBPROC 0x0200
#define SE_SBGENFS 0x0400
#define SE_SBGENFS_XATTR 0x0800
#define CONTEXT_STR "context"
#define FSCONTEXT_STR "fscontext"
#define ROOTCONTEXT_STR "rootcontext"
#define DEFCONTEXT_STR "defcontext"
#define SECLABEL_STR "seclabel"
struct netlbl_lsm_secattr;
extern int selinux_enabled_boot;
/*
* type_datum properties
* available at the kernel policy version >= POLICYDB_VERSION_BOUNDARY
*/
#define TYPEDATUM_PROPERTY_PRIMARY 0x0001
#define TYPEDATUM_PROPERTY_ATTRIBUTE 0x0002
/* limitation of boundary depth */
#define POLICYDB_BOUNDS_MAXDEPTH 4
struct selinux_avc;
struct selinux_policy;
struct selinux_state {
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
bool disabled;
#endif
#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
bool enforcing;
#endif
bool checkreqprot;
bool initialized;
bool policycap[__POLICYDB_CAPABILITY_MAX];
struct page *status_page;
struct mutex status_lock;
struct selinux_avc *avc;
struct selinux_policy __rcu *policy;
struct mutex policy_mutex;
} __randomize_layout;
void selinux_avc_init(struct selinux_avc **avc);
extern struct selinux_state selinux_state;
static inline bool selinux_initialized(const struct selinux_state *state)
{
/* do a synchronized load to avoid race conditions */
return smp_load_acquire(&state->initialized);
}
static inline void selinux_mark_initialized(struct selinux_state *state)
{
/* do a synchronized write to avoid race conditions */
smp_store_release(&state->initialized, true);
}
#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
static inline bool enforcing_enabled(struct selinux_state *state)
{
return READ_ONCE(state->enforcing);
}
static inline void enforcing_set(struct selinux_state *state, bool value)
{
WRITE_ONCE(state->enforcing, value);
}
#else
static inline bool enforcing_enabled(struct selinux_state *state)
{
return true;
}
static inline void enforcing_set(struct selinux_state *state, bool value)
{
}
#endif
static inline bool checkreqprot_get(const struct selinux_state *state)
{
return READ_ONCE(state->checkreqprot);
}
static inline void checkreqprot_set(struct selinux_state *state, bool value)
{
WRITE_ONCE(state->checkreqprot, value);
}
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static inline bool selinux_disabled(struct selinux_state *state)
{
return READ_ONCE(state->disabled);
}
static inline void selinux_mark_disabled(struct selinux_state *state)
{
WRITE_ONCE(state->disabled, true);
}
#else
static inline bool selinux_disabled(struct selinux_state *state)
{
return false;
}
#endif
static inline bool selinux_policycap_netpeer(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_NETPEER]);
}
static inline bool selinux_policycap_openperm(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_OPENPERM]);
}
static inline bool selinux_policycap_extsockclass(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_EXTSOCKCLASS]);
}
static inline bool selinux_policycap_alwaysnetwork(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_ALWAYSNETWORK]);
}
static inline bool selinux_policycap_cgroupseclabel(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_CGROUPSECLABEL]);
}
static inline bool selinux_policycap_nnp_nosuid_transition(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION]);
}
static inline bool selinux_policycap_genfs_seclabel_symlinks(void)
{
struct selinux_state *state = &selinux_state;
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS]);
}
struct selinux_policy_convert_data;
struct selinux_load_state {
struct selinux_policy *policy;
struct selinux_policy_convert_data *convert_data;
};
int security_mls_enabled(struct selinux_state *state);
int security_load_policy(struct selinux_state *state,
void *data, size_t len,
struct selinux_load_state *load_state);
void selinux_policy_commit(struct selinux_state *state,
struct selinux_load_state *load_state);
void selinux_policy_cancel(struct selinux_state *state,
struct selinux_load_state *load_state);
int security_read_policy(struct selinux_state *state,
void **data, size_t *len);
int security_policycap_supported(struct selinux_state *state,
unsigned int req_cap);
#define SEL_VEC_MAX 32
struct av_decision {
u32 allowed;
u32 auditallow;
u32 auditdeny;
u32 seqno;
u32 flags;
};
#define XPERMS_ALLOWED 1
#define XPERMS_AUDITALLOW 2
#define XPERMS_DONTAUDIT 4
#define security_xperm_set(perms, x) (perms[x >> 5] |= 1 << (x & 0x1f))
#define security_xperm_test(perms, x) (1 & (perms[x >> 5] >> (x & 0x1f)))
struct extended_perms_data {
u32 p[8];
};
struct extended_perms_decision {
u8 used;
u8 driver;
struct extended_perms_data *allowed;
struct extended_perms_data *auditallow;
struct extended_perms_data *dontaudit;
};
struct extended_perms {
u16 len; /* length associated decision chain */
struct extended_perms_data drivers; /* flag drivers that are used */
};
/* definitions of av_decision.flags */
#define AVD_FLAGS_PERMISSIVE 0x0001
void security_compute_av(struct selinux_state *state,
u32 ssid, u32 tsid,
u16 tclass, struct av_decision *avd,
struct extended_perms *xperms);
void security_compute_xperms_decision(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass,
u8 driver,
struct extended_perms_decision *xpermd);
void security_compute_av_user(struct selinux_state *state,
u32 ssid, u32 tsid,
u16 tclass, struct av_decision *avd);
int security_transition_sid(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass,
const struct qstr *qstr, u32 *out_sid);
int security_transition_sid_user(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass,
const char *objname, u32 *out_sid);
int security_member_sid(struct selinux_state *state, u32 ssid, u32 tsid,
u16 tclass, u32 *out_sid);
int security_change_sid(struct selinux_state *state, u32 ssid, u32 tsid,
u16 tclass, u32 *out_sid);
int security_sid_to_context(struct selinux_state *state, u32 sid,
char **scontext, u32 *scontext_len);
int security_sid_to_context_force(struct selinux_state *state,
u32 sid, char **scontext, u32 *scontext_len);
int security_sid_to_context_inval(struct selinux_state *state,
u32 sid, char **scontext, u32 *scontext_len);
int security_context_to_sid(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *out_sid, gfp_t gfp);
int security_context_str_to_sid(struct selinux_state *state,
const char *scontext, u32 *out_sid, gfp_t gfp);
int security_context_to_sid_default(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *out_sid, u32 def_sid, gfp_t gfp_flags);
int security_context_to_sid_force(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *sid);
int security_get_user_sids(struct selinux_state *state,
u32 callsid, char *username,
u32 **sids, u32 *nel);
int security_port_sid(struct selinux_state *state,
u8 protocol, u16 port, u32 *out_sid);
int security_ib_pkey_sid(struct selinux_state *state,
u64 subnet_prefix, u16 pkey_num, u32 *out_sid);
int security_ib_endport_sid(struct selinux_state *state,
const char *dev_name, u8 port_num, u32 *out_sid);
int security_netif_sid(struct selinux_state *state,
char *name, u32 *if_sid);
int security_node_sid(struct selinux_state *state,
u16 domain, void *addr, u32 addrlen,
u32 *out_sid);
int security_validate_transition(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 tclass);
int security_validate_transition_user(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 tclass);
int security_bounded_transition(struct selinux_state *state,
u32 oldsid, u32 newsid);
int security_sid_mls_copy(struct selinux_state *state,
u32 sid, u32 mls_sid, u32 *new_sid);
int security_net_peersid_resolve(struct selinux_state *state,
u32 nlbl_sid, u32 nlbl_type,
u32 xfrm_sid,
u32 *peer_sid);
int security_get_classes(struct selinux_policy *policy,
char ***classes, int *nclasses);
int security_get_permissions(struct selinux_policy *policy,
char *class, char ***perms, int *nperms);
int security_get_reject_unknown(struct selinux_state *state);
int security_get_allow_unknown(struct selinux_state *state);
#define SECURITY_FS_USE_XATTR 1 /* use xattr */
#define SECURITY_FS_USE_TRANS 2 /* use transition SIDs, e.g. devpts/tmpfs */
#define SECURITY_FS_USE_TASK 3 /* use task SIDs, e.g. pipefs/sockfs */
#define SECURITY_FS_USE_GENFS 4 /* use the genfs support */
#define SECURITY_FS_USE_NONE 5 /* no labeling support */
#define SECURITY_FS_USE_MNTPOINT 6 /* use mountpoint labeling */
#define SECURITY_FS_USE_NATIVE 7 /* use native label support */
#define SECURITY_FS_USE_MAX 7 /* Highest SECURITY_FS_USE_XXX */
int security_fs_use(struct selinux_state *state, struct super_block *sb);
int security_genfs_sid(struct selinux_state *state,
const char *fstype, char *name, u16 sclass,
u32 *sid);
int selinux_policy_genfs_sid(struct selinux_policy *policy,
const char *fstype, char *name, u16 sclass,
u32 *sid);
#ifdef CONFIG_NETLABEL
int security_netlbl_secattr_to_sid(struct selinux_state *state,
struct netlbl_lsm_secattr *secattr,
u32 *sid);
int security_netlbl_sid_to_secattr(struct selinux_state *state,
u32 sid,
struct netlbl_lsm_secattr *secattr);
#else
static inline int security_netlbl_secattr_to_sid(struct selinux_state *state,
struct netlbl_lsm_secattr *secattr,
u32 *sid)
{
return -EIDRM;
}
static inline int security_netlbl_sid_to_secattr(struct selinux_state *state,
u32 sid,
struct netlbl_lsm_secattr *secattr)
{
return -ENOENT;
}
#endif /* CONFIG_NETLABEL */
const char *security_get_initial_sid_context(u32 sid);
/*
* status notifier using mmap interface
*/
extern struct page *selinux_kernel_status_page(struct selinux_state *state);
#define SELINUX_KERNEL_STATUS_VERSION 1
struct selinux_kernel_status {
u32 version; /* version number of thie structure */
u32 sequence; /* sequence number of seqlock logic */
u32 enforcing; /* current setting of enforcing mode */
u32 policyload; /* times of policy reloaded */
u32 deny_unknown; /* current setting of deny_unknown */
/*
* The version > 0 supports above members.
*/
} __packed;
extern void selinux_status_update_setenforce(struct selinux_state *state,
int enforcing);
extern void selinux_status_update_policyload(struct selinux_state *state,
int seqno);
extern void selinux_complete_init(void);
extern int selinux_disable(struct selinux_state *state);
extern void exit_sel_fs(void);
extern struct path selinux_null;
extern struct vfsmount *selinuxfs_mount;
extern void selnl_notify_setenforce(int val);
extern void selnl_notify_policyload(u32 seqno);
extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
extern void avtab_cache_init(void);
extern void ebitmap_cache_init(void);
extern void hashtab_cache_init(void);
extern int security_sidtab_hash_stats(struct selinux_state *state, char *page);
#endif /* _SELINUX_SECURITY_H_ */