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ddc1a5cbc0
Shrink shmem's stack usage by eliminating the pseudo-vma from its folio
allocation. alloc_pages_mpol(gfp, order, pol, ilx, nid) becomes the
principal actor for passing mempolicy choice down to __alloc_pages(),
rather than vma_alloc_folio(gfp, order, vma, addr, hugepage).
vma_alloc_folio() and alloc_pages() remain, but as wrappers around
alloc_pages_mpol(). alloc_pages_bulk_*() untouched, except to provide the
additional args to policy_nodemask(), which subsumes policy_node().
Cleanup throughout, cutting out some unhelpful "helpers".
It would all be much simpler without MPOL_INTERLEAVE, but that adds a
dynamic to the constant mpol: complicated by v3.6 commit 09c231cb8b
("tmpfs: distribute interleave better across nodes"), which added ino bias
to the interleave, hidden from mm/mempolicy.c until this commit.
Hence "ilx" throughout, the "interleave index". Originally I thought it
could be done just with nid, but that's wrong: the nodemask may come from
the shared policy layer below a shmem vma, or it may come from the task
layer above a shmem vma; and without the final nodemask then nodeid cannot
be decided. And how ilx is applied depends also on page order.
The interleave index is almost always irrelevant unless MPOL_INTERLEAVE:
with one exception in alloc_pages_mpol(), where the NO_INTERLEAVE_INDEX
passed down from vma-less alloc_pages() is also used as hint not to use
THP-style hugepage allocation - to avoid the overhead of a hugepage arg
(though I don't understand why we never just added a GFP bit for THP - if
it actually needs a different allocation strategy from other pages of the
same order). vma_alloc_folio() still carries its hugepage arg here, but
it is not used, and should be removed when agreed.
get_vma_policy() no longer allows a NULL vma: over time I believe we've
eradicated all the places which used to need it e.g. swapoff and madvise
used to pass NULL vma to read_swap_cache_async(), but now know the vma.
[hughd@google.com: handle NULL mpol being passed to __read_swap_cache_async()]
Link: https://lkml.kernel.org/r/ea419956-4751-0102-21f7-9c93cb957892@google.com
Link: https://lkml.kernel.org/r/74e34633-6060-f5e3-aee-7040d43f2e93@google.com
Link: https://lkml.kernel.org/r/1738368e-bac0-fd11-ed7f-b87142a939fe@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun heo <tj@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Domenico Cerasuolo <mimmocerasuolo@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1879 lines
45 KiB
C
1879 lines
45 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/ipc/shm.c
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* Copyright (C) 1992, 1993 Krishna Balasubramanian
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* Many improvements/fixes by Bruno Haible.
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* Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
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* Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
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*
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* /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
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* BIGMEM support, Andrea Arcangeli <andrea@suse.de>
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* SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
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* HIGHMEM support, Ingo Molnar <mingo@redhat.com>
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* Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
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* Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
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* Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
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*
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* support for audit of ipc object properties and permission changes
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* Dustin Kirkland <dustin.kirkland@us.ibm.com>
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*
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* namespaces support
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* OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*
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* Better ipc lock (kern_ipc_perm.lock) handling
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* Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/init.h>
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#include <linux/file.h>
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#include <linux/mman.h>
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#include <linux/shmem_fs.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/capability.h>
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#include <linux/ptrace.h>
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#include <linux/seq_file.h>
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#include <linux/rwsem.h>
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#include <linux/nsproxy.h>
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#include <linux/mount.h>
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#include <linux/ipc_namespace.h>
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#include <linux/rhashtable.h>
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#include <linux/uaccess.h>
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#include "util.h"
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struct shmid_kernel /* private to the kernel */
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{
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struct kern_ipc_perm shm_perm;
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struct file *shm_file;
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unsigned long shm_nattch;
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unsigned long shm_segsz;
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time64_t shm_atim;
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time64_t shm_dtim;
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time64_t shm_ctim;
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struct pid *shm_cprid;
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struct pid *shm_lprid;
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struct ucounts *mlock_ucounts;
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/*
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* The task created the shm object, for
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* task_lock(shp->shm_creator)
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*/
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struct task_struct *shm_creator;
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/*
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* List by creator. task_lock(->shm_creator) required for read/write.
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* If list_empty(), then the creator is dead already.
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*/
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struct list_head shm_clist;
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struct ipc_namespace *ns;
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} __randomize_layout;
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/* shm_mode upper byte flags */
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#define SHM_DEST 01000 /* segment will be destroyed on last detach */
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#define SHM_LOCKED 02000 /* segment will not be swapped */
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struct shm_file_data {
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int id;
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struct ipc_namespace *ns;
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struct file *file;
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const struct vm_operations_struct *vm_ops;
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};
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#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
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static const struct file_operations shm_file_operations;
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static const struct vm_operations_struct shm_vm_ops;
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#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
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#define shm_unlock(shp) \
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ipc_unlock(&(shp)->shm_perm)
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static int newseg(struct ipc_namespace *, struct ipc_params *);
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static void shm_open(struct vm_area_struct *vma);
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static void shm_close(struct vm_area_struct *vma);
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static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
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#ifdef CONFIG_PROC_FS
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static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
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#endif
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void shm_init_ns(struct ipc_namespace *ns)
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{
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ns->shm_ctlmax = SHMMAX;
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ns->shm_ctlall = SHMALL;
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ns->shm_ctlmni = SHMMNI;
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ns->shm_rmid_forced = 0;
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ns->shm_tot = 0;
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ipc_init_ids(&shm_ids(ns));
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}
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/*
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* Called with shm_ids.rwsem (writer) and the shp structure locked.
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* Only shm_ids.rwsem remains locked on exit.
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*/
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static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
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{
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struct shmid_kernel *shp;
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shp = container_of(ipcp, struct shmid_kernel, shm_perm);
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WARN_ON(ns != shp->ns);
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if (shp->shm_nattch) {
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shp->shm_perm.mode |= SHM_DEST;
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/* Do not find it any more */
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ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
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shm_unlock(shp);
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} else
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shm_destroy(ns, shp);
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}
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#ifdef CONFIG_IPC_NS
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void shm_exit_ns(struct ipc_namespace *ns)
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{
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free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
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idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
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rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
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}
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#endif
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static int __init ipc_ns_init(void)
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{
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shm_init_ns(&init_ipc_ns);
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return 0;
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}
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pure_initcall(ipc_ns_init);
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void __init shm_init(void)
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{
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ipc_init_proc_interface("sysvipc/shm",
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#if BITS_PER_LONG <= 32
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" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
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#else
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" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
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#endif
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IPC_SHM_IDS, sysvipc_shm_proc_show);
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}
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static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
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{
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struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
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if (IS_ERR(ipcp))
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return ERR_CAST(ipcp);
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return container_of(ipcp, struct shmid_kernel, shm_perm);
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}
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static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
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{
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struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
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if (IS_ERR(ipcp))
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return ERR_CAST(ipcp);
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return container_of(ipcp, struct shmid_kernel, shm_perm);
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}
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/*
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* shm_lock_(check_) routines are called in the paths where the rwsem
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* is not necessarily held.
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*/
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static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
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{
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struct kern_ipc_perm *ipcp;
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rcu_read_lock();
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ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
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if (IS_ERR(ipcp))
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goto err;
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ipc_lock_object(ipcp);
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/*
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* ipc_rmid() may have already freed the ID while ipc_lock_object()
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* was spinning: here verify that the structure is still valid.
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* Upon races with RMID, return -EIDRM, thus indicating that
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* the ID points to a removed identifier.
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*/
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if (ipc_valid_object(ipcp)) {
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/* return a locked ipc object upon success */
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return container_of(ipcp, struct shmid_kernel, shm_perm);
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}
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ipc_unlock_object(ipcp);
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ipcp = ERR_PTR(-EIDRM);
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err:
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rcu_read_unlock();
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/*
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* Callers of shm_lock() must validate the status of the returned ipc
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* object pointer and error out as appropriate.
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*/
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return ERR_CAST(ipcp);
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}
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static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
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{
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rcu_read_lock();
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ipc_lock_object(&ipcp->shm_perm);
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}
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static void shm_rcu_free(struct rcu_head *head)
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{
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struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
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rcu);
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struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
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shm_perm);
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security_shm_free(&shp->shm_perm);
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kfree(shp);
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}
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/*
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* It has to be called with shp locked.
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* It must be called before ipc_rmid()
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*/
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static inline void shm_clist_rm(struct shmid_kernel *shp)
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{
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struct task_struct *creator;
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/* ensure that shm_creator does not disappear */
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rcu_read_lock();
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/*
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* A concurrent exit_shm may do a list_del_init() as well.
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* Just do nothing if exit_shm already did the work
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*/
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if (!list_empty(&shp->shm_clist)) {
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/*
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* shp->shm_creator is guaranteed to be valid *only*
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* if shp->shm_clist is not empty.
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*/
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creator = shp->shm_creator;
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task_lock(creator);
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/*
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* list_del_init() is a nop if the entry was already removed
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* from the list.
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*/
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list_del_init(&shp->shm_clist);
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task_unlock(creator);
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}
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rcu_read_unlock();
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}
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static inline void shm_rmid(struct shmid_kernel *s)
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{
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shm_clist_rm(s);
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ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
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}
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static int __shm_open(struct shm_file_data *sfd)
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{
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struct shmid_kernel *shp;
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shp = shm_lock(sfd->ns, sfd->id);
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if (IS_ERR(shp))
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return PTR_ERR(shp);
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if (shp->shm_file != sfd->file) {
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/* ID was reused */
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shm_unlock(shp);
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return -EINVAL;
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}
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shp->shm_atim = ktime_get_real_seconds();
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ipc_update_pid(&shp->shm_lprid, task_tgid(current));
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shp->shm_nattch++;
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shm_unlock(shp);
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return 0;
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}
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/* This is called by fork, once for every shm attach. */
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static void shm_open(struct vm_area_struct *vma)
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{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
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int err;
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|
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/* Always call underlying open if present */
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if (sfd->vm_ops->open)
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sfd->vm_ops->open(vma);
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err = __shm_open(sfd);
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/*
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* We raced in the idr lookup or with shm_destroy().
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* Either way, the ID is busted.
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*/
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WARN_ON_ONCE(err);
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}
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/*
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* shm_destroy - free the struct shmid_kernel
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*
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* @ns: namespace
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* @shp: struct to free
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*
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* It has to be called with shp and shm_ids.rwsem (writer) locked,
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* but returns with shp unlocked and freed.
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*/
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static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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struct file *shm_file;
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shm_file = shp->shm_file;
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shp->shm_file = NULL;
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ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
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shm_rmid(shp);
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shm_unlock(shp);
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if (!is_file_hugepages(shm_file))
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shmem_lock(shm_file, 0, shp->mlock_ucounts);
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fput(shm_file);
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ipc_update_pid(&shp->shm_cprid, NULL);
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ipc_update_pid(&shp->shm_lprid, NULL);
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ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
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}
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/*
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* shm_may_destroy - identifies whether shm segment should be destroyed now
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*
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* Returns true if and only if there are no active users of the segment and
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* one of the following is true:
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*
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* 1) shmctl(id, IPC_RMID, NULL) was called for this shp
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*
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* 2) sysctl kernel.shm_rmid_forced is set to 1.
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*/
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static bool shm_may_destroy(struct shmid_kernel *shp)
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{
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return (shp->shm_nattch == 0) &&
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(shp->ns->shm_rmid_forced ||
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(shp->shm_perm.mode & SHM_DEST));
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}
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|
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/*
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* remove the attach descriptor vma.
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* free memory for segment if it is marked destroyed.
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* The descriptor has already been removed from the current->mm->mmap list
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* and will later be kfree()d.
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*/
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static void __shm_close(struct shm_file_data *sfd)
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{
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struct shmid_kernel *shp;
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struct ipc_namespace *ns = sfd->ns;
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down_write(&shm_ids(ns).rwsem);
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/* remove from the list of attaches of the shm segment */
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shp = shm_lock(ns, sfd->id);
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|
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/*
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* We raced in the idr lookup or with shm_destroy().
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* Either way, the ID is busted.
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*/
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if (WARN_ON_ONCE(IS_ERR(shp)))
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goto done; /* no-op */
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ipc_update_pid(&shp->shm_lprid, task_tgid(current));
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shp->shm_dtim = ktime_get_real_seconds();
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shp->shm_nattch--;
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if (shm_may_destroy(shp))
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shm_destroy(ns, shp);
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else
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shm_unlock(shp);
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done:
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up_write(&shm_ids(ns).rwsem);
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}
|
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|
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static void shm_close(struct vm_area_struct *vma)
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|
{
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struct file *file = vma->vm_file;
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struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
/* Always call underlying close if present */
|
|
if (sfd->vm_ops->close)
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sfd->vm_ops->close(vma);
|
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|
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__shm_close(sfd);
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}
|
|
|
|
/* Called with ns->shm_ids(ns).rwsem locked */
|
|
static int shm_try_destroy_orphaned(int id, void *p, void *data)
|
|
{
|
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struct ipc_namespace *ns = data;
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struct kern_ipc_perm *ipcp = p;
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struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
|
|
|
|
/*
|
|
* We want to destroy segments without users and with already
|
|
* exit'ed originating process.
|
|
*
|
|
* As shp->* are changed under rwsem, it's safe to skip shp locking.
|
|
*/
|
|
if (!list_empty(&shp->shm_clist))
|
|
return 0;
|
|
|
|
if (shm_may_destroy(shp)) {
|
|
shm_lock_by_ptr(shp);
|
|
shm_destroy(ns, shp);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void shm_destroy_orphaned(struct ipc_namespace *ns)
|
|
{
|
|
down_write(&shm_ids(ns).rwsem);
|
|
if (shm_ids(ns).in_use)
|
|
idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
|
|
up_write(&shm_ids(ns).rwsem);
|
|
}
|
|
|
|
/* Locking assumes this will only be called with task == current */
|
|
void exit_shm(struct task_struct *task)
|
|
{
|
|
for (;;) {
|
|
struct shmid_kernel *shp;
|
|
struct ipc_namespace *ns;
|
|
|
|
task_lock(task);
|
|
|
|
if (list_empty(&task->sysvshm.shm_clist)) {
|
|
task_unlock(task);
|
|
break;
|
|
}
|
|
|
|
shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
|
|
shm_clist);
|
|
|
|
/*
|
|
* 1) Get pointer to the ipc namespace. It is worth to say
|
|
* that this pointer is guaranteed to be valid because
|
|
* shp lifetime is always shorter than namespace lifetime
|
|
* in which shp lives.
|
|
* We taken task_lock it means that shp won't be freed.
|
|
*/
|
|
ns = shp->ns;
|
|
|
|
/*
|
|
* 2) If kernel.shm_rmid_forced is not set then only keep track of
|
|
* which shmids are orphaned, so that a later set of the sysctl
|
|
* can clean them up.
|
|
*/
|
|
if (!ns->shm_rmid_forced)
|
|
goto unlink_continue;
|
|
|
|
/*
|
|
* 3) get a reference to the namespace.
|
|
* The refcount could be already 0. If it is 0, then
|
|
* the shm objects will be free by free_ipc_work().
|
|
*/
|
|
ns = get_ipc_ns_not_zero(ns);
|
|
if (!ns) {
|
|
unlink_continue:
|
|
list_del_init(&shp->shm_clist);
|
|
task_unlock(task);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* 4) get a reference to shp.
|
|
* This cannot fail: shm_clist_rm() is called before
|
|
* ipc_rmid(), thus the refcount cannot be 0.
|
|
*/
|
|
WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
|
|
|
|
/*
|
|
* 5) unlink the shm segment from the list of segments
|
|
* created by current.
|
|
* This must be done last. After unlinking,
|
|
* only the refcounts obtained above prevent IPC_RMID
|
|
* from destroying the segment or the namespace.
|
|
*/
|
|
list_del_init(&shp->shm_clist);
|
|
|
|
task_unlock(task);
|
|
|
|
/*
|
|
* 6) we have all references
|
|
* Thus lock & if needed destroy shp.
|
|
*/
|
|
down_write(&shm_ids(ns).rwsem);
|
|
shm_lock_by_ptr(shp);
|
|
/*
|
|
* rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
|
|
* safe to call ipc_rcu_putref here
|
|
*/
|
|
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
|
|
|
|
if (ipc_valid_object(&shp->shm_perm)) {
|
|
if (shm_may_destroy(shp))
|
|
shm_destroy(ns, shp);
|
|
else
|
|
shm_unlock(shp);
|
|
} else {
|
|
/*
|
|
* Someone else deleted the shp from namespace
|
|
* idr/kht while we have waited.
|
|
* Just unlock and continue.
|
|
*/
|
|
shm_unlock(shp);
|
|
}
|
|
|
|
up_write(&shm_ids(ns).rwsem);
|
|
put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
|
|
}
|
|
}
|
|
|
|
static vm_fault_t shm_fault(struct vm_fault *vmf)
|
|
{
|
|
struct file *file = vmf->vma->vm_file;
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
return sfd->vm_ops->fault(vmf);
|
|
}
|
|
|
|
static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
struct file *file = vma->vm_file;
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
if (sfd->vm_ops->may_split)
|
|
return sfd->vm_ops->may_split(vma, addr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long shm_pagesize(struct vm_area_struct *vma)
|
|
{
|
|
struct file *file = vma->vm_file;
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
if (sfd->vm_ops->pagesize)
|
|
return sfd->vm_ops->pagesize(vma);
|
|
|
|
return PAGE_SIZE;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(vma->vm_file);
|
|
int err = 0;
|
|
|
|
if (sfd->vm_ops->set_policy)
|
|
err = sfd->vm_ops->set_policy(vma, mpol);
|
|
return err;
|
|
}
|
|
|
|
static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
|
|
unsigned long addr, pgoff_t *ilx)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(vma->vm_file);
|
|
struct mempolicy *mpol = vma->vm_policy;
|
|
|
|
if (sfd->vm_ops->get_policy)
|
|
mpol = sfd->vm_ops->get_policy(vma, addr, ilx);
|
|
return mpol;
|
|
}
|
|
#endif
|
|
|
|
static int shm_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
int ret;
|
|
|
|
/*
|
|
* In case of remap_file_pages() emulation, the file can represent an
|
|
* IPC ID that was removed, and possibly even reused by another shm
|
|
* segment already. Propagate this case as an error to caller.
|
|
*/
|
|
ret = __shm_open(sfd);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = call_mmap(sfd->file, vma);
|
|
if (ret) {
|
|
__shm_close(sfd);
|
|
return ret;
|
|
}
|
|
sfd->vm_ops = vma->vm_ops;
|
|
#ifdef CONFIG_MMU
|
|
WARN_ON(!sfd->vm_ops->fault);
|
|
#endif
|
|
vma->vm_ops = &shm_vm_ops;
|
|
return 0;
|
|
}
|
|
|
|
static int shm_release(struct inode *ino, struct file *file)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
put_ipc_ns(sfd->ns);
|
|
fput(sfd->file);
|
|
shm_file_data(file) = NULL;
|
|
kfree(sfd);
|
|
return 0;
|
|
}
|
|
|
|
static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
if (!sfd->file->f_op->fsync)
|
|
return -EINVAL;
|
|
return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
|
|
}
|
|
|
|
static long shm_fallocate(struct file *file, int mode, loff_t offset,
|
|
loff_t len)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
if (!sfd->file->f_op->fallocate)
|
|
return -EOPNOTSUPP;
|
|
return sfd->file->f_op->fallocate(file, mode, offset, len);
|
|
}
|
|
|
|
static unsigned long shm_get_unmapped_area(struct file *file,
|
|
unsigned long addr, unsigned long len, unsigned long pgoff,
|
|
unsigned long flags)
|
|
{
|
|
struct shm_file_data *sfd = shm_file_data(file);
|
|
|
|
return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
|
|
pgoff, flags);
|
|
}
|
|
|
|
static const struct file_operations shm_file_operations = {
|
|
.mmap = shm_mmap,
|
|
.fsync = shm_fsync,
|
|
.release = shm_release,
|
|
.get_unmapped_area = shm_get_unmapped_area,
|
|
.llseek = noop_llseek,
|
|
.fallocate = shm_fallocate,
|
|
};
|
|
|
|
/*
|
|
* shm_file_operations_huge is now identical to shm_file_operations,
|
|
* but we keep it distinct for the sake of is_file_shm_hugepages().
|
|
*/
|
|
static const struct file_operations shm_file_operations_huge = {
|
|
.mmap = shm_mmap,
|
|
.fsync = shm_fsync,
|
|
.release = shm_release,
|
|
.get_unmapped_area = shm_get_unmapped_area,
|
|
.llseek = noop_llseek,
|
|
.fallocate = shm_fallocate,
|
|
};
|
|
|
|
bool is_file_shm_hugepages(struct file *file)
|
|
{
|
|
return file->f_op == &shm_file_operations_huge;
|
|
}
|
|
|
|
static const struct vm_operations_struct shm_vm_ops = {
|
|
.open = shm_open, /* callback for a new vm-area open */
|
|
.close = shm_close, /* callback for when the vm-area is released */
|
|
.fault = shm_fault,
|
|
.may_split = shm_may_split,
|
|
.pagesize = shm_pagesize,
|
|
#if defined(CONFIG_NUMA)
|
|
.set_policy = shm_set_policy,
|
|
.get_policy = shm_get_policy,
|
|
#endif
|
|
};
|
|
|
|
/**
|
|
* newseg - Create a new shared memory segment
|
|
* @ns: namespace
|
|
* @params: ptr to the structure that contains key, size and shmflg
|
|
*
|
|
* Called with shm_ids.rwsem held as a writer.
|
|
*/
|
|
static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|
{
|
|
key_t key = params->key;
|
|
int shmflg = params->flg;
|
|
size_t size = params->u.size;
|
|
int error;
|
|
struct shmid_kernel *shp;
|
|
size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
struct file *file;
|
|
char name[13];
|
|
vm_flags_t acctflag = 0;
|
|
|
|
if (size < SHMMIN || size > ns->shm_ctlmax)
|
|
return -EINVAL;
|
|
|
|
if (numpages << PAGE_SHIFT < size)
|
|
return -ENOSPC;
|
|
|
|
if (ns->shm_tot + numpages < ns->shm_tot ||
|
|
ns->shm_tot + numpages > ns->shm_ctlall)
|
|
return -ENOSPC;
|
|
|
|
shp = kmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);
|
|
if (unlikely(!shp))
|
|
return -ENOMEM;
|
|
|
|
shp->shm_perm.key = key;
|
|
shp->shm_perm.mode = (shmflg & S_IRWXUGO);
|
|
shp->mlock_ucounts = NULL;
|
|
|
|
shp->shm_perm.security = NULL;
|
|
error = security_shm_alloc(&shp->shm_perm);
|
|
if (error) {
|
|
kfree(shp);
|
|
return error;
|
|
}
|
|
|
|
sprintf(name, "SYSV%08x", key);
|
|
if (shmflg & SHM_HUGETLB) {
|
|
struct hstate *hs;
|
|
size_t hugesize;
|
|
|
|
hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
|
|
if (!hs) {
|
|
error = -EINVAL;
|
|
goto no_file;
|
|
}
|
|
hugesize = ALIGN(size, huge_page_size(hs));
|
|
|
|
/* hugetlb_file_setup applies strict accounting */
|
|
if (shmflg & SHM_NORESERVE)
|
|
acctflag = VM_NORESERVE;
|
|
file = hugetlb_file_setup(name, hugesize, acctflag,
|
|
HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
|
|
} else {
|
|
/*
|
|
* Do not allow no accounting for OVERCOMMIT_NEVER, even
|
|
* if it's asked for.
|
|
*/
|
|
if ((shmflg & SHM_NORESERVE) &&
|
|
sysctl_overcommit_memory != OVERCOMMIT_NEVER)
|
|
acctflag = VM_NORESERVE;
|
|
file = shmem_kernel_file_setup(name, size, acctflag);
|
|
}
|
|
error = PTR_ERR(file);
|
|
if (IS_ERR(file))
|
|
goto no_file;
|
|
|
|
shp->shm_cprid = get_pid(task_tgid(current));
|
|
shp->shm_lprid = NULL;
|
|
shp->shm_atim = shp->shm_dtim = 0;
|
|
shp->shm_ctim = ktime_get_real_seconds();
|
|
shp->shm_segsz = size;
|
|
shp->shm_nattch = 0;
|
|
shp->shm_file = file;
|
|
shp->shm_creator = current;
|
|
|
|
/* ipc_addid() locks shp upon success. */
|
|
error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
|
|
if (error < 0)
|
|
goto no_id;
|
|
|
|
shp->ns = ns;
|
|
|
|
task_lock(current);
|
|
list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
|
|
task_unlock(current);
|
|
|
|
/*
|
|
* shmid gets reported as "inode#" in /proc/pid/maps.
|
|
* proc-ps tools use this. Changing this will break them.
|
|
*/
|
|
file_inode(file)->i_ino = shp->shm_perm.id;
|
|
|
|
ns->shm_tot += numpages;
|
|
error = shp->shm_perm.id;
|
|
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
rcu_read_unlock();
|
|
return error;
|
|
|
|
no_id:
|
|
ipc_update_pid(&shp->shm_cprid, NULL);
|
|
ipc_update_pid(&shp->shm_lprid, NULL);
|
|
fput(file);
|
|
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
|
|
return error;
|
|
no_file:
|
|
call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Called with shm_ids.rwsem and ipcp locked.
|
|
*/
|
|
static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
|
|
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
|
|
if (shp->shm_segsz < params->u.size)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
long ksys_shmget(key_t key, size_t size, int shmflg)
|
|
{
|
|
struct ipc_namespace *ns;
|
|
static const struct ipc_ops shm_ops = {
|
|
.getnew = newseg,
|
|
.associate = security_shm_associate,
|
|
.more_checks = shm_more_checks,
|
|
};
|
|
struct ipc_params shm_params;
|
|
|
|
ns = current->nsproxy->ipc_ns;
|
|
|
|
shm_params.key = key;
|
|
shm_params.flg = shmflg;
|
|
shm_params.u.size = size;
|
|
|
|
return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
|
|
{
|
|
return ksys_shmget(key, size, shmflg);
|
|
}
|
|
|
|
static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
|
|
{
|
|
switch (version) {
|
|
case IPC_64:
|
|
return copy_to_user(buf, in, sizeof(*in));
|
|
case IPC_OLD:
|
|
{
|
|
struct shmid_ds out;
|
|
|
|
memset(&out, 0, sizeof(out));
|
|
ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
|
|
out.shm_segsz = in->shm_segsz;
|
|
out.shm_atime = in->shm_atime;
|
|
out.shm_dtime = in->shm_dtime;
|
|
out.shm_ctime = in->shm_ctime;
|
|
out.shm_cpid = in->shm_cpid;
|
|
out.shm_lpid = in->shm_lpid;
|
|
out.shm_nattch = in->shm_nattch;
|
|
|
|
return copy_to_user(buf, &out, sizeof(out));
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static inline unsigned long
|
|
copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
|
|
{
|
|
switch (version) {
|
|
case IPC_64:
|
|
if (copy_from_user(out, buf, sizeof(*out)))
|
|
return -EFAULT;
|
|
return 0;
|
|
case IPC_OLD:
|
|
{
|
|
struct shmid_ds tbuf_old;
|
|
|
|
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
|
|
return -EFAULT;
|
|
|
|
out->shm_perm.uid = tbuf_old.shm_perm.uid;
|
|
out->shm_perm.gid = tbuf_old.shm_perm.gid;
|
|
out->shm_perm.mode = tbuf_old.shm_perm.mode;
|
|
|
|
return 0;
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
|
|
{
|
|
switch (version) {
|
|
case IPC_64:
|
|
return copy_to_user(buf, in, sizeof(*in));
|
|
case IPC_OLD:
|
|
{
|
|
struct shminfo out;
|
|
|
|
if (in->shmmax > INT_MAX)
|
|
out.shmmax = INT_MAX;
|
|
else
|
|
out.shmmax = (int)in->shmmax;
|
|
|
|
out.shmmin = in->shmmin;
|
|
out.shmmni = in->shmmni;
|
|
out.shmseg = in->shmseg;
|
|
out.shmall = in->shmall;
|
|
|
|
return copy_to_user(buf, &out, sizeof(out));
|
|
}
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Calculate and add used RSS and swap pages of a shm.
|
|
* Called with shm_ids.rwsem held as a reader
|
|
*/
|
|
static void shm_add_rss_swap(struct shmid_kernel *shp,
|
|
unsigned long *rss_add, unsigned long *swp_add)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = file_inode(shp->shm_file);
|
|
|
|
if (is_file_hugepages(shp->shm_file)) {
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct hstate *h = hstate_file(shp->shm_file);
|
|
*rss_add += pages_per_huge_page(h) * mapping->nrpages;
|
|
} else {
|
|
#ifdef CONFIG_SHMEM
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
|
|
spin_lock_irq(&info->lock);
|
|
*rss_add += inode->i_mapping->nrpages;
|
|
*swp_add += info->swapped;
|
|
spin_unlock_irq(&info->lock);
|
|
#else
|
|
*rss_add += inode->i_mapping->nrpages;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called with shm_ids.rwsem held as a reader
|
|
*/
|
|
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
|
|
unsigned long *swp)
|
|
{
|
|
int next_id;
|
|
int total, in_use;
|
|
|
|
*rss = 0;
|
|
*swp = 0;
|
|
|
|
in_use = shm_ids(ns).in_use;
|
|
|
|
for (total = 0, next_id = 0; total < in_use; next_id++) {
|
|
struct kern_ipc_perm *ipc;
|
|
struct shmid_kernel *shp;
|
|
|
|
ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
|
|
if (ipc == NULL)
|
|
continue;
|
|
shp = container_of(ipc, struct shmid_kernel, shm_perm);
|
|
|
|
shm_add_rss_swap(shp, rss, swp);
|
|
|
|
total++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This function handles some shmctl commands which require the rwsem
|
|
* to be held in write mode.
|
|
* NOTE: no locks must be held, the rwsem is taken inside this function.
|
|
*/
|
|
static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
|
|
struct shmid64_ds *shmid64)
|
|
{
|
|
struct kern_ipc_perm *ipcp;
|
|
struct shmid_kernel *shp;
|
|
int err;
|
|
|
|
down_write(&shm_ids(ns).rwsem);
|
|
rcu_read_lock();
|
|
|
|
ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
|
|
&shmid64->shm_perm, 0);
|
|
if (IS_ERR(ipcp)) {
|
|
err = PTR_ERR(ipcp);
|
|
goto out_unlock1;
|
|
}
|
|
|
|
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
|
|
|
|
err = security_shm_shmctl(&shp->shm_perm, cmd);
|
|
if (err)
|
|
goto out_unlock1;
|
|
|
|
switch (cmd) {
|
|
case IPC_RMID:
|
|
ipc_lock_object(&shp->shm_perm);
|
|
/* do_shm_rmid unlocks the ipc object and rcu */
|
|
do_shm_rmid(ns, ipcp);
|
|
goto out_up;
|
|
case IPC_SET:
|
|
ipc_lock_object(&shp->shm_perm);
|
|
err = ipc_update_perm(&shmid64->shm_perm, ipcp);
|
|
if (err)
|
|
goto out_unlock0;
|
|
shp->shm_ctim = ktime_get_real_seconds();
|
|
break;
|
|
default:
|
|
err = -EINVAL;
|
|
goto out_unlock1;
|
|
}
|
|
|
|
out_unlock0:
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
out_unlock1:
|
|
rcu_read_unlock();
|
|
out_up:
|
|
up_write(&shm_ids(ns).rwsem);
|
|
return err;
|
|
}
|
|
|
|
static int shmctl_ipc_info(struct ipc_namespace *ns,
|
|
struct shminfo64 *shminfo)
|
|
{
|
|
int err = security_shm_shmctl(NULL, IPC_INFO);
|
|
if (!err) {
|
|
memset(shminfo, 0, sizeof(*shminfo));
|
|
shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
|
|
shminfo->shmmax = ns->shm_ctlmax;
|
|
shminfo->shmall = ns->shm_ctlall;
|
|
shminfo->shmmin = SHMMIN;
|
|
down_read(&shm_ids(ns).rwsem);
|
|
err = ipc_get_maxidx(&shm_ids(ns));
|
|
up_read(&shm_ids(ns).rwsem);
|
|
if (err < 0)
|
|
err = 0;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int shmctl_shm_info(struct ipc_namespace *ns,
|
|
struct shm_info *shm_info)
|
|
{
|
|
int err = security_shm_shmctl(NULL, SHM_INFO);
|
|
if (!err) {
|
|
memset(shm_info, 0, sizeof(*shm_info));
|
|
down_read(&shm_ids(ns).rwsem);
|
|
shm_info->used_ids = shm_ids(ns).in_use;
|
|
shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
|
|
shm_info->shm_tot = ns->shm_tot;
|
|
shm_info->swap_attempts = 0;
|
|
shm_info->swap_successes = 0;
|
|
err = ipc_get_maxidx(&shm_ids(ns));
|
|
up_read(&shm_ids(ns).rwsem);
|
|
if (err < 0)
|
|
err = 0;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int shmctl_stat(struct ipc_namespace *ns, int shmid,
|
|
int cmd, struct shmid64_ds *tbuf)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
int err;
|
|
|
|
memset(tbuf, 0, sizeof(*tbuf));
|
|
|
|
rcu_read_lock();
|
|
if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
|
|
shp = shm_obtain_object(ns, shmid);
|
|
if (IS_ERR(shp)) {
|
|
err = PTR_ERR(shp);
|
|
goto out_unlock;
|
|
}
|
|
} else { /* IPC_STAT */
|
|
shp = shm_obtain_object_check(ns, shmid);
|
|
if (IS_ERR(shp)) {
|
|
err = PTR_ERR(shp);
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Semantically SHM_STAT_ANY ought to be identical to
|
|
* that functionality provided by the /proc/sysvipc/
|
|
* interface. As such, only audit these calls and
|
|
* do not do traditional S_IRUGO permission checks on
|
|
* the ipc object.
|
|
*/
|
|
if (cmd == SHM_STAT_ANY)
|
|
audit_ipc_obj(&shp->shm_perm);
|
|
else {
|
|
err = -EACCES;
|
|
if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = security_shm_shmctl(&shp->shm_perm, cmd);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
ipc_lock_object(&shp->shm_perm);
|
|
|
|
if (!ipc_valid_object(&shp->shm_perm)) {
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
err = -EIDRM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
|
|
tbuf->shm_segsz = shp->shm_segsz;
|
|
tbuf->shm_atime = shp->shm_atim;
|
|
tbuf->shm_dtime = shp->shm_dtim;
|
|
tbuf->shm_ctime = shp->shm_ctim;
|
|
#ifndef CONFIG_64BIT
|
|
tbuf->shm_atime_high = shp->shm_atim >> 32;
|
|
tbuf->shm_dtime_high = shp->shm_dtim >> 32;
|
|
tbuf->shm_ctime_high = shp->shm_ctim >> 32;
|
|
#endif
|
|
tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
|
|
tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
|
|
tbuf->shm_nattch = shp->shm_nattch;
|
|
|
|
if (cmd == IPC_STAT) {
|
|
/*
|
|
* As defined in SUS:
|
|
* Return 0 on success
|
|
*/
|
|
err = 0;
|
|
} else {
|
|
/*
|
|
* SHM_STAT and SHM_STAT_ANY (both Linux specific)
|
|
* Return the full id, including the sequence number
|
|
*/
|
|
err = shp->shm_perm.id;
|
|
}
|
|
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
return err;
|
|
}
|
|
|
|
static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
struct file *shm_file;
|
|
int err;
|
|
|
|
rcu_read_lock();
|
|
shp = shm_obtain_object_check(ns, shmid);
|
|
if (IS_ERR(shp)) {
|
|
err = PTR_ERR(shp);
|
|
goto out_unlock1;
|
|
}
|
|
|
|
audit_ipc_obj(&(shp->shm_perm));
|
|
err = security_shm_shmctl(&shp->shm_perm, cmd);
|
|
if (err)
|
|
goto out_unlock1;
|
|
|
|
ipc_lock_object(&shp->shm_perm);
|
|
|
|
/* check if shm_destroy() is tearing down shp */
|
|
if (!ipc_valid_object(&shp->shm_perm)) {
|
|
err = -EIDRM;
|
|
goto out_unlock0;
|
|
}
|
|
|
|
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
|
|
kuid_t euid = current_euid();
|
|
|
|
if (!uid_eq(euid, shp->shm_perm.uid) &&
|
|
!uid_eq(euid, shp->shm_perm.cuid)) {
|
|
err = -EPERM;
|
|
goto out_unlock0;
|
|
}
|
|
if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
|
|
err = -EPERM;
|
|
goto out_unlock0;
|
|
}
|
|
}
|
|
|
|
shm_file = shp->shm_file;
|
|
if (is_file_hugepages(shm_file))
|
|
goto out_unlock0;
|
|
|
|
if (cmd == SHM_LOCK) {
|
|
struct ucounts *ucounts = current_ucounts();
|
|
|
|
err = shmem_lock(shm_file, 1, ucounts);
|
|
if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
|
|
shp->shm_perm.mode |= SHM_LOCKED;
|
|
shp->mlock_ucounts = ucounts;
|
|
}
|
|
goto out_unlock0;
|
|
}
|
|
|
|
/* SHM_UNLOCK */
|
|
if (!(shp->shm_perm.mode & SHM_LOCKED))
|
|
goto out_unlock0;
|
|
shmem_lock(shm_file, 0, shp->mlock_ucounts);
|
|
shp->shm_perm.mode &= ~SHM_LOCKED;
|
|
shp->mlock_ucounts = NULL;
|
|
get_file(shm_file);
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
rcu_read_unlock();
|
|
shmem_unlock_mapping(shm_file->f_mapping);
|
|
|
|
fput(shm_file);
|
|
return err;
|
|
|
|
out_unlock0:
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
out_unlock1:
|
|
rcu_read_unlock();
|
|
return err;
|
|
}
|
|
|
|
static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
|
|
{
|
|
int err;
|
|
struct ipc_namespace *ns;
|
|
struct shmid64_ds sem64;
|
|
|
|
if (cmd < 0 || shmid < 0)
|
|
return -EINVAL;
|
|
|
|
ns = current->nsproxy->ipc_ns;
|
|
|
|
switch (cmd) {
|
|
case IPC_INFO: {
|
|
struct shminfo64 shminfo;
|
|
err = shmctl_ipc_info(ns, &shminfo);
|
|
if (err < 0)
|
|
return err;
|
|
if (copy_shminfo_to_user(buf, &shminfo, version))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
case SHM_INFO: {
|
|
struct shm_info shm_info;
|
|
err = shmctl_shm_info(ns, &shm_info);
|
|
if (err < 0)
|
|
return err;
|
|
if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
case SHM_STAT:
|
|
case SHM_STAT_ANY:
|
|
case IPC_STAT: {
|
|
err = shmctl_stat(ns, shmid, cmd, &sem64);
|
|
if (err < 0)
|
|
return err;
|
|
if (copy_shmid_to_user(buf, &sem64, version))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
case IPC_SET:
|
|
if (copy_shmid_from_user(&sem64, buf, version))
|
|
return -EFAULT;
|
|
fallthrough;
|
|
case IPC_RMID:
|
|
return shmctl_down(ns, shmid, cmd, &sem64);
|
|
case SHM_LOCK:
|
|
case SHM_UNLOCK:
|
|
return shmctl_do_lock(ns, shmid, cmd);
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
|
|
{
|
|
return ksys_shmctl(shmid, cmd, buf, IPC_64);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
|
|
long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
|
|
{
|
|
int version = ipc_parse_version(&cmd);
|
|
|
|
return ksys_shmctl(shmid, cmd, buf, version);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
|
|
{
|
|
return ksys_old_shmctl(shmid, cmd, buf);
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
struct compat_shmid_ds {
|
|
struct compat_ipc_perm shm_perm;
|
|
int shm_segsz;
|
|
old_time32_t shm_atime;
|
|
old_time32_t shm_dtime;
|
|
old_time32_t shm_ctime;
|
|
compat_ipc_pid_t shm_cpid;
|
|
compat_ipc_pid_t shm_lpid;
|
|
unsigned short shm_nattch;
|
|
unsigned short shm_unused;
|
|
compat_uptr_t shm_unused2;
|
|
compat_uptr_t shm_unused3;
|
|
};
|
|
|
|
struct compat_shminfo64 {
|
|
compat_ulong_t shmmax;
|
|
compat_ulong_t shmmin;
|
|
compat_ulong_t shmmni;
|
|
compat_ulong_t shmseg;
|
|
compat_ulong_t shmall;
|
|
compat_ulong_t __unused1;
|
|
compat_ulong_t __unused2;
|
|
compat_ulong_t __unused3;
|
|
compat_ulong_t __unused4;
|
|
};
|
|
|
|
struct compat_shm_info {
|
|
compat_int_t used_ids;
|
|
compat_ulong_t shm_tot, shm_rss, shm_swp;
|
|
compat_ulong_t swap_attempts, swap_successes;
|
|
};
|
|
|
|
static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
|
|
int version)
|
|
{
|
|
if (in->shmmax > INT_MAX)
|
|
in->shmmax = INT_MAX;
|
|
if (version == IPC_64) {
|
|
struct compat_shminfo64 info;
|
|
memset(&info, 0, sizeof(info));
|
|
info.shmmax = in->shmmax;
|
|
info.shmmin = in->shmmin;
|
|
info.shmmni = in->shmmni;
|
|
info.shmseg = in->shmseg;
|
|
info.shmall = in->shmall;
|
|
return copy_to_user(buf, &info, sizeof(info));
|
|
} else {
|
|
struct shminfo info;
|
|
memset(&info, 0, sizeof(info));
|
|
info.shmmax = in->shmmax;
|
|
info.shmmin = in->shmmin;
|
|
info.shmmni = in->shmmni;
|
|
info.shmseg = in->shmseg;
|
|
info.shmall = in->shmall;
|
|
return copy_to_user(buf, &info, sizeof(info));
|
|
}
|
|
}
|
|
|
|
static int put_compat_shm_info(struct shm_info *ip,
|
|
struct compat_shm_info __user *uip)
|
|
{
|
|
struct compat_shm_info info;
|
|
|
|
memset(&info, 0, sizeof(info));
|
|
info.used_ids = ip->used_ids;
|
|
info.shm_tot = ip->shm_tot;
|
|
info.shm_rss = ip->shm_rss;
|
|
info.shm_swp = ip->shm_swp;
|
|
info.swap_attempts = ip->swap_attempts;
|
|
info.swap_successes = ip->swap_successes;
|
|
return copy_to_user(uip, &info, sizeof(info));
|
|
}
|
|
|
|
static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
|
|
int version)
|
|
{
|
|
if (version == IPC_64) {
|
|
struct compat_shmid64_ds v;
|
|
memset(&v, 0, sizeof(v));
|
|
to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
|
|
v.shm_atime = lower_32_bits(in->shm_atime);
|
|
v.shm_atime_high = upper_32_bits(in->shm_atime);
|
|
v.shm_dtime = lower_32_bits(in->shm_dtime);
|
|
v.shm_dtime_high = upper_32_bits(in->shm_dtime);
|
|
v.shm_ctime = lower_32_bits(in->shm_ctime);
|
|
v.shm_ctime_high = upper_32_bits(in->shm_ctime);
|
|
v.shm_segsz = in->shm_segsz;
|
|
v.shm_nattch = in->shm_nattch;
|
|
v.shm_cpid = in->shm_cpid;
|
|
v.shm_lpid = in->shm_lpid;
|
|
return copy_to_user(buf, &v, sizeof(v));
|
|
} else {
|
|
struct compat_shmid_ds v;
|
|
memset(&v, 0, sizeof(v));
|
|
to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
|
|
v.shm_perm.key = in->shm_perm.key;
|
|
v.shm_atime = in->shm_atime;
|
|
v.shm_dtime = in->shm_dtime;
|
|
v.shm_ctime = in->shm_ctime;
|
|
v.shm_segsz = in->shm_segsz;
|
|
v.shm_nattch = in->shm_nattch;
|
|
v.shm_cpid = in->shm_cpid;
|
|
v.shm_lpid = in->shm_lpid;
|
|
return copy_to_user(buf, &v, sizeof(v));
|
|
}
|
|
}
|
|
|
|
static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
|
|
int version)
|
|
{
|
|
memset(out, 0, sizeof(*out));
|
|
if (version == IPC_64) {
|
|
struct compat_shmid64_ds __user *p = buf;
|
|
return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
|
|
} else {
|
|
struct compat_shmid_ds __user *p = buf;
|
|
return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
|
|
}
|
|
}
|
|
|
|
static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
|
|
{
|
|
struct ipc_namespace *ns;
|
|
struct shmid64_ds sem64;
|
|
int err;
|
|
|
|
ns = current->nsproxy->ipc_ns;
|
|
|
|
if (cmd < 0 || shmid < 0)
|
|
return -EINVAL;
|
|
|
|
switch (cmd) {
|
|
case IPC_INFO: {
|
|
struct shminfo64 shminfo;
|
|
err = shmctl_ipc_info(ns, &shminfo);
|
|
if (err < 0)
|
|
return err;
|
|
if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
case SHM_INFO: {
|
|
struct shm_info shm_info;
|
|
err = shmctl_shm_info(ns, &shm_info);
|
|
if (err < 0)
|
|
return err;
|
|
if (put_compat_shm_info(&shm_info, uptr))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
case IPC_STAT:
|
|
case SHM_STAT_ANY:
|
|
case SHM_STAT:
|
|
err = shmctl_stat(ns, shmid, cmd, &sem64);
|
|
if (err < 0)
|
|
return err;
|
|
if (copy_compat_shmid_to_user(uptr, &sem64, version))
|
|
err = -EFAULT;
|
|
return err;
|
|
|
|
case IPC_SET:
|
|
if (copy_compat_shmid_from_user(&sem64, uptr, version))
|
|
return -EFAULT;
|
|
fallthrough;
|
|
case IPC_RMID:
|
|
return shmctl_down(ns, shmid, cmd, &sem64);
|
|
case SHM_LOCK:
|
|
case SHM_UNLOCK:
|
|
return shmctl_do_lock(ns, shmid, cmd);
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
|
|
{
|
|
return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
|
|
long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
|
|
{
|
|
int version = compat_ipc_parse_version(&cmd);
|
|
|
|
return compat_ksys_shmctl(shmid, cmd, uptr, version);
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
|
|
{
|
|
return compat_ksys_old_shmctl(shmid, cmd, uptr);
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
/*
|
|
* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
|
|
*
|
|
* NOTE! Despite the name, this is NOT a direct system call entrypoint. The
|
|
* "raddr" thing points to kernel space, and there has to be a wrapper around
|
|
* this.
|
|
*/
|
|
long do_shmat(int shmid, char __user *shmaddr, int shmflg,
|
|
ulong *raddr, unsigned long shmlba)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
unsigned long addr = (unsigned long)shmaddr;
|
|
unsigned long size;
|
|
struct file *file, *base;
|
|
int err;
|
|
unsigned long flags = MAP_SHARED;
|
|
unsigned long prot;
|
|
int acc_mode;
|
|
struct ipc_namespace *ns;
|
|
struct shm_file_data *sfd;
|
|
int f_flags;
|
|
unsigned long populate = 0;
|
|
|
|
err = -EINVAL;
|
|
if (shmid < 0)
|
|
goto out;
|
|
|
|
if (addr) {
|
|
if (addr & (shmlba - 1)) {
|
|
if (shmflg & SHM_RND) {
|
|
addr &= ~(shmlba - 1); /* round down */
|
|
|
|
/*
|
|
* Ensure that the round-down is non-nil
|
|
* when remapping. This can happen for
|
|
* cases when addr < shmlba.
|
|
*/
|
|
if (!addr && (shmflg & SHM_REMAP))
|
|
goto out;
|
|
} else
|
|
#ifndef __ARCH_FORCE_SHMLBA
|
|
if (addr & ~PAGE_MASK)
|
|
#endif
|
|
goto out;
|
|
}
|
|
|
|
flags |= MAP_FIXED;
|
|
} else if ((shmflg & SHM_REMAP))
|
|
goto out;
|
|
|
|
if (shmflg & SHM_RDONLY) {
|
|
prot = PROT_READ;
|
|
acc_mode = S_IRUGO;
|
|
f_flags = O_RDONLY;
|
|
} else {
|
|
prot = PROT_READ | PROT_WRITE;
|
|
acc_mode = S_IRUGO | S_IWUGO;
|
|
f_flags = O_RDWR;
|
|
}
|
|
if (shmflg & SHM_EXEC) {
|
|
prot |= PROT_EXEC;
|
|
acc_mode |= S_IXUGO;
|
|
}
|
|
|
|
/*
|
|
* We cannot rely on the fs check since SYSV IPC does have an
|
|
* additional creator id...
|
|
*/
|
|
ns = current->nsproxy->ipc_ns;
|
|
rcu_read_lock();
|
|
shp = shm_obtain_object_check(ns, shmid);
|
|
if (IS_ERR(shp)) {
|
|
err = PTR_ERR(shp);
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = -EACCES;
|
|
if (ipcperms(ns, &shp->shm_perm, acc_mode))
|
|
goto out_unlock;
|
|
|
|
err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
ipc_lock_object(&shp->shm_perm);
|
|
|
|
/* check if shm_destroy() is tearing down shp */
|
|
if (!ipc_valid_object(&shp->shm_perm)) {
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
err = -EIDRM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* We need to take a reference to the real shm file to prevent the
|
|
* pointer from becoming stale in cases where the lifetime of the outer
|
|
* file extends beyond that of the shm segment. It's not usually
|
|
* possible, but it can happen during remap_file_pages() emulation as
|
|
* that unmaps the memory, then does ->mmap() via file reference only.
|
|
* We'll deny the ->mmap() if the shm segment was since removed, but to
|
|
* detect shm ID reuse we need to compare the file pointers.
|
|
*/
|
|
base = get_file(shp->shm_file);
|
|
shp->shm_nattch++;
|
|
size = i_size_read(file_inode(base));
|
|
ipc_unlock_object(&shp->shm_perm);
|
|
rcu_read_unlock();
|
|
|
|
err = -ENOMEM;
|
|
sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
|
|
if (!sfd) {
|
|
fput(base);
|
|
goto out_nattch;
|
|
}
|
|
|
|
file = alloc_file_clone(base, f_flags,
|
|
is_file_hugepages(base) ?
|
|
&shm_file_operations_huge :
|
|
&shm_file_operations);
|
|
err = PTR_ERR(file);
|
|
if (IS_ERR(file)) {
|
|
kfree(sfd);
|
|
fput(base);
|
|
goto out_nattch;
|
|
}
|
|
|
|
sfd->id = shp->shm_perm.id;
|
|
sfd->ns = get_ipc_ns(ns);
|
|
sfd->file = base;
|
|
sfd->vm_ops = NULL;
|
|
file->private_data = sfd;
|
|
|
|
err = security_mmap_file(file, prot, flags);
|
|
if (err)
|
|
goto out_fput;
|
|
|
|
if (mmap_write_lock_killable(current->mm)) {
|
|
err = -EINTR;
|
|
goto out_fput;
|
|
}
|
|
|
|
if (addr && !(shmflg & SHM_REMAP)) {
|
|
err = -EINVAL;
|
|
if (addr + size < addr)
|
|
goto invalid;
|
|
|
|
if (find_vma_intersection(current->mm, addr, addr + size))
|
|
goto invalid;
|
|
}
|
|
|
|
addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
|
|
*raddr = addr;
|
|
err = 0;
|
|
if (IS_ERR_VALUE(addr))
|
|
err = (long)addr;
|
|
invalid:
|
|
mmap_write_unlock(current->mm);
|
|
if (populate)
|
|
mm_populate(addr, populate);
|
|
|
|
out_fput:
|
|
fput(file);
|
|
|
|
out_nattch:
|
|
down_write(&shm_ids(ns).rwsem);
|
|
shp = shm_lock(ns, shmid);
|
|
shp->shm_nattch--;
|
|
|
|
if (shm_may_destroy(shp))
|
|
shm_destroy(ns, shp);
|
|
else
|
|
shm_unlock(shp);
|
|
up_write(&shm_ids(ns).rwsem);
|
|
return err;
|
|
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
|
|
{
|
|
unsigned long ret;
|
|
long err;
|
|
|
|
err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
|
|
if (err)
|
|
return err;
|
|
force_successful_syscall_return();
|
|
return (long)ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
#ifndef COMPAT_SHMLBA
|
|
#define COMPAT_SHMLBA SHMLBA
|
|
#endif
|
|
|
|
COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
|
|
{
|
|
unsigned long ret;
|
|
long err;
|
|
|
|
err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
|
|
if (err)
|
|
return err;
|
|
force_successful_syscall_return();
|
|
return (long)ret;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* detach and kill segment if marked destroyed.
|
|
* The work is done in shm_close.
|
|
*/
|
|
long ksys_shmdt(char __user *shmaddr)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma;
|
|
unsigned long addr = (unsigned long)shmaddr;
|
|
int retval = -EINVAL;
|
|
#ifdef CONFIG_MMU
|
|
loff_t size = 0;
|
|
struct file *file;
|
|
VMA_ITERATOR(vmi, mm, addr);
|
|
#endif
|
|
|
|
if (addr & ~PAGE_MASK)
|
|
return retval;
|
|
|
|
if (mmap_write_lock_killable(mm))
|
|
return -EINTR;
|
|
|
|
/*
|
|
* This function tries to be smart and unmap shm segments that
|
|
* were modified by partial mlock or munmap calls:
|
|
* - It first determines the size of the shm segment that should be
|
|
* unmapped: It searches for a vma that is backed by shm and that
|
|
* started at address shmaddr. It records it's size and then unmaps
|
|
* it.
|
|
* - Then it unmaps all shm vmas that started at shmaddr and that
|
|
* are within the initially determined size and that are from the
|
|
* same shm segment from which we determined the size.
|
|
* Errors from do_munmap are ignored: the function only fails if
|
|
* it's called with invalid parameters or if it's called to unmap
|
|
* a part of a vma. Both calls in this function are for full vmas,
|
|
* the parameters are directly copied from the vma itself and always
|
|
* valid - therefore do_munmap cannot fail. (famous last words?)
|
|
*/
|
|
/*
|
|
* If it had been mremap()'d, the starting address would not
|
|
* match the usual checks anyway. So assume all vma's are
|
|
* above the starting address given.
|
|
*/
|
|
|
|
#ifdef CONFIG_MMU
|
|
for_each_vma(vmi, vma) {
|
|
/*
|
|
* Check if the starting address would match, i.e. it's
|
|
* a fragment created by mprotect() and/or munmap(), or it
|
|
* otherwise it starts at this address with no hassles.
|
|
*/
|
|
if ((vma->vm_ops == &shm_vm_ops) &&
|
|
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
|
|
|
|
/*
|
|
* Record the file of the shm segment being
|
|
* unmapped. With mremap(), someone could place
|
|
* page from another segment but with equal offsets
|
|
* in the range we are unmapping.
|
|
*/
|
|
file = vma->vm_file;
|
|
size = i_size_read(file_inode(vma->vm_file));
|
|
do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
|
|
NULL, false);
|
|
/*
|
|
* We discovered the size of the shm segment, so
|
|
* break out of here and fall through to the next
|
|
* loop that uses the size information to stop
|
|
* searching for matching vma's.
|
|
*/
|
|
retval = 0;
|
|
vma = vma_next(&vmi);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We need look no further than the maximum address a fragment
|
|
* could possibly have landed at. Also cast things to loff_t to
|
|
* prevent overflows and make comparisons vs. equal-width types.
|
|
*/
|
|
size = PAGE_ALIGN(size);
|
|
while (vma && (loff_t)(vma->vm_end - addr) <= size) {
|
|
/* finding a matching vma now does not alter retval */
|
|
if ((vma->vm_ops == &shm_vm_ops) &&
|
|
((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
|
|
(vma->vm_file == file)) {
|
|
do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
|
|
NULL, false);
|
|
}
|
|
|
|
vma = vma_next(&vmi);
|
|
}
|
|
|
|
#else /* CONFIG_MMU */
|
|
vma = vma_lookup(mm, addr);
|
|
/* under NOMMU conditions, the exact address to be destroyed must be
|
|
* given
|
|
*/
|
|
if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
|
|
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
|
|
retval = 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
mmap_write_unlock(mm);
|
|
return retval;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
|
|
{
|
|
return ksys_shmdt(shmaddr);
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
|
|
{
|
|
struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
|
|
struct user_namespace *user_ns = seq_user_ns(s);
|
|
struct kern_ipc_perm *ipcp = it;
|
|
struct shmid_kernel *shp;
|
|
unsigned long rss = 0, swp = 0;
|
|
|
|
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
|
|
shm_add_rss_swap(shp, &rss, &swp);
|
|
|
|
#if BITS_PER_LONG <= 32
|
|
#define SIZE_SPEC "%10lu"
|
|
#else
|
|
#define SIZE_SPEC "%21lu"
|
|
#endif
|
|
|
|
seq_printf(s,
|
|
"%10d %10d %4o " SIZE_SPEC " %5u %5u "
|
|
"%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
|
|
SIZE_SPEC " " SIZE_SPEC "\n",
|
|
shp->shm_perm.key,
|
|
shp->shm_perm.id,
|
|
shp->shm_perm.mode,
|
|
shp->shm_segsz,
|
|
pid_nr_ns(shp->shm_cprid, pid_ns),
|
|
pid_nr_ns(shp->shm_lprid, pid_ns),
|
|
shp->shm_nattch,
|
|
from_kuid_munged(user_ns, shp->shm_perm.uid),
|
|
from_kgid_munged(user_ns, shp->shm_perm.gid),
|
|
from_kuid_munged(user_ns, shp->shm_perm.cuid),
|
|
from_kgid_munged(user_ns, shp->shm_perm.cgid),
|
|
shp->shm_atim,
|
|
shp->shm_dtim,
|
|
shp->shm_ctim,
|
|
rss * PAGE_SIZE,
|
|
swp * PAGE_SIZE);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|