fs/xattr.c:setxattr(): improve handling of allocation failures

This allocation can be as large as 64k. - Add __GFP_NOWARN so the a falied kmalloc() is silent - Fall back to vmalloc() if the kmalloc() failed Cc: Dave Chinner <[email protected]> Cc: Dave Jones <[email protected]> Cc: David Rientjes <[email protected]> Cc: Al Viro <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
strager · Apr 5, 2012 · 44c8249 · 44c8249
1 parent 0d08d7b
commit 44c8249
Showing 1 changed file with 17 additions and 4 deletions.
diff --git a/fs/xattr.c b/fs/xattr.c
@@ -321,6 +321,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
 {
 	int error;
 	void *kvalue = NULL;
+	void *vvalue = NULL;	/* If non-NULL, we used vmalloc() */
 	char kname[XATTR_NAME_MAX + 1];
 
 	if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
@@ -335,13 +336,25 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
 	if (size) {
 		if (size > XATTR_SIZE_MAX)
 			return -E2BIG;
-		kvalue = memdup_user(value, size);
-		if (IS_ERR(kvalue))
-			return PTR_ERR(kvalue);
+		kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
+		if (!kvalue) {
+			vvalue = vmalloc(size);
+			if (!vvalue)
+				return -ENOMEM;
+			kvalue = vvalue;
+		}
+		if (copy_from_user(kvalue, value, size)) {
+			error = -EFAULT;
+			goto out;
+		}
 	}
 
 	error = vfs_setxattr(d, kname, kvalue, size, flags);
-	kfree(kvalue);
+out:
+	if (vvalue)
+		vfree(vvalue);
+	else
+		kfree(kvalue);
 	return error;
 }