1. 27 May, 2010 1 commit
    • npiggin@suse.de's avatar
      fs: introduce new truncate sequence · 7bb46a67
      npiggin@suse.de authored
      Introduce a new truncate calling sequence into fs/mm subsystems. Rather than
      setattr > vmtruncate > truncate, have filesystems call their truncate sequence
      from ->setattr if filesystem specific operations are required. vmtruncate is
      deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced
      previously should be used.
      simple_setattr is introduced for simple in-ram filesystems to implement
      the new truncate sequence. Eventually all filesystems should be converted
      to implement a setattr, and the default code in notify_change should go
      simple_setsize is also introduced to perform just the ATTR_SIZE portion
      of simple_setattr (ie. changing i_size and trimming pagecache).
      To implement the new truncate sequence:
      - filesystem specific manipulations (eg freeing blocks) must be done in
        the setattr method rather than ->truncate.
      - vmtruncate can not be used by core code to trim blocks past i_size in
        the event of write failure after allocation, so this must be performed
        in the fs code.
      - convert usage of helpers block_write_begin, nobh_write_begin,
        cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed
        variants. These avoid calling vmtruncate to trim blocks (see previous).
      - inode_setattr should not be used. generic_setattr is a new function
        to be used to copy simple attributes into the generic inode.
      - make use of the better opportunity to handle errors with the new sequence.
      Big problem with the previous calling sequence: the filesystem is not called
      until i_size has already changed.  This means it is not allowed to fail the
      call, and also it does not know what the previous i_size was. Also, generic
      code calling vmtruncate to truncate allocated blocks in case of error had
      no good way to return a meaningful error (or, for example, atomically handle
      block deallocation).
      Cc: Christoph Hellwig <hch@lst.de>
      Acked-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
  2. 06 Mar, 2010 1 commit
  3. 04 Mar, 2010 1 commit
  4. 24 Sep, 2009 1 commit
  5. 25 Mar, 2009 1 commit
  6. 13 Nov, 2008 1 commit
  7. 23 Oct, 2008 1 commit
  8. 26 Jul, 2008 2 commits
    • Miklos Szeredi's avatar
      [patch 4/4] vfs: immutable inode checking cleanup · beb29e05
      Miklos Szeredi authored
      Move the immutable and append-only checks from chmod, chown and utimes
      into notify_change().  Checks for immutable and append-only files are
      always performed by the VFS and not by the filesystem (see
      permission() and may_...() in namei.c), so these belong in
      notify_change(), and not in inode_change_ok().
      This should be completely equivalent.
      CC: Ulrich Drepper <drepper@redhat.com>
      CC: Michael Kerrisk <mtk.manpages@gmail.com>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    • Miklos Szeredi's avatar
      [patch 1/4] vfs: utimes: move owner check into inode_change_ok() · 9767d749
      Miklos Szeredi authored
      Add a new ia_valid flag: ATTR_TIMES_SET, to handle the
      cases neither ATTR_MTIME_SET nor ATTR_ATIME_SET is in the flags, yet
      the POSIX draft specifies that permission checking is performed the
      same way as if one or both of the times was explicitly set to a
      See the path "vfs: utimensat(): fix error checking for
      {UTIME_NOW,UTIME_OMIT} case" by Michael Kerrisk for the patch
      introducing this behavior.
      This is a cleanup, as well as allowing filesystems (NFS/fuse/...) to
      perform their own permission checking instead of the default.
      CC: Ulrich Drepper <drepper@redhat.com>
      CC: Michael Kerrisk <mtk.manpages@gmail.com>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
  9. 18 Oct, 2007 1 commit
    • Jeff Layton's avatar
      VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations · 6de0ec00
      Jeff Layton authored
      When an unprivileged process attempts to modify a file that has the setuid or
      setgid bits set, the VFS will attempt to clear these bits.  The VFS will set
      the ATTR_KILL_SUID or ATTR_KILL_SGID bits in the ia_valid mask, and then call
      notify_change to clear these bits and set the mode accordingly.
      With a networked filesystem (NFS and CIFS in particular but likely others),
      the client machine or process may not have credentials that allow for setting
      the mode.  In some situations, this can lead to file corruption, an operation
      failing outright because the setattr fails, or to races that lead to a mode
      change being reverted.
      In this situation, we'd like to just leave the handling of this to the server
      and ignore these bits.  The problem is that by the time the setattr op is
      called, the VFS has already reinterpreted the ATTR_KILL_* bits into a mode
      change.  The setattr operation has no way to know its intent.
      The following patch fixes this by making notify_change no longer clear the
      ATTR_KILL_SUID and ATTR_KILL_SGID bits in the ia_valid before handing it off
      to the setattr inode op.  setattr can then check for the presence of these
      bits, and if they're set it can assume that the mode change was only for the
      purposes of clearing these bits.
      This means that we now have an implicit assumption that notify_change is never
      called with ATTR_MODE and either ATTR_KILL_S*ID bit set.  Nothing currently
      enforces that, so this patch also adds a BUG() if that occurs.
      Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
      Cc: Michael Halcrow <mhalcrow@us.ibm.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Neil Brown <neilb@suse.de>
      Cc: "J. Bruce Fields" <bfields@fieldses.org>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Jeff Mahoney <jeffm@suse.com>
      Cc: "Vladimir V. Saveliev" <vs@namesys.com>
      Cc: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Cc: Steven French <sfrench@us.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  10. 17 Oct, 2007 1 commit
    • Serge E. Hallyn's avatar
      Implement file posix capabilities · b5376771
      Serge E. Hallyn authored
      Implement file posix capabilities.  This allows programs to be given a
      subset of root's powers regardless of who runs them, without having to use
      setuid and giving the binary all of root's powers.
      This version works with Kaigai Kohei's userspace tools, found at
      http://www.kaigai.gr.jp/index.php.  For more information on how to use this
      patch, Chris Friedhoff has posted a nice page at
      	Nov 27:
      	Incorporate fixes from Andrew Morton
      	(security-introduce-file-caps-tweaks and
      	Fix Kconfig dependency.
      	Fix change signaling behavior when file caps are not compiled in.
      	Nov 13:
      	Integrate comments from Alexey: Remove CONFIG_ ifdef from
      	capability.h, and use %zd for printing a size_t.
      	Nov 13:
      	Fix endianness warnings by sparse as suggested by Alexey
      	Nov 09:
      	Address warnings of unused variables at cap_bprm_set_security
      	when file capabilities are disabled, and simultaneously clean
      	up the code a little, by pulling the new code into a helper
      	Nov 08:
      	For pointers to required userspace tools and how to use
      	them, see http://www.friedhoff.org/fscaps.html.
      	Nov 07:
      	Fix the calculation of the highest bit checked in
      	Nov 07:
      	Allow file caps to be enabled without CONFIG_SECURITY, since
      	capabilities are the default.
      	Hook cap_task_setscheduler when !CONFIG_SECURITY.
      	Move capable(TASK_KILL) to end of cap_task_kill to reduce
      	audit messages.
      	Nov 05:
      	Add secondary calls in selinux/hooks.c to task_setioprio and
      	task_setscheduler so that selinux and capabilities with file
      	cap support can be stacked.
      	Sep 05:
      	As Seth Arnold points out, uid checks are out of place
      	for capability code.
      	Sep 01:
      	Define task_setscheduler, task_setioprio, cap_task_kill, and
      	task_setnice to make sure a user cannot affect a process in which
      	they called a program with some fscaps.
      	One remaining question is the note under task_setscheduler: are we
      	ok with CAP_SYS_NICE being sufficient to confine a process to a
      	It is a semantic change, as without fsccaps, attach_task doesn't
      	allow CAP_SYS_NICE to override the uid equivalence check.  But since
      	it uses security_task_setscheduler, which elsewhere is used where
      	CAP_SYS_NICE can be used to override the uid equivalence check,
      	fixing it might be tough.
      		 note: this also controls cpuset:attach_task.  Are we ok with
      		     CAP_SYS_NICE being used to confine to a cpuset?
      		 sys_setpriority uses this (through set_one_prio) for another
      		 process.  Need same checks as setrlimit
      	Aug 21:
      	Updated secureexec implementation to reflect the fact that
      	euid and uid might be the same and nonzero, but the process
      	might still have elevated caps.
      	Aug 15:
      	Handle endianness of xattrs.
      	Enforce capability version match between kernel and disk.
      	Enforce that no bits beyond the known max capability are
      	set, else return -EPERM.
      	With this extra processing, it may be worth reconsidering
      	doing all the work at bprm_set_security rather than
      	Aug 10:
      	Always call getxattr at bprm_set_security, rather than
      	caching it at d_instantiate.
      [morgan@kernel.org: file-caps clean up for linux/capability.h]
      [bunk@kernel.org: unexport cap_inode_killpriv]
      Signed-off-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: James Morris <jmorris@namei.org>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: Andrew Morgan <morgan@kernel.org>
      Signed-off-by: default avatarAndrew Morgan <morgan@kernel.org>
      Signed-off-by: default avatarAdrian Bunk <bunk@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  11. 17 Jul, 2007 1 commit
    • Satyam Sharma's avatar
      Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check · 3bd858ab
      Satyam Sharma authored
      Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
      users to it. This is done because we want to avoid bugs in the future
      where we check for only effective fsuid of the current task against a
      file's owning uid, without simultaneously checking for CAP_FOWNER as
      well, thus violating its semantics.
      [ XFS uses special macros and structures, and in general looked ...
      untouchable, so we leave it alone -- but it has been looked over. ]
      The (current->fsuid != inode->i_uid) check in generic_permission() and
      exec_permission_lite() is left alone, because those operations are
      covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
      falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.
      Signed-off-by: default avatarSatyam Sharma <ssatyam@cse.iitk.ac.in>
      Cc: Al Viro <viro@ftp.linux.org.uk>
      Acked-by: default avatarSerge E. Hallyn <serge@hallyn.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  12. 08 May, 2007 1 commit
  13. 11 Jan, 2006 1 commit
  14. 10 Jan, 2006 1 commit
  15. 08 Jan, 2006 1 commit
    • NeilBrown's avatar
      [PATCH] Fix some problems with truncate and mtime semantics. · 4a30131e
      NeilBrown authored
      SUS requires that when truncating a file to the size that it currently
        truncate and ftruncate should NOT modify ctime or mtime
        O_TRUNC SHOULD modify ctime and mtime.
      Currently mtime and ctime are always modified on most local
      filesystems (side effect of ->truncate) or never modified (on NFS).
      With this patch:
        ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when
          an update of these times is required whether size changes or not
          (via a new argument to do_truncate).  This allows NFS to do
          the right thing for O_TRUNC.
        inode_setattr nolonger forces ATTR_MTIME|ATTR_CTIME when the ATTR_SIZE
          sets the size to it's current value.  This allows local filesystems
          to do the right thing for f?truncate.
      Also, the logic in inode_setattr is changed a bit so there are two return
      points.  One returns the error from vmtruncate if it failed, the other
      returns 0 (there can be no other failure).
      Finally, if vmtruncate succeeds, and ATTR_SIZE is the only change
      requested, we now fall-through and mark_inode_dirty.  If a filesystem did
      not have a ->truncate function, then vmtruncate will have changed i_size,
      without marking the inode as 'dirty', and I think this is wrong.
      Signed-off-by: default avatarNeil Brown <neilb@suse.de>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  16. 30 Oct, 2005 1 commit
  17. 12 Jul, 2005 1 commit
    • Robert Love's avatar
      [PATCH] inotify · 0eeca283
      Robert Love authored
      inotify is intended to correct the deficiencies of dnotify, particularly
      its inability to scale and its terrible user interface:
              * dnotify requires the opening of one fd per each directory
                that you intend to watch. This quickly results in too many
                open files and pins removable media, preventing unmount.
              * dnotify is directory-based. You only learn about changes to
                directories. Sure, a change to a file in a directory affects
                the directory, but you are then forced to keep a cache of
                stat structures.
              * dnotify's interface to user-space is awful.  Signals?
      inotify provides a more usable, simple, powerful solution to file change
              * inotify's interface is a system call that returns a fd, not SIGIO.
      	  You get a single fd, which is select()-able.
              * inotify has an event that says "the filesystem that the item
                you were watching is on was unmounted."
              * inotify can watch directories or files.
      Inotify is currently used by Beagle (a desktop search infrastructure),
      Gamin (a FAM replacement), and other projects.
      See Documentation/filesystems/inotify.txt.
      Signed-off-by: default avatarRobert Love <rml@novell.com>
      Cc: John McCutchan <ttb@tentacle.dhs.org>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  18. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      Let it rip!