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SELinux: 2/3 change isec->sem to a mutex

PATCH In review Eric Paris 2 participants 2 messages Jul 27, 2006 SELinux security module

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Eric Paris

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PATCH 1/1 SELinux: 2/3 change isec->sem to a mutex

This patch converts the remaining isec->sem into a mutex. The same locking is provided as before only in the faster smaller mutex rather than slower sem.

Signed-off-by Eric Paris <[email protected]>
 security/selinux/hooks.c          |   13 +++++++------
 security/selinux/include/objsec.h |    2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)
security/selinux/hooks.c +7 -6
index a91c961..e03bada 100644
@@ -69,6 +69,7 @@ #include <linux/sysctl.h>
 #include <linux/audit.h>
 #include <linux/string.h>
 #include <linux/selinux.h>
+#include <linux/mutex.h>
 
 #include "avc.h"
 #include "objsec.h"

@@ -182,7 +183,7 @@ static int inode_alloc_security(struct i
 		return -ENOMEM;
 
 	memset(isec, 0, sizeof(*isec));
-	init_MUTEX(&isec->sem);
+	mutex_init(&isec->lock);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

@@ -843,13 +844,13 @@ #define INITCONTEXTLEN 255
 	char *context = NULL;
 	unsigned len = 0;
 	int rc = 0;
-	int hold_sem = 0;
+	int hold_lock = 0;
 
 	if (isec->initialized)
 		goto out;
 
-	down(&isec->sem);
-	hold_sem = 1;
+	mutex_lock(&isec->lock);
+	hold_lock = 1;
 	if (isec->initialized)
 		goto out;
 

@@ -991,8 +992,8 @@ out:
 	if (isec->sclass == SECCLASS_FILE)
 		isec->sclass = inode_mode_to_security_class(inode->i_mode);
 
-	if (hold_sem)
-		up(&isec->sem);
+	if (hold_lock)
+		mutex_unlock(&isec->lock);
 	return rc;
 }
security/selinux/include/objsec.h +1 -1
index 9401788..7841ff2 100644
@@ -44,7 +44,7 @@ struct inode_security_struct {
 	u32 sid;             /* SID of this object */
 	u16 sclass;       /* security class of this object */
 	unsigned char initialized;     /* initialization flag */
-	struct semaphore sem;
+	struct mutex lock;
 	unsigned char inherit;         /* inherit SID from parent entry */
 };

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#1 lore raw
Quoted 49 lines · Eric Paris

This patch converts the remaining isec->sem into a mutex. The same locking is provided as before only in the faster smaller mutex rather than slower sem.

Signed-off-by Eric Paris <[email protected]>
 security/selinux/hooks.c          |   13 +++++++------
 security/selinux/include/objsec.h |    2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)
security/selinux/hooks.c +5 -4
index a91c961..e03bada 100644
@@ -69,6 +69,7 @@ #include <linux/sysctl.h>
 #include <linux/audit.h>
 #include <linux/string.h>
 #include <linux/selinux.h>
+#include <linux/mutex.h>
 
 #include "avc.h"
 #include "objsec.h"

@@ -182,7 +183,7 @@ static int inode_alloc_security(struct i
 		return -ENOMEM;
 
 	memset(isec, 0, sizeof(*isec));
-	init_MUTEX(&isec->sem);
+	mutex_init(&isec->lock);
 	INIT_LIST_HEAD(&isec->list);
 	isec->inode = inode;
 	isec->sid = SECINITSID_UNLABELED;

@@ -843,13 +844,13 @@ #define INITCONTEXTLEN 255
 	char *context = NULL;
 	unsigned len = 0;
 	int rc = 0;
-	int hold_sem = 0;
+	int hold_lock = 0;
 
 	if (isec->initialized)
 		goto out;
 
-	down(&isec->sem);
-	hold_sem = 1;
+	mutex_lock(&isec->lock);
+	hold_lock = 1;
 	if (isec->initialized)
 		goto out;

security/selinux/hooks.c out: · line 998

Quoted 9 lines
security/selinux/hooks.c +2 -2
@@ -991,8 +992,8 @@ out:
 	if (isec->sclass == SECCLASS_FILE)
 		isec->sclass = inode_mode_to_security_class(inode->i_mode);
 
-	if (hold_sem)
-		up(&isec->sem);
+	if (hold_lock)
+		mutex_unlock(&isec->lock);
 	return rc;
 }

You didn't introduce it, but it would be nice to clean this up so that instead of using the hold_sem/hold_lock flag, we just use an alternate exit path for the unlocked case. Conditional release of a lock is ugly (my fault).

Signature · 8 lines
Stephen Smalley
National Security Agency


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