linux.git/fs/binfmt_misc.c, branch v5.8 Linux kernel source tree Merge branch 'akpm' (patches from Andrew) 2020-06-05T02:18:29+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-06-05T02:18:29+00:00 886d7de631da71e30909980fdbf318f7caade262 Merge yet more updates from Andrew Morton: - More MM work. 100ish more to go. Mike Rapoport's "mm: remove __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue - Various other little subsystems * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits) lib/ubsan.c: fix gcc-10 warnings tools/testing/selftests/vm: remove duplicate headers selftests: vm: pkeys: fix multilib builds for x86 selftests: vm: pkeys: use the correct page size on powerpc selftests/vm/pkeys: override access right definitions on powerpc selftests/vm/pkeys: test correct behaviour of pkey-0 selftests/vm/pkeys: introduce a sub-page allocator selftests/vm/pkeys: detect write violation on a mapped access-denied-key page selftests/vm/pkeys: associate key on a mapped page and detect write violation selftests/vm/pkeys: associate key on a mapped page and detect access violation selftests/vm/pkeys: improve checks to determine pkey support selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust() selftests/vm/pkeys: fix number of reserved powerpc pkeys selftests/vm/pkeys: introduce powerpc support selftests/vm/pkeys: introduce generic pkey abstractions selftests: vm: pkeys: use the correct huge page size selftests/vm/pkeys: fix alloc_random_pkey() to make it really random selftests/vm/pkeys: fix assertion in pkey_disable_set/clear() selftests/vm/pkeys: fix pkey_disable_clear() selftests: vm: pkeys: add helpers for pkey bits ... 
Merge yet more updates from Andrew Morton:

 - More MM work. 100ish more to go. Mike Rapoport's "mm: remove
   __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue

 - Various other little subsystems

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
  lib/ubsan.c: fix gcc-10 warnings
  tools/testing/selftests/vm: remove duplicate headers
  selftests: vm: pkeys: fix multilib builds for x86
  selftests: vm: pkeys: use the correct page size on powerpc
  selftests/vm/pkeys: override access right definitions on powerpc
  selftests/vm/pkeys: test correct behaviour of pkey-0
  selftests/vm/pkeys: introduce a sub-page allocator
  selftests/vm/pkeys: detect write violation on a mapped access-denied-key page
  selftests/vm/pkeys: associate key on a mapped page and detect write violation
  selftests/vm/pkeys: associate key on a mapped page and detect access violation
  selftests/vm/pkeys: improve checks to determine pkey support
  selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust()
  selftests/vm/pkeys: fix number of reserved powerpc pkeys
  selftests/vm/pkeys: introduce powerpc support
  selftests/vm/pkeys: introduce generic pkey abstractions
  selftests: vm: pkeys: use the correct huge page size
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really random
  selftests/vm/pkeys: fix assertion in pkey_disable_set/clear()
  selftests/vm/pkeys: fix pkey_disable_clear()
  selftests: vm: pkeys: add helpers for pkey bits
  ...
exec: simplify the copy_strings_kernel calling convention 2020-06-05T02:06:26+00:00 Christoph Hellwig hch@lst.de 2020-06-04T23:51:14+00:00 986db2d14a6dca6456b63b4f5c410ae2aab4ec9d copy_strings_kernel is always used with a single argument, adjust the calling convention to that. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Link: http://lkml.kernel.org/r/20200501104105.2621149-2-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
copy_strings_kernel is always used with a single argument,
adjust the calling convention to that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/20200501104105.2621149-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
exec: Compute file based creds only once 2020-05-30T03:00:54+00:00 Eric W. Biederman ebiederm@xmission.com 2020-05-30T03:00:54+00:00 56305aa9b6fab91a5555a45796b79c1b0a6353d1 Move the computation of creds from prepare_binfmt into begin_new_exec so that the creds need only be computed once. This is just code reorganization no semantic changes of any kind are made. Moving the computation is safe. I have looked through the kernel and verified none of the binfmts look at bprm->cred directly, and that there are no helpers that look at bprm->cred indirectly. Which means that it is not a problem to compute the bprm->cred later in the execution flow as it is not used until it becomes current->cred. A new function bprm_creds_from_file is added to contain the work that needs to be done. bprm_creds_from_file first computes which file bprm->executable or most likely bprm->file that the bprm->creds will be computed from. The funciton bprm_fill_uid is updated to receive the file instead of accessing bprm->file. The now unnecessary work needed to reset the bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid. A small comment to document that bprm_fill_uid now only deals with the work to handle suid and sgid files. The default case is already heandled by prepare_exec_creds. The function security_bprm_repopulate_creds is renamed security_bprm_creds_from_file and now is explicitly passed the file from which to compute the creds. The documentation of the bprm_creds_from_file security hook is updated to explain when the hook is called and what it needs to do. The file is passed from cap_bprm_creds_from_file into get_file_caps so that the caps are computed for the appropriate file. The now unnecessary work in cap_bprm_creds_from_file to reset the ambient capabilites has been removed. A small comment to document that the work of cap_bprm_creds_from_file is to read capabilities from the files secureity attribute and derive capabilities from the fact the user had uid 0 has been added. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
Move the computation of creds from prepare_binfmt into begin_new_exec
so that the creds need only be computed once.  This is just code
reorganization no semantic changes of any kind are made.

Moving the computation is safe.  I have looked through the kernel and
verified none of the binfmts look at bprm->cred directly, and that
there are no helpers that look at bprm->cred indirectly.  Which means
that it is not a problem to compute the bprm->cred later in the
execution flow as it is not used until it becomes current->cred.

A new function bprm_creds_from_file is added to contain the work that
needs to be done.  bprm_creds_from_file first computes which file
bprm->executable or most likely bprm->file that the bprm->creds
will be computed from.

The funciton bprm_fill_uid is updated to receive the file instead of
accessing bprm->file.  The now unnecessary work needed to reset the
bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid.
A small comment to document that bprm_fill_uid now only deals with the
work to handle suid and sgid files.  The default case is already
heandled by prepare_exec_creds.

The function security_bprm_repopulate_creds is renamed
security_bprm_creds_from_file and now is explicitly passed the file
from which to compute the creds.  The documentation of the
bprm_creds_from_file security hook is updated to explain when the hook
is called and what it needs to do.  The file is passed from
cap_bprm_creds_from_file into get_file_caps so that the caps are
computed for the appropriate file.  The now unnecessary work in
cap_bprm_creds_from_file to reset the ambient capabilites has been
removed.  A small comment to document that the work of
cap_bprm_creds_from_file is to read capabilities from the files
secureity attribute and derive capabilities from the fact the
user had uid 0 has been added.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
exec: Remove recursion from search_binary_handler 2020-05-21T15:16:57+00:00 Eric W. Biederman ebiederm@xmission.com 2020-05-18T23:43:20+00:00 bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 Recursion in kernel code is generally a bad idea as it can overflow the kernel stack. Recursion in exec also hides that the code is looping and that the loop changes bprm->file. Instead of recursing in search_binary_handler have the methods that would recurse set bprm->interpreter and return 0. Modify exec_binprm to loop when bprm->interpreter is set. Consolidate all of the reassignments of bprm->file in that loop to make it clear what is going on. The structure of the new loop in exec_binprm is that all errors return immediately, while successful completion (ret == 0 && !bprm->interpreter) just breaks out of the loop and runs what exec_bprm has always run upon successful completion. Fail if the an interpreter is being call after execfd has been set. The code has never properly handled an interpreter being called with execfd being set and with reassignments of bprm->file and the assignment of bprm->executable in generic code it has finally become possible to test and fail when if this problematic condition happens. With the reassignments of bprm->file and the assignment of bprm->executable moved into the generic code add a test to see if bprm->executable is being reassigned. In search_binary_handler remove the test for !bprm->file. With all reassignments of bprm->file moved to exec_binprm bprm->file can never be NULL in search_binary_handler. Link: https://lkml.kernel.org/r/87sgfwyd84.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
Recursion in kernel code is generally a bad idea as it can overflow
the kernel stack.  Recursion in exec also hides that the code is
looping and that the loop changes bprm->file.

Instead of recursing in search_binary_handler have the methods that
would recurse set bprm->interpreter and return 0.  Modify exec_binprm
to loop when bprm->interpreter is set.  Consolidate all of the
reassignments of bprm->file in that loop to make it clear what is
going on.

The structure of the new loop in exec_binprm is that all errors return
immediately, while successful completion (ret == 0 &&
!bprm->interpreter) just breaks out of the loop and runs what
exec_bprm has always run upon successful completion.

Fail if the an interpreter is being call after execfd has been set.
The code has never properly handled an interpreter being called with
execfd being set and with reassignments of bprm->file and the
assignment of bprm->executable in generic code it has finally become
possible to test and fail when if this problematic condition happens.

With the reassignments of bprm->file and the assignment of
bprm->executable moved into the generic code add a test to see if
bprm->executable is being reassigned.

In search_binary_handler remove the test for !bprm->file.  With all
reassignments of bprm->file moved to exec_binprm bprm->file can never
be NULL in search_binary_handler.

Link: https://lkml.kernel.org/r/87sgfwyd84.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
exec: Generic execfd support 2020-05-21T15:16:57+00:00 Eric W. Biederman ebiederm@xmission.com 2020-05-14T20:17:40+00:00 b8a61c9e7b4a0fec493d191429e9653d66a79ccc Most of the support for passing the file descriptor of an executable to an interpreter already lives in the generic code and in binfmt_elf. Rework the fields in binfmt_elf that deal with executable file descriptor passing to make executable file descriptor passing a first class concept. Move the fd_install from binfmt_misc into begin_new_exec after the new creds have been installed. This means that accessing the file through /proc/<pid>/fd/N is able to see the creds for the new executable before allowing access to the new executables files. Performing the install of the executables file descriptor after the point of no return also means that nothing special needs to be done on error. The exiting of the process will close all of it's open files. Move the would_dump from binfmt_misc into begin_new_exec right after would_dump is called on the bprm->file. This makes it obvious this case exists and that no nesting of bprm->file is currently supported. In binfmt_misc the movement of fd_install into generic code means that it's special error exit path is no longer needed. Link: https://lkml.kernel.org/r/87y2poyd91.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
Most of the support for passing the file descriptor of an executable
to an interpreter already lives in the generic code and in binfmt_elf.
Rework the fields in binfmt_elf that deal with executable file
descriptor passing to make executable file descriptor passing a first
class concept.

Move the fd_install from binfmt_misc into begin_new_exec after the new
creds have been installed.  This means that accessing the file through
/proc/<pid>/fd/N is able to see the creds for the new executable
before allowing access to the new executables files.

Performing the install of the executables file descriptor after
the point of no return also means that nothing special needs to
be done on error.  The exiting of the process will close all
of it's open files.

Move the would_dump from binfmt_misc into begin_new_exec right
after would_dump is called on the bprm->file.  This makes it
obvious this case exists and that no nesting of bprm->file is
currently supported.

In binfmt_misc the movement of fd_install into generic code means
that it's special error exit path is no longer needed.

Link: https://lkml.kernel.org/r/87y2poyd91.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
exec: Move the call of prepare_binprm into search_binary_handler 2020-05-21T15:16:57+00:00 Eric W. Biederman ebiederm@xmission.com 2020-05-14T03:25:20+00:00 8b72ca9004ed35104deb80b07990da5503bc5252 The code in prepare_binary_handler needs to be run every time search_binary_handler is called so move the call into search_binary_handler itself to make the code simpler and easier to understand. Link: https://lkml.kernel.org/r/87d070zrvx.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
The code in prepare_binary_handler needs to be run every time
search_binary_handler is called so move the call into search_binary_handler
itself to make the code simpler and easier to understand.

Link: https://lkml.kernel.org/r/87d070zrvx.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
exec: Allow load_misc_binary to call prepare_binprm unconditionally 2020-05-21T15:16:57+00:00 Eric W. Biederman ebiederm@xmission.com 2020-05-16T11:02:54+00:00 a16b3357b2b8e910bb614254d8a7e84d2bd59b4c Add a flag preserve_creds that binfmt_misc can set to prevent credentials from being updated. This allows binfmt_misc to always call prepare_binprm. Allowing the credential computation logic to be consolidated. Not replacing the credentials with the interpreters credentials is safe because because an open file descriptor to the executable is passed to the interpreter. As the interpreter does not need to reopen the executable it is guaranteed to see the same file that exec sees. Ref: c407c033de84 ("[PATCH] binfmt_misc: improve calculation of interpreter's credentials") Link: https://lkml.kernel.org/r/87imgszrwo.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
Add a flag preserve_creds that binfmt_misc can set to prevent
credentials from being updated.  This allows binfmt_misc to always
call prepare_binprm.  Allowing the credential computation logic to be
consolidated.

Not replacing the credentials with the interpreters credentials is
safe because because an open file descriptor to the executable is
passed to the interpreter.   As the interpreter does not need to
reopen the executable it is guaranteed to see the same file that
exec sees.

Ref: c407c033de84 ("[PATCH] binfmt_misc: improve calculation of interpreter's credentials")
Link: https://lkml.kernel.org/r/87imgszrwo.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19T17:42:02+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-07-19T17:42:02+00:00 933a90bf4f3505f8ec83bda21a3c7d70d7c2b426 Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ... 
Pull vfs mount updates from Al Viro:
 "The first part of mount updates.

  Convert filesystems to use the new mount API"

* 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  mnt_init(): call shmem_init() unconditionally
  constify ksys_mount() string arguments
  don't bother with registering rootfs
  init_rootfs(): don't bother with init_ramfs_fs()
  vfs: Convert smackfs to use the new mount API
  vfs: Convert selinuxfs to use the new mount API
  vfs: Convert securityfs to use the new mount API
  vfs: Convert apparmorfs to use the new mount API
  vfs: Convert openpromfs to use the new mount API
  vfs: Convert xenfs to use the new mount API
  vfs: Convert gadgetfs to use the new mount API
  vfs: Convert oprofilefs to use the new mount API
  vfs: Convert ibmasmfs to use the new mount API
  vfs: Convert qib_fs/ipathfs to use the new mount API
  vfs: Convert efivarfs to use the new mount API
  vfs: Convert configfs to use the new mount API
  vfs: Convert binfmt_misc to use the new mount API
  convenience helper: get_tree_single()
  convenience helper get_tree_nodev()
  vfs: Kill sget_userns()
  ...
vfs: Convert binfmt_misc to use the new mount API 2019-07-05T02:01:58+00:00 David Howells dhowells@redhat.com 2019-03-25T16:38:28+00:00 bc99a664e9be24e49e09da1250ede0c598d958d1 Convert the binfmt_misc filesystem to the new internal mount API as the old one will be obsoleted and removed. This allows greater flexibility in communication of mount parameters between userspace, the VFS and the filesystem. See Documentation/filesystems/mount_api.txt for more information. Signed-off-by: David Howells <dhowells@redhat.com> cc: Alexander Viro <viro@zeniv.linux.org.uk> cc: linux-fsdevel@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
Convert the binfmt_misc filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
treewide: Add SPDX license identifier for more missed files 2019-05-21T08:50:45+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-19T12:08:20+00:00 09c434b8a0047c69e48499de0107de312901e798 Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have MODULE_LICENCE("GPL*") inside which was used in the initial
   scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>