Commit Graph

38350 Commits

Author SHA1 Message Date
Jakub Kicinski
aaa25a2fa7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
tools/testing/selftests/net/mptcp/mptcp_join.sh
  34aa6e3bcc ("selftests: mptcp: add ip mptcp wrappers")

  857898eb4b ("selftests: mptcp: add missing join check")
  6ef84b1517 ("selftests: mptcp: more robust signal race test")
https://lore.kernel.org/all/20220221131842.468893-1-broonie@kernel.org/

drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/act.h
drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/ct.c
  fb7e76ea3f ("net/mlx5e: TC, Skip redundant ct clear actions")
  c63741b426 ("net/mlx5e: Fix MPLSoUDP encap to use MPLS action information")

  09bf979232 ("net/mlx5e: TC, Move pedit_headers_action to parse_attr")
  84ba8062e3 ("net/mlx5e: Test CT and SAMPLE on flow attr")
  efe6f961cd ("net/mlx5e: CT, Don't set flow flag CT for ct clear flow")
  3b49a7edec ("net/mlx5e: TC, Reject rules with multiple CT actions")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-24 17:54:25 -08:00
Linus Torvalds
f672ff9123 Merge tag 'net-5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf and netfilter.

  Current release - regressions:

   - bpf: fix crash due to out of bounds access into reg2btf_ids

   - mvpp2: always set port pcs ops, avoid null-deref

   - eth: marvell: fix driver load from initrd

   - eth: intel: revert "Fix reset bw limit when DCB enabled with 1 TC"

  Current release - new code bugs:

   - mptcp: fix race in overlapping signal events

  Previous releases - regressions:

   - xen-netback: revert hotplug-status changes causing devices to not
     be configured

   - dsa:
      - avoid call to __dev_set_promiscuity() while rtnl_mutex isn't
        held
      - fix panic when removing unoffloaded port from bridge

   - dsa: microchip: fix bridging with more than two member ports

  Previous releases - always broken:

   - bpf:
      - fix crash due to incorrect copy_map_value when both spin lock
        and timer are present in a single value
      - fix a bpf_timer initialization issue with clang
      - do not try bpf_msg_push_data with len 0
      - add schedule points in batch ops

   - nf_tables:
      - unregister flowtable hooks on netns exit
      - correct flow offload action array size
      - fix a couple of memory leaks

   - vsock: don't check owner in vhost_vsock_stop() while releasing

   - gso: do not skip outer ip header in case of ipip and net_failover

   - smc: use a mutex for locking "struct smc_pnettable"

   - openvswitch: fix setting ipv6 fields causing hw csum failure

   - mptcp: fix race in incoming ADD_ADDR option processing

   - sysfs: add check for netdevice being present to speed_show

   - sched: act_ct: fix flow table lookup after ct clear or switching
     zones

   - eth: intel: fixes for SR-IOV forwarding offloads

   - eth: broadcom: fixes for selftests and error recovery

   - eth: mellanox: flow steering and SR-IOV forwarding fixes

  Misc:

   - make __pskb_pull_tail() & pskb_carve_frag_list() drop_monitor
     friends not report freed skbs as drops

   - force inlining of checksum functions in net/checksum.h"

* tag 'net-5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (85 commits)
  net: mv643xx_eth: process retval from of_get_mac_address
  ping: remove pr_err from ping_lookup
  Revert "i40e: Fix reset bw limit when DCB enabled with 1 TC"
  openvswitch: Fix setting ipv6 fields causing hw csum failure
  ipv6: prevent a possible race condition with lifetimes
  net/smc: Use a mutex for locking "struct smc_pnettable"
  bnx2x: fix driver load from initrd
  Revert "xen-netback: Check for hotplug-status existence before watching"
  Revert "xen-netback: remove 'hotplug-status' once it has served its purpose"
  net/mlx5e: Fix VF min/max rate parameters interchange mistake
  net/mlx5e: Add missing increment of count
  net/mlx5e: MPLSoUDP decap, fix check for unsupported matches
  net/mlx5e: Fix MPLSoUDP encap to use MPLS action information
  net/mlx5e: Add feature check for set fec counters
  net/mlx5e: TC, Skip redundant ct clear actions
  net/mlx5e: TC, Reject rules with forward and drop actions
  net/mlx5e: TC, Reject rules with drop and modify hdr action
  net/mlx5e: kTLS, Use CHECKSUM_UNNECESSARY for device-offloaded packets
  net/mlx5e: Fix wrong return value on ioctl EEPROM query failure
  net/mlx5: Fix possible deadlock on rule deletion
  ...
2022-02-24 12:45:32 -08:00
Linus Torvalds
5c1ee56966 Merge branch 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:

 - Fix for a subtle bug in the recent release_agent permission check
   update

 - Fix for a long-standing race condition between cpuset and cpu hotplug

 - Comment updates

* 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: Fix kernel-doc
  cgroup-v1: Correct privileges check in release_agent writes
  cgroup: clarify cgroup_css_set_fork()
  cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug
2022-02-22 16:14:35 -08:00
Jiapeng Chong
c70cd039f1 cpuset: Fix kernel-doc
Fix the following W=1 kernel warnings:

kernel/cgroup/cpuset.c:3718: warning: expecting prototype for
cpuset_memory_pressure_bump(). Prototype was for
__cpuset_memory_pressure_bump() instead.

kernel/cgroup/cpuset.c:3568: warning: expecting prototype for
cpuset_node_allowed(). Prototype was for __cpuset_node_allowed()
instead.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2022-02-22 09:49:49 -10:00
Michal Koutný
467a726b75 cgroup-v1: Correct privileges check in release_agent writes
The idea is to check: a) the owning user_ns of cgroup_ns, b)
capabilities in init_user_ns.

The commit 24f6008564 ("cgroup-v1: Require capabilities to set
release_agent") got this wrong in the write handler of release_agent
since it checked user_ns of the opener (may be different from the owning
user_ns of cgroup_ns).
Secondly, to avoid possibly confused deputy, the capability of the
opener must be checked.

Fixes: 24f6008564 ("cgroup-v1: Require capabilities to set release_agent")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/stable/20220216121142.GB30035@blackbody.suse.cz/
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Masami Ichikawa(CIP) <masami.ichikawa@cybertrust.co.jp>
Signed-off-by: Tejun Heo <tj@kernel.org>
2022-02-22 08:12:22 -10:00
Christian Brauner
6d3971dab2 cgroup: clarify cgroup_css_set_fork()
With recent fixes for the permission checking when moving a task into a cgroup
using a file descriptor to a cgroup's cgroup.procs file and calling write() it
seems a good idea to clarify CLONE_INTO_CGROUP permission checking with a
comment.

Cc: Tejun Heo <tj@kernel.org>
Cc: <cgroups@vger.kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2022-02-22 07:35:19 -10:00
Linus Torvalds
3324e6e803 Merge tag 'locking_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Borislav Petkov:
 "Fix a NULL ptr dereference when dumping lockdep chains through
  /proc/lockdep_chains"

* tag 'locking_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Correct lock_classes index mapping
2022-02-20 12:50:50 -08:00
Linus Torvalds
0b0894ff78 Merge tag 'sched_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Borislav Petkov:
 "Fix task exposure order when forking tasks"

* tag 'sched_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix yet more sched_fork() races
2022-02-20 12:40:20 -08:00
Linus Torvalds
c1034d249d Merge tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd fix from Christian Brauner:
 "This fixes a problem reported by lockdep when installing a pidfd via
  fd_install() with siglock and the tasklisk write lock held in
  copy_process() when calling clone()/clone3() with CLONE_PIDFD.

  Originally a pidfd was created prior to holding any of these locks but
  this required a call to ksys_close(). So quite some time ago in
  6fd2fe494b ("copy_process(): don't use ksys_close() on cleanups") we
  switched to a get_unused_fd_flags() + fd_install() model.

  As part of that we moved fd_install() as late as possible. This was
  done for two main reasons. First, because we needed to ensure that we
  call fd_install() past the point of no return as once that's called
  the fd is live in the task's file table. Second, because we tried to
  ensure that the fd is visible in /proc/<pid>/fd/<pidfd> right when the
  task is visible.

  This fix moves the fd_install() to an even later point which means
  that a task will be visible in proc while the pidfd isn't yet under
  /proc/<pid>/fd/<pidfd>.

  While this is a user visible change it's very unlikely that this will
  have any impact. Nobody should be relying on that and if they do we
  need to come up with something better but again, it's doubtful this is
  relevant"

* tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  copy_process(): Move fd_install() out of sighand->siglock critical section
2022-02-20 10:55:05 -08:00
Linus Torvalds
2d3409ebc8 Merge branch 'ucount-rlimit-fixes-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucounts fixes from Eric Biederman:
 "Michal Koutný recently found some bugs in the enforcement of
  RLIMIT_NPROC in the recent ucount rlimit implementation.

  In this set of patches I have developed a very conservative approach
  changing only what is necessary to fix the bugs that I can see
  clearly. Cleanups and anything that is making the code more consistent
  can follow after we have the code working as it has historically.

  The problem is not so much inconsistencies (although those exist) but
  that it is very difficult to figure out what the code should be doing
  in the case of RLIMIT_NPROC.

  All other rlimits are only enforced where the resource is acquired
  (allocated). RLIMIT_NPROC by necessity needs to be enforced in an
  additional location, and our current implementation stumbled it's way
  into that implementation"

* 'ucount-rlimit-fixes-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  ucounts: Handle wrapping in is_ucounts_overlimit
  ucounts: Move RLIMIT_NPROC handling after set_user
  ucounts: Base set_cred_ucounts changes on the real user
  ucounts: Enforce RLIMIT_NPROC not RLIMIT_NPROC+1
  rlimit: Fix RLIMIT_NPROC enforcement failure caused by capability calls in set_user
2022-02-20 10:44:11 -08:00
Peter Zijlstra
b1e8206582 sched: Fix yet more sched_fork() races
Where commit 4ef0c5c6b5 ("kernel/sched: Fix sched_fork() access an
invalid sched_task_group") fixed a fork race vs cgroup, it opened up a
race vs syscalls by not placing the task on the runqueue before it
gets exposed through the pidhash.

Commit 13765de814 ("sched/fair: Fix fault in reweight_entity") is
trying to fix a single instance of this, instead fix the whole class
of issues, effectively reverting this commit.

Fixes: 4ef0c5c6b5 ("kernel/sched: Fix sched_fork() access an invalid sched_task_group")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Tested-by: Zhang Qiao <zhangqiao22@huawei.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lkml.kernel.org/r/YgoeCbwj5mbCR0qA@hirez.programming.kicks-ass.net
2022-02-19 11:11:05 +01:00
Jakub Kicinski
a3fc4b1d09 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
bpf-next 2022-02-17

We've added 29 non-merge commits during the last 8 day(s) which contain
a total of 34 files changed, 1502 insertions(+), 524 deletions(-).

The main changes are:

1) Add BTFGen support to bpftool which allows to use CO-RE in kernels without
   BTF info, from Mauricio Vásquez, Rafael David Tinoco, Lorenzo Fontana and
   Leonardo Di Donato. (Details: https://lpc.events/event/11/contributions/948/)

2) Prepare light skeleton to be used in both kernel module and user space
   and convert bpf_preload.ko to use light skeleton, from Alexei Starovoitov.

3) Rework bpftool's versioning scheme and align with libbpf's version number;
   also add linked libbpf version info to "bpftool version", from Quentin Monnet.

4) Add minimal C++ specific additions to bpftool's skeleton codegen to
   facilitate use of C skeletons in C++ applications, from Andrii Nakryiko.

5) Add BPF verifier sanity check whether relative offset on kfunc calls overflows
   desc->imm and reject the BPF program if the case, from Hou Tao.

6) Fix libbpf to use a dynamically allocated buffer for netlink messages to
   avoid receiving truncated messages on some archs, from Toke Høiland-Jørgensen.

7) Various follow-up fixes to the JIT bpf_prog_pack allocator, from Song Liu.

8) Various BPF selftest and vmtest.sh fixes, from Yucong Sun.

9) Fix bpftool pretty print handling on dumping map keys/values when no BTF
   is available, from Jiri Olsa and Yinjun Zhang.

10) Extend XDP frags selftest to check for invalid length, from Lorenzo Bianconi.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (29 commits)
  bpf: bpf_prog_pack: Set proper size before freeing ro_header
  selftests/bpf: Fix crash in core_reloc when bpftool btfgen fails
  selftests/bpf: Fix vmtest.sh to launch smp vm.
  libbpf: Fix memleak in libbpf_netlink_recv()
  bpftool: Fix C++ additions to skeleton
  bpftool: Fix pretty print dump for maps without BTF loaded
  selftests/bpf: Test "bpftool gen min_core_btf"
  bpftool: Gen min_core_btf explanation and examples
  bpftool: Implement btfgen_get_btf()
  bpftool: Implement "gen min_core_btf" logic
  bpftool: Add gen min_core_btf command
  libbpf: Expose bpf_core_{add,free}_cands() to bpftool
  libbpf: Split bpf_core_apply_relo()
  bpf: Reject kfunc calls that overflow insn->imm
  selftests/bpf: Add Skeleton templated wrapper as an example
  bpftool: Add C++-specific open/load/etc skeleton wrappers
  selftests/bpf: Fix GCC11 compiler warnings in -O2 mode
  bpftool: Fix the error when lookup in no-btf maps
  libbpf: Use dynamically allocated buffer when receiving netlink messages
  libbpf: Fix libbpf.map inheritance chain for LIBBPF_0.7.0
  ...
====================

Link: https://lore.kernel.org/r/20220217232027.29831-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 17:23:52 -08:00
Song Liu
d24d2a2b0a bpf: bpf_prog_pack: Set proper size before freeing ro_header
bpf_prog_pack_free() uses header->size to decide whether the header
should be freed with module_memfree() or the bpf_prog_pack logic.
However, in kvmalloc() failure path of bpf_jit_binary_pack_alloc(),
header->size is not set yet. As a result, bpf_prog_pack_free() may treat
a slice of a pack as a standalone kvmalloc'd header and call
module_memfree() on the whole pack. This in turn causes use-after-free by
other users of the pack.

Fix this by setting ro_header->size before freeing ro_header.

Fixes: 33c9805860 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]")
Reported-by: syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com
Reported-by: syzbot+ecb1e7e51c52f68f7481@syzkaller.appspotmail.com
Reported-by: syzbot+87f65c75f4a72db05445@syzkaller.appspotmail.com
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220217183001.1876034-1-song@kernel.org
2022-02-17 13:15:36 -08:00
Jakub Kicinski
93d11e0d76 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Fast path bpf marge for some -next work.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 12:22:28 -08:00
Jakub Kicinski
7a2fb91285 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:

====================
pull-request: bpf 2022-02-17

We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 8 files changed, 119 insertions(+), 15 deletions(-).

The main changes are:

1) Add schedule points in map batch ops, from Eric.

2) Fix bpf_msg_push_data with len 0, from Felix.

3) Fix crash due to incorrect copy_map_value, from Kumar.

4) Fix crash due to out of bounds access into reg2btf_ids, from Kumar.

5) Fix a bpf_timer initialization issue with clang, from Yonghong.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Add schedule points in batch ops
  bpf: Fix crash due to out of bounds access into reg2btf_ids.
  selftests: bpf: Check bpf_msg_push_data return value
  bpf: Fix a bpf_timer initialization issue
  bpf: Emit bpf_timer in vmlinux BTF
  selftests/bpf: Add test for bpf_timer overwriting crash
  bpf: Fix crash due to incorrect copy_map_value
  bpf: Do not try bpf_msg_push_data with len 0
====================

Link: https://lore.kernel.org/r/20220217190000.37925-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 12:01:55 -08:00
Jakub Kicinski
6b5567b1b2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 11:44:20 -08:00
Eric Dumazet
75134f16e7 bpf: Add schedule points in batch ops
syzbot reported various soft lockups caused by bpf batch operations.

 INFO: task kworker/1:1:27 blocked for more than 140 seconds.
 INFO: task hung in rcu_barrier

Nothing prevents batch ops to process huge amount of data,
we need to add schedule points in them.

Note that maybe_wait_bpf_programs(map) calls from
generic_map_delete_batch() can be factorized by moving
the call after the loop.

This will be done later in -next tree once we get this fix merged,
unless there is strong opinion doing this optimization sooner.

Fixes: aa2e93b8e5 ("bpf: Add generic support for update and delete batch ops")
Fixes: cb4d03ab49 ("bpf: Add generic support for lookup batch op")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Brian Vazquez <brianvv@google.com>
Link: https://lore.kernel.org/bpf/20220217181902.808742-1-eric.dumazet@gmail.com
2022-02-17 10:48:26 -08:00
Eric W. Biederman
0cbae9e24f ucounts: Handle wrapping in is_ucounts_overlimit
While examining is_ucounts_overlimit and reading the various messages
I realized that is_ucounts_overlimit fails to deal with counts that
may have wrapped.

Being wrapped should be a transitory state for counts and they should
never be wrapped for long, but it can happen so handle it.

Cc: stable@vger.kernel.org
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Link: https://lkml.kernel.org/r/20220216155832.680775-5-ebiederm@xmission.com
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:11:57 -06:00
Eric W. Biederman
c923a8e7ed ucounts: Move RLIMIT_NPROC handling after set_user
During set*id() which cred->ucounts to charge the the current process
to is not known until after set_cred_ucounts.  So move the
RLIMIT_NPROC checking into a new helper flag_nproc_exceeded and call
flag_nproc_exceeded after set_cred_ucounts.

This is very much an arbitrary subset of the places where we currently
change the RLIMIT_NPROC accounting, designed to preserve the existing
logic.

Fixing the existing logic will be the subject of another series of
changes.

Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220216155832.680775-4-ebiederm@xmission.com
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:11:26 -06:00
Eric W. Biederman
a55d07294f ucounts: Base set_cred_ucounts changes on the real user
Michal Koutný <mkoutny@suse.com> wrote:
> Tasks are associated to multiple users at once. Historically and as per
> setrlimit(2) RLIMIT_NPROC is enforce based on real user ID.
>
> The commit 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
> made the accounting structure "indexed" by euid and hence potentially
> account tasks differently.
>
> The effective user ID may be different e.g. for setuid programs but
> those are exec'd into already existing task (i.e. below limit), so
> different accounting is moot.
>
> Some special setresuid(2) users may notice the difference, justifying
> this fix.

I looked at cred->ucount and it is only used for rlimit operations
that were previously stored in cred->user.  Making the fact
cred->ucount can refer to a different user from cred->user a bug,
affecting all uses of cred->ulimit not just RLIMIT_NPROC.

Fix set_cred_ucounts to always use the real uid not the effective uid.

Further simplify set_cred_ucounts by noticing that set_cred_ucounts
somehow retained a draft version of the check to see if alloc_ucounts
was needed that checks the new->user and new->user_ns against the
current_real_cred().  Remove that draft version of the check.

All that matters for setting the cred->ucounts are the user_ns and uid
fields in the cred.

Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220207121800.5079-4-mkoutny@suse.com
Link: https://lkml.kernel.org/r/20220216155832.680775-3-ebiederm@xmission.com
Reported-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:11:02 -06:00
Eric W. Biederman
8f2f9c4d82 ucounts: Enforce RLIMIT_NPROC not RLIMIT_NPROC+1
Michal Koutný <mkoutny@suse.com> wrote:

> It was reported that v5.14 behaves differently when enforcing
> RLIMIT_NPROC limit, namely, it allows one more task than previously.
> This is consequence of the commit 21d1c5e386 ("Reimplement
> RLIMIT_NPROC on top of ucounts") that missed the sharpness of
> equality in the forking path.

This can be fixed either by fixing the test or by moving the increment
to be before the test.  Fix it my moving copy_creds which contains
the increment before is_ucounts_overlimit.

In the case of CLONE_NEWUSER the ucounts in the task_cred changes.
The function is_ucounts_overlimit needs to use the final version of
the ucounts for the new process.  Which means moving the
is_ucounts_overlimit test after copy_creds is necessary.

Both the test in fork and the test in set_user were semantically
changed when the code moved to ucounts.  The change of the test in
fork was bad because it was before the increment.  The test in
set_user was wrong and the change to ucounts fixed it.  So this
fix only restores the old behavior in one lcation not two.

Link: https://lkml.kernel.org/r/20220204181144.24462-1-mkoutny@suse.com
Link: https://lkml.kernel.org/r/20220216155832.680775-2-ebiederm@xmission.com
Cc: stable@vger.kernel.org
Reported-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:10:33 -06:00
Eric W. Biederman
c16bdeb5a3 rlimit: Fix RLIMIT_NPROC enforcement failure caused by capability calls in set_user
Solar Designer <solar@openwall.com> wrote:
> I'm not aware of anyone actually running into this issue and reporting
> it.  The systems that I personally know use suexec along with rlimits
> still run older/distro kernels, so would not yet be affected.
>
> So my mention was based on my understanding of how suexec works, and
> code review.  Specifically, Apache httpd has the setting RLimitNPROC,
> which makes it set RLIMIT_NPROC:
>
> https://httpd.apache.org/docs/2.4/mod/core.html#rlimitnproc
>
> The above documentation for it includes:
>
> "This applies to processes forked from Apache httpd children servicing
> requests, not the Apache httpd children themselves. This includes CGI
> scripts and SSI exec commands, but not any processes forked from the
> Apache httpd parent, such as piped logs."
>
> In code, there are:
>
> ./modules/generators/mod_cgid.c:        ( (cgid_req.limits.limit_nproc_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC,
> ./modules/generators/mod_cgi.c:        ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC,
> ./modules/filters/mod_ext_filter.c:    rv = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC, conf->limit_nproc);
>
> For example, in mod_cgi.c this is in run_cgi_child().
>
> I think this means an httpd child sets RLIMIT_NPROC shortly before it
> execs suexec, which is a SUID root program.  suexec then switches to the
> target user and execs the CGI script.
>
> Before 2863643fb8, the setuid() in suexec would set the flag, and the
> target user's process count would be checked against RLIMIT_NPROC on
> execve().  After 2863643fb8, the setuid() in suexec wouldn't set the
> flag because setuid() is (naturally) called when the process is still
> running as root (thus, has those limits bypass capabilities), and
> accordingly execve() would not check the target user's process count
> against RLIMIT_NPROC.

In commit 2863643fb8 ("set_user: add capability check when
rlimit(RLIMIT_NPROC) exceeds") capable calls were added to set_user to
make it more consistent with fork.  Unfortunately because of call site
differences those capable calls were checking the credentials of the
user before set*id() instead of after set*id().

This breaks enforcement of RLIMIT_NPROC for applications that set the
rlimit and then call set*id() while holding a full set of
capabilities.  The capabilities are only changed in the new credential
in security_task_fix_setuid().

The code in apache suexec appears to follow this pattern.

Commit 909cc4ae86f3 ("[PATCH] Fix two bugs with process limits
(RLIMIT_NPROC)") where this check was added describes the targes of this
capability check as:

  2/ When a root-owned process (e.g. cgiwrap) sets up process limits and then
      calls setuid, the setuid should fail if the user would then be running
      more than rlim_cur[RLIMIT_NPROC] processes, but it doesn't.  This patch
      adds an appropriate test.  With this patch, and per-user process limit
      imposed in cgiwrap really works.

So the original use case of this check also appears to match the broken
pattern.

Restore the enforcement of RLIMIT_NPROC by removing the bad capable
checks added in set_user.  This unfortunately restores the
inconsistent state the code has been in for the last 11 years, but
dealing with the inconsistencies looks like a larger problem.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20210907213042.GA22626@openwall.com/
Link: https://lkml.kernel.org/r/20220212221412.GA29214@openwall.com
Link: https://lkml.kernel.org/r/20220216155832.680775-1-ebiederm@xmission.com
Fixes: 2863643fb8 ("set_user: add capability check when rlimit(RLIMIT_NPROC) exceeds")
History-Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Reviewed-by: Solar Designer <solar@openwall.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:08:05 -06:00
Dmitry Torokhov
a8e8f851e8 module: fix building with sysfs disabled
Sysfs support might be disabled so we need to guard the code that
instantiates "compression" attribute with an #ifdef.

Fixes: b1ae6dc41e ("module: add in-kernel support for decompressing")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-02-16 12:51:32 -08:00
Kumar Kartikeya Dwivedi
45ce4b4f90 bpf: Fix crash due to out of bounds access into reg2btf_ids.
When commit e6ac2450d6 ("bpf: Support bpf program calling kernel function") added
kfunc support, it defined reg2btf_ids as a cheap way to translate the verifier
reg type to the appropriate btf_vmlinux BTF ID, however
commit c25b2ae136 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL")
moved the __BPF_REG_TYPE_MAX from the last member of bpf_reg_type enum to after
the base register types, and defined other variants using type flag
composition. However, now, the direct usage of reg->type to index into
reg2btf_ids may no longer fall into __BPF_REG_TYPE_MAX range, and hence lead to
out of bounds access and kernel crash on dereference of bad pointer.

Fixes: c25b2ae136 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220216201943.624869-1-memxor@gmail.com
2022-02-16 12:46:51 -08:00
Mauricio Vásquez
adb8fa195e libbpf: Split bpf_core_apply_relo()
BTFGen needs to run the core relocation logic in order to understand
what are the types involved in a given relocation.

Currently bpf_core_apply_relo() calculates and **applies** a relocation
to an instruction. Having both operations in the same function makes it
difficult to only calculate the relocation without patching the
instruction. This commit splits that logic in two different phases: (1)
calculate the relocation and (2) patch the instruction.

For the first phase bpf_core_apply_relo() is renamed to
bpf_core_calc_relo_insn() who is now only on charge of calculating the
relocation, the second phase uses the already existing
bpf_core_patch_insn(). bpf_object__relocate_core() uses both of them and
the BTFGen will use only bpf_core_calc_relo_insn().

Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com>
Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co>
Signed-off-by: Leonardo Di Donato <leonardo.didonato@elastic.co>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220215225856.671072-2-mauricio@kinvolk.io
2022-02-16 10:05:42 -08:00