commit 302ec300ef8a545a7fc7f667e5fd743b091c2eeb upstream.
Commit ecc0c469f277 ("autofs: don't fail mount for transient error") was
meant to replace an 'if' with a 'switch', but instead added the 'switch'
leaving the case in place.
Link: http://lkml.kernel.org/r/87zi6wstmw.fsf@notabene.neil.brown.name
Fixes: ecc0c469f277 ("autofs: don't fail mount for transient error")
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ecc0c469f27765ed1e2b967be0aa17cee1a60b76 upstream. Currently if the autofs kernel module gets an error when writing to the pipe which links to the daemon, then it marks the whole moutpoint as catatonic, and it will stop working. It is possible that the error is transient. This can happen if the daemon is slow and more than 16 requests queue up. If a subsequent process tries to queue a request, and is then signalled, the write to the pipe will return -ERESTARTSYS and autofs will take that as total failure. So change the code to assess -ERESTARTSYS and -ENOMEM as transient failures which only abort the current request, not the whole mountpoint. It isn't a crash or a data corruption, but having autofs mountpoints suddenly stop working is rather inconvenient. Ian said: : And given the problems with a half dozen (or so) user space applications : consuming large amounts of CPU under heavy mount and umount activity this : could happen more easily than we expect. Link: http://lkml.kernel.org/r/87y3norvgp.fsf@notabene.neil.brown.name Signed-off-by: NeilBrown <neilb@suse.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 93faccbbfa958a9668d3ab4e30f38dd205cee8d8 upstream.
To support unprivileged users mounting filesystems two permission
checks have to be performed: a test to see if the user allowed to
create a mount in the mount namespace, and a test to see if
the user is allowed to access the specified filesystem.
The automount case is special in that mounting the original filesystem
grants permission to mount the sub-filesystems, to any user who
happens to stumble across the their mountpoint and satisfies the
ordinary filesystem permission checks.
Attempting to handle the automount case by using override_creds
almost works. It preserves the idea that permission to mount
the original filesystem is permission to mount the sub-filesystem.
Unfortunately using override_creds messes up the filesystems
ordinary permission checks.
Solve this by being explicit that a mount is a submount by introducing
vfs_submount, and using it where appropriate.
vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let
sget and friends know that a mount is a submount so they can take appropriate
action.
sget and sget_userns are modified to not perform any permission checks
on submounts.
follow_automount is modified to stop using override_creds as that
has proven problemantic.
do_mount is modified to always remove the new MS_SUBMOUNT flag so
that we know userspace will never by able to specify it.
autofs4 is modified to stop using current_real_cred that was put in
there to handle the previous version of submount permission checking.
cifs is modified to pass the mountpoint all of the way down to vfs_submount.
debugfs is modified to pass the mountpoint all of the way down to
trace_automount by adding a new parameter. To make this change easier
a new typedef debugfs_automount_t is introduced to capture the type of
the debugfs automount function.
Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid")
Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds")
Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Seth Forshee reports that in 4.8-rcN some automounts are failing
because the requesting the automount changed.
The relevant call path is:
follow_automount()
->d_automount
autofs4_d_automount
autofs4_mount_wait
autofs4_wait
In autofs4_wait wq_uid and wq_gid are set to current_uid() and
current_gid respectively. With follow_automount now overriding creds
uid that we export to userspace changes and that breaks existing
setups.
To remove the regression set wq_uid and wq_gid from
current_real_cred()->uid and current_real_cred()->gid respectively.
This restores the current behavior as current->real_cred is identical
to current->cred except when override creds are used.
Cc: stable@vger.kernel.org
Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds")
Reported-by: Seth Forshee <seth.forshee@canonical.com>
Tested-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull qstr constification updates from Al Viro: "Fairly self-contained bunch - surprising lot of places passes struct qstr * as an argument when const struct qstr * would suffice; it complicates analysis for no good reason. I'd prefer to feed that separately from the assorted fixes (those are in #for-linus and with somewhat trickier topology)" * 'work.const-qstr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: qstr: constify instances in adfs qstr: constify instances in lustre qstr: constify instances in f2fs qstr: constify instances in ext2 qstr: constify instances in vfat qstr: constify instances in procfs qstr: constify instances in fuse qstr constify instances in fs/dcache.c qstr: constify instances in nfs qstr: constify instances in ocfs2 qstr: constify instances in autofs4 qstr: constify instances in hfs qstr: constify instances in hfsplus qstr: constify instances in logfs qstr: constify dentry_init_security
This changes the vfs dentry hashing to mix in the parent pointer at the _beginning_ of the hash, rather than at the end. That actually improves both the hash and the code generation, because we can move more of the computation to the "static" part of the dcache setup, and do less at lookup runtime. It turns out that a lot of other hash users also really wanted to mix in a base pointer as a 'salt' for the hash, and so the slightly extended interface ends up working well for other cases too. Users that want a string hash that is purely about the string pass in a 'salt' pointer of NULL. * merge branch 'salted-string-hash': fs/dcache.c: Save one 32-bit multiply in dcache lookup vfs: make the string hashes salt the hash
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
__vfs_write() returns a negative value in a error case. Link: http://lkml.kernel.org/r/20160616083108.6278.65815.stgit@pluto.themaw.net Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the standard pr_xxx() log macros directly for log prints instead of the AUTOFS_XXX() macros. Signed-off-by: Ian Kent <ikent@redhat.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>