Untangling ima mess, part 3: kill dead code in ima

Kill the 'update' argument of ima_path_check(), kill
dead code in ima.

Current rules: ima counters are bumped at the same time
when the file switches from put_filp() fodder to fput()
one.  Which happens exactly in two places - alloc_file()
and __dentry_open().  Nothing else needs to do that at
all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -1686,7 +1686,7 @@ struct file *do_filp_open(int dfd, const char *pathname,
 			path_put(&nd.root);
 		if (!IS_ERR(filp)) {
 			error = ima_path_check(&filp->f_path, filp->f_mode &
-				       (MAY_READ | MAY_WRITE | MAY_EXEC), 0);
+				       (MAY_READ | MAY_WRITE | MAY_EXEC));
 			if (error) {
 				fput(filp);
 				filp = ERR_PTR(error);
@@ -1747,7 +1747,7 @@ struct file *do_filp_open(int dfd, const char *pathname,
 	filp = nameidata_to_filp(&nd, open_flag);
 	if (!IS_ERR(filp)) {
 		error = ima_path_check(&filp->f_path, filp->f_mode &
-			       (MAY_READ | MAY_WRITE | MAY_EXEC), 0);
+			       (MAY_READ | MAY_WRITE | MAY_EXEC));
 		if (error) {
 			fput(filp);
 			filp = ERR_PTR(error);

fs/nfsd/vfs.c

@@ -2122,8 +2122,7 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
 	 */
 	path.mnt = exp->ex_path.mnt;
 	path.dentry = dentry;
-	err = ima_path_check(&path, acc & (MAY_READ | MAY_WRITE | MAY_EXEC),
-			     IMA_COUNT_LEAVE);
+	err = ima_path_check(&path, acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
 nfsd_out:
 	return err? nfserrno(err) : 0;
 }

include/linux/ima.h

@@ -13,18 +13,14 @@
 #include <linux/fs.h>
 struct linux_binprm;
 
-#define IMA_COUNT_UPDATE 1
-#define IMA_COUNT_LEAVE 0
-
 #ifdef CONFIG_IMA
 extern int ima_bprm_check(struct linux_binprm *bprm);
 extern int ima_inode_alloc(struct inode *inode);
 extern void ima_inode_free(struct inode *inode);
-extern int ima_path_check(struct path *path, int mask, int update_counts);
+extern int ima_path_check(struct path *path, int mask);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
 extern void ima_counts_get(struct file *file);
-extern void ima_counts_put(struct path *path, int mask);
 
 #else
 static inline int ima_bprm_check(struct linux_binprm *bprm)
@@ -42,7 +38,7 @@ static inline void ima_inode_free(struct inode *inode)
 	return;
 }
 
-static inline int ima_path_check(struct path *path, int mask, int update_counts)
+static inline int ima_path_check(struct path *path, int mask)
 {
 	return 0;
 }
@@ -62,9 +58,5 @@ static inline void ima_counts_get(struct file *file)
 	return;
 }
 
-static inline void ima_counts_put(struct path *path, int mask)
-{
-	return;
-}
 #endif /* CONFIG_IMA_H */
 #endif /* _LINUX_IMA_H */

security/integrity/ima/ima_main.c

@@ -49,20 +49,13 @@ static void ima_inc_counts(struct ima_iint_cache *iint, fmode_t mode)
 		iint->writecount++;
 }
 
-/*
- * Update the counts given open flags instead of fmode
- */
-static void ima_inc_counts_flags(struct ima_iint_cache *iint, int flags)
-{
-	ima_inc_counts(iint, (__force fmode_t)((flags+1) & O_ACCMODE));
-}
-
 /*
  * Decrement ima counts
  */
 static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
-			   fmode_t mode)
+			   struct file *file)
 {
+	mode_t mode = file->f_mode;
 	BUG_ON(!mutex_is_locked(&iint->mutex));
 
 	iint->opencount--;
@@ -92,12 +85,6 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
 	}
 }
 
-static void ima_dec_counts_flags(struct ima_iint_cache *iint,
-				 struct inode *inode, int flags)
-{
-	ima_dec_counts(iint, inode, (__force fmode_t)((flags+1) & O_ACCMODE));
-}
-
 /**
  * ima_file_free - called on __fput()
  * @file: pointer to file structure being freed
@@ -117,7 +104,7 @@ void ima_file_free(struct file *file)
 		return;
 
 	mutex_lock(&iint->mutex);
-	ima_dec_counts(iint, inode, file->f_mode);
+	ima_dec_counts(iint, inode, file);
 	mutex_unlock(&iint->mutex);
 	kref_put(&iint->refcount, iint_free);
 }
@@ -183,7 +170,7 @@ static int get_path_measurement(struct ima_iint_cache *iint, struct file *file,
  * Always return 0 and audit dentry_open failures.
  * (Return code will be based upon measurement appraisal.)
  */
-int ima_path_check(struct path *path, int mask, int update_counts)
+int ima_path_check(struct path *path, int mask)
 {
 	struct inode *inode = path->dentry->d_inode;
 	struct ima_iint_cache *iint;
@@ -197,8 +184,6 @@ int ima_path_check(struct path *path, int mask, int update_counts)
 		return 0;
 
 	mutex_lock(&iint->mutex);
-	if (update_counts)
-		ima_inc_counts_flags(iint, mask);
 
 	rc = ima_must_measure(iint, inode, MAY_READ, PATH_CHECK);
 	if (rc < 0)
@@ -268,35 +253,6 @@ static int process_measurement(struct file *file, const unsigned char *filename,
 	return rc;
 }
 
-/*
- * ima_counts_put - decrement file counts
- *
- * File counts are incremented in ima_path_check. On file open
- * error, such as ETXTBSY, decrement the counts to prevent
- * unnecessary imbalance messages.
- */
-void ima_counts_put(struct path *path, int mask)
-{
-	struct inode *inode = path->dentry->d_inode;
-	struct ima_iint_cache *iint;
-
-	/* The inode may already have been freed, freeing the iint
-	 * with it. Verify the inode is not NULL before dereferencing
-	 * it.
-	 */
-	if (!ima_initialized || !inode || !S_ISREG(inode->i_mode))
-		return;
-	iint = ima_iint_find_get(inode);
-	if (!iint)
-		return;
-
-	mutex_lock(&iint->mutex);
-	ima_dec_counts_flags(iint, inode, mask);
-	mutex_unlock(&iint->mutex);
-
-	kref_put(&iint->refcount, iint_free);
-}
-
 /*
  * ima_counts_get - increment file counts
  *