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security: testing the wrong variable in create_by_name()

PATCH In review Dan Carpenter 2 participants 2 messages Apr 22, 2010

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#0 lore raw

PATCH 1/1 security: testing the wrong variable in create_by_name()

There is a typo here. We should be testing "*dentry" instead of "dentry". If "*dentry" is an ERR_PTR, it gets dereferenced in either mkdir() or create() which would cause an OOPs.

security/inode.c +2 -2
index c3a7938..1c812e8 100644
@@ -161,13 +161,13 @@ static int create_by_name(const char *name, mode_t mode,
 
 	mutex_lock(&parent->d_inode->i_mutex);
 	*dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(dentry)) {
+	if (!IS_ERR(*dentry)) {
 		if ((mode & S_IFMT) = S_IFDIR)
 			error = mkdir(parent->d_inode, *dentry, mode);
 		else
 			error = create(parent->d_inode, *dentry, mode);
 	} else
-		error = PTR_ERR(dentry);
+		error = PTR_ERR(*dentry);
 	mutex_unlock(&parent->d_inode->i_mutex);
 
 	return error;
maintainer
#1 lore raw
Quoted 5 lines · Dan Carpenter

There is a typo here. We should be testing "*dentry" instead of "dentry". If "*dentry" is an ERR_PTR, it gets dereferenced in either mkdir() or create() which would cause an OOPs.

Looks correct -- queued for Linus.

Quoted 22 lines
security/inode.c +2 -2
index c3a7938..1c812e8 100644
@@ -161,13 +161,13 @@ static int create_by_name(const char *name, mode_t mode,
 
 	mutex_lock(&parent->d_inode->i_mutex);
 	*dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(dentry)) {
+	if (!IS_ERR(*dentry)) {
 		if ((mode & S_IFMT) = S_IFDIR)
 			error = mkdir(parent->d_inode, *dentry, mode);
 		else
 			error = create(parent->d_inode, *dentry, mode);
 	} else
-		error = PTR_ERR(dentry);
+		error = PTR_ERR(*dentry);
 	mutex_unlock(&parent->d_inode->i_mutex);
 
 	return error;
Signature · 2 lines
James Morris
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