On Tue, Nov 13, 2018 at 10:35 PM Stephen Smalley <sds@xxxxxxxxxxxxx> wrote:
> On 11/13/18 8:52 AM, Ondrej Mosnacek wrote:
> > This patch is non-functional and moves handling of initial SIDs into a
> > separate table. Note that the SIDs stored in the main table are now
> > shifted by SECINITSID_NUM and converted to/from the actual SIDs
> > transparently by helper functions.
>
> When you say "non-functional", you mean it doesn't make any functional
> changes, right? As opposed to leaving the kernel in a broken
> intermediate state until your 3rd patch?
I mean it *should* be non-functional on its own, unless I made a
mistake. I admit I didn't do very much testing on this patch, but I at
least checked that I can boot the kernel, load a policy and that
reported file contexts make sense.
>
> I think you need to double check that all references to
> state->ss->sidtab are preceded by a check of state->initialized since it
> could be NULL before first policy load and a system could come up with
> SELinux enabled but never load a policy.
Well, the original code does not initialize the sidtab field with
sidtab_init() either so state->ss->sidtab.htable would be NULL (or
some garbage pointer) after boot and any use of sidtab would cause a
GPF anyway.
Looking at the places that reference the sidtab (which are all
highlighted in the patch because of the switch to pointer type in the
struct selinux_ss definition), these don't seem to check for
state->initialized:
- security_port_sid
- security_ib_pkey_sid
- security_ib_endport_sid
- security_netif_sid
- security_node_sid
- security_sid_mls_copy, called from:
- selinux_socket_unix_stream_connect (avc_has_perm is called before)
- selinux_conn_sid, called from:
- selinux_sctp_assoc_request (selinux_policycap_extsockclass is
called before)
- selinux_inet_conn_request
- selinux_ip_postroute (selinux_policycap_netpeer is called before)
- security_net_peersid_resolve, called from:
- selinux_skb_peerlbl_sid, called from:
- selinux_socket_sock_rcv_skb (selinux_policycap_netpeer is called before)
- selinux_socket_getpeersec_dgram
- selinux_sctp_assoc_request (again)
- selinux_inet_conn_request (again)
- selinux_inet_conn_established
- selinux_ip_forward (selinux_policycap_netpeer is called before)
- selinux_ip_postroute (again)
- selinux_audit_rule_match
- security_netlbl_secattr_to_sid, called from:
- selinux_netlbl_sidlookup_cached, called from:
- selinux_netlbl_skbuff_getsid (netlbl_enabled is called before)
- selinux_netlbl_sock_rcv_skb (netlbl_enabled is called before)
- security_netlbl_sid_to_secattr, called from:
- selinux_netlbl_sock_genattr, called from:
- selinux_netlbl_socket_post_create, called from:
- selinux_socket_post_create
- selinux_netlbl_skbuff_setsid, called from:
- selinux_ip_forward (again)
- selinux_netlbl_sctp_assoc_request, called from:
- selinux_sctp_assoc_request (again)
- selinux_netlbl_inet_conn_request, called from:
- selinux_inet_conn_request (again)
I suppose in some (or all?) of these cases state->initialized might be
implicitly always 1, but at least in these it wasn't immediately
obvious to me.
Either way, such cases would already be buggy before this patch, since
they would happily access the policy structure (likely hitting some
NULL/invalid pointers) and most likely also dereference the invalid
htable pointer in sidtab.
>
> Aren't you still wasting a slot in the initial SIDs array, or did I miss
> something?
Yes, I am, because the original code doesn't seem to guard against
SECSID_NULL being loaded as initial SID into sidtab. I asked in the
other thread whether this is considered a bug, but I didn't get a
reply, so I left it sort of bug-to-bug compatible for now... Anyway,
it doesn't seem to make much sense to keep that behavior so I will
probably just go ahead and add the check to policydb_load_isids() and
shrink the table. You can expect it to be resolved in the final
patchset.
>
> >
> > This change doesn't make much sense on its own, but it simplifies
> > further sidtab overhaul in a succeeding patch.
> >
> > Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> > ---
> > security/selinux/ss/policydb.c | 10 ++-
> > security/selinux/ss/services.c | 88 ++++++++++--------
> > security/selinux/ss/services.h | 2 +-
> > security/selinux/ss/sidtab.c | 158 +++++++++++++++++++--------------
> > security/selinux/ss/sidtab.h | 14 +--
> > 5 files changed, 162 insertions(+), 110 deletions(-)
> >
> > diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> > index f4eadd3f7350..21e4bdbcf994 100644
> > --- a/security/selinux/ss/policydb.c
> > +++ b/security/selinux/ss/policydb.c
> > @@ -909,13 +909,21 @@ int policydb_load_isids(struct policydb *p, struct sidtab *s)
> > if (!c->context[0].user) {
> > pr_err("SELinux: SID %s was never defined.\n",
> > c->u.name);
> > + sidtab_destroy(s);
> > + goto out;
> > + }
> > + if (c->sid[0] > SECINITSID_NUM) {
> > + pr_err("SELinux: Initial SID %s out of range.\n",
> > + c->u.name);
> > + sidtab_destroy(s);
> > goto out;
> > }
> >
> > - rc = sidtab_insert(s, c->sid[0], &c->context[0]);
> > + rc = sidtab_set_initial(s, c->sid[0], &c->context[0]);
> > if (rc) {
> > pr_err("SELinux: unable to load initial SID %s.\n",
> > c->u.name);
> > + sidtab_destroy(s);
> > goto out;
> > }
> > }
> > diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> > index 7337db24a6a8..30170d4c567a 100644
> > --- a/security/selinux/ss/services.c
> > +++ b/security/selinux/ss/services.c
> > @@ -776,7 +776,7 @@ static int security_compute_validatetrans(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > if (!user)
> > tclass = unmap_class(&state->ss->map, orig_tclass);
> > @@ -876,7 +876,7 @@ int security_bounded_transition(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > rc = -EINVAL;
> > old_context = sidtab_search(sidtab, old_sid);
> > @@ -1034,7 +1034,7 @@ void security_compute_xperms_decision(struct selinux_state *state,
> > goto allow;
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > scontext = sidtab_search(sidtab, ssid);
> > if (!scontext) {
> > @@ -1123,7 +1123,7 @@ void security_compute_av(struct selinux_state *state,
> > goto allow;
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > scontext = sidtab_search(sidtab, ssid);
> > if (!scontext) {
> > @@ -1177,7 +1177,7 @@ void security_compute_av_user(struct selinux_state *state,
> > goto allow;
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > scontext = sidtab_search(sidtab, ssid);
> > if (!scontext) {
> > @@ -1315,7 +1315,7 @@ static int security_sid_to_context_core(struct selinux_state *state,
> > }
> > read_lock(&state->ss->policy_rwlock);
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> > if (force)
> > context = sidtab_search_force(sidtab, sid);
> > else
> > @@ -1483,7 +1483,7 @@ static int security_context_to_sid_core(struct selinux_state *state,
> > }
> > read_lock(&state->ss->policy_rwlock);
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> > rc = string_to_context_struct(policydb, sidtab, scontext2,
> > &context, def_sid);
> > if (rc == -EINVAL && force) {
> > @@ -1668,7 +1668,7 @@ static int security_compute_sid(struct selinux_state *state,
> > }
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > scontext = sidtab_search(sidtab, ssid);
> > if (!scontext) {
> > @@ -1925,10 +1925,7 @@ static int convert_context(u32 key,
> > struct user_datum *usrdatum;
> > char *s;
> > u32 len;
> > - int rc = 0;
> > -
> > - if (key <= SECINITSID_NUM)
> > - goto out;
> > + int rc;
> >
> > args = p;
> >
> > @@ -2090,9 +2087,8 @@ static int security_preserve_bools(struct selinux_state *state,
> > int security_load_policy(struct selinux_state *state, void *data, size_t len)
> > {
> > struct policydb *policydb;
> > - struct sidtab *sidtab;
> > + struct sidtab *oldsidtab, *newsidtab;
> > struct policydb *oldpolicydb, *newpolicydb;
> > - struct sidtab oldsidtab, newsidtab;
> > struct selinux_mapping *oldmapping;
> > struct selinux_map newmap;
> > struct convert_context_args args;
> > @@ -2108,27 +2104,37 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> > newpolicydb = oldpolicydb + 1;
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > +
> > + newsidtab = kmalloc(sizeof(*newsidtab), GFP_KERNEL);
> > + if (!newsidtab) {
> > + rc = -ENOMEM;
> > + goto out;
> > + }
> >
> > if (!state->initialized) {
> > rc = policydb_read(policydb, fp);
> > - if (rc)
> > + if (rc) {
> > + kfree(newsidtab);
> > goto out;
> > + }
> >
> > policydb->len = len;
> > rc = selinux_set_mapping(policydb, secclass_map,
> > &state->ss->map);
> > if (rc) {
> > + kfree(newsidtab);
> > policydb_destroy(policydb);
> > goto out;
> > }
> >
> > - rc = policydb_load_isids(policydb, sidtab);
> > + rc = policydb_load_isids(policydb, newsidtab);
> > if (rc) {
> > + kfree(newsidtab);
> > policydb_destroy(policydb);
> > goto out;
> > }
> >
> > + state->ss->sidtab = newsidtab;
> > security_load_policycaps(state);
> > state->initialized = 1;
> > seqno = ++state->ss->latest_granting;
> > @@ -2141,13 +2147,17 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> > goto out;
> > }
> >
> > + oldsidtab = state->ss->sidtab;
> > +
> > #if 0
> > - sidtab_hash_eval(sidtab, "sids");
> > + sidtab_hash_eval(oldsidtab, "sids");
> > #endif
> >
> > rc = policydb_read(newpolicydb, fp);
> > - if (rc)
> > + if (rc) {
> > + kfree(newsidtab);
> > goto out;
> > + }
> >
> > newpolicydb->len = len;
> > /* If switching between different policy types, log MLS status */
> > @@ -2156,10 +2166,11 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> > else if (!policydb->mls_enabled && newpolicydb->mls_enabled)
> > pr_info("SELinux: Enabling MLS support...\n");
> >
> > - rc = policydb_load_isids(newpolicydb, &newsidtab);
> > + rc = policydb_load_isids(newpolicydb, newsidtab);
> > if (rc) {
> > pr_err("SELinux: unable to load the initial SIDs\n");
> > policydb_destroy(newpolicydb);
> > + kfree(newsidtab);
> > goto out;
> > }
> >
> > @@ -2180,7 +2191,7 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> > args.state = state;
> > args.oldp = policydb;
> > args.newp = newpolicydb;
> > - rc = sidtab_convert(sidtab, &newsidtab, convert_context, &args);
> > + rc = sidtab_convert(oldsidtab, newsidtab, convert_context, &args);
> > if (rc) {
> > pr_err("SELinux: unable to convert the internal"
> > " representation of contexts in the new SID"
> > @@ -2190,12 +2201,11 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> >
> > /* Save the old policydb and SID table to free later. */
> > memcpy(oldpolicydb, policydb, sizeof(*policydb));
> > - sidtab_set(&oldsidtab, sidtab);
> >
> > /* Install the new policydb and SID table. */
> > write_lock_irq(&state->ss->policy_rwlock);
> > memcpy(policydb, newpolicydb, sizeof(*policydb));
> > - sidtab_set(sidtab, &newsidtab);
> > + state->ss->sidtab = newsidtab;
> > security_load_policycaps(state);
> > oldmapping = state->ss->map.mapping;
> > state->ss->map.mapping = newmap.mapping;
> > @@ -2205,7 +2215,8 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> >
> > /* Free the old policydb and SID table. */
> > policydb_destroy(oldpolicydb);
> > - sidtab_destroy(&oldsidtab);
> > + sidtab_destroy(oldsidtab);
> > + kfree(oldsidtab);
> > kfree(oldmapping);
> >
> > avc_ss_reset(state->avc, seqno);
> > @@ -2219,7 +2230,8 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
> >
> > err:
> > kfree(newmap.mapping);
> > - sidtab_destroy(&newsidtab);
> > + sidtab_destroy(newsidtab);
> > + kfree(newsidtab);
> > policydb_destroy(newpolicydb);
> >
> > out:
> > @@ -2256,7 +2268,7 @@ int security_port_sid(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > c = policydb->ocontexts[OCON_PORT];
> > while (c) {
> > @@ -2302,7 +2314,7 @@ int security_ib_pkey_sid(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > c = policydb->ocontexts[OCON_IBPKEY];
> > while (c) {
> > @@ -2348,7 +2360,7 @@ int security_ib_endport_sid(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > c = policydb->ocontexts[OCON_IBENDPORT];
> > while (c) {
> > @@ -2394,7 +2406,7 @@ int security_netif_sid(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > c = policydb->ocontexts[OCON_NETIF];
> > while (c) {
> > @@ -2459,7 +2471,7 @@ int security_node_sid(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > switch (domain) {
> > case AF_INET: {
> > @@ -2559,7 +2571,7 @@ int security_get_user_sids(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > context_init(&usercon);
> >
> > @@ -2661,7 +2673,7 @@ static inline int __security_genfs_sid(struct selinux_state *state,
> > u32 *sid)
> > {
> > struct policydb *policydb = &state->ss->policydb;
> > - struct sidtab *sidtab = &state->ss->sidtab;
> > + struct sidtab *sidtab = state->ss->sidtab;
> > int len;
> > u16 sclass;
> > struct genfs *genfs;
> > @@ -2747,7 +2759,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
> > read_lock(&state->ss->policy_rwlock);
> >
> > policydb = &state->ss->policydb;
> > - sidtab = &state->ss->sidtab;
> > + sidtab = state->ss->sidtab;
> >
> > c = policydb->ocontexts[OCON_FSUSE];
> > while (c) {
> > @@ -2953,7 +2965,7 @@ int security_sid_mls_copy(struct selinux_state *state,
> > u32 sid, u32 mls_sid, u32 *new_sid)
> > {
> > struct policydb *policydb = &state->ss->policydb;
> > - struct sidtab *sidtab = &state->ss->sidtab;
> > + struct sidtab *sidtab = state->ss->sidtab;
> > struct context *context1;
> > struct context *context2;
> > struct context newcon;
> > @@ -3044,7 +3056,7 @@ int security_net_peersid_resolve(struct selinux_state *state,
> > u32 *peer_sid)
> > {
> > struct policydb *policydb = &state->ss->policydb;
> > - struct sidtab *sidtab = &state->ss->sidtab;
> > + struct sidtab *sidtab = state->ss->sidtab;
> > int rc;
> > struct context *nlbl_ctx;
> > struct context *xfrm_ctx;
> > @@ -3405,7 +3417,7 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
> > goto out;
> > }
> >
> > - ctxt = sidtab_search(&state->ss->sidtab, sid);
> > + ctxt = sidtab_search(state->ss->sidtab, sid);
> > if (unlikely(!ctxt)) {
> > WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
> > sid);
> > @@ -3568,7 +3580,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
> > u32 *sid)
> > {
> > struct policydb *policydb = &state->ss->policydb;
> > - struct sidtab *sidtab = &state->ss->sidtab;
> > + struct sidtab *sidtab = state->ss->sidtab;
> > int rc;
> > struct context *ctx;
> > struct context ctx_new;
> > @@ -3646,7 +3658,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
> > read_lock(&state->ss->policy_rwlock);
> >
> > rc = -ENOENT;
> > - ctx = sidtab_search(&state->ss->sidtab, sid);
> > + ctx = sidtab_search(state->ss->sidtab, sid);
> > if (ctx == NULL)
> > goto out;
> >
> > diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h
> > index 24c7bdcc8075..9a36de860368 100644
> > --- a/security/selinux/ss/services.h
> > +++ b/security/selinux/ss/services.h
> > @@ -24,7 +24,7 @@ struct selinux_map {
> > };
> >
> > struct selinux_ss {
> > - struct sidtab sidtab;
> > + struct sidtab *sidtab;
> > struct policydb policydb;
> > rwlock_t policy_rwlock;
> > u32 latest_granting;
> > diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
> > index e66a2ab3d1c2..049ac1e6fd06 100644
> > --- a/security/selinux/ss/sidtab.c
> > +++ b/security/selinux/ss/sidtab.c
> > @@ -22,16 +22,24 @@ int sidtab_init(struct sidtab *s)
> > s->htable = kmalloc_array(SIDTAB_SIZE, sizeof(*s->htable), GFP_ATOMIC);
> > if (!s->htable)
> > return -ENOMEM;
> > +
> > + for (i = 0; i <= SECINITSID_NUM; i++)
> > + s->isids[i].set = 0;
> > +
> > for (i = 0; i < SIDTAB_SIZE; i++)
> > s->htable[i] = NULL;
> > +
> > + for (i = 0; i < SIDTAB_CACHE_LEN; i++)
> > + s->cache[i] = NULL;
> > +
> > s->nel = 0;
> > - s->next_sid = 1;
> > + s->next_sid = 0;
> > s->shutdown = 0;
> > spin_lock_init(&s->lock);
> > return 0;
> > }
> >
> > -int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
> > +static int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
> > {
> > int hvalue;
> > struct sidtab_node *prev, *cur, *newnode;
> > @@ -76,34 +84,53 @@ int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
> > return 0;
> > }
> >
> > -static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
> > +int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
> > +{
> > + struct sidtab_isid_entry *entry = &s->isids[sid];
> > + int rc = context_cpy(&entry->context, context);
> > + if (rc)
> > + return rc;
> > +
> > + entry->set = 1;
> > + return 0;
> > +}
> > +
> > +static struct context *sidtab_lookup(struct sidtab *s, u32 sid)
> > {
> > int hvalue;
> > struct sidtab_node *cur;
> >
> > - if (!s)
> > - return NULL;
> > -
> > hvalue = SIDTAB_HASH(sid);
> > cur = s->htable[hvalue];
> > while (cur && sid > cur->sid)
> > cur = cur->next;
> >
> > - if (force && cur && sid == cur->sid && cur->context.len)
> > - return &cur->context;
> > + if (!cur || sid != cur->sid)
> > + return NULL;
> >
> > - if (!cur || sid != cur->sid || cur->context.len) {
> > - /* Remap invalid SIDs to the unlabeled SID. */
> > - sid = SECINITSID_UNLABELED;
> > - hvalue = SIDTAB_HASH(sid);
> > - cur = s->htable[hvalue];
> > - while (cur && sid > cur->sid)
> > - cur = cur->next;
> > - if (!cur || sid != cur->sid)
> > - return NULL;
> > + return &cur->context;
> > +}
> > +
> > +static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
> > +{
> > + struct context *context;
> > + struct sidtab_isid_entry *entry;
> > +
> > + if (!s)
> > + return NULL;
> > +
> > + if (sid > SECINITSID_NUM) {
> > + u32 index = sid - (SECINITSID_NUM + 1);
> > + context = sidtab_lookup(s, index);
> > + } else {
> > + entry = &s->isids[sid];
> > + context = entry->set ? &entry->context : NULL;
> > }
> > + if (context && (!context->len || force))
> > + return context;
> >
> > - return &cur->context;
> > + entry = &s->isids[SECINITSID_UNLABELED];
> > + return entry->set ? &entry->context : NULL;
> > }
> >
> > struct context *sidtab_search(struct sidtab *s, u32 sid)
> > @@ -145,11 +172,7 @@ out:
> > static int clone_sid(u32 sid, struct context *context, void *arg)
> > {
> > struct sidtab *s = arg;
> > -
> > - if (sid > SECINITSID_NUM)
> > - return sidtab_insert(s, sid, context);
> > - else
> > - return 0;
> > + return sidtab_insert(s, sid, context);
> > }
> >
> > int sidtab_convert(struct sidtab *s, struct sidtab *news,
> > @@ -183,8 +206,8 @@ static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc
> > s->cache[0] = n;
> > }
> >
> > -static inline u32 sidtab_search_context(struct sidtab *s,
> > - struct context *context)
> > +static inline int sidtab_search_context(struct sidtab *s,
> > + struct context *context, u32 *sid)
> > {
> > int i;
> > struct sidtab_node *cur;
> > @@ -194,15 +217,17 @@ static inline u32 sidtab_search_context(struct sidtab *s,
> > while (cur) {
> > if (context_cmp(&cur->context, context)) {
> > sidtab_update_cache(s, cur, SIDTAB_CACHE_LEN - 1);
> > - return cur->sid;
> > + *sid = cur->sid;
> > + return 0;
> > }
> > cur = cur->next;
> > }
> > }
> > - return 0;
> > + return -ENOENT;
> > }
> >
> > -static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)
> > +static inline int sidtab_search_cache(struct sidtab *s, struct context *context,
> > + u32 *sid)
> > {
> > int i;
> > struct sidtab_node *node;
> > @@ -210,54 +235,67 @@ static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)
> > for (i = 0; i < SIDTAB_CACHE_LEN; i++) {
> > node = s->cache[i];
> > if (unlikely(!node))
> > - return 0;
> > + return -ENOENT;
> > if (context_cmp(&node->context, context)) {
> > sidtab_update_cache(s, node, i);
> > - return node->sid;
> > + *sid = node->sid;
> > + return 0;
> > }
> > }
> > - return 0;
> > + return -ENOENT;
> > }
> >
> > -int sidtab_context_to_sid(struct sidtab *s,
> > - struct context *context,
> > - u32 *out_sid)
> > +static int sidtab_reverse_lookup(struct sidtab *s, struct context *context,
> > + u32 *sid)
> > {
> > - u32 sid;
> > - int ret = 0;
> > + int ret;
> > unsigned long flags;
> >
> > - *out_sid = SECSID_NULL;
> > -
> > - sid = sidtab_search_cache(s, context);
> > - if (!sid)
> > - sid = sidtab_search_context(s, context);
> > - if (!sid) {
> > + ret = sidtab_search_cache(s, context, sid);
> > + if (ret)
> > + ret = sidtab_search_context(s, context, sid);
> > + if (ret) {
> > spin_lock_irqsave(&s->lock, flags);
> > /* Rescan now that we hold the lock. */
> > - sid = sidtab_search_context(s, context);
> > - if (sid)
> > + ret = sidtab_search_context(s, context, sid);
> > + if (!ret)
> > goto unlock_out;
> > /* No SID exists for the context. Allocate a new one. */
> > - if (s->next_sid == UINT_MAX || s->shutdown) {
> > + if (s->next_sid == (UINT_MAX - SECINITSID_NUM - 1) || s->shutdown) {
> > ret = -ENOMEM;
> > goto unlock_out;
> > }
> > - sid = s->next_sid++;
> > + *sid = s->next_sid++;
> > if (context->len)
> > pr_info("SELinux: Context %s is not valid (left unmapped).\n",
> > context->str);
> > - ret = sidtab_insert(s, sid, context);
> > + ret = sidtab_insert(s, *sid, context);
> > if (ret)
> > s->next_sid--;
> > unlock_out:
> > spin_unlock_irqrestore(&s->lock, flags);
> > }
> >
> > - if (ret)
> > - return ret;
> > + return ret;
> > +}
> > +
> > +int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid)
> > +{
> > + int rc;
> > + u32 i;
> > +
> > + for (i = 0; i <= SECINITSID_NUM; i++) {
> > + struct sidtab_isid_entry *entry = &s->isids[i];
> > + if (entry->set && context_cmp(context, &entry->context)) {
> > + *sid = i;
> > + return 0;
> > + }
> > + }
> >
> > - *out_sid = sid;
> > + rc = sidtab_reverse_lookup(s, context, sid);
> > + if (rc)
> > + return rc;
> > + *sid += SECINITSID_NUM + 1;
> > return 0;
> > }
> >
> > @@ -296,6 +334,11 @@ void sidtab_destroy(struct sidtab *s)
> > if (!s)
> > return;
> >
> > + for (i = 0; i <= SECINITSID_NUM; i++)
> > + if (s->isids[i].set)
> > + context_destroy(&s->isids[i].context);
> > +
> > +
> > for (i = 0; i < SIDTAB_SIZE; i++) {
> > cur = s->htable[i];
> > while (cur) {
> > @@ -311,18 +354,3 @@ void sidtab_destroy(struct sidtab *s)
> > s->nel = 0;
> > s->next_sid = 1;
> > }
> > -
> > -void sidtab_set(struct sidtab *dst, struct sidtab *src)
> > -{
> > - unsigned long flags;
> > - int i;
> > -
> > - spin_lock_irqsave(&src->lock, flags);
> > - dst->htable = src->htable;
> > - dst->nel = src->nel;
> > - dst->next_sid = src->next_sid;
> > - dst->shutdown = 0;
> > - for (i = 0; i < SIDTAB_CACHE_LEN; i++)
> > - dst->cache[i] = NULL;
> > - spin_unlock_irqrestore(&src->lock, flags);
> > -}
> > diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
> > index 26c74fe7afc0..e181db3589bc 100644
> > --- a/security/selinux/ss/sidtab.h
> > +++ b/security/selinux/ss/sidtab.h
> > @@ -22,6 +22,11 @@ struct sidtab_node {
> >
> > #define SIDTAB_SIZE SIDTAB_HASH_BUCKETS
> >
> > +struct sidtab_isid_entry {
> > + int set;
> > + struct context context;
> > +};
> > +
> > struct sidtab {
> > struct sidtab_node **htable;
> > unsigned int nel; /* number of elements */
> > @@ -30,10 +35,12 @@ struct sidtab {
> > #define SIDTAB_CACHE_LEN 3
> > struct sidtab_node *cache[SIDTAB_CACHE_LEN];
> > spinlock_t lock;
> > +
> > + struct sidtab_isid_entry isids[SECINITSID_NUM + 1];
> > };
> >
> > int sidtab_init(struct sidtab *s);
> > -int sidtab_insert(struct sidtab *s, u32 sid, struct context *context);
> > +int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context);
> > struct context *sidtab_search(struct sidtab *s, u32 sid);
> > struct context *sidtab_search_force(struct sidtab *s, u32 sid);
> >
> > @@ -43,13 +50,10 @@ int sidtab_convert(struct sidtab *s, struct sidtab *news,
> > void *args),
> > void *args);
> >
> > -int sidtab_context_to_sid(struct sidtab *s,
> > - struct context *context,
> > - u32 *sid);
> > +int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);
> >
> > void sidtab_hash_eval(struct sidtab *h, char *tag);
> > void sidtab_destroy(struct sidtab *s);
> > -void sidtab_set(struct sidtab *dst, struct sidtab *src);
> >
> > #endif /* _SS_SIDTAB_H_ */
> >
> >
>
--
Ondrej Mosnacek <omosnace at redhat dot com>
Associate Software Engineer, Security Technologies
Red Hat, Inc.
