From: Matt Fleming <matt@codeblueprint.co.uk>
Date: Mon, 15 Aug 2016 14:29:20 +0000 (+0100)
Subject: fs/efivarfs: Fix double kfree() in error path
X-Git-Tag: v4.9-rc1~166^2~2^2~8
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=22c2b77f419bdc9317f00b395283abd33157368e;p=karo-tx-linux.git

fs/efivarfs: Fix double kfree() in error path

Julia reported that we may double free 'name' in efivarfs_callback(),
and that this bug was introduced by commit 0d22f33bc37c ("efi: Don't
use spinlocks for efi vars").

Move one of the kfree()s until after the point at which we know we are
definitely on the success path.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Sylvain Chouleur <sylvain.chouleur@gmail.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
---

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 01e3d6e53944..d7a7c53803c1 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -157,14 +157,14 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 		goto fail_inode;
 	}
 
-	/* copied by the above to local storage in the dentry. */
-	kfree(name);
-
 	efivar_entry_size(entry, &size);
 	err = efivar_entry_add(entry, &efivarfs_list);
 	if (err)
 		goto fail_inode;
 
+	/* copied by the above to local storage in the dentry. */
+	kfree(name);
+
 	inode_lock(inode);
 	inode->i_private = entry;
 	i_size_write(inode, size + sizeof(entry->var.Attributes));