linux-stable.git/fs/exec.c, branch v5.2

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_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 
Signed-off-by: Greg Kroah-Hartman

fs/exec.c: move ->recursion_depth out of critical sections

2019-05-15T02:52:50+00:00

->recursion_depth is changed only by current, therefore decrementing can
be done without taking any locks.

Link: http://lkml.kernel.org/r/20190417213150.GA26474@avx2
Signed-off-by: Alexey Dobriyan 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

exec: increase BINPRM_BUF_SIZE to 256

2019-03-08T02:32:01+00:00

Large enterprise clients often run applications out of networked file
systems where the IT mandated layout of project volumes can end up
leading to paths that are longer than 128 characters.  Bumping this up
to the next order of two solves this problem in all but the most
egregious case while still fitting into a 512b slab.

[oleg@redhat.com: update comment, per Kees]
Link: http://lkml.kernel.org/r/20181112160956.GA28472@redhat.com
Signed-off-by: Oleg Nesterov 
Reported-by: Ben Woodard 
Reviewed-by: Andrew Morton 
Acked-by: Michal Hocko 
Acked-by: Kees Cook 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/exec.c: replace opencoded set_mask_bits()

2019-03-08T02:32:01+00:00

Link: http://lkml.kernel.org/r/1548275584-18096-2-git-send-email-vgupta@synopsys.com
Link: http://lkml.kernel.org/g/20150807115710.GA16897@redhat.com
Signed-off-by: Vineet Gupta 
Reviewed-by: Anthony Yznaga 
Acked-by: Oleg Nesterov 
Cc: Alexander Viro 
Cc: Peter Zijlstra (Intel) 
Cc: Chris Wilson 
Cc: Ingo Molnar 
Cc: Jani Nikula 
Cc: Miklos Szeredi 
Cc: Theodore Ts'o 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-03-06T16:14:05+00:00

Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - refcount conversions

   - Solve the rq->leaf_cfs_rq_list can of worms for real.

   - improve power-aware scheduling

   - add sysctl knob for Energy Aware Scheduling

   - documentation updates

   - misc other changes"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  kthread: Do not use TIMER_IRQSAFE
  kthread: Convert worker lock to raw spinlock
  sched/fair: Use non-atomic cpumask_{set,clear}_cpu()
  sched/fair: Remove unused 'sd' parameter from select_idle_smt()
  sched/wait: Use freezable_schedule() when possible
  sched/fair: Prune, fix and simplify the nohz_balancer_kick() comment block
  sched/fair: Explain LLC nohz kick condition
  sched/fair: Simplify nohz_balancer_kick()
  sched/topology: Fix percpu data types in struct sd_data & struct s_data
  sched/fair: Simplify post_init_entity_util_avg() by calling it with a task_struct pointer argument
  sched/fair: Fix O(nr_cgroups) in the load balancing path
  sched/fair: Optimize update_blocked_averages()
  sched/fair: Fix insertion in rq->leaf_cfs_rq_list
  sched/fair: Add tmp_alone_branch assertion
  sched/core: Use READ_ONCE()/WRITE_ONCE() in move_queued_task()/task_rq_lock()
  sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK
  sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity
  sched/fair: Update scale invariance of PELT
  sched/fair: Move the rq_of() helper function
  sched/core: Convert task_struct.stack_refcount to refcount_t
  ...

exec: Fix mem leak in kernel_read_file

2019-02-19T02:26:24+00:00

syzkaller report this:
BUG: memory leak
unreferenced object 0xffffc9000488d000 (size 9195520):
  comm "syz-executor.0", pid 2752, jiffies 4294787496 (age 18.757s)
  hex dump (first 32 bytes):
    ff ff ff ff ff ff ff ff a8 00 00 00 01 00 00 00  ................
    02 00 00 00 00 00 00 00 80 a1 7a c1 ff ff ff ff  ..........z.....
  backtrace:
    [<000000000863775c>] __vmalloc_node mm/vmalloc.c:1795 [inline]
    [<000000000863775c>] __vmalloc_node_flags mm/vmalloc.c:1809 [inline]
    [<000000000863775c>] vmalloc+0x8c/0xb0 mm/vmalloc.c:1831
    [<000000003f668111>] kernel_read_file+0x58f/0x7d0 fs/exec.c:924
    [<000000002385813f>] kernel_read_file_from_fd+0x49/0x80 fs/exec.c:993
    [<0000000011953ff1>] __do_sys_finit_module+0x13b/0x2a0 kernel/module.c:3895
    [<000000006f58491f>] do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
    [<00000000ee78baf4>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000241f889b>] 0xffffffffffffffff

It should goto 'out_free' lable to free allocated buf while kernel_read
fails.

Fixes: 39d637af5aa7 ("vfs: forbid write access when reading a file into memory")
Signed-off-by: YueHaibing 
Signed-off-by: Al Viro

sched/core: Convert sighand_struct.count to refcount_t

2019-02-04T07:53:52+00:00

atomic_t variables are currently used to implement reference
counters with the following properties:

 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable sighand_struct.count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

** Important note for maintainers:

Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.

The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.

Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.

Please double check that you don't have some undocumented
memory guarantees for this variable usage.

For the sighand_struct.count it might make a difference
in following places:

 - __cleanup_sighand: decrement in refcount_dec_and_test() only
   provides RELEASE ordering and control dependency on success
   vs. fully ordered atomic counterpart

Suggested-by: Kees Cook 
Signed-off-by: Elena Reshetova 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: David Windsor 
Reviewed-by: Hans Liljestrand 
Reviewed-by: Andrea Parri 
Reviewed-by: Oleg Nesterov 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: akpm@linux-foundation.org
Cc: viro@zeniv.linux.org.uk
Link: https://lkml.kernel.org/r/1547814450-18902-2-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar

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

2019-01-05T21:18:59+00:00

Pull trivial vfs updates from Al Viro:
 "A few cleanups + Neil's namespace_unlock() optimization"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  exec: make prepare_bprm_creds static
  genheaders: %-s had been there since v6; %-*s - since v7
  VFS: use synchronize_rcu_expedited() in namespace_unlock()
  iov_iter: reduce code duplication

fs/: remove caller signal_pending branch predictions

2019-01-04T21:13:48+00:00

This is already done for us internally by the signal machinery.

[akpm@linux-foundation.org: fix fs/buffer.c]
Link: http://lkml.kernel.org/r/20181116002713.8474-7-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

exec: separate MM_ANONPAGES and RLIMIT_STACK accounting

2019-01-04T21:13:47+00:00

get_arg_page() checks bprm->rlim_stack.rlim_cur and re-calculates the
"extra" size for argv/envp pointers every time, this is a bit ugly and
even not strictly correct: acct_arg_size() must not account this size.

Remove all the rlimit code in get_arg_page().  Instead, add bprm->argmin
calculated once at the start of __do_execve_file() and change
copy_strings to check bprm->p >= bprm->argmin.

The patch adds the new helper, prepare_arg_pages() which initializes
bprm->argc/envc and bprm->argmin.

[oleg@redhat.com: fix !CONFIG_MMU version of get_arg_page()]
  Link: http://lkml.kernel.org/r/20181126122307.GA1660@redhat.com
[akpm@linux-foundation.org: use max_t]
Link: http://lkml.kernel.org/r/20181112160910.GA28440@redhat.com
Signed-off-by: Oleg Nesterov 
Acked-by: Kees Cook 
Tested-by: Guenter Roeck 
Cc: "Eric W. Biederman" 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds