linux.git/ipc, branch v6.1.154

ipc: fix to protect IPCS lookups using RCU

2025-06-27T10:07:30+00:00

commit d66adabe91803ef34a8b90613c81267b5ded1472 upstream.

syzbot reported that it discovered a use-after-free vulnerability, [0]

[0]: https://lore.kernel.org/all/67af13f8.050a0220.21dd3.0038.GAE@google.com/

idr_for_each() is protected by rwsem, but this is not enough.  If it is
not protected by RCU read-critical region, when idr_for_each() calls
radix_tree_node_free() through call_rcu() to free the radix_tree_node
structure, the node will be freed immediately, and when reading the next
node in radix_tree_for_each_slot(), the already freed memory may be read.

Therefore, we need to add code to make sure that idr_for_each() is
protected within the RCU read-critical region when we call it in
shm_destroy_orphaned().

Link: https://lkml.kernel.org/r/20250424143322.18830-1-aha310510@gmail.com
Fixes: b34a6b1da371 ("ipc: introduce shm_rmid_forced sysctl")
Signed-off-by: Jeongjun Park 
Reported-by: syzbot+a2b84e569d06ca3a949c@syzkaller.appspotmail.com
Cc: Jeongjun Park 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Matthew Wilcox (Oracle) 
Cc: Vasiliy Kulikov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

ipc: fix memleak if msg_init_ns failed in create_ipc_ns

2024-12-14T18:54:06+00:00

commit bc8f5921cd69188627c08041276238de222ab466 upstream.

Percpu memory allocation may failed during create_ipc_ns however this
fail is not handled properly since ipc sysctls and mq sysctls is not
released properly. Fix this by release these two resource when failure.

Here is the kmemleak stack when percpu failed:

unreferenced object 0xffff88819de2a600 (size 512):
  comm "shmem_2nstest", pid 120711, jiffies 4300542254
  hex dump (first 32 bytes):
    60 aa 9d 84 ff ff ff ff fc 18 48 b2 84 88 ff ff  `.........H.....
    04 00 00 00 a4 01 00 00 20 e4 56 81 ff ff ff ff  ........ .V.....
  backtrace (crc be7cba35):
    [] __kmalloc_node_track_caller_noprof+0x333/0x420
    [] kmemdup_noprof+0x26/0x50
    [] setup_mq_sysctls+0x57/0x1d0
    [] copy_ipcs+0x29c/0x3b0
    [] create_new_namespaces+0x1d0/0x920
    [] copy_namespaces+0x2e9/0x3e0
    [] copy_process+0x29f3/0x7ff0
    [] kernel_clone+0xc0/0x650
    [] __do_sys_clone+0xa1/0xe0
    [] do_syscall_64+0xbf/0x1c0
    [] entry_SYSCALL_64_after_hwframe+0x4b/0x53

Link: https://lkml.kernel.org/r/20241023093129.3074301-1-mawupeng1@huawei.com
Fixes: 72d1e611082e ("ipc/msg: mitigate the lock contention with percpu counter")
Signed-off-by: Ma Wupeng 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table)

2024-08-11T10:35:51+00:00

[ Upstream commit 520713a93d550406dae14d49cdb8778d70cecdfd ]

Remove the 'table' argument from set_ownership as it is never used. This
change is a step towards putting "struct ctl_table" into .rodata and
eventually having sysctl core only use "const struct ctl_table".

The patch was created with the following coccinelle script:

  @@
  identifier func, head, table, uid, gid;
  @@

  void func(
    struct ctl_table_header *head,
  - struct ctl_table *table,
    kuid_t *uid, kgid_t *gid)
  { ... }

No additional occurrences of 'set_ownership' were found after doing a
tree-wide search.

Reviewed-by: Joel Granados 
Signed-off-by: Thomas Weißschuh 
Signed-off-by: Joel Granados 
Stable-dep-of: 98ca62ba9e2b ("sysctl: always initialize i_uid/i_gid")
Signed-off-by: Sasha Levin

sysctl: allow to change limits for posix messages queues

2024-08-11T10:35:51+00:00

[ Upstream commit f9436a5d0497f759330d07e1189565edd4456be8 ]

All parameters of posix messages queues (queues_max/msg_max/msgsize_max)
end up being limited by RLIMIT_MSGQUEUE.  The code in mqueue_get_inode is
where that limiting happens.

The RLIMIT_MSGQUEUE is bound to the user namespace and is counted
hierarchically.

We can allow root in the user namespace to modify the posix messages
queues parameters.

Link: https://lkml.kernel.org/r/6ad67f23d1459a4f4339f74aa73bac0ecf3995e1.1705333426.git.legion@kernel.org
Signed-off-by: Alexey Gladkov 
Signed-off-by: Eric W. Biederman 
Link: https://lkml.kernel.org/r/7eb21211c8622e91d226e63416b1b93c079f60ee.1663756794.git.legion@kernel.org
Cc: Christian Brauner 
Cc: Davidlohr Bueso 
Cc: Joel Granados 
Cc: Kees Cook 
Cc: Luis Chamberlain 
Cc: Manfred Spraul 
Signed-off-by: Andrew Morton 
Stable-dep-of: 98ca62ba9e2b ("sysctl: always initialize i_uid/i_gid")
Signed-off-by: Sasha Levin

sysctl: allow change system v ipc sysctls inside ipc namespace

2024-08-11T10:35:51+00:00

[ Upstream commit 50ec499b9a43e46200c9f7b7d723ab2e4af540b3 ]

Patch series "Allow to change ipc/mq sysctls inside ipc namespace", v3.

Right now ipc and mq limits count as per ipc namespace, but only real root
can change them.  By default, the current values of these limits are such
that it can only be reduced.  Since only root can change the values, it is
impossible to reduce these limits in the rootless container.

We can allow limit changes within ipc namespace because mq parameters are
limited by RLIMIT_MSGQUEUE and ipc parameters are not limited to anything
other than cgroups.

This patch (of 3):

Rootless containers are not allowed to modify kernel IPC parameters.

All default limits are set to such high values that in fact there are no
limits at all.  All limits are not inherited and are initialized to
default values when a new ipc_namespace is created.

For new ipc_namespace:

size_t       ipc_ns.shm_ctlmax = SHMMAX; // (ULONG_MAX - (1UL << 24))
size_t       ipc_ns.shm_ctlall = SHMALL; // (ULONG_MAX - (1UL << 24))
int          ipc_ns.shm_ctlmni = IPCMNI; // (1 << 15)
int          ipc_ns.shm_rmid_forced = 0;
unsigned int ipc_ns.msg_ctlmax = MSGMAX; // 8192
unsigned int ipc_ns.msg_ctlmni = MSGMNI; // 32000
unsigned int ipc_ns.msg_ctlmnb = MSGMNB; // 16384

The shm_tot (total amount of shared pages) has also ceased to be global,
it is located in ipc_namespace and is not inherited from anywhere.

In such conditions, it cannot be said that these limits limit anything.
The real limiter for them is cgroups.

If we allow rootless containers to change these parameters, then it can
only be reduced.

Link: https://lkml.kernel.org/r/cover.1705333426.git.legion@kernel.org
Link: https://lkml.kernel.org/r/d2f4603305cbfed58a24755aa61d027314b73a45.1705333426.git.legion@kernel.org
Signed-off-by: Alexey Gladkov 
Signed-off-by: Eric W. Biederman 
Link: https://lkml.kernel.org/r/e2d84d3ec0172cfff759e6065da84ce0cc2736f8.1663756794.git.legion@kernel.org
Cc: Christian Brauner 
Cc: Joel Granados 
Cc: Kees Cook 
Cc: Luis Chamberlain 
Cc: Manfred Spraul 
Cc: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Stable-dep-of: 98ca62ba9e2b ("sysctl: always initialize i_uid/i_gid")
Signed-off-by: Sasha Levin

ipc: fix memory leak in init_mqueue_fs()

2022-12-31T12:32:01+00:00

[ Upstream commit 12b677f2c697d61e5ddbcb6c1650050a39392f54 ]

When setup_mq_sysctls() failed in init_mqueue_fs(), mqueue_inode_cachep is
not released.  In order to fix this issue, the release path is reordered.

Link: https://lkml.kernel.org/r/20221209092929.1978875-1-shaozhengchao@huawei.com
Fixes: dc55e35f9e81 ("ipc: Store mqueue sysctls in the ipc namespace")
Signed-off-by: Zhengchao Shao 
Cc: Alexey Gladkov 
Cc: "Eric W. Biederman" 
Cc: Jingyu Wang 
Cc: Muchun Song 
Cc: Roman Gushchin 
Cc: Waiman Long 
Cc: Wei Yongjun 
Cc: YueHaibing 
Cc: Yu Zhe 
Cc: Manfred Spraul 
Cc: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

ipc/sem: Fix dangling sem_array access in semtimedop race

2022-12-05T18:54:44+00:00

When __do_semtimedop() goes to sleep because it has to wait for a
semaphore value becoming zero or becoming bigger than some threshold, it
links the on-stack sem_queue to the sem_array, then goes to sleep
without holding a reference on the sem_array.

When __do_semtimedop() comes back out of sleep, one of two things must
happen:

 a) We prove that the on-stack sem_queue has been disconnected from the
    (possibly freed) sem_array, making it safe to return from the stack
    frame that the sem_queue exists in.

 b) We stabilize our reference to the sem_array, lock the sem_array, and
    detach the sem_queue from the sem_array ourselves.

sem_array has RCU lifetime, so for case (b), the reference can be
stabilized inside an RCU read-side critical section by locklessly
checking whether the sem_queue is still connected to the sem_array.

However, the current code does the lockless check on sem_queue before
starting an RCU read-side critical section, so the result of the
lockless check immediately becomes useless.

Fix it by doing rcu_read_lock() before the lockless check.  Now RCU
ensures that if we observe the object being on our queue, the object
can't be freed until rcu_read_unlock().

This bug is only hittable on kernel builds with full preemption support
(either CONFIG_PREEMPT or PREEMPT_DYNAMIC with preempt=full).

Fixes: 370b262c896e ("ipc/sem: avoid idr tree lookup for interrupted semop")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn 
Signed-off-by: Linus Torvalds

ipc/shm: call underlying open/close vm_ops

2022-11-23T02:50:42+00:00

Shared memory segments can be created that are backed by hugetlb pages. 
When this happens, the vmas associated with any mappings (shmat) are
marked VM_HUGETLB, yet the vm_ops for such mappings are provided by
ipc/shm (shm_vm_ops).  There is a mechanism to call the underlying hugetlb
vm_ops, and this is done for most operations.  However, it is not done for
open and close.

This was not an issue until the introduction of the hugetlb vma_lock. 
This lock structure is pointed to by vm_private_data and the open/close
vm_ops help maintain this structure.  The special hugetlb routine called
at fork took care of structure updates at fork time.  However,
vma_splitting is not properly handled for ipc shared memory mappings
backed by hugetlb pages.  This can result in a "kernel NULL pointer
dereference" BUG or use after free as two vmas point to the same lock
structure.

Update the shm open and close routines to always call the underlying open
and close routines.

Link: https://lkml.kernel.org/r/20221114210018.49346-1-mike.kravetz@oracle.com
Fixes: 8d9bfb260814 ("hugetlb: add vma based lock for pmd sharing")
Signed-off-by: Mike Kravetz 
Reported-by: Doug Nelson 
Reported-by: 
Cc: Alexander Mikhalitsyn 
Cc: "Eric W . Biederman" 
Cc: Manfred Spraul 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton

ipc/msg.c: fix percpu_counter use after free

2022-10-28T20:37:22+00:00

These percpu counters are referenced in free_ipcs->freeque, so destroy
them later.

Fixes: 72d1e611082e ("ipc/msg: mitigate the lock contention with percpu counter")
Reported-by: syzbot+96e659d35b9d6b541152@syzkaller.appspotmail.com
Tested-by: Mark Rutland 
Cc: Jiebin Sun 
Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-12T18:00:22+00:00

Pull non-MM updates from Andrew Morton:

 - hfs and hfsplus kmap API modernization (Fabio Francesco)

 - make crash-kexec work properly when invoked from an NMI-time panic
   (Valentin Schneider)

 - ntfs bugfixes (Hawkins Jiawei)

 - improve IPC msg scalability by replacing atomic_t's with percpu
   counters (Jiebin Sun)

 - nilfs2 cleanups (Minghao Chi)

 - lots of other single patches all over the tree!

* tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits)
  include/linux/entry-common.h: remove has_signal comment of arch_do_signal_or_restart() prototype
  proc: test how it holds up with mapping'less process
  mailmap: update Frank Rowand email address
  ia64: mca: use strscpy() is more robust and safer
  init/Kconfig: fix unmet direct dependencies
  ia64: update config files
  nilfs2: replace WARN_ONs by nilfs_error for checkpoint acquisition failure
  fork: remove duplicate included header files
  init/main.c: remove unnecessary (void*) conversions
  proc: mark more files as permanent
  nilfs2: remove the unneeded result variable
  nilfs2: delete unnecessary checks before brelse()
  checkpatch: warn for non-standard fixes tag style
  usr/gen_init_cpio.c: remove unnecessary -1 values from int file
  ipc/msg: mitigate the lock contention with percpu counter
  percpu: add percpu_counter_add_local and percpu_counter_sub_local
  fs/ocfs2: fix repeated words in comments
  relay: use kvcalloc to alloc page array in relay_alloc_page_array
  proc: make config PROC_CHILDREN depend on PROC_FS
  fs: uninline inode_maybe_inc_iversion()
  ...