Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755640Ab2HTRaR (ORCPT ); Mon, 20 Aug 2012 13:30:17 -0400 Received: from mx.meyering.net ([88.168.87.75]:44792 "EHLO hx.meyering.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755348Ab2HTR3o (ORCPT ); Mon, 20 Aug 2012 13:29:44 -0400 From: Jim Meyering To: linux-kernel@vger.kernel.org Cc: Jim Meyering , Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , v9fs-developer@lists.sourceforge.net Subject: [PATCH] fs/9p: avoid debug OOPS when reading a long symlink Date: Mon, 20 Aug 2012 18:55:21 +0200 Message-Id: <1345481724-30108-3-git-send-email-jim@meyering.net> X-Mailer: git-send-email 1.7.12 In-Reply-To: <1345481724-30108-1-git-send-email-jim@meyering.net> References: <1345481724-30108-1-git-send-email-jim@meyering.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1345 Lines: 41 From: Jim Meyering Reading a symlink longer than the given buffer, a p9_debug use would try to print the link name (not NUL-terminated) using a %s format. Use %.*s instead, and replace the strncpy+strnlen with functionally equivalent strlen+memcpy. Signed-off-by: Jim Meyering --- fs/9p/vfs_inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index cbf9dbb..16ed405 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -1276,12 +1276,12 @@ static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen) } /* copy extension buffer into buffer */ - strncpy(buffer, st->extension, buflen); + retval = min(strlen(st->extension)+1, buflen); + memcpy(buffer, st->extension, retval); - p9_debug(P9_DEBUG_VFS, "%s -> %s (%s)\n", - dentry->d_name.name, st->extension, buffer); + p9_debug(P9_DEBUG_VFS, "%s -> %s (%.*s)\n", + dentry->d_name.name, st->extension, buflen, buffer); - retval = strnlen(buffer, buflen); done: p9stat_free(st); kfree(st); -- 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/