Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qg0-f45.google.com ([209.85.192.45]:64060 "EHLO mail-qg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751404AbaEWL6O (ORCPT ); Fri, 23 May 2014 07:58:14 -0400 Received: by mail-qg0-f45.google.com with SMTP id z60so7633784qgd.4 for ; Fri, 23 May 2014 04:58:14 -0700 (PDT) Message-ID: <537F37BD.9070005@gmail.com> Date: Fri, 23 May 2014 19:57:49 +0800 From: Kinglong Mee MIME-Version: 1.0 To: "J. Bruce Fields" CC: Linux NFS Mailing List , kinglongmee@gmail.com Subject: [PATCH 1/4] NFS4: Avoid NULL reference or double free in nfsd4_fslocs_free() Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: If fsloc_parse() failed at kzalloc(), fs/nfsd/export.c 411 412 fsloc->locations = kzalloc(fsloc->locations_count 413 * sizeof(struct nfsd4_fs_location), GFP_KERNEL); 414 if (!fsloc->locations) 415 return -ENOMEM; svc_export_parse() will call nfsd4_fslocs_free() with fsloc->locations = NULL, so that, "kfree(fsloc->locations[i].path);" will cause a crash. If fsloc_parse() failed after that, fsloc_parse() will call nfsd4_fslocs_free(), and svc_export_parse() will call it again, so that, a double free is caused. This patch checks the fsloc->locations, and set to NULL after it be freed. Signed-off-by: Kinglong Mee --- fs/nfsd/export.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 8513c59..9a41d3d 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -295,13 +295,19 @@ svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new, static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc) { + struct nfsd4_fs_location *locations = fsloc->locations; int i; + if (!locations) + return; + for (i = 0; i < fsloc->locations_count; i++) { - kfree(fsloc->locations[i].path); - kfree(fsloc->locations[i].hosts); + kfree(locations[i].path); + kfree(locations[i].hosts); } - kfree(fsloc->locations); + + kfree(locations); + fsloc->locations = NULL; } static void svc_export_put(struct kref *ref) -- 1.9.0