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-rw-r--r--security/selinux/include/security.h2
-rw-r--r--security/selinux/selinuxfs.c26
-rw-r--r--security/selinux/ss/policydb.c4
-rw-r--r--security/selinux/ss/policydb.h8
-rw-r--r--security/selinux/ss/services.c75
5 files changed, 106 insertions, 9 deletions
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 83bdd4d2a29e..39337afffec2 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -90,6 +90,8 @@ int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid);
int security_get_classes(char ***classes, int *nclasses);
int security_get_permissions(char *class, char ***perms, int *nperms);
+int security_get_reject_unknown(void);
+int security_get_allow_unknown(void);
#define SECURITY_FS_USE_XATTR 1 /* use xattr */
#define SECURITY_FS_USE_TRANS 2 /* use transition SIDs, e.g. devpts/tmpfs */
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index c9e92daedee2..f5f3e6da5da7 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -103,6 +103,8 @@ enum sel_inos {
SEL_MEMBER, /* compute polyinstantiation membership decision */
SEL_CHECKREQPROT, /* check requested protection, not kernel-applied one */
SEL_COMPAT_NET, /* whether to use old compat network packet controls */
+ SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */
+ SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */
SEL_INO_NEXT, /* The next inode number to use */
};
@@ -177,6 +179,23 @@ static const struct file_operations sel_enforce_ops = {
.write = sel_write_enforce,
};
+static ssize_t sel_read_handle_unknown(struct file *filp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ char tmpbuf[TMPBUFLEN];
+ ssize_t length;
+ ino_t ino = filp->f_path.dentry->d_inode->i_ino;
+ int handle_unknown = (ino == SEL_REJECT_UNKNOWN) ?
+ security_get_reject_unknown() : !security_get_allow_unknown();
+
+ length = scnprintf(tmpbuf, TMPBUFLEN, "%d", handle_unknown);
+ return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
+}
+
+static const struct file_operations sel_handle_unknown_ops = {
+ .read = sel_read_handle_unknown,
+};
+
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static ssize_t sel_write_disable(struct file * file, const char __user * buf,
size_t count, loff_t *ppos)
@@ -309,6 +328,11 @@ static ssize_t sel_write_load(struct file * file, const char __user * buf,
length = count;
out1:
+
+ printk(KERN_INFO "SELinux: policy loaded with handle_unknown=%s\n",
+ (security_get_reject_unknown() ? "reject" :
+ (security_get_allow_unknown() ? "allow" : "deny")));
+
audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
"policy loaded auid=%u",
audit_get_loginuid(current->audit_context));
@@ -1575,6 +1599,8 @@ static int sel_fill_super(struct super_block * sb, void * data, int silent)
[SEL_MEMBER] = {"member", &transaction_ops, S_IRUGO|S_IWUGO},
[SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR},
[SEL_COMPAT_NET] = {"compat_net", &sel_compat_net_ops, S_IRUGO|S_IWUSR},
+ [SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO},
+ [SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO},
/* last one */ {""}
};
ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 5ecbad7d8b9f..539828b229b2 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -674,6 +674,8 @@ void policydb_destroy(struct policydb *p)
}
kfree(p->type_attr_map);
+ kfree(p->undefined_perms);
+
return;
}
@@ -1527,6 +1529,8 @@ int policydb_read(struct policydb *p, void *fp)
goto bad;
}
}
+ p->reject_unknown = !!(le32_to_cpu(buf[1]) & REJECT_UNKNOWN);
+ p->allow_unknown = !!(le32_to_cpu(buf[1]) & ALLOW_UNKNOWN);
info = policydb_lookup_compat(p->policyvers);
if (!info) {
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 8319d5ff5944..844d310f4f1b 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -242,6 +242,10 @@ struct policydb {
struct ebitmap *type_attr_map;
unsigned int policyvers;
+
+ unsigned int reject_unknown : 1;
+ unsigned int allow_unknown : 1;
+ u32 *undefined_perms;
};
extern void policydb_destroy(struct policydb *p);
@@ -253,6 +257,10 @@ extern int policydb_read(struct policydb *p, void *fp);
#define POLICYDB_CONFIG_MLS 1
+/* the config flags related to unknown classes/perms are bits 2 and 3 */
+#define REJECT_UNKNOWN 0x00000002
+#define ALLOW_UNKNOWN 0x00000004
+
#define OBJECT_R "object_r"
#define OBJECT_R_VAL 1
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 6100fc023055..03140edf97a3 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -292,6 +292,7 @@ static int context_struct_compute_av(struct context *scontext,
struct class_datum *tclass_datum;
struct ebitmap *sattr, *tattr;
struct ebitmap_node *snode, *tnode;
+ const struct selinux_class_perm *kdefs = &selinux_class_perm;
unsigned int i, j;
/*
@@ -305,13 +306,6 @@ static int context_struct_compute_av(struct context *scontext,
tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
tclass = SECCLASS_NETLINK_SOCKET;
- if (!tclass || tclass > policydb.p_classes.nprim) {
- printk(KERN_ERR "security_compute_av: unrecognized class %d\n",
- tclass);
- return -EINVAL;
- }
- tclass_datum = policydb.class_val_to_struct[tclass - 1];
-
/*
* Initialize the access vectors to the default values.
*/
@@ -322,6 +316,36 @@ static int context_struct_compute_av(struct context *scontext,
avd->seqno = latest_granting;
/*
+ * Check for all the invalid cases.
+ * - tclass 0
+ * - tclass > policy and > kernel
+ * - tclass > policy but is a userspace class
+ * - tclass > policy but we do not allow unknowns
+ */
+ if (unlikely(!tclass))
+ goto inval_class;
+ if (unlikely(tclass > policydb.p_classes.nprim))
+ if (tclass > kdefs->cts_len ||
+ !kdefs->class_to_string[tclass - 1] ||
+ !policydb.allow_unknown)
+ goto inval_class;
+
+ /*
+ * Kernel class and we allow unknown so pad the allow decision
+ * the pad will be all 1 for unknown classes.
+ */
+ if (tclass <= kdefs->cts_len && policydb.allow_unknown)
+ avd->allowed = policydb.undefined_perms[tclass - 1];
+
+ /*
+ * Not in policy. Since decision is completed (all 1 or all 0) return.
+ */
+ if (unlikely(tclass > policydb.p_classes.nprim))
+ return 0;
+
+ tclass_datum = policydb.class_val_to_struct[tclass - 1];
+
+ /*
* If a specific type enforcement rule was defined for
* this permission check, then use it.
*/
@@ -387,6 +411,10 @@ static int context_struct_compute_av(struct context *scontext,
}
return 0;
+
+inval_class:
+ printk(KERN_ERR "%s: unrecognized class %d\n", __FUNCTION__, tclass);
+ return -EINVAL;
}
static int security_validtrans_handle_fail(struct context *ocontext,
@@ -1054,6 +1082,13 @@ static int validate_classes(struct policydb *p)
const char *def_class, *def_perm, *pol_class;
struct symtab *perms;
+ if (p->allow_unknown) {
+ u32 num_classes = kdefs->cts_len;
+ p->undefined_perms = kcalloc(num_classes, sizeof(u32), GFP_KERNEL);
+ if (!p->undefined_perms)
+ return -ENOMEM;
+ }
+
for (i = 1; i < kdefs->cts_len; i++) {
def_class = kdefs->class_to_string[i];
if (!def_class)
@@ -1062,6 +1097,10 @@ static int validate_classes(struct policydb *p)
printk(KERN_INFO
"security: class %s not defined in policy\n",
def_class);
+ if (p->reject_unknown)
+ return -EINVAL;
+ if (p->allow_unknown)
+ p->undefined_perms[i-1] = ~0U;
continue;
}
pol_class = p->p_class_val_to_name[i-1];
@@ -1087,12 +1126,16 @@ static int validate_classes(struct policydb *p)
printk(KERN_INFO
"security: permission %s in class %s not defined in policy\n",
def_perm, pol_class);
+ if (p->reject_unknown)
+ return -EINVAL;
+ if (p->allow_unknown)
+ p->undefined_perms[class_val-1] |= perm_val;
continue;
}
perdatum = hashtab_search(perms->table, def_perm);
if (perdatum == NULL) {
printk(KERN_ERR
- "security: permission %s in class %s not found in policy\n",
+ "security: permission %s in class %s not found in policy, bad policy\n",
def_perm, pol_class);
return -EINVAL;
}
@@ -1130,12 +1173,16 @@ static int validate_classes(struct policydb *p)
printk(KERN_INFO
"security: permission %s in class %s not defined in policy\n",
def_perm, pol_class);
+ if (p->reject_unknown)
+ return -EINVAL;
+ if (p->allow_unknown)
+ p->undefined_perms[class_val-1] |= (1 << j);
continue;
}
perdatum = hashtab_search(perms->table, def_perm);
if (perdatum == NULL) {
printk(KERN_ERR
- "security: permission %s in class %s not found in policy\n",
+ "security: permission %s in class %s not found in policy, bad policy\n",
def_perm, pol_class);
return -EINVAL;
}
@@ -2102,6 +2149,16 @@ err:
return rc;
}
+int security_get_reject_unknown(void)
+{
+ return policydb.reject_unknown;
+}
+
+int security_get_allow_unknown(void)
+{
+ return policydb.allow_unknown;
+}
+
struct selinux_audit_rule {
u32 au_seqno;
struct context au_ctxt;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.