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-rw-r--r--security/selinux/ss/services.c157
-rw-r--r--security/selinux/ss/sidtab.c21
-rw-r--r--security/selinux/ss/sidtab.h4
3 files changed, 145 insertions, 37 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 4a907e008a98..6f095c0dc658 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1551,6 +1551,7 @@ static int security_context_to_sid_core(struct selinux_state *state,
if (!str)
goto out;
}
+retry:
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -1564,6 +1565,15 @@ static int security_context_to_sid_core(struct selinux_state *state,
} else if (rc)
goto out_unlock;
rc = sidtab_context_to_sid(sidtab, &context, sid);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ if (context.str) {
+ str = context.str;
+ context.str = NULL;
+ }
+ context_destroy(&context);
+ goto retry;
+ }
context_destroy(&context);
out_unlock:
rcu_read_unlock();
@@ -1713,7 +1723,7 @@ static int security_compute_sid(struct selinux_state *state,
struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
- struct class_datum *cladatum = NULL;
+ struct class_datum *cladatum;
struct context *scontext, *tcontext, newcontext;
struct sidtab_entry *sentry, *tentry;
struct avtab_key avkey;
@@ -1735,6 +1745,8 @@ static int security_compute_sid(struct selinux_state *state,
goto out;
}
+retry:
+ cladatum = NULL;
context_init(&newcontext);
rcu_read_lock();
@@ -1879,6 +1891,11 @@ static int security_compute_sid(struct selinux_state *state,
}
/* Obtain the sid for the context. */
rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ context_destroy(&newcontext);
+ goto retry;
+ }
out_unlock:
rcu_read_unlock();
context_destroy(&newcontext);
@@ -2190,6 +2207,7 @@ void selinux_policy_commit(struct selinux_state *state,
struct selinux_load_state *load_state)
{
struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
+ unsigned long flags;
u32 seqno;
oldpolicy = rcu_dereference_protected(state->policy,
@@ -2211,7 +2229,13 @@ void selinux_policy_commit(struct selinux_state *state,
seqno = newpolicy->latest_granting;
/* Install the new policy. */
- rcu_assign_pointer(state->policy, newpolicy);
+ if (oldpolicy) {
+ sidtab_freeze_begin(oldpolicy->sidtab, &flags);
+ rcu_assign_pointer(state->policy, newpolicy);
+ sidtab_freeze_end(oldpolicy->sidtab, &flags);
+ } else {
+ rcu_assign_pointer(state->policy, newpolicy);
+ }
/* Load the policycaps from the new policy */
security_load_policycaps(state, newpolicy);
@@ -2355,13 +2379,15 @@ int security_port_sid(struct selinux_state *state,
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
- int rc = 0;
+ int rc;
if (!selinux_initialized(state)) {
*out_sid = SECINITSID_PORT;
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2380,6 +2406,10 @@ int security_port_sid(struct selinux_state *state,
if (!c->sid[0]) {
rc = sidtab_context_to_sid(sidtab, &c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2406,13 +2436,15 @@ int security_ib_pkey_sid(struct selinux_state *state,
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
- int rc = 0;
+ int rc;
if (!selinux_initialized(state)) {
*out_sid = SECINITSID_UNLABELED;
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2433,6 +2465,10 @@ int security_ib_pkey_sid(struct selinux_state *state,
rc = sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2458,13 +2494,15 @@ int security_ib_endport_sid(struct selinux_state *state,
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
- int rc = 0;
+ int rc;
if (!selinux_initialized(state)) {
*out_sid = SECINITSID_UNLABELED;
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2485,6 +2523,10 @@ int security_ib_endport_sid(struct selinux_state *state,
if (!c->sid[0]) {
rc = sidtab_context_to_sid(sidtab, &c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2508,7 +2550,7 @@ int security_netif_sid(struct selinux_state *state,
struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
- int rc = 0;
+ int rc;
struct ocontext *c;
if (!selinux_initialized(state)) {
@@ -2516,6 +2558,8 @@ int security_netif_sid(struct selinux_state *state,
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2532,10 +2576,18 @@ int security_netif_sid(struct selinux_state *state,
if (!c->sid[0] || !c->sid[1]) {
rc = sidtab_context_to_sid(sidtab, &c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
rc = sidtab_context_to_sid(sidtab, &c->context[1],
&c->sid[1]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2585,6 +2637,7 @@ int security_node_sid(struct selinux_state *state,
return 0;
}
+retry:
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2633,6 +2686,10 @@ int security_node_sid(struct selinux_state *state,
rc = sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2674,18 +2731,24 @@ int security_get_user_sids(struct selinux_state *state,
struct sidtab *sidtab;
struct context *fromcon, usercon;
u32 *mysids = NULL, *mysids2, sid;
- u32 mynel = 0, maxnel = SIDS_NEL;
+ u32 i, j, mynel, maxnel = SIDS_NEL;
struct user_datum *user;
struct role_datum *role;
struct ebitmap_node *rnode, *tnode;
- int rc = 0, i, j;
+ int rc;
*sids = NULL;
*nel = 0;
if (!selinux_initialized(state))
- goto out;
+ return 0;
+
+ mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
+ if (!mysids)
+ return -ENOMEM;
+retry:
+ mynel = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2705,11 +2768,6 @@ int security_get_user_sids(struct selinux_state *state,
usercon.user = user->value;
- rc = -ENOMEM;
- mysids = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC);
- if (!mysids)
- goto out_unlock;
-
ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
role = policydb->role_val_to_struct[i];
usercon.role = i + 1;
@@ -2721,6 +2779,10 @@ int security_get_user_sids(struct selinux_state *state,
continue;
rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out_unlock;
if (mynel < maxnel) {
@@ -2743,14 +2805,14 @@ out_unlock:
rcu_read_unlock();
if (rc || !mynel) {
kfree(mysids);
- goto out;
+ return rc;
}
rc = -ENOMEM;
mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
if (!mysids2) {
kfree(mysids);
- goto out;
+ return rc;
}
for (i = 0, j = 0; i < mynel; i++) {
struct av_decision dummy_avd;
@@ -2763,12 +2825,10 @@ out_unlock:
mysids2[j++] = mysids[i];
cond_resched();
}
- rc = 0;
kfree(mysids);
*sids = mysids2;
*nel = j;
-out:
- return rc;
+ return 0;
}
/**
@@ -2781,6 +2841,9 @@ out:
* Obtain a SID to use for a file in a filesystem that
* cannot support xattr or use a fixed labeling behavior like
* transition SIDs or task SIDs.
+ *
+ * WARNING: This function may return -ESTALE, indicating that the caller
+ * must retry the operation after re-acquiring the policy pointer!
*/
static inline int __security_genfs_sid(struct selinux_policy *policy,
const char *fstype,
@@ -2859,11 +2922,13 @@ int security_genfs_sid(struct selinux_state *state,
return 0;
}
- rcu_read_lock();
- policy = rcu_dereference(state->policy);
- retval = __security_genfs_sid(policy,
- fstype, path, orig_sclass, sid);
- rcu_read_unlock();
+ do {
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ retval = __security_genfs_sid(policy, fstype, path,
+ orig_sclass, sid);
+ rcu_read_unlock();
+ } while (retval == -ESTALE);
return retval;
}
@@ -2886,7 +2951,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
- int rc = 0;
+ int rc;
struct ocontext *c;
struct superblock_security_struct *sbsec = sb->s_security;
const char *fstype = sb->s_type->name;
@@ -2897,6 +2962,8 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -2914,6 +2981,10 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
if (!c->sid[0]) {
rc = sidtab_context_to_sid(sidtab, &c->context[0],
&c->sid[0]);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
goto out;
}
@@ -2921,6 +2992,10 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
} else {
rc = __security_genfs_sid(policy, fstype, "/",
SECCLASS_DIR, &sbsec->sid);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc) {
sbsec->behavior = SECURITY_FS_USE_NONE;
rc = 0;
@@ -3130,12 +3205,13 @@ int security_sid_mls_copy(struct selinux_state *state,
u32 len;
int rc;
- rc = 0;
if (!selinux_initialized(state)) {
*new_sid = sid;
- goto out;
+ return 0;
}
+retry:
+ rc = 0;
context_init(&newcon);
rcu_read_lock();
@@ -3194,10 +3270,14 @@ int security_sid_mls_copy(struct selinux_state *state,
}
}
rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ context_destroy(&newcon);
+ goto retry;
+ }
out_unlock:
rcu_read_unlock();
context_destroy(&newcon);
-out:
return rc;
}
@@ -3790,6 +3870,8 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
return 0;
}
+retry:
+ rc = 0;
rcu_read_lock();
policy = rcu_dereference(state->policy);
policydb = &policy->policydb;
@@ -3816,23 +3898,24 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
goto out;
}
rc = -EIDRM;
- if (!mls_context_isvalid(policydb, &ctx_new))
- goto out_free;
+ if (!mls_context_isvalid(policydb, &ctx_new)) {
+ ebitmap_destroy(&ctx_new.range.level[0].cat);
+ goto out;
+ }
rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
+ ebitmap_destroy(&ctx_new.range.level[0].cat);
+ if (rc == -ESTALE) {
+ rcu_read_unlock();
+ goto retry;
+ }
if (rc)
- goto out_free;
+ goto out;
security_netlbl_cache_add(secattr, *sid);
-
- ebitmap_destroy(&ctx_new.range.level[0].cat);
} else
*sid = SECSID_NULL;
- rcu_read_unlock();
- return 0;
-out_free:
- ebitmap_destroy(&ctx_new.range.level[0].cat);
out:
rcu_read_unlock();
return rc;
diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index 5ee190bd30f5..656d50b09f76 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -39,6 +39,7 @@ int sidtab_init(struct sidtab *s)
for (i = 0; i < SECINITSID_NUM; i++)
s->isids[i].set = 0;
+ s->frozen = false;
s->count = 0;
s->convert = NULL;
hash_init(s->context_to_sid);
@@ -281,6 +282,15 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
if (*sid)
goto out_unlock;
+ if (unlikely(s->frozen)) {
+ /*
+ * This sidtab is now frozen - tell the caller to abort and
+ * get the new one.
+ */
+ rc = -ESTALE;
+ goto out_unlock;
+ }
+
count = s->count;
convert = s->convert;
@@ -474,6 +484,17 @@ void sidtab_cancel_convert(struct sidtab *s)
spin_unlock_irqrestore(&s->lock, flags);
}
+void sidtab_freeze_begin(struct sidtab *s, unsigned long *flags) __acquires(&s->lock)
+{
+ spin_lock_irqsave(&s->lock, *flags);
+ s->frozen = true;
+ s->convert = NULL;
+}
+void sidtab_freeze_end(struct sidtab *s, unsigned long *flags) __releases(&s->lock)
+{
+ spin_unlock_irqrestore(&s->lock, *flags);
+}
+
static void sidtab_destroy_entry(struct sidtab_entry *entry)
{
context_destroy(&entry->context);
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index 80c744d07ad6..4eff0e49dcb2 100644
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -86,6 +86,7 @@ struct sidtab {
u32 count;
/* access only under spinlock */
struct sidtab_convert_params *convert;
+ bool frozen;
spinlock_t lock;
#if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0
@@ -125,6 +126,9 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params);
void sidtab_cancel_convert(struct sidtab *s);
+void sidtab_freeze_begin(struct sidtab *s, unsigned long *flags) __acquires(&s->lock);
+void sidtab_freeze_end(struct sidtab *s, unsigned long *flags) __releases(&s->lock);
+
int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);
void sidtab_destroy(struct sidtab *s);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.