Fwd: Bug#764331: mount: "mount --bind -o remount" doesn't preserve flags

Fwd: Bug#764331: mount: "mount --bind -o remount" doesn't preserve flags

[Phillip Susi]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I thought that it had been established that the kernel did not support
any other flags with MS_BIND, but this bug report seems to show that
it did, and the new util-linux silently discards the flags.  Is this a
bug?


- -------- Forwarded Message --------
Subject: Bug#764331: mount: "mount --bind -o remount" doesn't preserve
flags
Resent-Date: Tue, 07 Oct 2014 10:36:01 +0000
Resent-From: Kusanagi Kouichi <slash@ac.auone-net.jp>
Resent-To: debian-bugs-dist@lists.debian.org
Resent-CC: Debian util-linux Maintainers <ah-util-linux@debian.org>
Date: Tue, 07 Oct 2014 10:21:55 +0000
From: Kusanagi Kouichi <slash@ac.auone-net.jp>
Reply-To: Kusanagi Kouichi <slash@ac.auone-net.jp>, 764331@bugs.debian.org
To: Debian Bug Tracking System <submit@bugs.debian.org>

Package: mount
Version: 2.25.1-3
Severity: normal

Since I upgraded mount from 2.20.1-5.11 to 2.25.1-3,
"mount --bind -o remount" doesn't preserve flags anymore.

# mount -V
mount from util-linux 2.20.1 (with libblkid and selinux support)
# grep /tmp /proc/self/mountinfo
24 15 0:22 / /tmp rw,nosuid,nodev,relatime - tmpfs /tmp rw
# strace -e trace=mount mount --bind -o remount,noexec /tmp
mount("tmp", "/tmp", 0x4104a4,
MS_MGC_VAL|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_REMOUNT|MS_BIND, NULL) = 0
+++ exited with 0 +++
# grep /tmp /proc/self/mountinfo
24 15 0:22 / /tmp rw,nosuid,nodev,noexec,relatime - tmpfs /tmp rw

# mount -V
mount from util-linux 2.25.1 (libmount 2.25.0: selinux, assert, debug)
# grep /tmp /proc/self/mountinfo
24 15 0:22 / /tmp rw,nosuid,nodev,relatime - tmpfs /tmp rw
# strace -e trace=mount mount --bind -o remount,noexec /tmp
mount("none", "/tmp", 0x125a2f0,
MS_MGC_VAL|MS_NOEXEC|MS_REMOUNT|MS_BIND, NULL) = 0
+++ exited with 0 +++
# grep /tmp /proc/self/mountinfo
24 15 0:22 / /tmp rw,noexec,relatime - tmpfs /tmp rw

- -- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.17.0-rc7 (SMP w/4 CPU cores)
Locale: LANG=ja_JP.eucJP, LC_CTYPE=ja_JP.eucJP (charmap=EUC-JP)
Shell: /bin/sh linked to /bin/dash

Versions of packages mount depends on:
ii  libc6          2.19-11
ii  libmount1      2.25.1-3
ii  libselinux1    2.3-2
ii  libsmartcols1  2.25.1-3

mount recommends no packages.

Versions of packages mount suggests:
pn  nfs-common  <none>

- -- no debconf information



-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.17 (MingW32)

iQEcBAEBAgAGBQJUM/GtAAoJEI5FoCIzSKrwMt0IAJXE1nKf1Qul61ZGTp+8PrkP
jECbRXXOAgzGniZc8M8ZoTLTbnPsbuvHjLNkhgBpha5o6a3lulEX4sOJq4uWp4wD
zFLMKRIa4QxbKvvGlLUyulbmMju53GCZk2ZGXrP5YMMhlpQFhbbN1TTzpgbTrtSS
7939KUTfDUZozm1MbauQqP8/yweOcRN88SHplRT5M+547Fw21/954a8nY2+XwZS4
mNcUpgnz/X6dMje9w3pkAYq/vxNtdtQ61J1IVXionWzBFjp0kVp2f+QNdADgqt06
UpFltonLCiAbHfIhCGEeDM48d5r9xEV/AroszeKq3Xlq2Blyk1CP2/nMmF9cqoM=
=nO6i
-----END PGP SIGNATURE-----

Re: Fwd: Bug#764331: mount: "mount --bind -o remount" doesn't preserve flags

[Karel Zak]

On Tue, Oct 07, 2014 at 09:59:09AM -0400, Phillip Susi wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> I thought that it had been established that the kernel did not support
> any other flags with MS_BIND, but this bug report seems to show that
> it did, and the new util-linux silently discards the flags.  Is this a
> bug?

 Seems like a bug, I'll try to play with that tomorrow. Thanks!

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Fwd: Bug#764331: mount: "mount --bind -o remount" doesn't preserve flags

[Karel Zak]

On Tue, Oct 07, 2014 at 09:59:09AM -0400, Phillip Susi wrote:
> I thought that it had been established that the kernel did not support
> any other flags with MS_BIND, but this bug report seems to show that
> it did, and the new util-linux silently discards the flags.  Is this a
> bug?

It only happens when you use "--bind" rather than "-o bind".

# strace -e mount ./mount  -o bind,remount,nosuid  /mnt/test
mount("/dev/sdb", "/mnt/test", 0x225ad60, MS_NOSUID|MS_NOEXEC|MS_REMOUNT|MS_RELATIME|MS_BIND, "stripe=32") = 0

# strace -e mount ./mount --bind -o remount,nosuid  /mnt/test 
mount("none", "/mnt/test", 0x6d6240, MS_MGC_VAL|MS_NOSUID|MS_REMOUNT|MS_BIND, NULL) = 0

Fixed in git tree, will be in 2.25.2. Thanks!

    Karel


> 
> 
> - -------- Forwarded Message --------
> Subject: Bug#764331: mount: "mount --bind -o remount" doesn't preserve
> flags
> Resent-Date: Tue, 07 Oct 2014 10:36:01 +0000
> Resent-From: Kusanagi Kouichi <slash@ac.auone-net.jp>
> Resent-To: debian-bugs-dist@lists.debian.org
> Resent-CC: Debian util-linux Maintainers <ah-util-linux@debian.org>
> Date: Tue, 07 Oct 2014 10:21:55 +0000
> From: Kusanagi Kouichi <slash@ac.auone-net.jp>
> Reply-To: Kusanagi Kouichi <slash@ac.auone-net.jp>, 764331@bugs.debian.org
> To: Debian Bug Tracking System <submit@bugs.debian.org>
> 
> Package: mount
> Version: 2.25.1-3
> Severity: normal
> 
> Since I upgraded mount from 2.20.1-5.11 to 2.25.1-3,
> "mount --bind -o remount" doesn't preserve flags anymore.
> 
> # mount -V
> mount from util-linux 2.20.1 (with libblkid and selinux support)
> # grep /tmp /proc/self/mountinfo
> 24 15 0:22 / /tmp rw,nosuid,nodev,relatime - tmpfs /tmp rw
> # strace -e trace=mount mount --bind -o remount,noexec /tmp
> mount("tmp", "/tmp", 0x4104a4,
> MS_MGC_VAL|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_REMOUNT|MS_BIND, NULL) = 0
> +++ exited with 0 +++
> # grep /tmp /proc/self/mountinfo
> 24 15 0:22 / /tmp rw,nosuid,nodev,noexec,relatime - tmpfs /tmp rw
> 
> # mount -V
> mount from util-linux 2.25.1 (libmount 2.25.0: selinux, assert, debug)
> # grep /tmp /proc/self/mountinfo
> 24 15 0:22 / /tmp rw,nosuid,nodev,relatime - tmpfs /tmp rw
> # strace -e trace=mount mount --bind -o remount,noexec /tmp
> mount("none", "/tmp", 0x125a2f0,
> MS_MGC_VAL|MS_NOEXEC|MS_REMOUNT|MS_BIND, NULL) = 0
> +++ exited with 0 +++
> # grep /tmp /proc/self/mountinfo
> 24 15 0:22 / /tmp rw,noexec,relatime - tmpfs /tmp rw
> 
> - -- System Information:
> Debian Release: jessie/sid
>   APT prefers unstable
>   APT policy: (500, 'unstable'), (1, 'experimental')
> Architecture: amd64 (x86_64)
> 
> Kernel: Linux 3.17.0-rc7 (SMP w/4 CPU cores)
> Locale: LANG=ja_JP.eucJP, LC_CTYPE=ja_JP.eucJP (charmap=EUC-JP)
> Shell: /bin/sh linked to /bin/dash
> 
> Versions of packages mount depends on:
> ii  libc6          2.19-11
> ii  libmount1      2.25.1-3
> ii  libselinux1    2.3-2
> ii  libsmartcols1  2.25.1-3
> 
> mount recommends no packages.
> 
> Versions of packages mount suggests:
> pn  nfs-common  <none>
> 
> - -- no debconf information
> 
> 
> 
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v2.0.17 (MingW32)
> 
> iQEcBAEBAgAGBQJUM/GtAAoJEI5FoCIzSKrwMt0IAJXE1nKf1Qul61ZGTp+8PrkP
> jECbRXXOAgzGniZc8M8ZoTLTbnPsbuvHjLNkhgBpha5o6a3lulEX4sOJq4uWp4wD
> zFLMKRIa4QxbKvvGlLUyulbmMju53GCZk2ZGXrP5YMMhlpQFhbbN1TTzpgbTrtSS
> 7939KUTfDUZozm1MbauQqP8/yweOcRN88SHplRT5M+547Fw21/954a8nY2+XwZS4
> mNcUpgnz/X6dMje9w3pkAYq/vxNtdtQ61J1IVXionWzBFjp0kVp2f+QNdADgqt06
> UpFltonLCiAbHfIhCGEeDM48d5r9xEV/AroszeKq3Xlq2Blyk1CP2/nMmF9cqoM=
> =nO6i
> -----END PGP SIGNATURE-----
> --
> To unsubscribe from this list: send the line "unsubscribe util-linux" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com