1 files changed, 103 insertions, 169 deletions

diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c
index 86d98a8e291b..d12ca337e649 100644
--- a/security/selinux/ss/avtab.c
+++ b/security/selinux/ss/avtab.c
@@ -1,74 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Implementation of the access vector table type.
  *
  * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
  */
 
-/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
- *
- *	Added conditional policy language extensions
- *
- * Copyright (C) 2003 Tresys Technology, LLC
- *	This program is free software; you can redistribute it and/or modify
- *	it under the terms of the GNU General Public License as published by
- *	the Free Software Foundation, version 2.
+/* Updated: Frank Mayer <mayerf@tresys.com> and
+ *          Karl MacMillan <kmacmillan@tresys.com>
+ *          Added conditional policy language extensions
+ *          Copyright (C) 2003 Tresys Technology, LLC
  *
  * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
- *	Tuned number of hash slots for avtab to reduce memory usage
+ *          Tuned number of hash slots for avtab to reduce memory usage
  */
 
+#include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include "avtab.h"
 #include "policydb.h"
+#include "hash.h"
 
 static struct kmem_cache *avtab_node_cachep __ro_after_init;
 static struct kmem_cache *avtab_xperms_cachep __ro_after_init;
 
-/* Based on MurmurHash3, written by Austin Appleby and placed in the
- * public domain.
- */
 static inline u32 avtab_hash(const struct avtab_key *keyp, u32 mask)
 {
-	static const u32 c1 = 0xcc9e2d51;
-	static const u32 c2 = 0x1b873593;
-	static const u32 r1 = 15;
-	static const u32 r2 = 13;
-	static const u32 m  = 5;
-	static const u32 n  = 0xe6546b64;
-
-	u32 hash = 0;
-
-#define mix(input) do { \
-		u32 v = input; \
-		v *= c1; \
-		v = (v << r1) | (v >> (32 - r1)); \
-		v *= c2; \
-		hash ^= v; \
-		hash = (hash << r2) | (hash >> (32 - r2)); \
-		hash = hash * m + n; \
-	} while (0)
-
-	mix(keyp->target_class);
-	mix(keyp->target_type);
-	mix(keyp->source_type);
-
-#undef mix
-
-	hash ^= hash >> 16;
-	hash *= 0x85ebca6b;
-	hash ^= hash >> 13;
-	hash *= 0xc2b2ae35;
-	hash ^= hash >> 16;
-
-	return hash & mask;
+	return av_hash((u32)keyp->target_class, (u32)keyp->target_type,
+		       (u32)keyp->source_type, mask);
 }
 
-static struct avtab_node*
-avtab_insert_node(struct avtab *h, u32 hvalue,
-		  struct avtab_node *prev,
-		  const struct avtab_key *key, const struct avtab_datum *datum)
+static struct avtab_node *avtab_insert_node(struct avtab *h,
+					    struct avtab_node **dst,
+					    const struct avtab_key *key,
+					    const struct avtab_datum *datum)
 {
 	struct avtab_node *newnode;
 	struct avtab_extended_perms *xperms;
@@ -89,55 +55,58 @@ avtab_insert_node(struct avtab *h, u32 hvalue,
 		newnode->datum.u.data = datum->u.data;
 	}
 
-	if (prev) {
-		newnode->next = prev->next;
-		prev->next = newnode;
-	} else {
-		struct avtab_node **n = &h->htable[hvalue];
-
-		newnode->next = *n;
-		*n = newnode;
-	}
+	newnode->next = *dst;
+	*dst = newnode;
 
 	h->nel++;
 	return newnode;
 }
 
+static int avtab_node_cmp(const struct avtab_key *key1,
+			  const struct avtab_key *key2)
+{
+	u16 specified = key1->specified & ~(AVTAB_ENABLED | AVTAB_ENABLED_OLD);
+
+	if (key1->source_type == key2->source_type &&
+	    key1->target_type == key2->target_type &&
+	    key1->target_class == key2->target_class &&
+	    (specified & key2->specified))
+		return 0;
+	if (key1->source_type < key2->source_type)
+		return -1;
+	if (key1->source_type == key2->source_type &&
+	    key1->target_type < key2->target_type)
+		return -1;
+	if (key1->source_type == key2->source_type &&
+	    key1->target_type == key2->target_type &&
+	    key1->target_class < key2->target_class)
+		return -1;
+	return 1;
+}
+
 static int avtab_insert(struct avtab *h, const struct avtab_key *key,
 			const struct avtab_datum *datum)
 {
 	u32 hvalue;
 	struct avtab_node *prev, *cur, *newnode;
-	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+	int cmp;
 
 	if (!h || !h->nslot || h->nel == U32_MAX)
 		return -EINVAL;
 
 	hvalue = avtab_hash(key, h->mask);
-	for (prev = NULL, cur = h->htable[hvalue];
-	     cur;
+	for (prev = NULL, cur = h->htable[hvalue]; cur;
 	     prev = cur, cur = cur->next) {
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class == cur->key.target_class &&
-		    (specified & cur->key.specified)) {
-			/* extended perms may not be unique */
-			if (specified & AVTAB_XPERMS)
-				break;
+		cmp = avtab_node_cmp(key, &cur->key);
+		/* extended perms may not be unique */
+		if (cmp == 0 && !(key->specified & AVTAB_XPERMS))
 			return -EEXIST;
-		}
-		if (key->source_type < cur->key.source_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type < cur->key.target_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class < cur->key.target_class)
+		if (cmp <= 0)
 			break;
 	}
 
-	newnode = avtab_insert_node(h, hvalue, prev, key, datum);
+	newnode = avtab_insert_node(h, prev ? &prev->next : &h->htable[hvalue],
+				    key, datum);
 	if (!newnode)
 		return -ENOMEM;
 
@@ -154,30 +123,19 @@ struct avtab_node *avtab_insert_nonunique(struct avtab *h,
 {
 	u32 hvalue;
 	struct avtab_node *prev, *cur;
-	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+	int cmp;
 
 	if (!h || !h->nslot || h->nel == U32_MAX)
 		return NULL;
 	hvalue = avtab_hash(key, h->mask);
-	for (prev = NULL, cur = h->htable[hvalue];
-	     cur;
+	for (prev = NULL, cur = h->htable[hvalue]; cur;
 	     prev = cur, cur = cur->next) {
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class == cur->key.target_class &&
-		    (specified & cur->key.specified))
-			break;
-		if (key->source_type < cur->key.source_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type < cur->key.target_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class < cur->key.target_class)
+		cmp = avtab_node_cmp(key, &cur->key);
+		if (cmp <= 0)
 			break;
 	}
-	return avtab_insert_node(h, hvalue, prev, key, datum);
+	return avtab_insert_node(h, prev ? &prev->next : &h->htable[hvalue],
+				 key, datum);
 }
 
 /* This search function returns a node pointer, and can be used in
@@ -188,57 +146,38 @@ struct avtab_node *avtab_search_node(struct avtab *h,
 {
 	u32 hvalue;
 	struct avtab_node *cur;
-	u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+	int cmp;
 
 	if (!h || !h->nslot)
 		return NULL;
 
 	hvalue = avtab_hash(key, h->mask);
-	for (cur = h->htable[hvalue]; cur;
-	     cur = cur->next) {
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class == cur->key.target_class &&
-		    (specified & cur->key.specified))
+	for (cur = h->htable[hvalue]; cur; cur = cur->next) {
+		cmp = avtab_node_cmp(key, &cur->key);
+		if (cmp == 0)
 			return cur;
-
-		if (key->source_type < cur->key.source_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type < cur->key.target_type)
-			break;
-		if (key->source_type == cur->key.source_type &&
-		    key->target_type == cur->key.target_type &&
-		    key->target_class < cur->key.target_class)
+		if (cmp < 0)
 			break;
 	}
 	return NULL;
 }
 
-struct avtab_node*
-avtab_search_node_next(struct avtab_node *node, u16 specified)
+struct avtab_node *avtab_search_node_next(struct avtab_node *node,
+					  u16 specified)
 {
+	struct avtab_key tmp_key;
 	struct avtab_node *cur;
+	int cmp;
 
 	if (!node)
 		return NULL;
-
-	specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
+	tmp_key = node->key;
+	tmp_key.specified = specified;
 	for (cur = node->next; cur; cur = cur->next) {
-		if (node->key.source_type == cur->key.source_type &&
-		    node->key.target_type == cur->key.target_type &&
-		    node->key.target_class == cur->key.target_class &&
-		    (specified & cur->key.specified))
+		cmp = avtab_node_cmp(&tmp_key, &cur->key);
+		if (cmp == 0)
 			return cur;
-
-		if (node->key.source_type < cur->key.source_type)
-			break;
-		if (node->key.source_type == cur->key.source_type &&
-		    node->key.target_type < cur->key.target_type)
-			break;
-		if (node->key.source_type == cur->key.source_type &&
-		    node->key.target_type == cur->key.target_type &&
-		    node->key.target_class < cur->key.target_class)
+		if (cmp < 0)
 			break;
 	}
 	return NULL;
@@ -298,13 +237,7 @@ int avtab_alloc(struct avtab *h, u32 nrules)
 	u32 nslot = 0;
 
 	if (nrules != 0) {
-		u32 shift = 1;
-		u32 work = nrules >> 3;
-		while (work) {
-			work >>= 1;
-			shift++;
-		}
-		nslot = 1 << shift;
+		nslot = nrules > 3 ? rounddown_pow_of_two(nrules / 2) : 2;
 		if (nslot > MAX_AVTAB_HASH_BUCKETS)
 			nslot = MAX_AVTAB_HASH_BUCKETS;
 
@@ -344,17 +277,19 @@ void avtab_hash_eval(struct avtab *h, const char *tag)
 
 			if (chain_len > max_chain_len)
 				max_chain_len = chain_len;
-			chain2_len_sum += (unsigned long long)chain_len * chain_len;
+			chain2_len_sum +=
+				(unsigned long long)chain_len * chain_len;
 		}
 	}
 
 	pr_debug("SELinux: %s:  %d entries and %d/%d buckets used, "
-	       "longest chain length %d sum of chain length^2 %llu\n",
-	       tag, h->nel, slots_used, h->nslot, max_chain_len,
-	       chain2_len_sum);
+		 "longest chain length %d, sum of chain length^2 %llu\n",
+		 tag, h->nel, slots_used, h->nslot, max_chain_len,
+		 chain2_len_sum);
 }
 #endif /* CONFIG_SECURITY_SELINUX_DEBUG */
 
+/* clang-format off */
 static const uint16_t spec_order[] = {
 	AVTAB_ALLOWED,
 	AVTAB_AUDITDENY,
@@ -366,11 +301,12 @@ static const uint16_t spec_order[] = {
 	AVTAB_XPERMS_AUDITALLOW,
 	AVTAB_XPERMS_DONTAUDIT
 };
+/* clang-format on */
 
-int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
+int avtab_read_item(struct avtab *a, struct policy_file *fp, struct policydb *pol,
 		    int (*insertf)(struct avtab *a, const struct avtab_key *k,
 				   const struct avtab_datum *d, void *p),
-		    void *p)
+		    void *p, bool conditional)
 {
 	__le16 buf16[4];
 	u16 enabled;
@@ -395,9 +331,8 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
 		if (items2 > ARRAY_SIZE(buf32)) {
 			pr_err("SELinux: avtab: entry overflow\n");
 			return -EINVAL;
-
 		}
-		rc = next_entry(buf32, fp, sizeof(u32)*items2);
+		rc = next_entry(buf32, fp, sizeof(u32) * items2);
 		if (rc) {
 			pr_err("SELinux: avtab: truncated entry\n");
 			return rc;
@@ -430,8 +365,7 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
 			pr_err("SELinux: avtab: null entry\n");
 			return -EINVAL;
 		}
-		if ((val & AVTAB_AV) &&
-		    (val & AVTAB_TYPE)) {
+		if ((val & AVTAB_AV) && (val & AVTAB_TYPE)) {
 			pr_err("SELinux: avtab: entry has both access vectors and types\n");
 			return -EINVAL;
 		}
@@ -458,7 +392,7 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
 		return 0;
 	}
 
-	rc = next_entry(buf16, fp, sizeof(u16)*4);
+	rc = next_entry(buf16, fp, sizeof(u16) * 4);
 	if (rc) {
 		pr_err("SELinux: avtab: truncated entry\n");
 		return rc;
@@ -477,21 +411,25 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
 		return -EINVAL;
 	}
 
-	set = 0;
-	for (i = 0; i < ARRAY_SIZE(spec_order); i++) {
-		if (key.specified & spec_order[i])
-			set++;
-	}
+	set = hweight16(key.specified & (AVTAB_XPERMS | AVTAB_TYPE | AVTAB_AV));
 	if (!set || set > 1) {
 		pr_err("SELinux:  avtab:  more than one specifier\n");
 		return -EINVAL;
 	}
 
 	if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) &&
-			(key.specified & AVTAB_XPERMS)) {
+	    (key.specified & AVTAB_XPERMS)) {
 		pr_err("SELinux:  avtab:  policy version %u does not "
-				"support extended permissions rules and one "
-				"was specified\n", vers);
+		       "support extended permissions rules and one "
+		       "was specified\n",
+		       vers);
+		return -EINVAL;
+	} else if ((vers < POLICYDB_VERSION_COND_XPERMS) &&
+		   (key.specified & AVTAB_XPERMS) && conditional) {
+		pr_err("SELinux:  avtab:  policy version %u does not "
+		       "support extended permissions rules in conditional "
+		       "policies and one was specified\n",
+		       vers);
 		return -EINVAL;
 	} else if (key.specified & AVTAB_XPERMS) {
 		memset(&xperms, 0, sizeof(struct avtab_extended_perms));
@@ -505,7 +443,8 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
 			pr_err("SELinux: avtab: truncated entry\n");
 			return rc;
 		}
-		rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p));
+		rc = next_entry(buf32, fp,
+				sizeof(u32) * ARRAY_SIZE(xperms.perms.p));
 		if (rc) {
 			pr_err("SELinux: avtab: truncated entry\n");
 			return rc;
@@ -535,13 +474,12 @@ static int avtab_insertf(struct avtab *a, const struct avtab_key *k,
 	return avtab_insert(a, k, d);
 }
 
-int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
+int avtab_read(struct avtab *a, struct policy_file *fp, struct policydb *pol)
 {
 	int rc;
 	__le32 buf[1];
 	u32 nel, i;
 
-
 	rc = next_entry(buf, fp, sizeof(u32));
 	if (rc < 0) {
 		pr_err("SELinux: avtab: truncated table\n");
@@ -559,7 +497,7 @@ int avtab_read(struct avtab *a, void *fp, struct policydb *pol)
 		goto bad;
 
 	for (i = 0; i < nel; i++) {
-		rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL);
+		rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL, false);
 		if (rc) {
 			if (rc == -ENOMEM)
 				pr_err("SELinux: avtab: out of memory\n");
@@ -579,7 +517,7 @@ bad:
 	goto out;
 }
 
-int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
+int avtab_write_item(struct policydb *p, const struct avtab_node *cur, struct policy_file *fp)
 {
 	__le16 buf16[4];
 	__le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)];
@@ -595,7 +533,8 @@ int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
 		return rc;
 
 	if (cur->key.specified & AVTAB_XPERMS) {
-		rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp);
+		rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1,
+			       fp);
 		if (rc)
 			return rc;
 		rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp);
@@ -604,7 +543,7 @@ int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
 		for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++)
 			buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]);
 		rc = put_entry(buf32, sizeof(u32),
-				ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp);
+			       ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp);
 	} else {
 		buf32[0] = cpu_to_le32(cur->datum.u.data);
 		rc = put_entry(buf32, sizeof(u32), 1, fp);
@@ -614,7 +553,7 @@ int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp)
 	return 0;
 }
 
-int avtab_write(struct policydb *p, struct avtab *a, void *fp)
+int avtab_write(struct policydb *p, struct avtab *a, struct policy_file *fp)
 {
 	u32 i;
 	int rc = 0;
@@ -627,8 +566,7 @@ int avtab_write(struct policydb *p, struct avtab *a, void *fp)
 		return rc;
 
 	for (i = 0; i < a->nslot; i++) {
-		for (cur = a->htable[i]; cur;
-		     cur = cur->next) {
+		for (cur = a->htable[i]; cur; cur = cur->next) {
 			rc = avtab_write_item(p, cur, fp);
 			if (rc)
 				return rc;
@@ -640,10 +578,6 @@ int avtab_write(struct policydb *p, struct avtab *a, void *fp)
 
 void __init avtab_cache_init(void)
 {
-	avtab_node_cachep = kmem_cache_create("avtab_node",
-					      sizeof(struct avtab_node),
-					      0, SLAB_PANIC, NULL);
-	avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms",
-						sizeof(struct avtab_extended_perms),
-						0, SLAB_PANIC, NULL);
+	avtab_node_cachep = KMEM_CACHE(avtab_node, SLAB_PANIC);
+	avtab_xperms_cachep = KMEM_CACHE(avtab_extended_perms, SLAB_PANIC);
 }