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From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
To: selinux@vger.kernel.org
Cc: Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <stephen.smalley.work@gmail.com>,
	Ondrej Mosnacek <omosnace@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH] selinux: use u32 as bit type in ebitmap code
Date: Fri, 15 Mar 2024 18:32:28 +0100
Message-ID: <20240315173234.637629-1-cgzones@googlemail.com>
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The extensible bitmap supports bit positions up to U32_MAX due to the
type of the member highbit being u32.  Use u32 consistently as the type
for bit positions to announce to callers what range of values is
supported.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
v4:
  - apply format style
  I hope i addressed all comment from [1] in [2].
v3:
  - revert type change of unrelated iter variable
  - use U32_MAX instead of (u32)-1
v2: avoid declarations in init-clauses of for loops

[1]: https://lore.kernel.org/selinux/67cee6245e2895e81a0177c4c1ed01ba.paul@paul-moore.com/
[2]: https://lore.kernel.org/selinux/CAJ2a_DdLR40CB6Ua5cNjYhtexNmGkzQRsVrJn+dhVaZO-aVKsA@mail.gmail.com/

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 security/selinux/ss/ebitmap.c | 31 +++++++++++++++-------------
 security/selinux/ss/ebitmap.h | 38 ++++++++++++++++-------------------
 2 files changed, 34 insertions(+), 35 deletions(-)

diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c
index 67c1a73cd5ee..8177f1c3c774 100644
--- a/security/selinux/ss/ebitmap.c
+++ b/security/selinux/ss/ebitmap.c
@@ -21,7 +21,7 @@
 #include "ebitmap.h"
 #include "policydb.h"
 
-#define BITS_PER_U64 (sizeof(u64) * 8)
+#define BITS_PER_U64 ((u32)(sizeof(u64) * 8))
 
 static struct kmem_cache *ebitmap_node_cachep __ro_after_init;
 
@@ -79,7 +79,8 @@ int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
 		const struct ebitmap *e2)
 {
 	struct ebitmap_node *n;
-	int bit, rc;
+	u32 bit;
+	int rc;
 
 	ebitmap_init(dst);
 
@@ -256,7 +257,7 @@ int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
 	return 1;
 }
 
-int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit)
+int ebitmap_get_bit(const struct ebitmap *e, u32 bit)
 {
 	const struct ebitmap_node *n;
 
@@ -273,7 +274,7 @@ int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit)
 	return 0;
 }
 
-int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
+int ebitmap_set_bit(struct ebitmap *e, u32 bit, int value)
 {
 	struct ebitmap_node *n, *prev, *new;
 
@@ -284,7 +285,7 @@ int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
 			if (value) {
 				ebitmap_node_set_bit(n, bit);
 			} else {
-				unsigned int s;
+				u32 s;
 
 				ebitmap_node_clr_bit(n, bit);
 
@@ -362,12 +363,12 @@ void ebitmap_destroy(struct ebitmap *e)
 int ebitmap_read(struct ebitmap *e, void *fp)
 {
 	struct ebitmap_node *n = NULL;
-	u32 mapunit, count, startbit, index;
+	u32 mapunit, count, startbit, index, i;
 	__le32 ebitmap_start;
 	u64 map;
 	__le64 mapbits;
 	__le32 buf[3];
-	int rc, i;
+	int rc;
 
 	ebitmap_init(e);
 
@@ -381,7 +382,7 @@ int ebitmap_read(struct ebitmap *e, void *fp)
 
 	if (mapunit != BITS_PER_U64) {
 		pr_err("SELinux: ebitmap: map size %u does not "
-		       "match my size %zd (high bit was %d)\n",
+		       "match my size %d (high bit was %d)\n",
 		       mapunit, BITS_PER_U64, e->highbit);
 		goto bad;
 	}
@@ -469,19 +470,20 @@ int ebitmap_read(struct ebitmap *e, void *fp)
 int ebitmap_write(const struct ebitmap *e, void *fp)
 {
 	struct ebitmap_node *n;
-	u32 count;
+	u32 bit, count, last_bit, last_startbit;
 	__le32 buf[3];
 	u64 map;
-	int bit, last_bit, last_startbit, rc;
+	int rc;
 
 	buf[0] = cpu_to_le32(BITS_PER_U64);
 
 	count = 0;
 	last_bit = 0;
-	last_startbit = -1;
+	last_startbit = U32_MAX;
 	ebitmap_for_each_positive_bit(e, n, bit)
 	{
-		if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
+		if (last_startbit == U32_MAX ||
+		    rounddown(bit, BITS_PER_U64) > last_startbit) {
 			count++;
 			last_startbit = rounddown(bit, BITS_PER_U64);
 		}
@@ -495,10 +497,11 @@ int ebitmap_write(const struct ebitmap *e, void *fp)
 		return rc;
 
 	map = 0;
-	last_startbit = INT_MIN;
+	last_startbit = U32_MAX;
 	ebitmap_for_each_positive_bit(e, n, bit)
 	{
-		if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
+		if (last_startbit == U32_MAX ||
+		    rounddown(bit, BITS_PER_U64) > last_startbit) {
 			__le64 buf64[1];
 
 			/* this is the very first bit */
diff --git a/security/selinux/ss/ebitmap.h b/security/selinux/ss/ebitmap.h
index 02798b35eecc..24d7d8b3cda3 100644
--- a/security/selinux/ss/ebitmap.h
+++ b/security/selinux/ss/ebitmap.h
@@ -46,10 +46,10 @@ struct ebitmap {
 
 #define ebitmap_length(e) ((e)->highbit)
 
-static inline unsigned int ebitmap_start_positive(const struct ebitmap *e,
-						  struct ebitmap_node **n)
+static inline u32 ebitmap_start_positive(const struct ebitmap *e,
+					 struct ebitmap_node **n)
 {
-	unsigned int ofs;
+	u32 ofs;
 
 	for (*n = e->node; *n; *n = (*n)->next) {
 		ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
@@ -64,11 +64,10 @@ static inline void ebitmap_init(struct ebitmap *e)
 	memset(e, 0, sizeof(*e));
 }
 
-static inline unsigned int ebitmap_next_positive(const struct ebitmap *e,
-						 struct ebitmap_node **n,
-						 unsigned int bit)
+static inline u32 ebitmap_next_positive(const struct ebitmap *e,
+					struct ebitmap_node **n, u32 bit)
 {
-	unsigned int ofs;
+	u32 ofs;
 
 	ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
 	if (ofs < EBITMAP_SIZE)
@@ -87,11 +86,10 @@ static inline unsigned int ebitmap_next_positive(const struct ebitmap *e,
 #define EBITMAP_NODE_OFFSET(node, bit) \
 	(((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
 
-static inline int ebitmap_node_get_bit(const struct ebitmap_node *n,
-				       unsigned int bit)
+static inline int ebitmap_node_get_bit(const struct ebitmap_node *n, u32 bit)
 {
-	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
-	unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
+	u32 index = EBITMAP_NODE_INDEX(n, bit);
+	u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
 
 	BUG_ON(index >= EBITMAP_UNIT_NUMS);
 	if ((n->maps[index] & (EBITMAP_BIT << ofs)))
@@ -99,21 +97,19 @@ static inline int ebitmap_node_get_bit(const struct ebitmap_node *n,
 	return 0;
 }
 
-static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
-					unsigned int bit)
+static inline void ebitmap_node_set_bit(struct ebitmap_node *n, u32 bit)
 {
-	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
-	unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
+	u32 index = EBITMAP_NODE_INDEX(n, bit);
+	u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
 
 	BUG_ON(index >= EBITMAP_UNIT_NUMS);
 	n->maps[index] |= (EBITMAP_BIT << ofs);
 }
 
-static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
-					unsigned int bit)
+static inline void ebitmap_node_clr_bit(struct ebitmap_node *n, u32 bit)
 {
-	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
-	unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
+	u32 index = EBITMAP_NODE_INDEX(n, bit);
+	u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
 
 	BUG_ON(index >= EBITMAP_UNIT_NUMS);
 	n->maps[index] &= ~(EBITMAP_BIT << ofs);
@@ -130,8 +126,8 @@ int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
 		const struct ebitmap *e2);
 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
 		     u32 last_e2bit);
-int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit);
-int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
+int ebitmap_get_bit(const struct ebitmap *e, u32 bit);
+int ebitmap_set_bit(struct ebitmap *e, u32 bit, int value);
 void ebitmap_destroy(struct ebitmap *e);
 int ebitmap_read(struct ebitmap *e, void *fp);
 int ebitmap_write(const struct ebitmap *e, void *fp);
-- 
2.43.0