From patchwork Fri Jan 29 01:15:43 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 575110 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 5E13E14031B; Fri, 29 Jan 2016 12:20:04 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aOxjF-0005ej-8i; Fri, 29 Jan 2016 01:20:01 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aOxj4-0005Yd-Qk for kernel-team@lists.ubuntu.com; Fri, 29 Jan 2016 01:19:50 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aOxj4-00054a-Di; Fri, 29 Jan 2016 01:19:50 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aOxj1-0004gc-J0; Thu, 28 Jan 2016 17:19:47 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.19.y-ckt 005/210] ovl: use a minimal buffer in ovl_copy_xattr Date: Thu, 28 Jan 2016 17:15:43 -0800 Message-Id: <1454030348-17736-6-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1454030348-17736-1-git-send-email-kamal@canonical.com> References: <1454030348-17736-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Cc: Kamal Mostafa , Miklos Szeredi X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.19.8-ckt14 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Vito Caputo commit e4ad29fa0d224d05e08b2858e65f112fd8edd4fe upstream. Rather than always allocating the high-order XATTR_SIZE_MAX buffer which is costly and prone to failure, only allocate what is needed and realloc if necessary. Fixes https://github.com/coreos/bugs/issues/489 Signed-off-by: Miklos Szeredi Signed-off-by: Kamal Mostafa --- fs/overlayfs/copy_up.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 37b1b9e..76c1460 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -22,9 +22,9 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) { - ssize_t list_size, size; - char *buf, *name, *value; - int error; + ssize_t list_size, size, value_size = 0; + char *buf, *name, *value = NULL; + int uninitialized_var(error); if (!old->d_inode->i_op->getxattr || !new->d_inode->i_op->getxattr) @@ -41,29 +41,40 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) if (!buf) return -ENOMEM; - error = -ENOMEM; - value = kmalloc(XATTR_SIZE_MAX, GFP_KERNEL); - if (!value) - goto out; - list_size = vfs_listxattr(old, buf, list_size); if (list_size <= 0) { error = list_size; - goto out_free_value; + goto out; } for (name = buf; name < (buf + list_size); name += strlen(name) + 1) { - size = vfs_getxattr(old, name, value, XATTR_SIZE_MAX); +retry: + size = vfs_getxattr(old, name, value, value_size); + if (size == -ERANGE) + size = vfs_getxattr(old, name, NULL, 0); + if (size < 0) { error = size; - goto out_free_value; + break; + } + + if (size > value_size) { + void *new; + + new = krealloc(value, size, GFP_KERNEL); + if (!new) { + error = -ENOMEM; + break; + } + value = new; + value_size = size; + goto retry; } + error = vfs_setxattr(new, name, value, size, 0); if (error) - goto out_free_value; + break; } - -out_free_value: kfree(value); out: kfree(buf);