linux-toradex.git/fs/autofs4/dev-ioctl.c, branch v3.14.37

autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation

2015-03-18T12:31:30+00:00

commit 0a280962dc6e117e0e4baa668453f753579265d9 upstream.

X-Coverup: just ask spender
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

autofs4: allow autofs to work outside the initial PID namespace

2014-01-24T00:36:58+00:00

Enable autofs4 to work in a "container".  oz_pgrp is converted from
pid_t to struct pid and this is stored at mount time based on the
"pgrp=" option or if the option is missing then the current pgrp.

The "pgrp=" option is interpreted in the PID namespace of the current
process.  This option is flawed in that it doesn't carry the namespace
information, so it should be deprecated.  AFAICS the autofs daemon
always sends the current pgrp, which is the default anyway.

The oz_pgrp is also set from the AUTOFS_DEV_IOCTL_SETPIPEFD_CMD ioctl.
This ioctl sets oz_pgrp to the current pgrp.  It is not allowed to
change the pid namespace.

oz_pgrp is used mainly to determine whether the process traversing the
autofs mount tree is the autofs daemon itself or not.  This function now
compares the pid pointers instead of the pid_t values.

One other use of oz_pgrp is in autofs4_show_options.  There is shows the
virtual pid number (i.e.  the one that is valid inside the PID namespace
of the calling process)

For debugging printk convert oz_pgrp to the value in the initial pid
namespace.

Signed-off-by: Sukadev Bhattiprolu 
Signed-off-by: Miklos Szeredi 
Acked-by: Serge Hallyn 
Cc: Eric Biederman 
Acked-by: Ian Kent 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

file->f_op is never NULL...

2013-10-25T03:34:54+00:00

Signed-off-by: Al Viro

autofs4 - fix device ioctl mount lookup

2013-09-09T02:07:47+00:00

When reconnecting to automounts at startup an autofs ioctl is used
to find the device and inode of existing mounts so they can be used
to open a file descriptor of possibly covered mounts.

At this time the the caller might not yet "own" the mount so it can
trigger calling ->d_automount(). This causes automount to hang when
trying to reconnect to direct or offset mount types.

Consequently kern_path() can't be used but kern_path_mountpoint() can be.

Signed-off-by: Ian Kent 
Cc: Jeff Layton 
Cc: Al Viro 
Signed-off-by: Al Viro

new helper: file_inode(file)

2013-02-23T04:31:31+00:00

Signed-off-by: Al Viro

userns: Support autofs4 interacing with multiple user namespaces

2012-11-15T06:05:32+00:00

Use kuid_t and kgid_t in struct autofs_info and struct autofs_wait_queue.

When creating directories and symlinks default the uid and gid of
the mount requester to the global root uid and gid.  autofs4_wait
will update these fields when a mount is requested.

When generating autofsv5 packets report the uid and gid of the mount
requestor in user namespace of the process that opened the pipe,
reporting unmapped uids and gids as overflowuid and overflowgid.

In autofs_dev_ioctl_requester return the uid and gid of the last mount
requester converted into the calling processes user namespace.  When the
uid or gid don't map return overflowuid and overflowgid as appropriate,
allowing failure to find a mount requester to be distinguished from
failure to map a mount requester.

The uid and gid mount options specifying the user and group of the
root autofs inode are converted into kuid and kgid as they are parsed
defaulting to the current uid and current gid of the process that
mounts autofs.

Mounting of autofs for the present remains confined to processes in
the initial user namespace.

Cc: Ian Kent 
Acked-by: Serge Hallyn 
Signed-off-by: Eric W. Biederman

autofs4: don't open-code fd_install()

2012-09-27T01:08:51+00:00

The only difference between autofs_dev_ioctl_fd_install() and
fd_install() is __set_close_on_exec() done by the latter.  Just
use get_unused_fd_flags(O_CLOEXEC) to allocate the descriptor
and be done with that...

Signed-off-by: Al Viro

switch dentry_open() to struct path, make it grab references itself

2012-07-22T20:01:29+00:00

Signed-off-by: Al Viro

autofs: make the autofsv5 packet file descriptor use a packetized pipe

2012-04-29T20:30:08+00:00

The autofs packet size has had a very unfortunate size problem on x86:
because the alignment of 'u64' differs in 32-bit and 64-bit modes, and
because the packet data was not 8-byte aligned, the size of the autofsv5
packet structure differed between 32-bit and 64-bit modes despite
looking otherwise identical (300 vs 304 bytes respectively).

We first fixed that up by making the 64-bit compat mode know about this
problem in commit a32744d4abae ("autofs: work around unhappy compat
problem on x86-64"), and that made a 32-bit 'systemd' work happily on a
64-bit kernel because everything then worked the same way as on a 32-bit
kernel.

But it turned out that 'automount' had actually known and worked around
this problem in user space, so fixing the kernel to do the proper 32-bit
compatibility handling actually *broke* 32-bit automount on a 64-bit
kernel, because it knew that the packet sizes were wrong and expected
those incorrect sizes.

As a result, we ended up reverting that compatibility mode fix, and
thus breaking systemd again, in commit fcbf94b9dedd.

With both automount and systemd doing a single read() system call, and
verifying that they get *exactly* the size they expect but using
different sizes, it seemed that fixing one of them inevitably seemed to
break the other.  At one point, a patch I seriously considered applying
from Michael Tokarev did a "strcmp()" to see if it was automount that
was doing the operation.  Ugly, ugly.

However, a prettier solution exists now thanks to the packetized pipe
mode.  By marking the communication pipe as being packetized (by simply
setting the O_DIRECT flag), we can always just write the bigger packet
size, and if user-space does a smaller read, it will just get that
partial end result and the extra alignment padding will simply be thrown
away.

This makes both automount and systemd happy, since they now get the size
they asked for, and the kernel side of autofs simply no longer needs to
care - it could pad out the packet arbitrarily.

Of course, if there is some *other* user of autofs (please, please,
please tell me it ain't so - and we haven't heard of any) that tries to
read the packets with multiple writes, that other user will now be
broken - the whole point of the packetized mode is that one system call
gets exactly one packet, and you cannot read a packet in pieces.

Tested-by: Michael Tokarev 
Cc: Alan Cox 
Cc: David Miller 
Cc: Ian Kent 
Cc: Thomas Meyer 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

Revert "autofs: work around unhappy compat problem on x86-64"

2012-04-28T15:29:56+00:00

This reverts commit a32744d4abae24572eff7269bc17895c41bd0085.

While that commit was technically the right thing to do, and made the
x86-64 compat mode work identically to native 32-bit mode (and thus
fixing the problem with a 32-bit systemd install on a 64-bit kernel), it
turns out that the automount binaries had workarounds for this compat
problem.

Now, the workarounds are disgusting: doing an "uname()" to find out the
architecture of the kernel, and then comparing it for the 64-bit cases
and fixing up the size of the read() in automount for those.  And they
were confused: it's not actually a generic 64-bit issue at all, it's
very much tied to just x86-64, which has different alignment for an
'u64' in 64-bit mode than in 32-bit mode.

But the end result is that fixing the compat layer actually breaks the
case of a 32-bit automount on a x86-64 kernel.

There are various approaches to fix this (including just doing a
"strcmp()" on current->comm and comparing it to "automount"), but I
think that I will do the one that teaches pipes about a special "packet
mode", which will allow user space to not have to care too deeply about
the padding at the end of the autofs packet.

That change will make the compat workaround unnecessary, so let's revert
it first, and get automount working again in compat mode.  The
packetized pipes will then fix autofs for systemd.

Reported-and-requested-by: Michael Tokarev 
Cc: Ian Kent 
Cc: stable@kernel.org # for 3.3
Signed-off-by: Linus Torvalds