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  1. 21 Mar, 2012 2 commits
  3. 29 Feb, 2012 1 commit
  5. 03 May, 2011 1 commit
  7. 31 Mar, 2011 1 commit
  9. 29 Jun, 2010 1 commit
    • Mike Frysinger's avatar
      flat: tweak default stack alignment · 2952095c
      Mike Frysinger authored 
      The recent commit 1f0ce8b3

 ("mm: Move ARCH_SLAB_MINALIGN and
ARCH_KMALLOC_MINALIGN to <linux/slab_def.h>") which moved the
ARCH_SLAB_MINALIGN default into the global header inadvertently broke FLAT
for a bunch of systems.  Blackfin systems now fail on any FLAT exec with:
Unable to read code+data+bss, errno 14 When your /init is a FLAT binary,
obviously this can be annoying ;).

This stems from the alignment usage in the FLAT loader.  The behavior
before was that FLAT would default to ARCH_SLAB_MINALIGN only if it was
defined, and this was only defined by arches when they wanted a larger
alignment value.  Otherwise it'd default to pointer alignment.  Arguably,
this is kind of hokey that the FLAT is semi-abusing defines it shouldn't.

So let's merge the two alignment requirements so the floor is never 0.
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
Cc: David McCullough <davidm@snapgear.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2952095c
  11. 04 Jun, 2010 2 commits
  13. 21 Apr, 2010 1 commit
  15. 06 Mar, 2010 1 commit
  17. 29 Jan, 2010 1 commit
    • Linus Torvalds's avatar
      Split 'flush_old_exec' into two functions · 221af7f8
      Linus Torvalds authored 
      
'flush_old_exec()' is the point of no return when doing an execve(), and
it is pretty badly misnamed.  It doesn't just flush the old executable
environment, it also starts up the new one.

Which is very inconvenient for things like setting up the new
personality, because we want the new personality to affect the starting
of the new environment, but at the same time we do _not_ want the new
personality to take effect if flushing the old one fails.

As a result, the x86-64 '32-bit' personality is actually done using this
insane "I'm going to change the ABI, but I haven't done it yet" bit
(TIF_ABI_PENDING), with SET_PERSONALITY() not actually setting the
personality, but just the "pending" bit, so that "flush_thread()" can do
the actual personality magic.

This patch in no way changes any of that insanity, but it does split the
'flush_old_exec()' function up into a preparatory part that can fail
(still called flush_old_exec()), and a new part that will actually set
up the new exec environment (setup_new_exec()).  All callers are changed
to trivially comply with the new world order.
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      221af7f8
  19. 17 Dec, 2009 1 commit
  21. 24 Sep, 2009 1 commit
  23. 07 Aug, 2009 1 commit
  25. 29 May, 2009 1 commit
    • Oskar Schirmer's avatar
      flat: fix data sections alignment · c3dc5bec
      Oskar Schirmer authored 
      
The flat loader uses an architecture's flat_stack_align() to align the
stack but assumes word-alignment is enough for the data sections.

However, on the Xtensa S6000 we have registers up to 128bit width
which can be used from userspace and therefor need userspace stack and
data-section alignment of at least this size.

This patch drops flat_stack_align() and uses the same alignment that
is required for slab caches, ARCH_SLAB_MINALIGN, or wordsize if it's
not defined by the architecture.

It also fixes m32r which was obviously kaput, aligning an
uninitialized stack entry instead of the stack pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarOskar Schirmer <os@emlix.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: default avatarPaul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: default avatarJohannes Weiner <jw@emlix.com>
Acked-by: default avatarMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c3dc5bec
  27. 08 Jan, 2009 1 commit
  29. 13 Nov, 2008 1 commit
    • David Howells's avatar
      CRED: Make execve() take advantage of copy-on-write credentials · a6f76f23
      David Howells authored 
      
Make execve() take advantage of copy-on-write credentials, allowing it to set
up the credentials in advance, and then commit the whole lot after the point
of no return.

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     The credential bits from struct linux_binprm are, for the most part,
     replaced with a single credentials pointer (bprm->cred).  This means that
     all the creds can be calculated in advance and then applied at the point
     of no return with no possibility of failure.

     I would like to replace bprm->cap_effective with:

	cap_isclear(bprm->cap_effective)

     but this seems impossible due to special behaviour for processes of pid 1
     (they always retain their parent's capability masks where normally they'd
     be changed - see cap_bprm_set_creds()).

     The following sequence of events now happens:

     (a) At the start of do_execve, the current task's cred_exec_mutex is
     	 locked to prevent PTRACE_ATTACH from obsoleting the calculation of
     	 creds that we make.

     (a) prepare_exec_creds() is then called to make a copy of the current
     	 task's credentials and prepare it.  This copy is then assigned to
     	 bprm->cred.

  	 This renders security_bprm_alloc() and security_bprm_free()
     	 unnecessary, and so they've been removed.

     (b) The determination of unsafe execution is now performed immediately
     	 after (a) rather than later on in the code.  The result is stored in
     	 bprm->unsafe for future reference.

     (c) prepare_binprm() is called, possibly multiple times.

     	 (i) This applies the result of set[ug]id binaries to the new creds
     	     attached to bprm->cred.  Personality bit clearance is recorded,
     	     but now deferred on the basis that the exec procedure may yet
     	     fail.

         (ii) This then calls the new security_bprm_set_creds().  This should
	     calculate the new LSM and capability credentials into *bprm->cred.

	     This folds together security_bprm_set() and parts of
	     security_bprm_apply_creds() (these two have been removed).
	     Anything that might fail must be done at this point.

         (iii) bprm->cred_prepared is set to 1.

	     bprm->cred_prepared is 0 on the first pass of the security
	     calculations, and 1 on all subsequent passes.  This allows SELinux
	     in (ii) to base its calculations only on the initial script and
	     not on the interpreter.

     (d) flush_old_exec() is called to commit the task to execution.  This
     	 performs the following steps with regard to credentials:

	 (i) Clear pdeath_signal and set dumpable on certain circumstances that
	     may not be covered by commit_creds().

         (ii) Clear any bits in current->personality that were deferred from
             (c.i).

     (e) install_exec_creds() [compute_creds() as was] is called to install the
     	 new credentials.  This performs the following steps with regard to
     	 credentials:

         (i) Calls security_bprm_committing_creds() to apply any security
             requirements, such as flushing unauthorised files in SELinux, that
             must be done before the credentials are changed.

	     This is made up of bits of security_bprm_apply_creds() and
	     security_bprm_post_apply_creds(), both of which have been removed.
	     This function is not allowed to fail; anything that might fail
	     must have been done in (c.ii).

         (ii) Calls commit_creds() to apply the new credentials in a single
             assignment (more or less).  Possibly pdeath_signal and dumpable
             should be part of struct creds.

	 (iii) Unlocks the task's cred_replace_mutex, thus allowing
	     PTRACE_ATTACH to take place.

         (iv) Clears The bprm->cred pointer as the credentials it was holding
             are now immutable.

         (v) Calls security_bprm_committed_creds() to apply any security
             alterations that must be done after the creds have been changed.
             SELinux uses this to flush signals and signal handlers.

     (f) If an error occurs before (d.i), bprm_free() will call abort_creds()
     	 to destroy the proposed new credentials and will then unlock
     	 cred_replace_mutex.  No changes to the credentials will have been
     	 made.

 (2) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_bprm_alloc(), ->bprm_alloc_security()
     (*) security_bprm_free(), ->bprm_free_security()

     	 Removed in favour of preparing new credentials and modifying those.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()
     (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds()

     	 Removed; split between security_bprm_set_creds(),
     	 security_bprm_committing_creds() and security_bprm_committed_creds().

     (*) security_bprm_set(), ->bprm_set_security()

     	 Removed; folded into security_bprm_set_creds().

     (*) security_bprm_set_creds(), ->bprm_set_creds()

     	 New.  The new credentials in bprm->creds should be checked and set up
     	 as appropriate.  bprm->cred_prepared is 0 on the first call, 1 on the
     	 second and subsequent calls.

     (*) security_bprm_committing_creds(), ->bprm_committing_creds()
     (*) security_bprm_committed_creds(), ->bprm_committed_creds()

     	 New.  Apply the security effects of the new credentials.  This
     	 includes closing unauthorised files in SELinux.  This function may not
     	 fail.  When the former is called, the creds haven't yet been applied
     	 to the process; when the latter is called, they have.

 	 The former may access bprm->cred, the latter may not.

 (3) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) The bprm_security_struct struct has been removed in favour of using
     	 the credentials-under-construction approach.

     (c) flush_unauthorized_files() now takes a cred pointer and passes it on
     	 to inode_has_perm(), file_has_perm() and dentry_open().
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarJames Morris <jmorris@namei.org>
Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      a6f76f23
  31. 16 Oct, 2008 1 commit
  33. 11 Aug, 2008 1 commit
  35. 26 Jul, 2008 1 commit
    • Roland McGrath's avatar
      tracehook: exec · 6341c393
      Roland McGrath authored 
      
This moves all the ptrace hooks related to exec into tracehook.h inlines.

This also lifts the calls for tracing out of the binfmt load_binary hooks
into search_binary_handler() after it calls into the binfmt module.  This
change has no effect, since all the binfmt modules' load_binary functions
did the call at the end on success, and now search_binary_handler() does
it immediately after return if successful.  We consolidate the repeated
code, and binfmt modules no longer need to import ptrace_notify().
Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6341c393
  37. 06 Jun, 2008 1 commit
  39. 29 Apr, 2008 2 commits
    • Matt Helsley's avatar
      procfs task exe symlink · 925d1c40
      Matt Helsley authored 
      
The kernel implements readlink of /proc/pid/exe by getting the file from
the first executable VMA.  Then the path to the file is reconstructed and
reported as the result.

Because of the VMA walk the code is slightly different on nommu systems.
This patch avoids separate /proc/pid/exe code on nommu systems.  Instead of
walking the VMAs to find the first executable file-backed VMA we store a
reference to the exec'd file in the mm_struct.

That reference would prevent the filesystem holding the executable file
from being unmounted even after unmapping the VMAs.  So we track the number
of VM_EXECUTABLE VMAs and drop the new reference when the last one is
unmapped.  This avoids pinning the mounted filesystem.

[akpm@linux-foundation.org: improve comments]
[yamamoto@valinux.co.jp: fix dup_mmap]
Signed-off-by: default avatarMatt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: David Howells <dhowells@redhat.com>
Cc:"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarYAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      925d1c40
    • Adrian Bunk's avatar
      make BINFMT_FLAT a bool · 3202e181
      Adrian Bunk authored 
      
I have not yet seen anyone saying he has a reasonable use case for using
BINFMT_FLAT modular on his embedded device.

Considering that fs/binfmt_flat.c even lacks a MODULE_LICENSE() I really doubt
there is any, and this patch therefore makes BINFMT_FLAT a bool.
Signed-off-by: default avatarAdrian Bunk <bunk@kernel.org>
Acked-by: default avatarBryan Wu <cooloney.lkml@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3202e181
  41. 15 Feb, 2008 1 commit
  43. 08 Feb, 2008 1 commit
  45. 17 Oct, 2007 2 commits
    • Andrew Morton's avatar
      binfmt_flat: warning fixes · 0e647c04
      Andrew Morton authored 
      
Fix this lot:

fs/binfmt_flat.c: In function `decompress_exec':
fs/binfmt_flat.c:293: warning: label `out' defined but not used
fs/binfmt_flat.c: In function `load_flat_file':
fs/binfmt_flat.c:462: warning: unsigned int format, long int arg (arg 3)
fs/binfmt_flat.c:462: warning: unsigned int format, long int arg (arg 4)
fs/binfmt_flat.c:518: warning: comparison of distinct pointer types lacks a cast
fs/binfmt_flat.c:549: warning: passing arg 1 of `ksize' makes pointer from integer without a cast
fs/binfmt_flat.c:601: warning: passing arg 1 of `ksize' makes pointer from integer without a cast
fs/binfmt_flat.c: In function `load_flat_binary':
fs/binfmt_flat.c:116: warning: 'dummy' might be used uninitialized in this function
Acked-by: default avatarGreg Ungerer <gerg@uclinux.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0e647c04
    • Neil Horman's avatar
      core_pattern: ignore RLIMIT_CORE if core_pattern is a pipe · 7dc0b22e
      Neil Horman authored 
      
For some time /proc/sys/kernel/core_pattern has been able to set its output
destination as a pipe, allowing a user space helper to receive and
intellegently process a core.  This infrastructure however has some
shortcommings which can be enhanced.  Specifically:

1) The coredump code in the kernel should ignore RLIMIT_CORE limitation
   when core_pattern is a pipe, since file system resources are not being
   consumed in this case, unless the user application wishes to save the core,
   at which point the app is restricted by usual file system limits and
   restrictions.

2) The core_pattern code should be able to parse and pass options to the
   user space helper as an argv array.  The real core limit of the uid of the
   crashing proces should also be passable to the user space helper (since it
   is overridden to zero when called).

3) Some miscellaneous bugs need to be cleaned up (specifically the
   recognition of a recursive core dump, should the user mode helper itself
   crash.  Also, the core dump code in the kernel should not wait for the user
   mode helper to exit, since the same context is responsible for writing to
   the pipe, and a read of the pipe by the user mode helper will result in a
   deadlock.

This patch:

Remove the check of RLIMIT_CORE if core_pattern is a pipe.  In the event that
core_pattern is a pipe, the entire core will be fed to the user mode helper.
Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7dc0b22e
  47. 03 Oct, 2007 2 commits
  49. 09 Jun, 2007 1 commit
  51. 09 Feb, 2007 1 commit
  53. 08 Dec, 2006 1 commit
  55. 30 Jun, 2006 1 commit
  57. 26 Jun, 2006 1 commit
  59. 21 May, 2006 1 commit
    • Andrew Morton's avatar
      [PATCH] binfmt_flat: don't check for EMFILE · df88912a
      Andrew Morton authored 
      
Bernd Schmidt points out that binfmt_flat is now leaving the exec file open
while the application runs.  This offsets all the application's fd numbers.
We should have closed the file within exec(), not at exit()-time.

But there doesn't seem to be a lot of point in doing all this just to avoid
going over RLIMIT_NOFILE by one fd for a few microseconds.  So take the EMFILE
checking out again.  This will cause binfmt_flat to again fail LTP's
exec-should-return-EMFILE-when-fdtable-is-full test.  That test appears to be
wrong anyway - Open Group specs say nothing about exec() returning EMFILE.

Cc: Bernd Schmidt <bernd.schmidt@analog.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      df88912a
  61. 25 Mar, 2006 1 commit
  63. 10 Jan, 2006 2 commits
  65. 30 Oct, 2005 1 commit
  67. 02 Sep, 2005 1 commit