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smack_lsm.c
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/*
* Simplified MAC Kernel (smack) security module
*
* This file contains the smack hook function implementations.
*
* Authors:
* Casey Schaufler <casey@schaufler-ca.com>
* Jarkko Sakkinen <jarkko.sakkinen@intel.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
* Copyright (C) 2010 Nokia Corporation
* Copyright (C) 2011 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/icmpv6.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/cipso_ipv4.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
#include <linux/parser.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include "smack.h"
#define TRANS_TRUE "TRUE"
#define TRANS_TRUE_SIZE 4
#define SMK_CONNECTING 0
#define SMK_RECEIVING 1
#define SMK_SENDING 2
#ifdef SMACK_IPV6_PORT_LABELING
DEFINE_MUTEX(smack_ipv6_lock);
static LIST_HEAD(smk_ipv6_port_list);
#endif
static struct kmem_cache *smack_inode_cache;
struct kmem_cache *smack_rule_cache;
int smack_enabled;
#define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
static struct {
const char *name;
int len;
int opt;
} smk_mount_opts[] = {
A(fsdefault), A(fsfloor), A(fshat), A(fsroot), A(fstransmute)
};
#undef A
static int match_opt_prefix(char *s, int l, char **arg)
{
int i;
for (i = 0; i < ARRAY_SIZE(smk_mount_opts); i++) {
size_t len = smk_mount_opts[i].len;
if (len > l || memcmp(s, smk_mount_opts[i].name, len))
continue;
if (len == l || s[len] != '=')
continue;
*arg = s + len + 1;
return smk_mount_opts[i].opt;
}
return Opt_error;
}
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static char *smk_bu_mess[] = {
"Bringup Error", /* Unused */
"Bringup", /* SMACK_BRINGUP_ALLOW */
"Unconfined Subject", /* SMACK_UNCONFINED_SUBJECT */
"Unconfined Object", /* SMACK_UNCONFINED_OBJECT */
};
static void smk_bu_mode(int mode, char *s)
{
int i = 0;
if (mode & MAY_READ)
s[i++] = 'r';
if (mode & MAY_WRITE)
s[i++] = 'w';
if (mode & MAY_EXEC)
s[i++] = 'x';
if (mode & MAY_APPEND)
s[i++] = 'a';
if (mode & MAY_TRANSMUTE)
s[i++] = 't';
if (mode & MAY_LOCK)
s[i++] = 'l';
if (i == 0)
s[i++] = '-';
s[i] = '\0';
}
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_note(char *note, struct smack_known *sskp,
struct smack_known *oskp, int mode, int rc)
{
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s\n", smk_bu_mess[rc],
sskp->smk_known, oskp->smk_known, acc, note);
return 0;
}
#else
#define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_current(char *note, struct smack_known *oskp,
int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, oskp->smk_known,
acc, current->comm, note);
return 0;
}
#else
#define smk_bu_current(note, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_task(struct task_struct *otp, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct smack_known *smk_task = smk_of_task_struct(otp);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) %s to %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, smk_task->smk_known, acc,
current->comm, otp->comm);
return 0;
}
#else
#define smk_bu_task(otp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_inode(struct inode *inode, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
if (rc == SMACK_UNCONFINED_SUBJECT &&
(mode & (MAY_WRITE | MAY_APPEND)))
isp->smk_flags |= SMK_INODE_IMPURE;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) inode=(%s %ld) %s\n", smk_bu_mess[rc],
tsp->smk_task->smk_known, isp->smk_inode->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, current->comm);
return 0;
}
#else
#define smk_bu_inode(inode, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_file(struct file *file, int mode, int rc)
{
struct task_smack *tsp = smack_cred(current_cred());
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file_inode(file);
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_file(file, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_credfile(const struct cred *cred, struct file *file,
int mode, int rc)
{
struct task_smack *tsp = smack_cred(cred);
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file_inode(file);
struct inode_smack *isp = smack_inode(inode);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (isp->smk_flags & SMK_INODE_IMPURE)
pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
inode->i_sb->s_id, inode->i_ino, current->comm);
if (rc <= 0)
return rc;
if (rc > SMACK_UNCONFINED_OBJECT)
rc = 0;
smk_bu_mode(mode, acc);
pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_credfile(cred, file, mode, RC) (RC)
#endif
/**
* smk_fetch - Fetch the smack label from a file.
* @name: type of the label (attribute)
* @ip: a pointer to the inode
* @dp: a pointer to the dentry
*
* Returns a pointer to the master list entry for the Smack label,
* NULL if there was no label to fetch, or an error code.
*/
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
struct dentry *dp)
{
int rc;
char *buffer;
struct smack_known *skp = NULL;
if (!(ip->i_opflags & IOP_XATTR))
return ERR_PTR(-EOPNOTSUPP);
buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
if (buffer == NULL)
return ERR_PTR(-ENOMEM);
rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
if (rc < 0)
skp = ERR_PTR(rc);
else if (rc == 0)
skp = NULL;
else
skp = smk_import_entry(buffer, rc);
kfree(buffer);
return skp;
}
/**
* init_inode_smack - initialize an inode security blob
* @isp: the blob to initialize
* @skp: a pointer to the Smack label entry to use in the blob
*
*/
static void init_inode_smack(struct inode *inode, struct smack_known *skp)
{
struct inode_smack *isp = smack_inode(inode);
isp->smk_inode = skp;
isp->smk_flags = 0;
mutex_init(&isp->smk_lock);
}
/**
* init_task_smack - initialize a task security blob
* @tsp: blob to initialize
* @task: a pointer to the Smack label for the running task
* @forked: a pointer to the Smack label for the forked task
*
*/
static void init_task_smack(struct task_smack *tsp, struct smack_known *task,
struct smack_known *forked)
{
tsp->smk_task = task;
tsp->smk_forked = forked;
INIT_LIST_HEAD(&tsp->smk_rules);
INIT_LIST_HEAD(&tsp->smk_relabel);
mutex_init(&tsp->smk_rules_lock);
}
/**
* smk_copy_rules - copy a rule set
* @nhead: new rules header pointer
* @ohead: old rules header pointer
* @gfp: type of the memory for the allocation
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_rule *nrp;
struct smack_rule *orp;
int rc = 0;
list_for_each_entry_rcu(orp, ohead, list) {
nrp = kmem_cache_zalloc(smack_rule_cache, gfp);
if (nrp == NULL) {
rc = -ENOMEM;
break;
}
*nrp = *orp;
list_add_rcu(&nrp->list, nhead);
}
return rc;
}
/**
* smk_copy_relabel - copy smk_relabel labels list
* @nhead: new rules header pointer
* @ohead: old rules header pointer
* @gfp: type of the memory for the allocation
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_known_list_elem *nklep;
struct smack_known_list_elem *oklep;
list_for_each_entry(oklep, ohead, list) {
nklep = kzalloc(sizeof(struct smack_known_list_elem), gfp);
if (nklep == NULL) {
smk_destroy_label_list(nhead);
return -ENOMEM;
}
nklep->smk_label = oklep->smk_label;
list_add(&nklep->list, nhead);
}
return 0;
}
/**
* smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
* @mode - input mode in form of PTRACE_MODE_*
*
* Returns a converted MAY_* mode usable by smack rules
*/
static inline unsigned int smk_ptrace_mode(unsigned int mode)
{
if (mode & PTRACE_MODE_ATTACH)
return MAY_READWRITE;
if (mode & PTRACE_MODE_READ)
return MAY_READ;
return 0;
}
/**
* smk_ptrace_rule_check - helper for ptrace access
* @tracer: tracer process
* @tracee_known: label entry of the process that's about to be traced
* @mode: ptrace attachment mode (PTRACE_MODE_*)
* @func: name of the function that called us, used for audit
*
* Returns 0 on access granted, -error on error
*/
static int smk_ptrace_rule_check(struct task_struct *tracer,
struct smack_known *tracee_known,
unsigned int mode, const char *func)
{
int rc;
struct smk_audit_info ad, *saip = NULL;
struct task_smack *tsp;
struct smack_known *tracer_known;
const struct cred *tracercred;
if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, tracer);
saip = &ad;
}
rcu_read_lock();
tracercred = __task_cred(tracer);
tsp = smack_cred(tracercred);
tracer_known = smk_of_task(tsp);
if ((mode & PTRACE_MODE_ATTACH) &&
(smack_ptrace_rule == SMACK_PTRACE_EXACT ||
smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
if (tracer_known->smk_known == tracee_known->smk_known)
rc = 0;
else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
rc = -EACCES;
else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
rc = 0;
else
rc = -EACCES;
if (saip)
smack_log(tracer_known->smk_known,
tracee_known->smk_known,
0, rc, saip);
rcu_read_unlock();
return rc;
}
/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
rcu_read_unlock();
return rc;
}
/*
* LSM hooks.
* We he, that is fun!
*/
/**
* smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
* @ctp: child task pointer
* @mode: ptrace attachment mode (PTRACE_MODE_*)
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks.
*/
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
struct smack_known *skp;
skp = smk_of_task_struct(ctp);
return smk_ptrace_rule_check(current, skp, mode, __func__);
}
/**
* smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
* @ptp: parent task pointer
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks, and require PTRACE_MODE_ATTACH.
*/
static int smack_ptrace_traceme(struct task_struct *ptp)
{
int rc;
struct smack_known *skp;
skp = smk_of_task(smack_cred(current_cred()));
rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
return rc;
}
/**
* smack_syslog - Smack approval on syslog
* @type: message type
*
* Returns 0 on success, error code otherwise.
*/
static int smack_syslog(int typefrom_file)
{
int rc = 0;
struct smack_known *skp = smk_of_current();
if (smack_privileged(CAP_MAC_OVERRIDE))
return 0;
if (smack_syslog_label != NULL && smack_syslog_label != skp)
rc = -EACCES;
return rc;
}
/*
* Superblock Hooks.
*/
/**
* smack_sb_alloc_security - allocate a superblock blob
* @sb: the superblock getting the blob
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_sb_alloc_security(struct super_block *sb)
{
struct superblock_smack *sbsp;
sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
if (sbsp == NULL)
return -ENOMEM;
sbsp->smk_root = &smack_known_floor;
sbsp->smk_default = &smack_known_floor;
sbsp->smk_floor = &smack_known_floor;
sbsp->smk_hat = &smack_known_hat;
/*
* SMK_SB_INITIALIZED will be zero from kzalloc.
*/
sb->s_security = sbsp;
return 0;
}
/**
* smack_sb_free_security - free a superblock blob
* @sb: the superblock getting the blob
*
*/
static void smack_sb_free_security(struct super_block *sb)
{
kfree(sb->s_security);
sb->s_security = NULL;
}
struct smack_mnt_opts {
const char *fsdefault, *fsfloor, *fshat, *fsroot, *fstransmute;
};
static void smack_free_mnt_opts(void *mnt_opts)
{
struct smack_mnt_opts *opts = mnt_opts;
kfree(opts->fsdefault);
kfree(opts->fsfloor);
kfree(opts->fshat);
kfree(opts->fsroot);
kfree(opts->fstransmute);
kfree(opts);
}
static int smack_add_opt(int token, const char *s, void **mnt_opts)
{
struct smack_mnt_opts *opts = *mnt_opts;
if (!opts) {
opts = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
if (!opts)
return -ENOMEM;
*mnt_opts = opts;
}
if (!s)
return -ENOMEM;
switch (token) {
case Opt_fsdefault:
if (opts->fsdefault)
goto out_opt_err;
opts->fsdefault = s;
break;
case Opt_fsfloor:
if (opts->fsfloor)
goto out_opt_err;
opts->fsfloor = s;
break;
case Opt_fshat:
if (opts->fshat)
goto out_opt_err;
opts->fshat = s;
break;
case Opt_fsroot:
if (opts->fsroot)
goto out_opt_err;
opts->fsroot = s;
break;
case Opt_fstransmute:
if (opts->fstransmute)
goto out_opt_err;
opts->fstransmute = s;
break;
}
return 0;
out_opt_err:
pr_warn("Smack: duplicate mount options\n");
return -EINVAL;
}
/**
* smack_fs_context_dup - Duplicate the security data on fs_context duplication
* @fc: The new filesystem context.
* @src_fc: The source filesystem context being duplicated.
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
struct smack_mnt_opts *dst, *src = src_fc->security;
if (!src)
return 0;
fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
if (!fc->security)
return -ENOMEM;
dst = fc->security;
if (src->fsdefault) {
dst->fsdefault = kstrdup(src->fsdefault, GFP_KERNEL);
if (!dst->fsdefault)
return -ENOMEM;
}
if (src->fsfloor) {
dst->fsfloor = kstrdup(src->fsfloor, GFP_KERNEL);
if (!dst->fsfloor)
return -ENOMEM;
}
if (src->fshat) {
dst->fshat = kstrdup(src->fshat, GFP_KERNEL);
if (!dst->fshat)
return -ENOMEM;
}
if (src->fsroot) {
dst->fsroot = kstrdup(src->fsroot, GFP_KERNEL);
if (!dst->fsroot)
return -ENOMEM;
}
if (src->fstransmute) {
dst->fstransmute = kstrdup(src->fstransmute, GFP_KERNEL);
if (!dst->fstransmute)
return -ENOMEM;
}
return 0;
}
static const struct fs_parameter_spec smack_param_specs[] = {
fsparam_string("fsdefault", Opt_fsdefault),
fsparam_string("fsfloor", Opt_fsfloor),
fsparam_string("fshat", Opt_fshat),
fsparam_string("fsroot", Opt_fsroot),
fsparam_string("fstransmute", Opt_fstransmute),
{}
};
static const struct fs_parameter_description smack_fs_parameters = {
.name = "smack",
.specs = smack_param_specs,
};
/**
* smack_fs_context_parse_param - Parse a single mount parameter
* @fc: The new filesystem context being constructed.
* @param: The parameter.
*
* Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
* error.
*/
static int smack_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
struct fs_parse_result result;
int opt, rc;
opt = fs_parse(fc, &smack_fs_parameters, param, &result);
if (opt < 0)
return opt;
rc = smack_add_opt(opt, param->string, &fc->security);
if (!rc)
param->string = NULL;
return rc;
}
static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
char *from = options, *to = options;
bool first = true;
while (1) {
char *next = strchr(from, ',');
int token, len, rc;
char *arg = NULL;
if (next)
len = next - from;
else
len = strlen(from);
token = match_opt_prefix(from, len, &arg);
if (token != Opt_error) {
arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
rc = smack_add_opt(token, arg, mnt_opts);
if (unlikely(rc)) {
kfree(arg);
if (*mnt_opts)
smack_free_mnt_opts(*mnt_opts);
*mnt_opts = NULL;
return rc;
}
} else {
if (!first) { // copy with preceding comma
from--;
len++;
}
if (to != from)
memmove(to, from, len);
to += len;
first = false;
}
if (!from[len])
break;
from += len + 1;
}
*to = '\0';
return 0;
}
/**
* smack_set_mnt_opts - set Smack specific mount options
* @sb: the file system superblock
* @opts: Smack mount options
* @kern_flags: mount option from kernel space or user space
* @set_kern_flags: where to store converted mount opts
*
* Returns 0 on success, an error code on failure
*
* Allow filesystems with binary mount data to explicitly set Smack mount
* labels.
*/
static int smack_set_mnt_opts(struct super_block *sb,
void *mnt_opts,
unsigned long kern_flags,
unsigned long *set_kern_flags)
{
struct dentry *root = sb->s_root;
struct inode *inode = d_backing_inode(root);
struct superblock_smack *sp = sb->s_security;
struct inode_smack *isp;
struct smack_known *skp;
struct smack_mnt_opts *opts = mnt_opts;
bool transmute = false;
if (sp->smk_flags & SMK_SB_INITIALIZED)
return 0;
if (inode->i_security == NULL) {
int rc = lsm_inode_alloc(inode);
if (rc)
return rc;
}
if (!smack_privileged(CAP_MAC_ADMIN)) {
/*
* Unprivileged mounts don't get to specify Smack values.
*/
if (opts)
return -EPERM;
/*
* Unprivileged mounts get root and default from the caller.
*/
skp = smk_of_current();
sp->smk_root = skp;
sp->smk_default = skp;
/*
* For a handful of fs types with no user-controlled
* backing store it's okay to trust security labels
* in the filesystem. The rest are untrusted.
*/
if (sb->s_user_ns != &init_user_ns &&
sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
sb->s_magic != RAMFS_MAGIC) {
transmute = true;
sp->smk_flags |= SMK_SB_UNTRUSTED;
}
}
sp->smk_flags |= SMK_SB_INITIALIZED;
if (opts) {
if (opts->fsdefault) {
skp = smk_import_entry(opts->fsdefault, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_default = skp;
}
if (opts->fsfloor) {
skp = smk_import_entry(opts->fsfloor, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_floor = skp;
}
if (opts->fshat) {
skp = smk_import_entry(opts->fshat, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_hat = skp;
}
if (opts->fsroot) {
skp = smk_import_entry(opts->fsroot, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
}
if (opts->fstransmute) {
skp = smk_import_entry(opts->fstransmute, 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
transmute = true;
}
}
/*
* Initialize the root inode.
*/
init_inode_smack(inode, sp->smk_root);
if (transmute) {
isp = smack_inode(inode);
isp->smk_flags |= SMK_INODE_TRANSMUTE;
}
return 0;
}
/**
* smack_sb_statfs - Smack check on statfs
* @dentry: identifies the file system in question
*
* Returns 0 if current can read the floor of the filesystem,
* and error code otherwise
*/
static int smack_sb_statfs(struct dentry *dentry)
{
struct superblock_smack *sbp = dentry->d_sb->s_security;
int rc;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
return rc;
}
/*
* BPRM hooks
*/
/**
* smack_bprm_set_creds - set creds for exec
* @bprm: the exec information
*
* Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
*/
static int smack_bprm_set_creds(struct linux_binprm *bprm)
{
struct inode *inode = file_inode(bprm->file);
struct task_smack *bsp = smack_cred(bprm->cred);
struct inode_smack *isp;
struct superblock_smack *sbsp;
int rc;
if (bprm->called_set_creds)
return 0;
isp = smack_inode(inode);
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
sbsp = inode->i_sb->s_security;
if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
isp->smk_task != sbsp->smk_root)
return 0;
if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
struct task_struct *tracer;
rc = 0;
rcu_read_lock();
tracer = ptrace_parent(current);
if (likely(tracer != NULL))
rc = smk_ptrace_rule_check(tracer,
isp->smk_task,
PTRACE_MODE_ATTACH,
__func__);
rcu_read_unlock();
if (rc != 0)
return rc;
} else if (bprm->unsafe)
return -EPERM;
bsp->smk_task = isp->smk_task;
bprm->per_clear |= PER_CLEAR_ON_SETID;
/* Decide if this is a secure exec. */
if (bsp->smk_task != bsp->smk_forked)
bprm->secureexec = 1;
return 0;
}
/*
* Inode hooks
*/
/**
* smack_inode_alloc_security - allocate an inode blob
* @inode: the inode in need of a blob
*
* Returns 0 if it gets a blob, -ENOMEM otherwise
*/
static int smack_inode_alloc_security(struct inode *inode)
{
struct smack_known *skp = smk_of_current();
init_inode_smack(inode, skp);
return 0;
}
/**
* smack_inode_init_security - copy out the smack from an inode
* @inode: the newly created inode
* @dir: containing directory object
* @qstr: unused
* @name: where to put the attribute name
* @value: where to put the attribute value
* @len: where to put the length of the attribute
*
* Returns 0 if it all works out, -ENOMEM if there's no memory
*/
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr, const char **name,
void **value, size_t *len)
{
struct inode_smack *issp = smack_inode(inode);
struct smack_known *skp = smk_of_current();
struct smack_known *isp = smk_of_inode(inode);
struct smack_known *dsp = smk_of_inode(dir);
int may;
if (name)
*name = XATTR_SMACK_SUFFIX;
if (value && len) {
rcu_read_lock();
may = smk_access_entry(skp->smk_known, dsp->smk_known,
&skp->smk_rules);
rcu_read_unlock();