linux-toradex.git/fs/proc/base.c, branch v4.9.113

proc: fix /proc/*/map_files lookup

2018-05-30T05:50:25+00:00

[ Upstream commit ac7f1061c2c11bb8936b1b6a94cdb48de732f7a4 ]

Current code does:

	if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)

However sscanf() is broken garbage.

It silently accepts whitespace between format specifiers
(did you know that?).

It silently accepts valid strings which result in integer overflow.

Do not use sscanf() for any even remotely reliable parsing code.

	OK
	# readlink '/proc/1/map_files/55a23af39000-55a23b05b000'
	/lib/systemd/systemd

	broken
	# readlink '/proc/1/map_files/               55a23af39000-55a23b05b000'
	/lib/systemd/systemd

	broken
	# readlink '/proc/1/map_files/55a23af39000-55a23b05b000    '
	/lib/systemd/systemd

	very broken
	# readlink '/proc/1/map_files/1000000000000000055a23af39000-55a23b05b000'
	/lib/systemd/systemd

Andrei said:

: This patch breaks criu.  It was a bug in criu.  And this bug is on a minor
: path, which works when memfd_create() isn't available.  It is a reason why
: I ask to not backport this patch to stable kernels.
:
: In CRIU this bug can be triggered, only if this patch will be backported
: to a kernel which version is lower than v3.16.

Link: http://lkml.kernel.org/r/20171120212706.GA14325@avx2
Signed-off-by: Alexey Dobriyan 
Cc: Pavel Emelyanov 
Cc: Andrei Vagin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

proc: do not access cmdline nor environ from file-backed areas

2018-05-19T08:27:00+00:00

commit 7f7ccc2ccc2e70c6054685f5e3522efa81556830 upstream.

proc_pid_cmdline_read() and environ_read() directly access the target
process' VM to retrieve the command line and environment. If this
process remaps these areas onto a file via mmap(), the requesting
process may experience various issues such as extra delays if the
underlying device is slow to respond.

Let's simply refuse to access file-backed areas in these functions.
For this we add a new FOLL_ANON gup flag that is passed to all calls
to access_remote_vm(). The code already takes care of such failures
(including unmapped areas). Accesses via /proc/pid/mem were not
changed though.

This was assigned CVE-2018-1120.

Note for stable backports: the patch may apply to kernels prior to 4.11
but silently miss one location; it must be checked that no call to
access_remote_vm() keeps zero as the last argument.

Reported-by: Qualys Security Advisory 
Cc: Linus Torvalds 
Cc: Andy Lutomirski 
Cc: Oleg Nesterov 
Cc: stable@vger.kernel.org
Signed-off-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

proc: add a schedule point in proc_pid_readdir()

2017-06-17T04:41:56+00:00

[ Upstream commit 3ba4bceef23206349d4130ddf140819b365de7c8 ]

We have seen proc_pid_readdir() invocations holding cpu for more than 50
ms.  Add a cond_resched() to be gentle with other tasks.

[akpm@linux-foundation.org: coding style fix]
Link: http://lkml.kernel.org/r/1484238380.15816.42.camel@edumazet-glaptop3.roam.corp.google.com
Signed-off-by: Eric Dumazet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

proc: fix NULL dereference when reading /proc//auxv

2016-10-28T01:43:43+00:00

Reading auxv of any kernel thread results in NULL pointer dereferencing
in auxv_read() where mm can be NULL.  Fix that by checking for NULL mm
and bailing out early.  This is also the original behavior changed by
recent commit c5317167854e ("proc: switch auxv to use of __mem_open()").

  # cat /proc/2/auxv
  Unable to handle kernel NULL pointer dereference at virtual address 000000a8
  Internal error: Oops: 17 [#1] PREEMPT SMP ARM
  CPU: 3 PID: 113 Comm: cat Not tainted 4.9.0-rc1-ARCH+ #1
  Hardware name: BCM2709
  task: ea3b0b00 task.stack: e99b2000
  PC is at auxv_read+0x24/0x4c
  LR is at do_readv_writev+0x2fc/0x37c
  Process cat (pid: 113, stack limit = 0xe99b2210)
  Call chain:
    auxv_read
    do_readv_writev
    vfs_readv
    default_file_splice_read
    splice_direct_to_actor
    do_splice_direct
    do_sendfile
    SyS_sendfile64
    ret_fast_syscall

Fixes: c5317167854e ("proc: switch auxv to use of __mem_open()")
Link: http://lkml.kernel.org/r/1476966200-14457-1-git-send-email-chianglungyu@gmail.com
Signed-off-by: Leon Yu 
Acked-by: Oleg Nesterov 
Acked-by: Michal Hocko 
Cc: Al Viro 
Cc: Kees Cook 
Cc: John Stultz 
Cc: Mateusz Guzik 
Cc: Janis Danisevskis 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: don't use FOLL_FORCE for reading cmdline and environment

2016-10-25T02:00:44+00:00

Now that Lorenzo cleaned things up and made the FOLL_FORCE users
explicit, it becomes obvious how some of them don't really need
FOLL_FORCE at all.

So remove FOLL_FORCE from the proc code that reads the command line and
arguments from user space.

The mem_rw() function actually does want FOLL_FORCE, because gdd (and
possibly many other debuggers) use it as a much more convenient version
of PTRACE_PEEKDATA, but we should consider making the FOLL_FORCE part
conditional on actually being a ptracer.  This does not actually do
that, just moves adds a comment to that effect and moves the gup_flags
settings next to each other.

Signed-off-by: Linus Torvalds

mm: replace access_remote_vm() write parameter with gup_flags

2016-10-19T15:12:14+00:00

This removes the 'write' argument from access_remote_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.

We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.

Signed-off-by: Lorenzo Stoakes 
Acked-by: Michal Hocko 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-10-11T03:16:43+00:00

Pull more vfs updates from Al Viro:
 ">rename2() work from Miklos + current_time() from Deepa"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: Replace current_fs_time() with current_time()
  fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
  fs: Replace CURRENT_TIME with current_time() for inode timestamps
  fs: proc: Delete inode time initializations in proc_alloc_inode()
  vfs: Add current_time() api
  vfs: add note about i_op->rename changes to porting
  fs: rename "rename2" i_op to "rename"
  vfs: remove unused i_op->rename
  fs: make remaining filesystems use .rename2
  libfs: support RENAME_NOREPLACE in simple_rename()
  fs: support RENAME_NOREPLACE for local filesystems
  ncpfs: fix unused variable warning

Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-10-10T20:04:49+00:00

Pull misc vfs updates from Al Viro:
 "Assorted misc bits and pieces.

  There are several single-topic branches left after this (rename2
  series from Miklos, current_time series from Deepa Dinamani, xattr
  series from Andreas, uaccess stuff from from me) and I'd prefer to
  send those separately"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
  proc: switch auxv to use of __mem_open()
  hpfs: support FIEMAP
  cifs: get rid of unused arguments of CIFSSMBWrite()
  posix_acl: uapi header split
  posix_acl: xattr representation cleanups
  fs/aio.c: eliminate redundant loads in put_aio_ring_file
  fs/internal.h: add const to ns_dentry_operations declaration
  compat: remove compat_printk()
  fs/buffer.c: make __getblk_slow() static
  proc: unsigned file descriptors
  fs/file: more unsigned file descriptors
  fs: compat: remove redundant check of nr_segs
  cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
  cifs: don't use memcpy() to copy struct iov_iter
  get rid of separate multipage fault-in primitives
  fs: Avoid premature clearing of capabilities
  fs: Give dentry to inode_change_ok() instead of inode
  fuse: Propagate dentry down to inode_change_ok()
  ceph: Propagate dentry down to inode_change_ok()
  xfs: Propagate dentry down to inode_change_ok()
  ...

Merge remote-tracking branch 'jk/vfs' into work.misc

2016-10-08T15:06:08+00:00

proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self

2016-10-08T01:46:30+00:00

In changing from checking ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)
to capable(CAP_SYS_NICE), I missed that ptrace_my_access succeeds when p
== current, but the CAP_SYS_NICE doesn't.

Thus while the previous commit was intended to loosen the needed
privileges to modify a processes timerslack, it needlessly restricted a
task modifying its own timerslack via the proc//timerslack_ns
(which is permitted also via the PR_SET_TIMERSLACK method).

This patch corrects this by checking if p == current before checking the
CAP_SYS_NICE value.

This patch applies on top of my two previous patches currently in -mm

Link: http://lkml.kernel.org/r/1471906870-28624-1-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz 
Acked-by: Kees Cook 
Cc: "Serge E. Hallyn" 
Cc: Thomas Gleixner 
Cc: Arjan van de Ven 
Cc: Oren Laadan 
Cc: Ruchi Kandoi 
Cc: Rom Lemarchand 
Cc: Todd Kjos 
Cc: Colin Cross 
Cc: Nick Kralevich 
Cc: Dmitry Shmidt 
Cc: Elliott Hughes 
Cc: Android Kernel Team 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds