[PATCH] SELinux: change isec semaphore to a mutex
Eric Paris [Tue, 26 Sep 2006 06:32:01 +0000 (23:32 -0700)]
This patch converts the remaining isec->sem into a mutex.  Very similar
locking is provided as before only in the faster smaller mutex rather than a
semaphore.  An out_unlock path is introduced rather than the conditional
unlocking found in the original code.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

security/selinux/hooks.c
security/selinux/include/objsec.h
security/selinux/ss/services.c

index 14a7819..63ad57a 100644 (file)
@@ -71,6 +71,7 @@
 #include <linux/audit.h>
 #include <linux/string.h>
 #include <linux/selinux.h>
+#include <linux/mutex.h>
 
 #include "avc.h"
 #include "objsec.h"
@@ -185,7 +186,7 @@ static int inode_alloc_security(struct inode *inode)
                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;
@@ -843,15 +844,13 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
        char *context = NULL;
        unsigned len = 0;
        int rc = 0;
-       int hold_sem = 0;
 
        if (isec->initialized)
                goto out;
 
-       down(&isec->sem);
-       hold_sem = 1;
+       mutex_lock(&isec->lock);
        if (isec->initialized)
-               goto out;
+               goto out_unlock;
 
        sbsec = inode->i_sb->s_security;
        if (!sbsec->initialized) {
@@ -862,7 +861,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                if (list_empty(&isec->list))
                        list_add(&isec->list, &sbsec->isec_head);
                spin_unlock(&sbsec->isec_lock);
-               goto out;
+               goto out_unlock;
        }
 
        switch (sbsec->behavior) {
@@ -885,7 +884,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                        printk(KERN_WARNING "%s:  no dentry for dev=%s "
                               "ino=%ld\n", __FUNCTION__, inode->i_sb->s_id,
                               inode->i_ino);
-                       goto out;
+                       goto out_unlock;
                }
 
                len = INITCONTEXTLEN;
@@ -893,7 +892,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                if (!context) {
                        rc = -ENOMEM;
                        dput(dentry);
-                       goto out;
+                       goto out_unlock;
                }
                rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
                                           context, len);
@@ -903,7 +902,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                                                   NULL, 0);
                        if (rc < 0) {
                                dput(dentry);
-                               goto out;
+                               goto out_unlock;
                        }
                        kfree(context);
                        len = rc;
@@ -911,7 +910,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                        if (!context) {
                                rc = -ENOMEM;
                                dput(dentry);
-                               goto out;
+                               goto out_unlock;
                        }
                        rc = inode->i_op->getxattr(dentry,
                                                   XATTR_NAME_SELINUX,
@@ -924,7 +923,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                                       "%d for dev=%s ino=%ld\n", __FUNCTION__,
                                       -rc, inode->i_sb->s_id, inode->i_ino);
                                kfree(context);
-                               goto out;
+                               goto out_unlock;
                        }
                        /* Map ENODATA to the default file SID */
                        sid = sbsec->def_sid;
@@ -960,7 +959,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                                             isec->sclass,
                                             &sid);
                if (rc)
-                       goto out;
+                       goto out_unlock;
                isec->sid = sid;
                break;
        case SECURITY_FS_USE_MNTPOINT:
@@ -978,7 +977,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
                                                          isec->sclass,
                                                          &sid);
                                if (rc)
-                                       goto out;
+                                       goto out_unlock;
                                isec->sid = sid;
                        }
                }
@@ -987,12 +986,11 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 
        isec->initialized = 1;
 
+out_unlock:
+       mutex_unlock(&isec->lock);
 out:
        if (isec->sclass == SECCLASS_FILE)
                isec->sclass = inode_mode_to_security_class(inode->i_mode);
-
-       if (hold_sem)
-               up(&isec->sem);
        return rc;
 }
 
index 0a39bfd..7d5a028 100644 (file)
@@ -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 */
 };
 
index 988079f..0c219a1 100644 (file)
@@ -2578,7 +2578,7 @@ int selinux_netlbl_inode_permission(struct inode *inode, int mask)
        sock = SOCKET_I(inode);
        isec = inode->i_security;
        sksec = sock->sk->sk_security;
-       down(&isec->sem);
+       mutex_lock(&isec->lock);
        if (unlikely(sksec->nlbl_state == NLBL_REQUIRE &&
                     (mask & (MAY_WRITE | MAY_APPEND)))) {
                lock_sock(sock->sk);
@@ -2586,7 +2586,7 @@ int selinux_netlbl_inode_permission(struct inode *inode, int mask)
                release_sock(sock->sk);
        } else
                rc = 0;
-       up(&isec->sem);
+       mutex_unlock(&isec->lock);
 
        return rc;
 }