From: "Darrick J. Wong" Subject: Re: [PATCH V4] mke2fs: disallow creating FS on a loop mounted file with no option Date: Sat, 30 Nov 2013 12:35:45 -0800 Message-ID: <20131130203545.GA9535@birch.djwong.org> References: <527B309D.4090706@sx.jp.nec.com> <003901ceeccb$ce268430$6a738c90$@sx.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "'Andreas Dilger'" , tytso@mit.edu, linux-ext4@vger.kernel.org To: Kazuya Mio Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:46559 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747Ab3K3UgP (ORCPT ); Sat, 30 Nov 2013 15:36:15 -0500 Content-Disposition: inline In-Reply-To: <003901ceeccb$ce268430$6a738c90$@sx.jp.nec.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Nov 29, 2013 at 03:25:31PM +0900, Kazuya Mio wrote: > Ping? > Any comments/suggestions will be welcome. I /think/ it looks fine... --D > > Regards, > Kazuya Mio > > > 2013/11/07 15:18:05, k-mio@sx.jp.nec.com wrote: > > > > When /etc/mtab is a symlink of /proc/mounts, mke2fs without -FF option > > can create a filesystem on the image file that is mounted. > > According to mke2fs man page, we should specify -FF option in this case. > > > > This patch protects filesystem from unintended mke2fs caused by human error. > > > > How to reproduce: > > # mke2fs -t ext4 -Fq fs.img > > # mount -o loop fs.img /mnt/mp1 > > # mke2fs -t ext4 -Fq fs.img && echo "mke2fs success" > > mke2fs success > > > > Signed-off-by: Kazuya Mio > > --- > > configure.in | 1 + > > lib/ext2fs/ismounted.c | 41 +++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 42 insertions(+) > > diff --git a/configure.in b/configure.in > > index 049dc11..fef8d9b 100644 > > --- a/configure.in > > +++ b/configure.in > > @@ -920,6 +920,7 @@ AC_CHECK_HEADERS(m4_flatten([ > > linux/falloc.h > > linux/fd.h > > linux/major.h > > + linux/loop.h > > net/if_dl.h > > netinet/in.h > > sys/disklabel.h > > diff --git a/lib/ext2fs/ismounted.c b/lib/ext2fs/ismounted.c > > index 2c1bd75..6c6ecff 100644 > > --- a/lib/ext2fs/ismounted.c > > +++ b/lib/ext2fs/ismounted.c > > @@ -21,6 +21,13 @@ > > #ifdef HAVE_LINUX_FD_H > > #include > > #endif > > +#ifdef HAVE_LINUX_LOOP_H > > +#include > > +#include > > +#ifdef HAVE_LINUX_MAJOR_H > > +#include > > +#endif /* HAVE_LINUX_MAJOR_H */ > > +#endif /* HAVE_LINUX_LOOP_H */ > > #ifdef HAVE_MNTENT_H > > #include > > #endif > > @@ -35,6 +42,36 @@ > > #include "ext2_fs.h" > > #include "ext2fs.h" > > > > +/* > > + * Check to see if a regular file is mounted. > > + * If /etc/mtab/ is a symlink of /proc/mounts, you will need the following check > > + * because the name in /proc/mounts is a loopback device not a regular file. > > + */ > > +static int check_loop_mounted(const char *mnt_fsname, dev_t mnt_rdev, > > + dev_t file_dev, ino_t file_ino) > > +{ > > +#if defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H) > > + struct loop_info64 loopinfo; > > + int loop_fd, ret; > > + > > + if (major(mnt_rdev) == LOOP_MAJOR) { > > + loop_fd = open(mnt_fsname, O_RDONLY); > > + if (loop_fd < 0) > > + return -1; > > + > > + ret = ioctl(loop_fd, LOOP_GET_STATUS64, &loopinfo); > > + close(loop_fd); > > + if (ret < 0) > > + return -1; > > + > > + if (file_dev == loopinfo.lo_device && > > + file_ino == loopinfo.lo_inode) > > + return 1; > > + } > > +#endif /* defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H) */ > > + return 0; > > +} > > + > > #ifdef HAVE_SETMNTENT > > /* > > * Helper function which checks a file in /etc/mtab format to see if a > > @@ -82,6 +119,10 @@ static errcode_t check_mntent_file(const char *mtab_file, const char *file, > > #ifndef __GNU__ > > if (file_rdev && (file_rdev == st_buf.st_rdev)) > > break; > > + if (check_loop_mounted(mnt->mnt_fsname, > > + st_buf.st_rdev, file_dev, > > + file_ino) == 1) > > + break; > > #endif /* __GNU__ */ > > } else { > > if (file_dev && ((file_dev == st_buf.st_dev) && > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html