linux.git/kernel, branch v5.16 Linux kernel source tree Merge branch 'for-5.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2022-01-07T23:58:06+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-01-07T23:58:06+00:00 d1587f7bfe9a0f97a75d42ac1489aeda551106bc Pull cgroup fixes from Tejun Heo: "This contains the cgroup.procs permission check fixes so that they use the credentials at the time of open rather than write, which also fixes the cgroup namespace lifetime bug" * 'for-5.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: selftests: cgroup: Test open-time cgroup namespace usage for migration checks selftests: cgroup: Test open-time credential usage for migration checks selftests: cgroup: Make cg_create() use 0755 for permission instead of 0644 cgroup: Use open-time cgroup namespace for process migration perm checks cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv cgroup: Use open-time credentials for process migraton perm checks 
Pull cgroup fixes from Tejun Heo:
 "This contains the cgroup.procs permission check fixes so that they use
  the credentials at the time of open rather than write, which also
  fixes the cgroup namespace lifetime bug"

* 'for-5.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  selftests: cgroup: Test open-time cgroup namespace usage for migration checks
  selftests: cgroup: Test open-time credential usage for migration checks
  selftests: cgroup: Make cg_create() use 0755 for permission instead of 0644
  cgroup: Use open-time cgroup namespace for process migration perm checks
  cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv
  cgroup: Use open-time credentials for process migraton perm checks
Merge tag 'trace-v5.16-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 2022-01-06T23:00:43+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-01-06T23:00:43+00:00 b2b436ec0205abde78ef8fd438758125ffbb0fec Pull tracing fixes from Steven Rostedt: "Three minor tracing fixes: - Fix missing prototypes in sample module for direct functions - Fix check of valid buffer in get_trace_buf() - Fix annotations of percpu pointers" * tag 'trace-v5.16-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Tag trace_percpu_buffer as a percpu pointer tracing: Fix check for trace_percpu_buffer validity in get_trace_buf() ftrace/samples: Add missing prototypes direct functions 
Pull tracing fixes from Steven Rostedt:
 "Three minor tracing fixes:

   - Fix missing prototypes in sample module for direct functions

   - Fix check of valid buffer in get_trace_buf()

   - Fix annotations of percpu pointers"

* tag 'trace-v5.16-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Tag trace_percpu_buffer as a percpu pointer
  tracing: Fix check for trace_percpu_buffer validity in get_trace_buf()
  ftrace/samples: Add missing prototypes direct functions
cgroup: Use open-time cgroup namespace for process migration perm checks 2022-01-06T21:02:29+00:00 Tejun Heo tj@kernel.org 2022-01-06T21:02:29+00:00 e57457641613fef0d147ede8bd6a3047df588b95 cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's cgroup namespace which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes cgroup remember the cgroup namespace at the time of open and uses it for migration permission checks instad of current's. Note that this only applies to cgroup2 as cgroup1 doesn't have namespace support. This also fixes a use-after-free bug on cgroupns reported in https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Note that backporting this fix also requires the preceding patch. Reported-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Reported-by: syzbot+50f5cf33a284ce738b62@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Fixes: 5136f6365ce3 ("cgroup: implement "nsdelegate" mount option") Signed-off-by: Tejun Heo <tj@kernel.org> 
cgroup process migration permission checks are performed at write time as
whether a given operation is allowed or not is dependent on the content of
the write - the PID. This currently uses current's cgroup namespace which is
a potential security weakness as it may allow scenarios where a less
privileged process tricks a more privileged one into writing into a fd that
it created.

This patch makes cgroup remember the cgroup namespace at the time of open
and uses it for migration permission checks instad of current's. Note that
this only applies to cgroup2 as cgroup1 doesn't have namespace support.

This also fixes a use-after-free bug on cgroupns reported in

 https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com

Note that backporting this fix also requires the preceding patch.

Reported-by: "Eric W. Biederman" <ebiederm@xmission.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Reported-by: syzbot+50f5cf33a284ce738b62@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com
Fixes: 5136f6365ce3 ("cgroup: implement "nsdelegate" mount option")
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv 2022-01-06T21:02:29+00:00 Tejun Heo tj@kernel.org 2022-01-06T21:02:29+00:00 0d2b5955b36250a9428c832664f2079cbf723bec of->priv is currently used by each interface file implementation to store private information. This patch collects the current two private data usages into struct cgroup_file_ctx which is allocated and freed by the common path. This allows generic private data which applies to multiple files, which will be used to in the following patch. Note that cgroup_procs iterator is now embedded as procs.iter in the new cgroup_file_ctx so that it doesn't need to be allocated and freed separately. v2: union dropped from cgroup_file_ctx and the procs iterator is embedded in cgroup_file_ctx as suggested by Linus. v3: Michal pointed out that cgroup1's procs pidlist uses of->priv too. Converted. Didn't change to embedded allocation as cgroup1 pidlists get stored for caching. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michal Koutný <mkoutny@suse.com> 
of->priv is currently used by each interface file implementation to store
private information. This patch collects the current two private data usages
into struct cgroup_file_ctx which is allocated and freed by the common path.
This allows generic private data which applies to multiple files, which will
be used to in the following patch.

Note that cgroup_procs iterator is now embedded as procs.iter in the new
cgroup_file_ctx so that it doesn't need to be allocated and freed
separately.

v2: union dropped from cgroup_file_ctx and the procs iterator is embedded in
    cgroup_file_ctx as suggested by Linus.

v3: Michal pointed out that cgroup1's procs pidlist uses of->priv too.
    Converted. Didn't change to embedded allocation as cgroup1 pidlists get
    stored for caching.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
cgroup: Use open-time credentials for process migraton perm checks 2022-01-06T21:02:28+00:00 Tejun Heo tj@kernel.org 2022-01-06T21:02:28+00:00 1756d7994ad85c2479af6ae5a9750b92324685af cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's credentials which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes both cgroup2 and cgroup1 process migration interfaces to use the credentials saved at the time of open (file->f_cred) instead of current's. Reported-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Fixes: 187fe84067bd ("cgroup: require write perm on common ancestor when moving processes on the default hierarchy") Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
cgroup process migration permission checks are performed at write time as
whether a given operation is allowed or not is dependent on the content of
the write - the PID. This currently uses current's credentials which is a
potential security weakness as it may allow scenarios where a less
privileged process tricks a more privileged one into writing into a fd that
it created.

This patch makes both cgroup2 and cgroup1 process migration interfaces to
use the credentials saved at the time of open (file->f_cred) instead of
current's.

Reported-by: "Eric W. Biederman" <ebiederm@xmission.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Fixes: 187fe84067bd ("cgroup: require write perm on common ancestor when moving processes on the default hierarchy")
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
tracing: Tag trace_percpu_buffer as a percpu pointer 2022-01-05T23:53:49+00:00 Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com 2021-12-23T10:34:39+00:00 f28439db470cca8b6b082239314e9fd10bd39034 Tag trace_percpu_buffer as a percpu pointer to resolve warnings reported by sparse: /linux/kernel/trace/trace.c:3218:46: warning: incorrect type in initializer (different address spaces) /linux/kernel/trace/trace.c:3218:46: expected void const [noderef] __percpu *__vpp_verify /linux/kernel/trace/trace.c:3218:46: got struct trace_buffer_struct * /linux/kernel/trace/trace.c:3234:9: warning: incorrect type in initializer (different address spaces) /linux/kernel/trace/trace.c:3234:9: expected void const [noderef] __percpu *__vpp_verify /linux/kernel/trace/trace.c:3234:9: got int * Link: https://lkml.kernel.org/r/ebabd3f23101d89cb75671b68b6f819f5edc830b.1640255304.git.naveen.n.rao@linux.vnet.ibm.com Cc: stable@vger.kernel.org Reported-by: kernel test robot <lkp@intel.com> Fixes: 07d777fe8c398 ("tracing: Add percpu buffers for trace_printk()") Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
Tag trace_percpu_buffer as a percpu pointer to resolve warnings
reported by sparse:
  /linux/kernel/trace/trace.c:3218:46: warning: incorrect type in initializer (different address spaces)
  /linux/kernel/trace/trace.c:3218:46:    expected void const [noderef] __percpu *__vpp_verify
  /linux/kernel/trace/trace.c:3218:46:    got struct trace_buffer_struct *
  /linux/kernel/trace/trace.c:3234:9: warning: incorrect type in initializer (different address spaces)
  /linux/kernel/trace/trace.c:3234:9:    expected void const [noderef] __percpu *__vpp_verify
  /linux/kernel/trace/trace.c:3234:9:    got int *

Link: https://lkml.kernel.org/r/ebabd3f23101d89cb75671b68b6f819f5edc830b.1640255304.git.naveen.n.rao@linux.vnet.ibm.com

Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 07d777fe8c398 ("tracing: Add percpu buffers for trace_printk()")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix check for trace_percpu_buffer validity in get_trace_buf() 2022-01-05T23:51:25+00:00 Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com 2021-12-23T10:34:38+00:00 823e670f7ed616d0ce993075c8afe0217885f79d With the new osnoise tracer, we are seeing the below splat: Kernel attempted to read user page (c7d880000) - exploit attempt? (uid: 0) BUG: Unable to handle kernel data access on read at 0xc7d880000 Faulting instruction address: 0xc0000000002ffa10 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries ... NIP [c0000000002ffa10] __trace_array_vprintk.part.0+0x70/0x2f0 LR [c0000000002ff9fc] __trace_array_vprintk.part.0+0x5c/0x2f0 Call Trace: [c0000008bdd73b80] [c0000000001c49cc] put_prev_task_fair+0x3c/0x60 (unreliable) [c0000008bdd73be0] [c000000000301430] trace_array_printk_buf+0x70/0x90 [c0000008bdd73c00] [c0000000003178b0] trace_sched_switch_callback+0x250/0x290 [c0000008bdd73c90] [c000000000e70d60] __schedule+0x410/0x710 [c0000008bdd73d40] [c000000000e710c0] schedule+0x60/0x130 [c0000008bdd73d70] [c000000000030614] interrupt_exit_user_prepare_main+0x264/0x270 [c0000008bdd73de0] [c000000000030a70] syscall_exit_prepare+0x150/0x180 [c0000008bdd73e10] [c00000000000c174] system_call_vectored_common+0xf4/0x278 osnoise tracer on ppc64le is triggering osnoise_taint() for negative duration in get_int_safe_duration() called from trace_sched_switch_callback()->thread_exit(). The problem though is that the check for a valid trace_percpu_buffer is incorrect in get_trace_buf(). The check is being done after calculating the pointer for the current cpu, rather than on the main percpu pointer. Fix the check to be against trace_percpu_buffer. Link: https://lkml.kernel.org/r/a920e4272e0b0635cf20c444707cbce1b2c8973d.1640255304.git.naveen.n.rao@linux.vnet.ibm.com Cc: stable@vger.kernel.org Fixes: e2ace001176dc9 ("tracing: Choose static tp_printk buffer by explicit nesting count") Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> 
With the new osnoise tracer, we are seeing the below splat:
    Kernel attempted to read user page (c7d880000) - exploit attempt? (uid: 0)
    BUG: Unable to handle kernel data access on read at 0xc7d880000
    Faulting instruction address: 0xc0000000002ffa10
    Oops: Kernel access of bad area, sig: 11 [#1]
    LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
    ...
    NIP [c0000000002ffa10] __trace_array_vprintk.part.0+0x70/0x2f0
    LR [c0000000002ff9fc] __trace_array_vprintk.part.0+0x5c/0x2f0
    Call Trace:
    [c0000008bdd73b80] [c0000000001c49cc] put_prev_task_fair+0x3c/0x60 (unreliable)
    [c0000008bdd73be0] [c000000000301430] trace_array_printk_buf+0x70/0x90
    [c0000008bdd73c00] [c0000000003178b0] trace_sched_switch_callback+0x250/0x290
    [c0000008bdd73c90] [c000000000e70d60] __schedule+0x410/0x710
    [c0000008bdd73d40] [c000000000e710c0] schedule+0x60/0x130
    [c0000008bdd73d70] [c000000000030614] interrupt_exit_user_prepare_main+0x264/0x270
    [c0000008bdd73de0] [c000000000030a70] syscall_exit_prepare+0x150/0x180
    [c0000008bdd73e10] [c00000000000c174] system_call_vectored_common+0xf4/0x278

osnoise tracer on ppc64le is triggering osnoise_taint() for negative
duration in get_int_safe_duration() called from
trace_sched_switch_callback()->thread_exit().

The problem though is that the check for a valid trace_percpu_buffer is
incorrect in get_trace_buf(). The check is being done after calculating
the pointer for the current cpu, rather than on the main percpu pointer.
Fix the check to be against trace_percpu_buffer.

Link: https://lkml.kernel.org/r/a920e4272e0b0635cf20c444707cbce1b2c8973d.1640255304.git.naveen.n.rao@linux.vnet.ibm.com

Cc: stable@vger.kernel.org
Fixes: e2ace001176dc9 ("tracing: Choose static tp_printk buffer by explicit nesting count")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Merge branch 'akpm' (patches from Andrew) 2021-12-25T20:30:03+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-12-25T20:30:03+00:00 d0cc67b2781654ac71c73d303e0347e5e9b10ad3 Merge misc fixes from Andrew Morton: "9 patches. Subsystems affected by this patch series: mm (kfence, mempolicy, memory-failure, pagemap, pagealloc, damon, and memory-failure), core-kernel, and MAINTAINERS" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() mm/damon/dbgfs: protect targets destructions with kdamond_lock mm/page_alloc: fix __alloc_size attribute for alloc_pages_exact_nid mm: delete unsafe BUG from page_cache_add_speculative() mm, hwpoison: fix condition in free hugetlb page path MAINTAINERS: mark more list instances as moderated kernel/crash_core: suppress unknown crashkernel parameter warning mm: mempolicy: fix THP allocations escaping mempolicy restrictions kfence: fix memory leak when cat kfence objects 
Merge misc fixes from Andrew Morton:
 "9 patches.

  Subsystems affected by this patch series: mm (kfence, mempolicy,
  memory-failure, pagemap, pagealloc, damon, and memory-failure),
  core-kernel, and MAINTAINERS"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page()
  mm/damon/dbgfs: protect targets destructions with kdamond_lock
  mm/page_alloc: fix __alloc_size attribute for alloc_pages_exact_nid
  mm: delete unsafe BUG from page_cache_add_speculative()
  mm, hwpoison: fix condition in free hugetlb page path
  MAINTAINERS: mark more list instances as moderated
  kernel/crash_core: suppress unknown crashkernel parameter warning
  mm: mempolicy: fix THP allocations escaping mempolicy restrictions
  kfence: fix memory leak when cat kfence objects
kernel/crash_core: suppress unknown crashkernel parameter warning 2021-12-25T20:20:55+00:00 Philipp Rudo prudo@redhat.com 2021-12-25T05:12:39+00:00 71d2bcec2d4d69ff109c497e6611d6c53c8926d4 When booting with crashkernel= on the kernel command line a warning similar to Kernel command line: ro console=ttyS0 crashkernel=256M Unknown kernel command line parameters "crashkernel=256M", will be passed to user space. is printed. This comes from crashkernel= being parsed independent from the kernel parameter handling mechanism. So the code in init/main.c doesn't know that crashkernel= is a valid kernel parameter and prints this incorrect warning. Suppress the warning by adding a dummy early_param handler for crashkernel=. Link: https://lkml.kernel.org/r/20211208133443.6867-1-prudo@redhat.com Fixes: 86d1919a4fb0 ("init: print out unknown kernel parameters") Signed-off-by: Philipp Rudo <prudo@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Andrew Halaney <ahalaney@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
When booting with crashkernel= on the kernel command line a warning
similar to

    Kernel command line: ro console=ttyS0 crashkernel=256M
    Unknown kernel command line parameters "crashkernel=256M", will be passed to user space.

is printed.

This comes from crashkernel= being parsed independent from the kernel
parameter handling mechanism.  So the code in init/main.c doesn't know
that crashkernel= is a valid kernel parameter and prints this incorrect
warning.

Suppress the warning by adding a dummy early_param handler for
crashkernel=.

Link: https://lkml.kernel.org/r/20211208133443.6867-1-prudo@redhat.com
Fixes: 86d1919a4fb0 ("init: print out unknown kernel parameters")
Signed-off-by: Philipp Rudo <prudo@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'ucount-rlimit-fixes-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-12-23T23:27:02+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-12-23T23:27:02+00:00 7fe2bc1b64650fa6e3a7088786a983766676fd84 Pull ucount fix from Eric Biederman: "This fixes a silly logic bug in the ucount rlimits code, where it was comparing against the wrong limit" * 'ucount-rlimit-fixes-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ucounts: Fix rlimit max values check 
Pull ucount fix from Eric Biederman:
 "This fixes a silly logic bug in the ucount rlimits code, where it was
  comparing against the wrong limit"

* 'ucount-rlimit-fixes-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ucounts: Fix rlimit max values check