1. 28 Jul, 2016 5 commits
  2. 25 Jul, 2016 6 commits
  3. 27 May, 2016 1 commit
    • Arnd Bergmann's avatar
      remove lots of IS_ERR_VALUE abuses · 287980e4
      Arnd Bergmann authored
      Most users of IS_ERR_VALUE() in the kernel are wrong, as they
      pass an 'int' into a function that takes an 'unsigned long'
      argument. This happens to work because the type is sign-extended
      on 64-bit architectures before it gets converted into an
      unsigned type.
      
      However, anything that passes an 'unsigned short' or 'unsigned int'
      argument into IS_ERR_VALUE() is guaranteed to be broken, as are
      8-bit integers and types that are wider than 'unsigned long'.
      
      Andrzej Hajda has already fixed a lot of the worst abusers that
      were causing actual bugs, but it would be nice to prevent any
      users that are not passing 'unsigned long' arguments.
      
      This patch changes all users of IS_ERR_VALUE() that I could find
      on 32-bit ARM randconfig builds and x86 allmodconfig. For the
      moment, this doesn't change the definition of IS_ERR_VALUE()
      because there are probably still architecture specific users
      elsewhere.
      
      Almost all the warnings I got are for files that are better off
      using 'if (err)' or 'if (err < 0)'.
      The only legitimate user I could find that we get a warning for
      is the (32-bit only) freescale fman driver, so I did not remove
      the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
      For 9pfs, I just worked around one user whose calling conventions
      are so obscure that I did not dare change the behavior.
      
      I was using this definition for testing:
      
       #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
             unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))
      
      which ends up making all 16-bit or wider types work correctly with
      the most plausible interpretation of what IS_ERR_VALUE() was supposed
      to return according to its users, but also causes a compile-time
      warning for any users that do not pass an 'unsigned long' argument.
      
      I suggested this approach earlier this year, but back then we ended
      up deciding to just fix the users that are obviously broken. After
      the initial warning that caused me to get involved in the discussion
      (fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
      asked me to send the whole thing again.
      
      [ Updated the 9p parts as per Al Viro  - Linus ]
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Cc: Andrzej Hajda <a.hajda@samsung.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Link: https://lkml.org/lkml/2016/1/7/363
      Link: https://lkml.org/lkml/2016/5/27/486
      Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      287980e4
  4. 04 Jun, 2014 1 commit
  5. 29 Apr, 2013 1 commit
  6. 23 Feb, 2013 1 commit
  7. 29 Nov, 2012 1 commit
  8. 05 Oct, 2012 1 commit
  9. 31 May, 2012 1 commit
  10. 21 Apr, 2012 1 commit
    • Linus Torvalds's avatar
      VM: add "vm_mmap()" helper function · 6be5ceb0
      Linus Torvalds authored
      This continues the theme started with vm_brk() and vm_munmap():
      vm_mmap() does the same thing as do_mmap(), but additionally does the
      required VM locking.
      
      This uninlines (and rewrites it to be clearer) do_mmap(), which sadly
      duplicates it in mm/mmap.c and mm/nommu.c.  But that way we don't have
      to export our internal do_mmap_pgoff() function.
      
      Some day we hopefully don't have to export do_mmap() either, if all
      modular users can become the simpler vm_mmap() instead.  We're actually
      very close to that already, with the notable exception of the (broken)
      use in i810, and a couple of stragglers in binfmt_elf.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6be5ceb0
  11. 28 Mar, 2012 1 commit
  12. 21 Mar, 2012 2 commits
  13. 29 Feb, 2012 1 commit
  14. 03 May, 2011 1 commit
  15. 31 Mar, 2011 1 commit
  16. 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
  17. 04 Jun, 2010 2 commits
  18. 21 Apr, 2010 1 commit
  19. 06 Mar, 2010 1 commit
  20. 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
  21. 17 Dec, 2009 1 commit
  22. 24 Sep, 2009 1 commit
  23. 07 Aug, 2009 1 commit
  24. 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
  25. 08 Jan, 2009 1 commit
  26. 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
  27. 16 Oct, 2008 1 commit
  28. 11 Aug, 2008 1 commit
  29. 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