| /* |
| * 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/uaccess.h> |
| |
| #include "util.h" |
| |
| 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); |
| |
| if (shp->shm_nattch) { |
| shp->shm_perm.mode |= SHM_DEST; |
| /* Do not find it any more */ |
| shp->shm_perm.key = IPC_PRIVATE; |
| 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); |
| } |
| #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 = ipc_lock(&shm_ids(ns), id); |
| |
| /* |
| * Callers of shm_lock() must validate the status of the returned ipc |
| * object pointer (as returned by ipc_lock()), and error out as |
| * appropriate. |
| */ |
| if (IS_ERR(ipcp)) |
| return (void *)ipcp; |
| return container_of(ipcp, struct shmid_kernel, shm_perm); |
| } |
| |
| 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 ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); |
| struct shmid_kernel *shp = ipc_rcu_to_struct(p); |
| |
| security_shm_free(shp); |
| ipc_rcu_free(head); |
| } |
| |
| static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) |
| { |
| list_del(&s->shm_clist); |
| ipc_rmid(&shm_ids(ns), &s->shm_perm); |
| } |
| |
| |
| static int __shm_open(struct vm_area_struct *vma) |
| { |
| struct file *file = vma->vm_file; |
| struct shm_file_data *sfd = shm_file_data(file); |
| struct shmid_kernel *shp; |
| |
| shp = shm_lock(sfd->ns, sfd->id); |
| |
| if (IS_ERR(shp)) |
| return PTR_ERR(shp); |
| |
| shp->shm_atim = get_seconds(); |
| shp->shm_lprid = task_tgid_vnr(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) |
| { |
| int err = __shm_open(vma); |
| /* |
| * 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(ns, shp); |
| shm_unlock(shp); |
| if (!is_file_hugepages(shm_file)) |
| shmem_lock(shm_file, 0, shp->mlock_user); |
| else if (shp->mlock_user) |
| user_shm_unlock(i_size_read(file_inode(shm_file)), |
| shp->mlock_user); |
| fput(shm_file); |
| ipc_rcu_putref(shp, 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 ipc_namespace *ns, struct shmid_kernel *shp) |
| { |
| return (shp->shm_nattch == 0) && |
| (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 vm_area_struct *vma) |
| { |
| struct file *file = vma->vm_file; |
| struct shm_file_data *sfd = shm_file_data(file); |
| 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 */ |
| |
| shp->shm_lprid = task_tgid_vnr(current); |
| shp->shm_dtim = get_seconds(); |
| shp->shm_nattch--; |
| if (shm_may_destroy(ns, shp)) |
| shm_destroy(ns, shp); |
| else |
| shm_unlock(shp); |
| done: |
| up_write(&shm_ids(ns).rwsem); |
| } |
| |
| /* 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 (shp->shm_creator != NULL) |
| return 0; |
| |
| if (shm_may_destroy(ns, 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) |
| { |
| struct ipc_namespace *ns = task->nsproxy->ipc_ns; |
| struct shmid_kernel *shp, *n; |
| |
| if (list_empty(&task->sysvshm.shm_clist)) |
| return; |
| |
| /* |
| * 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) { |
| down_read(&shm_ids(ns).rwsem); |
| list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist) |
| shp->shm_creator = NULL; |
| /* |
| * Only under read lock but we are only called on current |
| * so no entry on the list will be shared. |
| */ |
| list_del(&task->sysvshm.shm_clist); |
| up_read(&shm_ids(ns).rwsem); |
| return; |
| } |
| |
| /* |
| * Destroy all already created segments, that were not yet mapped, |
| * and mark any mapped as orphan to cover the sysctl toggling. |
| * Destroy is skipped if shm_may_destroy() returns false. |
| */ |
| down_write(&shm_ids(ns).rwsem); |
| list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) { |
| shp->shm_creator = NULL; |
| |
| if (shm_may_destroy(ns, shp)) { |
| shm_lock_by_ptr(shp); |
| shm_destroy(ns, shp); |
| } |
| } |
| |
| /* Remove the list head from any segments still attached. */ |
| list_del(&task->sysvshm.shm_clist); |
| up_write(&shm_ids(ns).rwsem); |
| } |
| |
| static int 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); |
| } |
| |
| #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 |
| * removed IPC ID: propogate shm_lock() error to caller. |
| */ |
| ret = __shm_open(vma); |
| if (ret) |
| return ret; |
| |
| ret = sfd->file->f_op->mmap(sfd->file, vma); |
| if (ret) { |
| shm_close(vma); |
| 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); |
| 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, |
| #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]; |
| int id; |
| 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 = ipc_rcu_alloc(sizeof(*shp)); |
| if (!shp) |
| return -ENOMEM; |
| |
| shp->shm_perm.key = key; |
| shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
| shp->mlock_user = NULL; |
| |
| shp->shm_perm.security = NULL; |
| error = security_shm_alloc(shp); |
| if (error) { |
| ipc_rcu_putref(shp, ipc_rcu_free); |
| 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, |
| &shp->mlock_user, 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 = task_tgid_vnr(current); |
| shp->shm_lprid = 0; |
| shp->shm_atim = shp->shm_dtim = 0; |
| shp->shm_ctim = get_seconds(); |
| shp->shm_segsz = size; |
| shp->shm_nattch = 0; |
| shp->shm_file = file; |
| shp->shm_creator = current; |
| |
| id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); |
| if (id < 0) { |
| error = id; |
| goto no_id; |
| } |
| |
| list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist); |
| |
| /* |
| * 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: |
| if (is_file_hugepages(file) && shp->mlock_user) |
| user_shm_unlock(size, shp->mlock_user); |
| fput(file); |
| no_file: |
| ipc_rcu_putref(shp, shm_rcu_free); |
| return error; |
| } |
| |
| /* |
| * Called with shm_ids.rwsem and ipcp locked. |
| */ |
| static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) |
| { |
| struct shmid_kernel *shp; |
| |
| shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| return security_shm_associate(shp, shmflg); |
| } |
| |
| /* |
| * Called with shm_ids.rwsem and ipcp locked. |
| */ |
| static inline 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; |
| } |
| |
| SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) |
| { |
| struct ipc_namespace *ns; |
| static const struct ipc_ops shm_ops = { |
| .getnew = newseg, |
| .associate = shm_security, |
| .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); |
| } |
| |
| 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 shmid_ds __user *buf, int version) |
| { |
| struct kern_ipc_perm *ipcp; |
| struct shmid64_ds shmid64; |
| struct shmid_kernel *shp; |
| int err; |
| |
| if (cmd == IPC_SET) { |
| if (copy_shmid_from_user(&shmid64, buf, version)) |
| return -EFAULT; |
| } |
| |
| down_write(&shm_ids(ns).rwsem); |
| rcu_read_lock(); |
| |
| ipcp = ipcctl_pre_down_nolock(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, 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 = get_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_nolock(struct ipc_namespace *ns, int shmid, |
| int cmd, int version, void __user *buf) |
| { |
| int err; |
| struct shmid_kernel *shp; |
| |
| /* preliminary security checks for *_INFO */ |
| if (cmd == IPC_INFO || cmd == SHM_INFO) { |
| err = security_shm_shmctl(NULL, cmd); |
| if (err) |
| return err; |
| } |
| |
| switch (cmd) { |
| case IPC_INFO: |
| { |
| struct shminfo64 shminfo; |
| |
| 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; |
| if (copy_shminfo_to_user(buf, &shminfo, version)) |
| return -EFAULT; |
| |
| down_read(&shm_ids(ns).rwsem); |
| err = ipc_get_maxid(&shm_ids(ns)); |
| up_read(&shm_ids(ns).rwsem); |
| |
| if (err < 0) |
| err = 0; |
| goto out; |
| } |
| case SHM_INFO: |
| { |
| struct shm_info shm_info; |
| |
| 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_maxid(&shm_ids(ns)); |
| up_read(&shm_ids(ns).rwsem); |
| if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { |
| err = -EFAULT; |
| goto out; |
| } |
| |
| err = err < 0 ? 0 : err; |
| goto out; |
| } |
| case SHM_STAT: |
| case IPC_STAT: |
| { |
| struct shmid64_ds tbuf; |
| int result; |
| |
| rcu_read_lock(); |
| if (cmd == SHM_STAT) { |
| shp = shm_obtain_object(ns, shmid); |
| if (IS_ERR(shp)) { |
| err = PTR_ERR(shp); |
| goto out_unlock; |
| } |
| result = shp->shm_perm.id; |
| } else { |
| shp = shm_obtain_object_check(ns, shmid); |
| if (IS_ERR(shp)) { |
| err = PTR_ERR(shp); |
| goto out_unlock; |
| } |
| result = 0; |
| } |
| |
| err = -EACCES; |
| if (ipcperms(ns, &shp->shm_perm, S_IRUGO)) |
| goto out_unlock; |
| |
| err = security_shm_shmctl(shp, cmd); |
| if (err) |
| goto out_unlock; |
| |
| memset(&tbuf, 0, sizeof(tbuf)); |
| 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; |
| tbuf.shm_cpid = shp->shm_cprid; |
| tbuf.shm_lpid = shp->shm_lprid; |
| tbuf.shm_nattch = shp->shm_nattch; |
| rcu_read_unlock(); |
| |
| if (copy_shmid_to_user(buf, &tbuf, version)) |
| err = -EFAULT; |
| else |
| err = result; |
| goto out; |
| } |
| default: |
| return -EINVAL; |
| } |
| |
| out_unlock: |
| rcu_read_unlock(); |
| out: |
| return err; |
| } |
| |
| SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) |
| { |
| struct shmid_kernel *shp; |
| int err, version; |
| struct ipc_namespace *ns; |
| |
| if (cmd < 0 || shmid < 0) |
| return -EINVAL; |
| |
| version = ipc_parse_version(&cmd); |
| ns = current->nsproxy->ipc_ns; |
| |
| switch (cmd) { |
| case IPC_INFO: |
| case SHM_INFO: |
| case SHM_STAT: |
| case IPC_STAT: |
| return shmctl_nolock(ns, shmid, cmd, version, buf); |
| case IPC_RMID: |
| case IPC_SET: |
| return shmctl_down(ns, shmid, cmd, buf, version); |
| case SHM_LOCK: |
| case SHM_UNLOCK: |
| { |
| struct file *shm_file; |
| |
| 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, 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 user_struct *user = current_user(); |
| |
| err = shmem_lock(shm_file, 1, user); |
| if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) { |
| shp->shm_perm.mode |= SHM_LOCKED; |
| shp->mlock_user = user; |
| } |
| goto out_unlock0; |
| } |
| |
| /* SHM_UNLOCK */ |
| if (!(shp->shm_perm.mode & SHM_LOCKED)) |
| goto out_unlock0; |
| shmem_lock(shm_file, 0, shp->mlock_user); |
| shp->shm_perm.mode &= ~SHM_LOCKED; |
| shp->mlock_user = 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; |
| } |
| default: |
| return -EINVAL; |
| } |
| |
| out_unlock0: |
| ipc_unlock_object(&shp->shm_perm); |
| out_unlock1: |
| rcu_read_unlock(); |
| return err; |
| } |
| |
| /* |
| * 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 size; |
| struct file *file; |
| int err; |
| unsigned long flags; |
| unsigned long prot; |
| int acc_mode; |
| struct ipc_namespace *ns; |
| struct shm_file_data *sfd; |
| struct path path; |
| fmode_t f_mode; |
| unsigned long populate = 0; |
| |
| err = -EINVAL; |
| if (shmid < 0) |
| goto out; |
| else if ((addr = (ulong)shmaddr)) { |
| if (addr & (shmlba - 1)) { |
| if (shmflg & SHM_RND) |
| addr &= ~(shmlba - 1); /* round down */ |
| else |
| #ifndef __ARCH_FORCE_SHMLBA |
| if (addr & ~PAGE_MASK) |
| #endif |
| goto out; |
| } |
| flags = MAP_SHARED | MAP_FIXED; |
| } else { |
| if ((shmflg & SHM_REMAP)) |
| goto out; |
| |
| flags = MAP_SHARED; |
| } |
| |
| if (shmflg & SHM_RDONLY) { |
| prot = PROT_READ; |
| acc_mode = S_IRUGO; |
| f_mode = FMODE_READ; |
| } else { |
| prot = PROT_READ | PROT_WRITE; |
| acc_mode = S_IRUGO | S_IWUGO; |
| f_mode = FMODE_READ | FMODE_WRITE; |
| } |
| 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, 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; |
| } |
| |
| path = shp->shm_file->f_path; |
| path_get(&path); |
| shp->shm_nattch++; |
| size = i_size_read(d_inode(path.dentry)); |
| ipc_unlock_object(&shp->shm_perm); |
| rcu_read_unlock(); |
| |
| err = -ENOMEM; |
| sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); |
| if (!sfd) { |
| path_put(&path); |
| goto out_nattch; |
| } |
| |
| file = alloc_file(&path, f_mode, |
| is_file_hugepages(shp->shm_file) ? |
| &shm_file_operations_huge : |
| &shm_file_operations); |
| err = PTR_ERR(file); |
| if (IS_ERR(file)) { |
| kfree(sfd); |
| path_put(&path); |
| goto out_nattch; |
| } |
| |
| file->private_data = sfd; |
| file->f_mapping = shp->shm_file->f_mapping; |
| sfd->id = shp->shm_perm.id; |
| sfd->ns = get_ipc_ns(ns); |
| sfd->file = shp->shm_file; |
| sfd->vm_ops = NULL; |
| |
| err = security_mmap_file(file, prot, flags); |
| if (err) |
| goto out_fput; |
| |
| if (down_write_killable(¤t->mm->mmap_sem)) { |
| 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_pgoff(file, addr, size, prot, flags, 0, &populate); |
| *raddr = addr; |
| err = 0; |
| if (IS_ERR_VALUE(addr)) |
| err = (long)addr; |
| invalid: |
| up_write(¤t->mm->mmap_sem); |
| 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(ns, 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; |
| } |
| |
| /* |
| * detach and kill segment if marked destroyed. |
| * The work is done in shm_close. |
| */ |
| SYSCALL_DEFINE1(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; |
| struct vm_area_struct *next; |
| #endif |
| |
| if (addr & ~PAGE_MASK) |
| return retval; |
| |
| if (down_write_killable(&mm->mmap_sem)) |
| 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. |
| */ |
| vma = find_vma(mm, addr); |
| |
| #ifdef CONFIG_MMU |
| while (vma) { |
| next = vma->vm_next; |
| |
| /* |
| * 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); |
| /* |
| * 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 = next; |
| break; |
| } |
| vma = next; |
| } |
| |
| /* |
| * 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) { |
| next = vma->vm_next; |
| |
| /* 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); |
| vma = next; |
| } |
| |
| #else /* CONFIG_MMU */ |
| /* 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); |
| retval = 0; |
| } |
| |
| #endif |
| |
| up_write(&mm->mmap_sem); |
| return retval; |
| } |
| |
| #ifdef CONFIG_PROC_FS |
| static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
| { |
| struct user_namespace *user_ns = seq_user_ns(s); |
| struct shmid_kernel *shp = it; |
| unsigned long rss = 0, swp = 0; |
| |
| 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 %10lu %10lu %10lu " |
| SIZE_SPEC " " SIZE_SPEC "\n", |
| shp->shm_perm.key, |
| shp->shm_perm.id, |
| shp->shm_perm.mode, |
| shp->shm_segsz, |
| shp->shm_cprid, |
| shp->shm_lprid, |
| 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 |