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* make simple_positive() publicAl Viro2015-06-241-5/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* don't pass nameidata to ->follow_link()Al Viro2015-05-111-1/+1
| | | | | | | its only use is getting passed to nd_jump_link(), which can obtain it from current->nameidata Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new ->follow_link() and ->put_link() calling conventionsAl Viro2015-05-111-3/+2
| | | | | | | | | | | | | | | | | | | a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: normal filesystems (and lustre): d_inode() annotationsDavid Howells2015-04-156-18/+18
| | | | | | | that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs: switch to __vfs_write()Al Viro2015-04-122-2/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocationAl Viro2015-02-221-2/+6
| | | | | | X-Coverup: just ask spender Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)David Howells2015-02-222-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: Wrong format for printing dentryRasmus Villemoes2015-02-201-1/+1
| | | | | | | | %pD for struct file*, %pd for struct dentry*. Fixes: a455589f181e ("assorted conversions to %p[dD]") Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* assorted conversions to %p[dD]Al Viro2014-11-192-35/+18
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* move d_rcu from overlapping d_child to overlapping d_aliasAl Viro2014-11-032-7/+7
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: d_manage() should return -EISDIR when appropriate in rcu-walk mode.NeilBrown2014-10-141-6/+20
| | | | | | | | | | | | | | | | | | | | | | If rcu-walk mode we don't *have* to return -EISDIR for non-mount-traps as we will simply drop into REF-walk and handling DCACHE_NEED_AUTOMOUNT dentrys the slow way. But it is better if we do when possible. In 'oz_mode', use the same condition as ref-walk: if not a mountpoint, then it must be -EISDIR. In regular mode there are most tests needed. Most of them can be performed without taking any spinlocks. If we find a directory that isn't obviously empty, and isn't mounted on, we need to call 'simple_empty()' which does take a spinlock. If this turned out to hurt performance, some other approach could be found to signal when a directory is known to be empty. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: avoid taking fs_lock during rcu-walkNeilBrown2014-10-142-8/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | ->fs_lock protects AUTOFS_INF_EXPIRING. We need to be sure that once the flag is set, no new references beneath the dentry are taken. So rcu-walk currently needs to take fs_lock before checking the flag. This hurts performance. Change the expiry to a two-stage process. First set AUTOFS_INF_NO_RCU which forces any path walk into ref-walk mode, then drop the lock and call synchronize_rcu(). Once that returns we can be sure no rcu-walk is active beneath the dentry and we can check reference counts again. Now during an RCU-walk we can test AUTOFS_INF_EXPIRING without taking the lock as along as we test AUTOFS_INF_NO_RCU too. If either are set, we must abort the RCU-walk If neither are set, we know that refcounts will be tested again after we finish the RCU-walk so we are safe to continue. ->fs_lock is still taken in d_manage() to check for a non-trap directory. That will be resolved in the next patch. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: make "autofs4_can_expire" idempotent.NeilBrown2014-10-141-6/+4
| | | | | | | | | | | | | | Have a "test" function change the value it is testing can be confusing, particularly as a future patch will be calling this function twice. So move the update for 'last_used' to avoid repeat expiry to the place where the final determination on what to expire is known. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: factor should_expire() out of autofs4_expire_indirect.NeilBrown2014-10-141-74/+88
| | | | | | | | | | Future patch will potentially call this twice, so make it separate. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: allow RCU-walk to walk through autofs4NeilBrown2014-10-144-18/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This series teaches autofs about RCU-walk so that we don't drop straight into REF-walk when we hit an autofs directory, and so that we avoid spinlocks as much as possible when performing an RCU-walk. This is needed so that the benefits of the recent NFS support for RCU-walk are fully available when NFS filesystems are automounted. Patches have been carefully reviewed and tested both with test suites and in production - thanks a lot to Ian Kent for his support there. This patch (of 6): Any attempt to look up a pathname that passes though an autofs4 mount is currently forced out of RCU-walk into REF-walk. This can significantly hurt performance of many-thread work loads on many-core systems, especially if the automounted filesystem supports RCU-walk but doesn't get to benefit from it. So if autofs4_d_manage is called with rcu_walk set, only fail with -ECHILD if it is necessary to wait longer than a spinlock. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs - remove obsolete d_invalidate() from expireIan Kent2014-10-091-6/+0
| | | | | | | | | | | | | | | | | | | | | | | Biederman's umount-on-rmdir series changes d_invalidate() to sumarily remove mounts under the passed in dentry regardless of whether they are busy or not. So calling this in fs/autofs4/expire.c:autofs4_tree_busy() is definitely the wrong thing to do becuase it will silently umount entries instead of just cleaning stale dentrys. But this call shouldn't be needed and testing shows that automounting continues to function without it. As Al Viro correctly surmises the original intent of the call was to perform what shrink_dcache_parent() does. If at some time in the future I see stale dentries accumulating following failed mounts I'll revisit the issue and possibly add a shrink_dcache_parent() call if needed. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: comment typo: remove a a doubled wordNeilBrown2014-08-091-1/+1
| | | | | | | Signed-off-by: NeilBrown <neilb@suse.de> 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>
* autofs4: remove some unused inline functionsNeilBrown2014-08-091-49/+0
| | | | | | | | | | | {__,}manage_dentry_{set,clear}_{automount,transit} are 4 unused inline functions. Discard them. Signed-off-by: NeilBrown <neilb@suse.de> 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>
* autofs4: don't take spinlock when not needed in autofs4_lookup_expiringNeilBrown2014-08-091-2/+6
| | | | | | | | | | | If the expiring_list is empty, we can avoid a costly spinlock in the rcu-walk path through autofs4_d_manage (once the rest of the path becomes rcu-walk friendly). Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: remove a redundant assignmentNeilBrown2014-08-091-1/+0
| | | | | | | | | | | | | | The variable 'ino' already exists and already has the correct value. The d_fsdata of a dentry is never changed after the d_fsdata is instantiated, so this new assignment cannot be necessary. It was introduced in commit b5b801779d59 ("autofs4: Add d_manage() dentry operation"). Signed-off-by: NeilBrown <neilb@suse.de> 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>
* autofs4: remove unused autofs4_ispending()NeilBrown2014-08-091-14/+0
| | | | | | | Signed-off-by: NeilBrown <neilb@suse.de> 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>
* autofs4: fix false positive compile errorIan Kent2014-07-031-1/+1
| | | | | | | | | | | | | | | | | | On strict build environments we can see: fs/autofs4/inode.c: In function 'autofs4_fill_super': fs/autofs4/inode.c:312: error: 'pgrp' may be used uninitialized in this function make[2]: *** [fs/autofs4/inode.o] Error 1 make[1]: *** [fs/autofs4] Error 2 make: *** [fs] Error 2 make: *** Waiting for unfinished jobs.... This is due to the use of pgrp_set being used to indicate pgrp has has been set rather than initializing pgrp itself. 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>
* fs/autofs4/dev-ioctl.c: add __init to autofs_dev_ioctl_initFabian Frederick2014-06-051-1/+1
| | | | | | | | | autofs_dev_ioctl_init is only called by __init init_autofs4_fs Signed-off-by: Fabian Frederick <fabf@skynet.be> 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>
* autofs: fix lockref lookupIan Kent2014-05-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | autofs needs to be able to see private data dentry flags for its dentrys that are being created but not yet hashed and for its dentrys that have been rmdir()ed but not yet freed. It needs to do this so it can block processes in these states until a status has been returned to indicate the given operation is complete. It does this by keeping two lists, active and expring, of dentrys in this state and uses ->d_release() to keep them stable while it checks the reference count to determine if they should be used. But with the recent lockref changes dentrys being freed sometimes don't transition to a reference count of 0 before being freed so autofs can occassionally use a dentry that is invalid which can lead to a panic. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: check dev ioctl size before allocatingSasha Levin2014-04-091-0/+3
| | | | | | | | | | | | | There wasn't any check of the size passed from userspace before trying to allocate the memory required. This meant that userspace might request more space than allowed, triggering an OOM. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 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>
* autofs: fix symlinks aren't checked for expiryIan Kent2014-01-242-0/+18
| | | | | | | | | | | | | | | | | | | | | | The autofs4 module doesn't consider symlinks for expire as it did in the older autofs v3 module (so it's actually a long standing regression). The user space daemon has focused on the use of bind mounts instead of symlinks for a long time now and that's why this has not been noticed. But with the future addition of amd map parsing to automount(8), not to mention amd itself (of am-utils), symlink expiry will be needed. The direct and offset mount types can't be symlinks and the tree mounts of version 4 were always real mounts so only indirect mounts need expire symlinks. Since the current users of the autofs4 module haven't reported this as a problem to date this patch probably isn't a candidate for backport to stable. Signed-off-by: Ian Kent <ikent@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs: use IS_ROOT to replace root dentry checksRui Xiang2014-01-241-3/+3
| | | | | | | | | | Use the helper macro !IS_ROOT to replace parent != dentry->d_parent. Just clean up. Signed-off-by: Rui Xiang <rui.xiang@huawei.com> 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>
* autofs: fix the return value of autofs4_fill_superRui Xiang2014-01-241-5/+8
| | | | | | | | | | | While kzallocing sbi/ino fails, it should return -ENOMEM. And it should return the err value from autofs_prepare_pipe. Signed-off-by: Rui Xiang <rui.xiang@huawei.com> 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>
* autofs4: translate pids to the right namespace for the daemonMiklos Szeredi2014-01-241-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | The PID and the TGID of the process triggering the mount are sent to the daemon. Currently the global pid values are sent (ones valid in the initial pid namespace) but this is wrong if the autofs daemon itself is not running in the initial pid namespace. So send the pid values that are valid in the namespace of the autofs daemon. The namespace to use is taken from the oz_pgrp pid pointer, which was set at mount time to the mounting process' pid namespace. If the pid translation fails (the triggering process is in an unrelated pid namespace) then the automount fails with ENOENT. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Eric Biederman <ebiederm@xmission.com> Acked-by: Ian Kent <raven@themaw.net> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: allow autofs to work outside the initial PID namespaceSukadev Bhattiprolu2014-01-243-13/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <sukadev@us.ibm.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Eric Biederman <ebiederm@xmission.com> Acked-by: Ian Kent <raven@themaw.net> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4: make freeing sbi rcu-delayedAl Viro2013-10-252-9/+5
| | | | | | makes ->d_managed() safety in RCU mode independent from vfsmount_lock Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* file->f_op is never NULL...Al Viro2013-10-252-7/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: close the races around autofs4_notify_daemon()Al Viro2013-09-171-10/+3
| | | | | | | | | | Don't drop ->wq_mutex before calling autofs4_notify_daemon() only to regain it there. Besides being pointless, that opens a race window where autofs4_wait_release() could've come and freed wq->name.name. And do the debugging printk in the "reused an existing wq" case before dropping ->wq_mutex - the same reason... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Ian Kent <raven@themaw.net>
* autofs4 - fix device ioctl mount lookupIan Kent2013-09-091-11/+12
| | | | | | | | | | | | | | | | | 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 <raven@themaw.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* helper for reading ->d_countAl Viro2013-07-052-5/+5
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [readdir] switch dcache_readdir() users to ->iterate()Al Viro2013-06-291-2/+2
| | | | | | | new helpers - dir_emit_dot(file, ctx, dentry), dir_emit_dotdot(file, ctx), dir_emit_dots(file, ctx). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs - remove autofs dentry mount checkDavid Jeffery2013-05-061-9/+0
| | | | | | | | | | | | | | | | | | | When checking if an autofs mount point is busy it isn't sufficient to only check if it's a mount point. For example, if the mount of an offset mountpoint in a tree is denied for this host by its export and the dentry becomes a process working directory the check incorrectly returns the mount as not in use at expire. This can happen since the default when mounting within a tree is nostrict, which means ingnore mount fails on mounts within the tree and continue. The nostrict option is meant to allow mounting in this case. Signed-off-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Ian Kent <raven@themaw.net> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs - fix sparse warning for autofs4_d_manage()Claudiu Ghioc2013-05-061-1/+1
| | | | | | | | | | | | | Fixed the sparse warning: fs/autofs4/root.c:411:5: warning: symbol 'autofs4_d_manage' was not declared. Should it be static?" [ Clearly it should be static as the function is declared static at the top of root.c. - imk ] Signed-off-by: Claudiu Ghioc <claudiu.ghioc@gmail.com> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: Limit sys_mount to only request filesystem modules.Eric W. Biederman2013-03-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Reported-by: Kees Cook <keescook@google.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* autofs4 - autofs4_catatonic_mode(): remove redundant null check on kfree()Tim Gardner2013-03-011-4/+2
| | | | | | | | | | | smatch analysis: fs/autofs4/waitq.c:46 autofs4_catatonic_mode() info: redundant null check on wq->name.name calling kfree() Signed-off-by: Tim Gardner <tim.gardner@canonical.com> Signed-off-by: Ian Kent <raven@themaw.net> Cc: autofs@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs - Fix sparse warning: context imbalance in autofs4_d_automount() ↵Peter Huewe2013-03-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | different lock contexts for basic block Sparse complains: fs/autofs4/root.c:409:9: sparse: context imbalance in 'autofs4_d_automount' - different lock contexts for basic block This was introduced by commit f55fb0c24386 ("autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mount") The function autofs4_d_automount can be left with the (&sbi->fs_lock) held if sbi->version <= 4 and simple_empty(dentry) == false so the warning seems valid. --> Add an spin_unlock in this case before we jump to done Unfortunately compile tested only. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Peter Huewe <peterhuewe@gmx.de> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: change return values from -EACCES to -EPERMZhao Hongjiang2013-02-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | According to SUSv3: [EACCES] Permission denied. An attempt was made to access a file in a way forbidden by its file access permissions. [EPERM] Operation not permitted. An attempt was made to perform an operation limited to processes with appropriate privileges or to the owner of a file or other resource. So -EPERM should be returned if capability checks fails. Strictly speaking this is an API change since the error code user sees is altered. Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: file_inode(file)Al Viro2013-02-233-4/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-12-184-17/+24
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace changes from Eric Biederman: "While small this set of changes is very significant with respect to containers in general and user namespaces in particular. The user space interface is now complete. This set of changes adds support for unprivileged users to create user namespaces and as a user namespace root to create other namespaces. The tyranny of supporting suid root preventing unprivileged users from using cool new kernel features is broken. This set of changes completes the work on setns, adding support for the pid, user, mount namespaces. This set of changes includes a bunch of basic pid namespace cleanups/simplifications. Of particular significance is the rework of the pid namespace cleanup so it no longer requires sending out tendrils into all kinds of unexpected cleanup paths for operation. At least one case of broken error handling is fixed by this cleanup. The files under /proc/<pid>/ns/ have been converted from regular files to magic symlinks which prevents incorrect caching by the VFS, ensuring the files always refer to the namespace the process is currently using and ensuring that the ptrace_mayaccess permission checks are always applied. The files under /proc/<pid>/ns/ have been given stable inode numbers so it is now possible to see if different processes share the same namespaces. Through the David Miller's net tree are changes to relax many of the permission checks in the networking stack to allowing the user namespace root to usefully use the networking stack. Similar changes for the mount namespace and the pid namespace are coming through my tree. Two small changes to add user namespace support were commited here adn in David Miller's -net tree so that I could complete the work on the /proc/<pid>/ns/ files in this tree. Work remains to make it safe to build user namespaces and 9p, afs, ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the Kconfig guard remains in place preventing that user namespaces from being built when any of those filesystems are enabled. Future design work remains to allow root users outside of the initial user namespace to mount more than just /proc and /sys." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits) proc: Usable inode numbers for the namespace file descriptors. proc: Fix the namespace inode permission checks. proc: Generalize proc inode allocation userns: Allow unprivilged mounts of proc and sysfs userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file procfs: Print task uids and gids in the userns that opened the proc file userns: Implement unshare of the user namespace userns: Implent proc namespace operations userns: Kill task_user_ns userns: Make create_new_namespaces take a user_ns parameter userns: Allow unprivileged use of setns. userns: Allow unprivileged users to create new namespaces userns: Allow setting a userns mapping to your current uid. userns: Allow chown and setgid preservation userns: Allow unprivileged users to create user namespaces. userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped userns: fix return value on mntns_install() failure vfs: Allow unprivileged manipulation of the mount namespace. vfs: Only support slave subtrees across different user namespaces vfs: Add a user namespace reference from struct mnt_namespace ...
| * userns: Support autofs4 interacing with multiple user namespacesEric W. Biederman2012-11-154-17/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <raven@themaw.net> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | autofs4 - use simple_empty() for empty directory checkIan Kent2012-12-141-17/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For direct (and offset) mounts, if an automounted mount is manually umounted the trigger mount dentry can appear non-empty causing it to not trigger mounts. This can also happen if there is a file handle leak in a user space automounting application. This happens because, when a ioctl control file handle is opened on the mount, a cursor dentry is created which causes list_empty() to see the dentry as non-empty. Since there is a case where listing the directory of these dentrys is needed, the use of dcache_dir_*() functions for .open() and .release() is needed. Consequently simple_empty() must be used instead of list_empty() when checking for an empty directory. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mountIan Kent2012-12-142-34/+36
|/ | | | | | | | | | | | | | | The DCACHE_NEED_AUTOMOUNT flag is cleared on mount and set on expire for autofs rootless multi-mount dentrys to prevent unnecessary calls to ->d_automount(). Since DCACHE_MANAGE_TRANSIT is always set on autofs dentrys ->d_managed() is always called so the check can be done in ->d_manage() without the need to change the flag. This still avoids unnecessary calls to ->d_automount(), adds negligible overhead and eliminates a seriously ugly check in the expire code. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* autofs4 - fix reset pending flag on mount failIan Kent2012-10-111-2/+4
| | | | | | | | | | | | | In autofs4_d_automount(), if a mount fail occurs the AUTOFS_INF_PENDING mount pending flag is not cleared. One effect of this is when using the "browse" option, directory entry attributes show up with all "?"s due to the incorrect callback and subsequent failure return (when in fact no callback should be made). Signed-off-by: Ian Kent <ikent@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* make get_file() return its argumentAl Viro2012-09-271-2/+1
| | | | | | simplifies a bunch of callers... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* autofs4: don't open-code fd_install()Al Viro2012-09-271-16/+2
| | | | | | | | | 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 <viro@zeniv.linux.org.uk>
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