20 Jan, 2021

1 commit

  • commit eb351d75ce1e75b4f793d609efac08426ca50acd upstream.

    Fix the build error:

    mm/process_vm_access.c:277:5: error: implicit declaration of function 'in_compat_syscall'; did you mean 'in_ia32_syscall'? [-Werror=implicit-function-declaration]

    Fixes: 38dc5079da7081e "Fix compat regression in process_vm_rw()"
    Reported-by: syzbot+5b0d0de84d6c65b8dd2b@syzkaller.appspotmail.com
    Cc: Kyle Huey
    Cc: Jens Axboe
    Cc: Al Viro
    Cc: Christoph Hellwig
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds
    Signed-off-by: Greg Kroah-Hartman

    Andrew Morton
     

28 Oct, 2020

2 commits

  • With e.g. m68k/defconfig:

    mm/process_vm_access.c: In function ‘process_vm_rw’:
    mm/process_vm_access.c:277:5: error: implicit declaration of function ‘in_compat_syscall’ [-Werror=implicit-function-declaration]
    277 | in_compat_syscall());
    | ^~~~~~~~~~~~~~~~~

    Fix this by adding #include .

    Reported-by: noreply@ellerman.id.au
    Reported-by: damian
    Reported-by: Naresh Kamboju
    Fixes: 38dc5079da7081e8 ("Fix compat regression in process_vm_rw()")
    Signed-off-by: Geert Uytterhoeven
    Acked-by: Jens Axboe
    Signed-off-by: Linus Torvalds

    Geert Uytterhoeven
     
  • The removal of compat_process_vm_{readv,writev} didn't change
    process_vm_rw(), which always assumes it's not doing a compat syscall.

    Instead of passing in 'false' unconditionally for 'compat', make it
    conditional on in_compat_syscall().

    [ Both Al and Christoph point out that trying to access a 64-bit process
    from a 32-bit one cannot work anyway, and is likely better prohibited,
    but that's a separate issue - Linus ]

    Fixes: c3973b401ef2 ("mm: remove compat_process_vm_{readv,writev}")
    Reported-and-tested-by: Kyle Huey
    Signed-off-by: Jens Axboe
    Acked-by: Al Viro
    Reviewed-by: Christoph Hellwig
    Signed-off-by: Linus Torvalds

    Jens Axboe
     

03 Oct, 2020

3 commits

  • Now that import_iovec handles compat iovecs, the native syscalls
    can be used for the compat case as well.

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • Use in compat_syscall to import either native or the compat iovecs, and
    remove the now superflous compat_import_iovec.

    This removes the need for special compat logic in most callers, and
    the remaining ones can still be simplified by using __import_iovec
    with a bool compat parameter.

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • Split rw_copy_check_uvector into two new helpers with more sensible
    calling conventions:

    - iovec_from_user copies a iovec from userspace either into the provided
    stack buffer if it fits, or allocates a new buffer for it. Returns
    the actually used iovec. It also verifies that iov_len does fit a
    signed type, and handles compat iovecs if the compat flag is set.
    - __import_iovec consolidates the native and compat versions of
    import_iovec. It calls iovec_from_user, then validates each iovec
    actually points to user addresses, and ensures the total length
    doesn't overflow.

    This has two major implications:

    - the access_process_vm case loses the total lenght checking, which
    wasn't required anyway, given that each call receives two iovecs
    for the local and remote side of the operation, and it verifies
    the total length on the local side already.
    - instead of a single loop there now are two loops over the iovecs.
    Given that the iovecs are cache hot this doesn't make a major
    difference

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     

13 Aug, 2020

1 commit

  • After the cleanup of page fault accounting, gup does not need to pass
    task_struct around any more. Remove that parameter in the whole gup
    stack.

    Signed-off-by: Peter Xu
    Signed-off-by: Andrew Morton
    Reviewed-by: John Hubbard
    Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
    Signed-off-by: Linus Torvalds

    Peter Xu
     

10 Jun, 2020

1 commit

  • This change converts the existing mmap_sem rwsem calls to use the new mmap
    locking API instead.

    The change is generated using coccinelle with the following rule:

    // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

    @@
    expression mm;
    @@
    (
    -init_rwsem
    +mmap_init_lock
    |
    -down_write
    +mmap_write_lock
    |
    -down_write_killable
    +mmap_write_lock_killable
    |
    -down_write_trylock
    +mmap_write_trylock
    |
    -up_write
    +mmap_write_unlock
    |
    -downgrade_write
    +mmap_write_downgrade
    |
    -down_read
    +mmap_read_lock
    |
    -down_read_killable
    +mmap_read_lock_killable
    |
    -down_read_trylock
    +mmap_read_trylock
    |
    -up_read
    +mmap_read_unlock
    )
    -(&mm->mmap_sem)
    +(mm)

    Signed-off-by: Michel Lespinasse
    Signed-off-by: Andrew Morton
    Reviewed-by: Daniel Jordan
    Reviewed-by: Laurent Dufour
    Reviewed-by: Vlastimil Babka
    Cc: Davidlohr Bueso
    Cc: David Rientjes
    Cc: Hugh Dickins
    Cc: Jason Gunthorpe
    Cc: Jerome Glisse
    Cc: John Hubbard
    Cc: Liam Howlett
    Cc: Matthew Wilcox
    Cc: Peter Zijlstra
    Cc: Ying Han
    Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
    Signed-off-by: Linus Torvalds

    Michel Lespinasse
     

25 Mar, 2020

1 commit


01 Feb, 2020

2 commits

  • In order to provide a clearer, more symmetric API for pinning and
    unpinning DMA pages. This way, pin_user_pages*() calls match up with
    unpin_user_pages*() calls, and the API is a lot closer to being
    self-explanatory.

    Link: http://lkml.kernel.org/r/20200107224558.2362728-23-jhubbard@nvidia.com
    Signed-off-by: John Hubbard
    Reviewed-by: Jan Kara
    Cc: Alex Williamson
    Cc: Aneesh Kumar K.V
    Cc: Björn Töpel
    Cc: Christoph Hellwig
    Cc: Daniel Vetter
    Cc: Dan Williams
    Cc: Hans Verkuil
    Cc: Ira Weiny
    Cc: Jason Gunthorpe
    Cc: Jason Gunthorpe
    Cc: Jens Axboe
    Cc: Jerome Glisse
    Cc: Jonathan Corbet
    Cc: Kirill A. Shutemov
    Cc: Leon Romanovsky
    Cc: Mauro Carvalho Chehab
    Cc: Mike Rapoport
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    John Hubbard
     
  • Convert process_vm_access to use the new pin_user_pages_remote() call,
    which sets FOLL_PIN. Setting FOLL_PIN is now required for code that
    requires tracking of pinned pages.

    Also, release the pages via put_user_page*().

    Also, rename "pages" to "pinned_pages", as this makes for easier reading
    of process_vm_rw_single_vec().

    Link: http://lkml.kernel.org/r/20200107224558.2362728-15-jhubbard@nvidia.com
    Signed-off-by: John Hubbard
    Reviewed-by: Jan Kara
    Reviewed-by: Jérôme Glisse
    Reviewed-by: Ira Weiny
    Cc: Alex Williamson
    Cc: Aneesh Kumar K.V
    Cc: Björn Töpel
    Cc: Christoph Hellwig
    Cc: Daniel Vetter
    Cc: Dan Williams
    Cc: Hans Verkuil
    Cc: Jason Gunthorpe
    Cc: Jason Gunthorpe
    Cc: Jens Axboe
    Cc: Jonathan Corbet
    Cc: Kirill A. Shutemov
    Cc: Leon Romanovsky
    Cc: Mauro Carvalho Chehab
    Cc: Mike Rapoport
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    John Hubbard
     

31 May, 2019

1 commit

  • Based on 1 normalized pattern(s):

    this program is free software you can redistribute it and or modify
    it under the terms of the gnu general public license as published by
    the free software foundation either version 2 of the license or at
    your option any later version

    extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-or-later

    has been chosen to replace the boilerplate/reference in 3029 file(s).

    Signed-off-by: Thomas Gleixner
    Reviewed-by: Allison Randal
    Cc: linux-spdx@vger.kernel.org
    Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
    Signed-off-by: Greg Kroah-Hartman

    Thomas Gleixner
     

07 Feb, 2018

3 commits


02 Mar, 2017

1 commit

  • We are going to split out of , which
    will have to be picked up from other headers and a couple of .c files.

    Create a trivial placeholder file that just
    maps to to make this patch obviously correct and
    bisectable.

    The APIs that are going to be moved first are:

    mm_alloc()
    __mmdrop()
    mmdrop()
    mmdrop_async_fn()
    mmdrop_async()
    mmget_not_zero()
    mmput()
    mmput_async()
    get_task_mm()
    mm_access()
    mm_release()

    Include the new header in the files that are going to need it.

    Acked-by: Linus Torvalds
    Cc: Mike Galbraith
    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: Ingo Molnar

    Ingo Molnar
     

15 Dec, 2016

1 commit

  • Unexport the low-level __get_user_pages_unlocked() function and replaces
    invocations with calls to more appropriate higher-level functions.

    In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked()
    with get_user_pages_unlocked() since we can now pass gup_flags.

    In async_pf_execute() and process_vm_rw_single_vec() we need to pass
    different tsk, mm arguments so get_user_pages_remote() is the sane
    replacement in these cases (having added manual acquisition and release
    of mmap_sem.)

    Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH
    flag. However, this flag was originally silently dropped by commit
    1e9877902dc7 ("mm/gup: Introduce get_user_pages_remote()"), so this
    appears to have been unintentional and reintroducing it is therefore not
    an issue.

    [akpm@linux-foundation.org: coding-style fixes]
    Link: http://lkml.kernel.org/r/20161027095141.2569-3-lstoakes@gmail.com
    Signed-off-by: Lorenzo Stoakes
    Acked-by: Michal Hocko
    Cc: Jan Kara
    Cc: Hugh Dickins
    Cc: Dave Hansen
    Cc: Rik van Riel
    Cc: Mel Gorman
    Cc: Paolo Bonzini
    Cc: Radim Krcmar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Lorenzo Stoakes
     

19 Oct, 2016

1 commit

  • This removes the redundant 'write' and 'force' parameters from
    __get_user_pages_unlocked() to make the use of FOLL_FORCE explicit in
    callers as use of this flag can result in surprising behaviour (and
    hence bugs) within the mm subsystem.

    Signed-off-by: Lorenzo Stoakes
    Acked-by: Paolo Bonzini
    Reviewed-by: Jan Kara
    Acked-by: Michal Hocko
    Signed-off-by: Linus Torvalds

    Lorenzo Stoakes
     

16 Feb, 2016

1 commit

  • For protection keys, we need to understand whether protections
    should be enforced in software or not. In general, we enforce
    protections when working on our own task, but not when on others.
    We call these "current" and "remote" operations.

    This patch introduces a new get_user_pages() variant:

    get_user_pages_remote()

    Which is a replacement for when get_user_pages() is called on
    non-current tsk/mm.

    We also introduce a new gup flag: FOLL_REMOTE which can be used
    for the "__" gup variants to get this new behavior.

    The uprobes is_trap_at_addr() location holds mmap_sem and
    calls get_user_pages(current->mm) on an instruction address. This
    makes it a pretty unique gup caller. Being an instruction access
    and also really originating from the kernel (vs. the app), I opted
    to consider this a 'remote' access where protection keys will not
    be enforced.

    Without protection keys, this patch should not change any behavior.

    Signed-off-by: Dave Hansen
    Reviewed-by: Thomas Gleixner
    Cc: Andrea Arcangeli
    Cc: Andrew Morton
    Cc: Andy Lutomirski
    Cc: Borislav Petkov
    Cc: Brian Gerst
    Cc: Dave Hansen
    Cc: Denys Vlasenko
    Cc: H. Peter Anvin
    Cc: Kirill A. Shutemov
    Cc: Linus Torvalds
    Cc: Naoya Horiguchi
    Cc: Peter Zijlstra
    Cc: Rik van Riel
    Cc: Srikar Dronamraju
    Cc: Vlastimil Babka
    Cc: jack@suse.cz
    Cc: linux-mm@kvack.org
    Link: http://lkml.kernel.org/r/20160212210154.3F0E51EA@viggo.jf.intel.com
    Signed-off-by: Ingo Molnar

    Dave Hansen
     

21 Jan, 2016

1 commit

  • By checking the effective credentials instead of the real UID / permitted
    capabilities, ensure that the calling process actually intended to use its
    credentials.

    To ensure that all ptrace checks use the correct caller credentials (e.g.
    in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS
    flag), use two new flags and require one of them to be set.

    The problem was that when a privileged task had temporarily dropped its
    privileges, e.g. by calling setreuid(0, user_uid), with the intent to
    perform following syscalls with the credentials of a user, it still passed
    ptrace access checks that the user would not be able to pass.

    While an attacker should not be able to convince the privileged task to
    perform a ptrace() syscall, this is a problem because the ptrace access
    check is reused for things in procfs.

    In particular, the following somewhat interesting procfs entries only rely
    on ptrace access checks:

    /proc/$pid/stat - uses the check for determining whether pointers
    should be visible, useful for bypassing ASLR
    /proc/$pid/maps - also useful for bypassing ASLR
    /proc/$pid/cwd - useful for gaining access to restricted
    directories that contain files with lax permissions, e.g. in
    this scenario:
    lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar
    drwx------ root root /root
    drwxr-xr-x root root /root/foobar
    -rw-r--r-- root root /root/foobar/secret

    Therefore, on a system where a root-owned mode 6755 binary changes its
    effective credentials as described and then dumps a user-specified file,
    this could be used by an attacker to reveal the memory layout of root's
    processes or reveal the contents of files he is not allowed to access
    (through /proc/$pid/cwd).

    [akpm@linux-foundation.org: fix warning]
    Signed-off-by: Jann Horn
    Acked-by: Kees Cook
    Cc: Casey Schaufler
    Cc: Oleg Nesterov
    Cc: Ingo Molnar
    Cc: James Morris
    Cc: "Serge E. Hallyn"
    Cc: Andy Shevchenko
    Cc: Andy Lutomirski
    Cc: Al Viro
    Cc: "Eric W. Biederman"
    Cc: Willy Tarreau
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jann Horn
     

12 Apr, 2015

1 commit


12 Feb, 2015

1 commit

  • This allows those get_user_pages calls to pass FAULT_FLAG_ALLOW_RETRY to
    the page fault in order to release the mmap_sem during the I/O.

    Signed-off-by: Andrea Arcangeli
    Reviewed-by: Kirill A. Shutemov
    Cc: Andres Lagar-Cavilla
    Cc: Peter Feiner
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Arcangeli
     

07 May, 2014

2 commits


13 Apr, 2014

1 commit

  • Pull vfs updates from Al Viro:
    "The first vfs pile, with deep apologies for being very late in this
    window.

    Assorted cleanups and fixes, plus a large preparatory part of iov_iter
    work. There's a lot more of that, but it'll probably go into the next
    merge window - it *does* shape up nicely, removes a lot of
    boilerplate, gets rid of locking inconsistencie between aio_write and
    splice_write and I hope to get Kent's direct-io rewrite merged into
    the same queue, but some of the stuff after this point is having
    (mostly trivial) conflicts with the things already merged into
    mainline and with some I want more testing.

    This one passes LTP and xfstests without regressions, in addition to
    usual beating. BTW, readahead02 in ltp syscalls testsuite has started
    giving failures since "mm/readahead.c: fix readahead failure for
    memoryless NUMA nodes and limit readahead pages" - might be a false
    positive, might be a real regression..."

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
    missing bits of "splice: fix racy pipe->buffers uses"
    cifs: fix the race in cifs_writev()
    ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
    kill generic_file_buffered_write()
    ocfs2_file_aio_write(): switch to generic_perform_write()
    ceph_aio_write(): switch to generic_perform_write()
    xfs_file_buffered_aio_write(): switch to generic_perform_write()
    export generic_perform_write(), start getting rid of generic_file_buffer_write()
    generic_file_direct_write(): get rid of ppos argument
    btrfs_file_aio_write(): get rid of ppos
    kill the 5th argument of generic_file_buffered_write()
    kill the 4th argument of __generic_file_aio_write()
    lustre: don't open-code kernel_recvmsg()
    ocfs2: don't open-code kernel_recvmsg()
    drbd: don't open-code kernel_recvmsg()
    constify blk_rq_map_user_iov() and friends
    lustre: switch to kernel_sendmsg()
    ocfs2: don't open-code kernel_sendmsg()
    take iov_iter stuff to mm/iov_iter.c
    process_vm_access: tidy up a bit
    ...

    Linus Torvalds
     

04 Apr, 2014

1 commit

  • Mark function as static in process_vm_access.c because it is not used
    outside this file.

    This eliminates the following warning in mm/process_vm_access.c:

    mm/process_vm_access.c:416:1: warning: no previous prototype for `compat_process_vm_rw' [-Wmissing-prototypes]

    [akpm@linux-foundation.org: remove unneeded asmlinkage - compat_process_vm_rw isn't referenced from asm]
    Signed-off-by: Rashika Kheria
    Reviewed-by: Josh Triplett
    Acked-by: David Rientjes
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rashika Kheria
     

02 Apr, 2014

10 commits


06 Mar, 2014

1 commit


13 Mar, 2013

1 commit

  • Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
    compat_process_vm_rw() shows that the compatibility code requires an
    explicit "access_ok()" check before calling
    compat_rw_copy_check_uvector(). The same difference seems to appear when
    we compare fs/read_write.c:do_readv_writev() to
    fs/compat.c:compat_do_readv_writev().

    This subtle difference between the compat and non-compat requirements
    should probably be debated, as it seems to be error-prone. In fact,
    there are two others sites that use this function in the Linux kernel,
    and they both seem to get it wrong:

    Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
    also ends up calling compat_rw_copy_check_uvector() through
    aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
    be missing. Same situation for
    security/keys/compat.c:compat_keyctl_instantiate_key_iov().

    I propose that we add the access_ok() check directly into
    compat_rw_copy_check_uvector(), so callers don't have to worry about it,
    and it therefore makes the compat call code similar to its non-compat
    counterpart. Place the access_ok() check in the same location where
    copy_from_user() can trigger a -EFAULT error in the non-compat code, so
    the ABI behaviors are alike on both compat and non-compat.

    While we are here, fix compat_do_readv_writev() so it checks for
    compat_rw_copy_check_uvector() negative return values.

    And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
    handling.

    Acked-by: Linus Torvalds
    Acked-by: Al Viro
    Signed-off-by: Mathieu Desnoyers
    Signed-off-by: Linus Torvalds

    Mathieu Desnoyers
     

01 Jun, 2012

1 commit

  • A cleanup of rw_copy_check_uvector and compat_rw_copy_check_uvector after
    changes made to support CMA in an earlier patch.

    Rather than having an additional check_access parameter to these
    functions, the first paramater type is overloaded to allow the caller to
    specify CHECK_IOVEC_ONLY which means check that the contents of the iovec
    are valid, but do not check the memory that they point to. This is used
    by process_vm_readv/writev where we need to validate that a iovec passed
    to the syscall is valid but do not want to check the memory that it points
    to at this point because it refers to an address space in another process.

    Signed-off-by: Chris Yeoh
    Reviewed-by: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christopher Yeoh
     

03 Feb, 2012

1 commit

  • This fixes the race in process_vm_core found by Oleg (see

    http://article.gmane.org/gmane.linux.kernel/1235667/

    for details).

    This has been updated since I last sent it as the creation of the new
    mm_access() function did almost exactly the same thing as parts of the
    previous version of this patch did.

    In order to use mm_access() even when /proc isn't enabled, we move it to
    kernel/fork.c where other related process mm access functions already
    are.

    Signed-off-by: Chris Yeoh
    Signed-off-by: Linus Torvalds

    Christopher Yeoh