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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /ipc/shm.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'ipc/shm.c')
-rw-r--r--ipc/shm.c1883
1 files changed, 1883 insertions, 0 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
new file mode 100644
index 000000000..bd2fcc4d4
--- /dev/null
+++ b/ipc/shm.c
@@ -0,0 +1,1883 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/ipc/shm.c
+ * Copyright (C) 1992, 1993 Krishna Balasubramanian
+ * Many improvements/fixes by Bruno Haible.
+ * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
+ * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
+ *
+ * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
+ * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
+ * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
+ * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
+ * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
+ * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
+ * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ *
+ * namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
+ *
+ * Better ipc lock (kern_ipc_perm.lock) handling
+ * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
+ */
+
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/shm.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/mman.h>
+#include <linux/shmem_fs.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <linux/capability.h>
+#include <linux/ptrace.h>
+#include <linux/seq_file.h>
+#include <linux/rwsem.h>
+#include <linux/nsproxy.h>
+#include <linux/mount.h>
+#include <linux/ipc_namespace.h>
+#include <linux/rhashtable.h>
+
+#include <linux/uaccess.h>
+
+#include "util.h"
+
+struct shmid_kernel /* private to the kernel */
+{
+ struct kern_ipc_perm shm_perm;
+ struct file *shm_file;
+ unsigned long shm_nattch;
+ unsigned long shm_segsz;
+ time64_t shm_atim;
+ time64_t shm_dtim;
+ time64_t shm_ctim;
+ struct pid *shm_cprid;
+ struct pid *shm_lprid;
+ struct ucounts *mlock_ucounts;
+
+ /*
+ * The task created the shm object, for
+ * task_lock(shp->shm_creator)
+ */
+ struct task_struct *shm_creator;
+
+ /*
+ * List by creator. task_lock(->shm_creator) required for read/write.
+ * If list_empty(), then the creator is dead already.
+ */
+ struct list_head shm_clist;
+ struct ipc_namespace *ns;
+} __randomize_layout;
+
+/* shm_mode upper byte flags */
+#define SHM_DEST 01000 /* segment will be destroyed on last detach */
+#define SHM_LOCKED 02000 /* segment will not be swapped */
+
+struct shm_file_data {
+ int id;
+ struct ipc_namespace *ns;
+ struct file *file;
+ const struct vm_operations_struct *vm_ops;
+};
+
+#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
+
+static const struct file_operations shm_file_operations;
+static const struct vm_operations_struct shm_vm_ops;
+
+#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
+
+#define shm_unlock(shp) \
+ ipc_unlock(&(shp)->shm_perm)
+
+static int newseg(struct ipc_namespace *, struct ipc_params *);
+static void shm_open(struct vm_area_struct *vma);
+static void shm_close(struct vm_area_struct *vma);
+static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
+#ifdef CONFIG_PROC_FS
+static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
+#endif
+
+void shm_init_ns(struct ipc_namespace *ns)
+{
+ ns->shm_ctlmax = SHMMAX;
+ ns->shm_ctlall = SHMALL;
+ ns->shm_ctlmni = SHMMNI;
+ ns->shm_rmid_forced = 0;
+ ns->shm_tot = 0;
+ ipc_init_ids(&shm_ids(ns));
+}
+
+/*
+ * Called with shm_ids.rwsem (writer) and the shp structure locked.
+ * Only shm_ids.rwsem remains locked on exit.
+ */
+static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
+{
+ struct shmid_kernel *shp;
+
+ shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+ WARN_ON(ns != shp->ns);
+
+ if (shp->shm_nattch) {
+ shp->shm_perm.mode |= SHM_DEST;
+ /* Do not find it any more */
+ ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
+ shm_unlock(shp);
+ } else
+ shm_destroy(ns, shp);
+}
+
+#ifdef CONFIG_IPC_NS
+void shm_exit_ns(struct ipc_namespace *ns)
+{
+ free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
+ idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
+ rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
+}
+#endif
+
+static int __init ipc_ns_init(void)
+{
+ shm_init_ns(&init_ipc_ns);
+ return 0;
+}
+
+pure_initcall(ipc_ns_init);
+
+void __init shm_init(void)
+{
+ ipc_init_proc_interface("sysvipc/shm",
+#if BITS_PER_LONG <= 32
+ " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
+#else
+ " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
+#endif
+ IPC_SHM_IDS, sysvipc_shm_proc_show);
+}
+
+static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return ERR_CAST(ipcp);
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return ERR_CAST(ipcp);
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+/*
+ * shm_lock_(check_) routines are called in the paths where the rwsem
+ * is not necessarily held.
+ */
+static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp;
+
+ rcu_read_lock();
+ ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
+ if (IS_ERR(ipcp))
+ goto err;
+
+ ipc_lock_object(ipcp);
+ /*
+ * ipc_rmid() may have already freed the ID while ipc_lock_object()
+ * was spinning: here verify that the structure is still valid.
+ * Upon races with RMID, return -EIDRM, thus indicating that
+ * the ID points to a removed identifier.
+ */
+ if (ipc_valid_object(ipcp)) {
+ /* return a locked ipc object upon success */
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+ }
+
+ ipc_unlock_object(ipcp);
+ ipcp = ERR_PTR(-EIDRM);
+err:
+ rcu_read_unlock();
+ /*
+ * Callers of shm_lock() must validate the status of the returned ipc
+ * object pointer and error out as appropriate.
+ */
+ return ERR_CAST(ipcp);
+}
+
+static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
+{
+ rcu_read_lock();
+ ipc_lock_object(&ipcp->shm_perm);
+}
+
+static void shm_rcu_free(struct rcu_head *head)
+{
+ struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
+ rcu);
+ struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
+ shm_perm);
+ security_shm_free(&shp->shm_perm);
+ kfree(shp);
+}
+
+/*
+ * It has to be called with shp locked.
+ * It must be called before ipc_rmid()
+ */
+static inline void shm_clist_rm(struct shmid_kernel *shp)
+{
+ struct task_struct *creator;
+
+ /* ensure that shm_creator does not disappear */
+ rcu_read_lock();
+
+ /*
+ * A concurrent exit_shm may do a list_del_init() as well.
+ * Just do nothing if exit_shm already did the work
+ */
+ if (!list_empty(&shp->shm_clist)) {
+ /*
+ * shp->shm_creator is guaranteed to be valid *only*
+ * if shp->shm_clist is not empty.
+ */
+ creator = shp->shm_creator;
+
+ task_lock(creator);
+ /*
+ * list_del_init() is a nop if the entry was already removed
+ * from the list.
+ */
+ list_del_init(&shp->shm_clist);
+ task_unlock(creator);
+ }
+ rcu_read_unlock();
+}
+
+static inline void shm_rmid(struct shmid_kernel *s)
+{
+ shm_clist_rm(s);
+ ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
+}
+
+
+static int __shm_open(struct shm_file_data *sfd)
+{
+ struct shmid_kernel *shp;
+
+ shp = shm_lock(sfd->ns, sfd->id);
+
+ if (IS_ERR(shp))
+ return PTR_ERR(shp);
+
+ if (shp->shm_file != sfd->file) {
+ /* ID was reused */
+ shm_unlock(shp);
+ return -EINVAL;
+ }
+
+ shp->shm_atim = ktime_get_real_seconds();
+ ipc_update_pid(&shp->shm_lprid, task_tgid(current));
+ shp->shm_nattch++;
+ shm_unlock(shp);
+ return 0;
+}
+
+/* This is called by fork, once for every shm attach. */
+static void shm_open(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ int err;
+
+ /* Always call underlying open if present */
+ if (sfd->vm_ops->open)
+ sfd->vm_ops->open(vma);
+
+ err = __shm_open(sfd);
+ /*
+ * We raced in the idr lookup or with shm_destroy().
+ * Either way, the ID is busted.
+ */
+ WARN_ON_ONCE(err);
+}
+
+/*
+ * shm_destroy - free the struct shmid_kernel
+ *
+ * @ns: namespace
+ * @shp: struct to free
+ *
+ * It has to be called with shp and shm_ids.rwsem (writer) locked,
+ * but returns with shp unlocked and freed.
+ */
+static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+ struct file *shm_file;
+
+ shm_file = shp->shm_file;
+ shp->shm_file = NULL;
+ ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ shm_rmid(shp);
+ shm_unlock(shp);
+ if (!is_file_hugepages(shm_file))
+ shmem_lock(shm_file, 0, shp->mlock_ucounts);
+ fput(shm_file);
+ ipc_update_pid(&shp->shm_cprid, NULL);
+ ipc_update_pid(&shp->shm_lprid, NULL);
+ ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
+}
+
+/*
+ * shm_may_destroy - identifies whether shm segment should be destroyed now
+ *
+ * Returns true if and only if there are no active users of the segment and
+ * one of the following is true:
+ *
+ * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
+ *
+ * 2) sysctl kernel.shm_rmid_forced is set to 1.
+ */
+static bool shm_may_destroy(struct shmid_kernel *shp)
+{
+ return (shp->shm_nattch == 0) &&
+ (shp->ns->shm_rmid_forced ||
+ (shp->shm_perm.mode & SHM_DEST));
+}
+
+/*
+ * remove the attach descriptor vma.
+ * free memory for segment if it is marked destroyed.
+ * The descriptor has already been removed from the current->mm->mmap list
+ * and will later be kfree()d.
+ */
+static void __shm_close(struct shm_file_data *sfd)
+{
+ struct shmid_kernel *shp;
+ struct ipc_namespace *ns = sfd->ns;
+
+ down_write(&shm_ids(ns).rwsem);
+ /* remove from the list of attaches of the shm segment */
+ shp = shm_lock(ns, sfd->id);
+
+ /*
+ * We raced in the idr lookup or with shm_destroy().
+ * Either way, the ID is busted.
+ */
+ if (WARN_ON_ONCE(IS_ERR(shp)))
+ goto done; /* no-op */
+
+ ipc_update_pid(&shp->shm_lprid, task_tgid(current));
+ shp->shm_dtim = ktime_get_real_seconds();
+ shp->shm_nattch--;
+ if (shm_may_destroy(shp))
+ shm_destroy(ns, shp);
+ else
+ shm_unlock(shp);
+done:
+ up_write(&shm_ids(ns).rwsem);
+}
+
+static void shm_close(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+
+ /* Always call underlying close if present */
+ if (sfd->vm_ops->close)
+ sfd->vm_ops->close(vma);
+
+ __shm_close(sfd);
+}
+
+/* Called with ns->shm_ids(ns).rwsem locked */
+static int shm_try_destroy_orphaned(int id, void *p, void *data)
+{
+ struct ipc_namespace *ns = data;
+ struct kern_ipc_perm *ipcp = p;
+ 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 *new)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ int err = 0;
+
+ if (sfd->vm_ops->set_policy)
+ err = sfd->vm_ops->set_policy(vma, new);
+ return err;
+}
+
+static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct file *file = vma->vm_file;
+ struct shm_file_data *sfd = shm_file_data(file);
+ struct mempolicy *pol = NULL;
+
+ if (sfd->vm_ops->get_policy)
+ pol = sfd->vm_ops->get_policy(vma, addr);
+ else if (vma->vm_policy)
+ pol = vma->vm_policy;
+
+ return pol;
+}
+#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, &current->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, &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_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
+ mas_pause(&vmi.mas);
+ /*
+ * 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_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
+ mas_pause(&vmi.mas);
+ }
+
+ 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