![Hugh Dickins](/assets/img/avatar_default.png)
SUSv3 says the shmdt() function shall fail with EINVAL if the value of shmaddr is not the data segment start address of a shared memory segment: our sys_shmdt needs to reject a shmaddr which is not page-aligned. Does it have the potential to break existing apps? Hugh says "sys_shmdt() just does the wrong (unexpected) thing with a misaligned address: it'll fail on what you might expect it to succeed on, and only succeed on what it should definitely fail on. "That is, I think it behaves as if shmaddr gets rounded up, when the only understandable behaviour would be if it rounded it down. "Which does mean you'd have to be devious to see anything but EINVAL from a misaligned shmaddr there, so it's not terribly important." Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
922 lines
21 KiB
C
922 lines
21 KiB
C
/*
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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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*/
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#include <linux/config.h>
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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 <asm/uaccess.h>
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#include "util.h"
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static struct file_operations shm_file_operations;
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static struct vm_operations_struct shm_vm_ops;
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static struct ipc_ids shm_ids;
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#define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
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#define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
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#define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
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#define shm_buildid(id, seq) \
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ipc_buildid(&shm_ids, id, seq)
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static int newseg (key_t key, int shmflg, size_t size);
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static void shm_open (struct vm_area_struct *shmd);
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static void shm_close (struct vm_area_struct *shmd);
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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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size_t shm_ctlmax = SHMMAX;
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size_t shm_ctlall = SHMALL;
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int shm_ctlmni = SHMMNI;
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static int shm_tot; /* total number of shared memory pages */
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void __init shm_init (void)
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{
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ipc_init_ids(&shm_ids, 1);
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ipc_init_proc_interface("sysvipc/shm",
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" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
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&shm_ids,
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sysvipc_shm_proc_show);
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}
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static inline int shm_checkid(struct shmid_kernel *s, int id)
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{
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if (ipc_checkid(&shm_ids,&s->shm_perm,id))
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return -EIDRM;
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return 0;
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}
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static inline struct shmid_kernel *shm_rmid(int id)
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{
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return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
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}
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static inline int shm_addid(struct shmid_kernel *shp)
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{
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return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
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}
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static inline void shm_inc (int id) {
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struct shmid_kernel *shp;
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if(!(shp = shm_lock(id)))
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BUG();
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shp->shm_atim = get_seconds();
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shp->shm_lprid = current->tgid;
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shp->shm_nattch++;
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shm_unlock(shp);
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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 *shmd)
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{
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shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
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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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* @shp: struct to free
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*
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* It has to be called with shp and shm_ids.sem 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 shmid_kernel *shp)
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{
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shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
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shm_rmid (shp->id);
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shm_unlock(shp);
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if (!is_file_hugepages(shp->shm_file))
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shmem_lock(shp->shm_file, 0, shp->mlock_user);
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else
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user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
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shp->mlock_user);
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fput (shp->shm_file);
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security_shm_free(shp);
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ipc_rcu_putref(shp);
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}
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/*
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* remove the attach descriptor shmd.
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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 vm_area_struct *shmd)
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{
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struct file * file = shmd->vm_file;
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int id = file->f_dentry->d_inode->i_ino;
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struct shmid_kernel *shp;
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down (&shm_ids.sem);
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/* remove from the list of attaches of the shm segment */
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if(!(shp = shm_lock(id)))
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BUG();
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shp->shm_lprid = current->tgid;
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shp->shm_dtim = get_seconds();
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shp->shm_nattch--;
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if(shp->shm_nattch == 0 &&
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shp->shm_perm.mode & SHM_DEST)
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shm_destroy (shp);
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else
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shm_unlock(shp);
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up (&shm_ids.sem);
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}
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static int shm_mmap(struct file * file, struct vm_area_struct * vma)
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{
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int ret;
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ret = shmem_mmap(file, vma);
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if (ret == 0) {
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vma->vm_ops = &shm_vm_ops;
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shm_inc(file->f_dentry->d_inode->i_ino);
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}
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return ret;
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}
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static struct file_operations shm_file_operations = {
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.mmap = shm_mmap,
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#ifndef CONFIG_MMU
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.get_unmapped_area = shmem_get_unmapped_area,
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#endif
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};
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static struct vm_operations_struct shm_vm_ops = {
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.open = shm_open, /* callback for a new vm-area open */
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.close = shm_close, /* callback for when the vm-area is released */
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.nopage = shmem_nopage,
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#if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
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.set_policy = shmem_set_policy,
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.get_policy = shmem_get_policy,
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#endif
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};
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static int newseg (key_t key, int shmflg, size_t size)
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{
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int error;
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struct shmid_kernel *shp;
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int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
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struct file * file;
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char name[13];
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int id;
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if (size < SHMMIN || size > shm_ctlmax)
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return -EINVAL;
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if (shm_tot + numpages >= shm_ctlall)
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return -ENOSPC;
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shp = ipc_rcu_alloc(sizeof(*shp));
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if (!shp)
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return -ENOMEM;
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shp->shm_perm.key = key;
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shp->shm_perm.mode = (shmflg & S_IRWXUGO);
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shp->mlock_user = NULL;
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shp->shm_perm.security = NULL;
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error = security_shm_alloc(shp);
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if (error) {
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ipc_rcu_putref(shp);
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return error;
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}
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if (shmflg & SHM_HUGETLB) {
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/* hugetlb_zero_setup takes care of mlock user accounting */
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file = hugetlb_zero_setup(size);
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shp->mlock_user = current->user;
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} else {
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int acctflag = VM_ACCOUNT;
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/*
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* Do not allow no accounting for OVERCOMMIT_NEVER, even
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* if it's asked for.
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*/
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if ((shmflg & SHM_NORESERVE) &&
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sysctl_overcommit_memory != OVERCOMMIT_NEVER)
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acctflag = 0;
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sprintf (name, "SYSV%08x", key);
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file = shmem_file_setup(name, size, acctflag);
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}
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error = PTR_ERR(file);
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if (IS_ERR(file))
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goto no_file;
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error = -ENOSPC;
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id = shm_addid(shp);
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if(id == -1)
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goto no_id;
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shp->shm_cprid = current->tgid;
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shp->shm_lprid = 0;
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shp->shm_atim = shp->shm_dtim = 0;
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shp->shm_ctim = get_seconds();
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shp->shm_segsz = size;
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shp->shm_nattch = 0;
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shp->id = shm_buildid(id,shp->shm_perm.seq);
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shp->shm_file = file;
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file->f_dentry->d_inode->i_ino = shp->id;
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/* Hugetlb ops would have already been assigned. */
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if (!(shmflg & SHM_HUGETLB))
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file->f_op = &shm_file_operations;
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shm_tot += numpages;
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shm_unlock(shp);
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return shp->id;
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no_id:
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fput(file);
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no_file:
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security_shm_free(shp);
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ipc_rcu_putref(shp);
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return error;
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}
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asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
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{
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struct shmid_kernel *shp;
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int err, id = 0;
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down(&shm_ids.sem);
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if (key == IPC_PRIVATE) {
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err = newseg(key, shmflg, size);
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} else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
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if (!(shmflg & IPC_CREAT))
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err = -ENOENT;
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else
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err = newseg(key, shmflg, size);
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} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
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err = -EEXIST;
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} else {
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shp = shm_lock(id);
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if(shp==NULL)
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BUG();
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if (shp->shm_segsz < size)
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err = -EINVAL;
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else if (ipcperms(&shp->shm_perm, shmflg))
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err = -EACCES;
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else {
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int shmid = shm_buildid(id, shp->shm_perm.seq);
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err = security_shm_associate(shp, shmflg);
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if (!err)
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err = shmid;
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}
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shm_unlock(shp);
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}
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up(&shm_ids.sem);
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return err;
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}
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static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
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{
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switch(version) {
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case IPC_64:
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return copy_to_user(buf, in, sizeof(*in));
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case IPC_OLD:
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{
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struct shmid_ds out;
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ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
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out.shm_segsz = in->shm_segsz;
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out.shm_atime = in->shm_atime;
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out.shm_dtime = in->shm_dtime;
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out.shm_ctime = in->shm_ctime;
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out.shm_cpid = in->shm_cpid;
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out.shm_lpid = in->shm_lpid;
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out.shm_nattch = in->shm_nattch;
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return copy_to_user(buf, &out, sizeof(out));
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}
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default:
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return -EINVAL;
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}
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}
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struct shm_setbuf {
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uid_t uid;
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gid_t gid;
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mode_t mode;
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};
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static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
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{
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switch(version) {
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case IPC_64:
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{
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struct shmid64_ds tbuf;
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if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
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return -EFAULT;
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out->uid = tbuf.shm_perm.uid;
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out->gid = tbuf.shm_perm.gid;
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out->mode = tbuf.shm_perm.mode;
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return 0;
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}
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case IPC_OLD:
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{
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struct shmid_ds tbuf_old;
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if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
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return -EFAULT;
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out->uid = tbuf_old.shm_perm.uid;
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out->gid = tbuf_old.shm_perm.gid;
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out->mode = tbuf_old.shm_perm.mode;
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return 0;
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}
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default:
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return -EINVAL;
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}
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}
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|
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static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
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{
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switch(version) {
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case IPC_64:
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return copy_to_user(buf, in, sizeof(*in));
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case IPC_OLD:
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{
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struct shminfo out;
|
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|
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if(in->shmmax > INT_MAX)
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out.shmmax = INT_MAX;
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else
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out.shmmax = (int)in->shmmax;
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|
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out.shmmin = in->shmmin;
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out.shmmni = in->shmmni;
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out.shmseg = in->shmseg;
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out.shmall = in->shmall;
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return copy_to_user(buf, &out, sizeof(out));
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}
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default:
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return -EINVAL;
|
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}
|
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}
|
|
|
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static void shm_get_stat(unsigned long *rss, unsigned long *swp)
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{
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int i;
|
|
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*rss = 0;
|
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*swp = 0;
|
|
|
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for (i = 0; i <= shm_ids.max_id; i++) {
|
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struct shmid_kernel *shp;
|
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struct inode *inode;
|
|
|
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shp = shm_get(i);
|
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if(!shp)
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continue;
|
|
|
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inode = shp->shm_file->f_dentry->d_inode;
|
|
|
|
if (is_file_hugepages(shp->shm_file)) {
|
|
struct address_space *mapping = inode->i_mapping;
|
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*rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
|
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} else {
|
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struct shmem_inode_info *info = SHMEM_I(inode);
|
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spin_lock(&info->lock);
|
|
*rss += inode->i_mapping->nrpages;
|
|
*swp += info->swapped;
|
|
spin_unlock(&info->lock);
|
|
}
|
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}
|
|
}
|
|
|
|
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
|
|
{
|
|
struct shm_setbuf setbuf;
|
|
struct shmid_kernel *shp;
|
|
int err, version;
|
|
|
|
if (cmd < 0 || shmid < 0) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
version = ipc_parse_version(&cmd);
|
|
|
|
switch (cmd) { /* replace with proc interface ? */
|
|
case IPC_INFO:
|
|
{
|
|
struct shminfo64 shminfo;
|
|
|
|
err = security_shm_shmctl(NULL, cmd);
|
|
if (err)
|
|
return err;
|
|
|
|
memset(&shminfo,0,sizeof(shminfo));
|
|
shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
|
|
shminfo.shmmax = shm_ctlmax;
|
|
shminfo.shmall = shm_ctlall;
|
|
|
|
shminfo.shmmin = SHMMIN;
|
|
if(copy_shminfo_to_user (buf, &shminfo, version))
|
|
return -EFAULT;
|
|
/* reading a integer is always atomic */
|
|
err= shm_ids.max_id;
|
|
if(err<0)
|
|
err = 0;
|
|
goto out;
|
|
}
|
|
case SHM_INFO:
|
|
{
|
|
struct shm_info shm_info;
|
|
|
|
err = security_shm_shmctl(NULL, cmd);
|
|
if (err)
|
|
return err;
|
|
|
|
memset(&shm_info,0,sizeof(shm_info));
|
|
down(&shm_ids.sem);
|
|
shm_info.used_ids = shm_ids.in_use;
|
|
shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
|
|
shm_info.shm_tot = shm_tot;
|
|
shm_info.swap_attempts = 0;
|
|
shm_info.swap_successes = 0;
|
|
err = shm_ids.max_id;
|
|
up(&shm_ids.sem);
|
|
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;
|
|
memset(&tbuf, 0, sizeof(tbuf));
|
|
shp = shm_lock(shmid);
|
|
if(shp==NULL) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
} else if(cmd==SHM_STAT) {
|
|
err = -EINVAL;
|
|
if (shmid > shm_ids.max_id)
|
|
goto out_unlock;
|
|
result = shm_buildid(shmid, shp->shm_perm.seq);
|
|
} else {
|
|
err = shm_checkid(shp,shmid);
|
|
if(err)
|
|
goto out_unlock;
|
|
result = 0;
|
|
}
|
|
err=-EACCES;
|
|
if (ipcperms (&shp->shm_perm, S_IRUGO))
|
|
goto out_unlock;
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
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;
|
|
tbuf.shm_cpid = shp->shm_cprid;
|
|
tbuf.shm_lpid = shp->shm_lprid;
|
|
if (!is_file_hugepages(shp->shm_file))
|
|
tbuf.shm_nattch = shp->shm_nattch;
|
|
else
|
|
tbuf.shm_nattch = file_count(shp->shm_file) - 1;
|
|
shm_unlock(shp);
|
|
if(copy_shmid_to_user (buf, &tbuf, version))
|
|
err = -EFAULT;
|
|
else
|
|
err = result;
|
|
goto out;
|
|
}
|
|
case SHM_LOCK:
|
|
case SHM_UNLOCK:
|
|
{
|
|
shp = shm_lock(shmid);
|
|
if(shp==NULL) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
err = shm_checkid(shp,shmid);
|
|
if(err)
|
|
goto out_unlock;
|
|
|
|
if (!capable(CAP_IPC_LOCK)) {
|
|
err = -EPERM;
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid)
|
|
goto out_unlock;
|
|
if (cmd == SHM_LOCK &&
|
|
!current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock;
|
|
|
|
if(cmd==SHM_LOCK) {
|
|
struct user_struct * user = current->user;
|
|
if (!is_file_hugepages(shp->shm_file)) {
|
|
err = shmem_lock(shp->shm_file, 1, user);
|
|
if (!err) {
|
|
shp->shm_perm.mode |= SHM_LOCKED;
|
|
shp->mlock_user = user;
|
|
}
|
|
}
|
|
} else if (!is_file_hugepages(shp->shm_file)) {
|
|
shmem_lock(shp->shm_file, 0, shp->mlock_user);
|
|
shp->shm_perm.mode &= ~SHM_LOCKED;
|
|
shp->mlock_user = NULL;
|
|
}
|
|
shm_unlock(shp);
|
|
goto out;
|
|
}
|
|
case IPC_RMID:
|
|
{
|
|
/*
|
|
* We cannot simply remove the file. The SVID states
|
|
* that the block remains until the last person
|
|
* detaches from it, then is deleted. A shmat() on
|
|
* an RMID segment is legal in older Linux and if
|
|
* we change it apps break...
|
|
*
|
|
* Instead we set a destroyed flag, and then blow
|
|
* the name away when the usage hits zero.
|
|
*/
|
|
down(&shm_ids.sem);
|
|
shp = shm_lock(shmid);
|
|
err = -EINVAL;
|
|
if (shp == NULL)
|
|
goto out_up;
|
|
err = shm_checkid(shp, shmid);
|
|
if(err)
|
|
goto out_unlock_up;
|
|
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid &&
|
|
!capable(CAP_SYS_ADMIN)) {
|
|
err=-EPERM;
|
|
goto out_unlock_up;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock_up;
|
|
|
|
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 (shp);
|
|
up(&shm_ids.sem);
|
|
goto out;
|
|
}
|
|
|
|
case IPC_SET:
|
|
{
|
|
if (copy_shmid_from_user (&setbuf, buf, version)) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
|
|
return err;
|
|
down(&shm_ids.sem);
|
|
shp = shm_lock(shmid);
|
|
err=-EINVAL;
|
|
if(shp==NULL)
|
|
goto out_up;
|
|
err = shm_checkid(shp,shmid);
|
|
if(err)
|
|
goto out_unlock_up;
|
|
err=-EPERM;
|
|
if (current->euid != shp->shm_perm.uid &&
|
|
current->euid != shp->shm_perm.cuid &&
|
|
!capable(CAP_SYS_ADMIN)) {
|
|
goto out_unlock_up;
|
|
}
|
|
|
|
err = security_shm_shmctl(shp, cmd);
|
|
if (err)
|
|
goto out_unlock_up;
|
|
|
|
shp->shm_perm.uid = setbuf.uid;
|
|
shp->shm_perm.gid = setbuf.gid;
|
|
shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
|
|
| (setbuf.mode & S_IRWXUGO);
|
|
shp->shm_ctim = get_seconds();
|
|
break;
|
|
}
|
|
|
|
default:
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
err = 0;
|
|
out_unlock_up:
|
|
shm_unlock(shp);
|
|
out_up:
|
|
up(&shm_ids.sem);
|
|
goto out;
|
|
out_unlock:
|
|
shm_unlock(shp);
|
|
out:
|
|
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)
|
|
{
|
|
struct shmid_kernel *shp;
|
|
unsigned long addr;
|
|
unsigned long size;
|
|
struct file * file;
|
|
int err;
|
|
unsigned long flags;
|
|
unsigned long prot;
|
|
unsigned long o_flags;
|
|
int acc_mode;
|
|
void *user_addr;
|
|
|
|
if (shmid < 0) {
|
|
err = -EINVAL;
|
|
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
|
|
return -EINVAL;
|
|
}
|
|
flags = MAP_SHARED | MAP_FIXED;
|
|
} else {
|
|
if ((shmflg & SHM_REMAP))
|
|
return -EINVAL;
|
|
|
|
flags = MAP_SHARED;
|
|
}
|
|
|
|
if (shmflg & SHM_RDONLY) {
|
|
prot = PROT_READ;
|
|
o_flags = O_RDONLY;
|
|
acc_mode = S_IRUGO;
|
|
} else {
|
|
prot = PROT_READ | PROT_WRITE;
|
|
o_flags = O_RDWR;
|
|
acc_mode = S_IRUGO | S_IWUGO;
|
|
}
|
|
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...
|
|
*/
|
|
shp = shm_lock(shmid);
|
|
if(shp == NULL) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
err = shm_checkid(shp,shmid);
|
|
if (err) {
|
|
shm_unlock(shp);
|
|
goto out;
|
|
}
|
|
if (ipcperms(&shp->shm_perm, acc_mode)) {
|
|
shm_unlock(shp);
|
|
err = -EACCES;
|
|
goto out;
|
|
}
|
|
|
|
err = security_shm_shmat(shp, shmaddr, shmflg);
|
|
if (err) {
|
|
shm_unlock(shp);
|
|
return err;
|
|
}
|
|
|
|
file = shp->shm_file;
|
|
size = i_size_read(file->f_dentry->d_inode);
|
|
shp->shm_nattch++;
|
|
shm_unlock(shp);
|
|
|
|
down_write(¤t->mm->mmap_sem);
|
|
if (addr && !(shmflg & SHM_REMAP)) {
|
|
user_addr = ERR_PTR(-EINVAL);
|
|
if (find_vma_intersection(current->mm, addr, addr + size))
|
|
goto invalid;
|
|
/*
|
|
* If shm segment goes below stack, make sure there is some
|
|
* space left for the stack to grow (at least 4 pages).
|
|
*/
|
|
if (addr < current->mm->start_stack &&
|
|
addr > current->mm->start_stack - size - PAGE_SIZE * 5)
|
|
goto invalid;
|
|
}
|
|
|
|
user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
|
|
|
|
invalid:
|
|
up_write(¤t->mm->mmap_sem);
|
|
|
|
down (&shm_ids.sem);
|
|
if(!(shp = shm_lock(shmid)))
|
|
BUG();
|
|
shp->shm_nattch--;
|
|
if(shp->shm_nattch == 0 &&
|
|
shp->shm_perm.mode & SHM_DEST)
|
|
shm_destroy (shp);
|
|
else
|
|
shm_unlock(shp);
|
|
up (&shm_ids.sem);
|
|
|
|
*raddr = (unsigned long) user_addr;
|
|
err = 0;
|
|
if (IS_ERR(user_addr))
|
|
err = PTR_ERR(user_addr);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
|
|
{
|
|
unsigned long ret;
|
|
long err;
|
|
|
|
err = do_shmat(shmid, shmaddr, shmflg, &ret);
|
|
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.
|
|
*/
|
|
asmlinkage long sys_shmdt(char __user *shmaddr)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma, *next;
|
|
unsigned long addr = (unsigned long)shmaddr;
|
|
loff_t size = 0;
|
|
int retval = -EINVAL;
|
|
|
|
if (addr & ~PAGE_MASK)
|
|
return retval;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
|
|
/*
|
|
* 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.
|
|
* 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);
|
|
|
|
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 || is_vm_hugetlb_page(vma)) &&
|
|
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
|
|
|
|
|
|
size = vma->vm_file->f_dentry->d_inode->i_size;
|
|
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 comparisions 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 || is_vm_hugetlb_page(vma)) &&
|
|
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
|
|
|
|
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
|
|
vma = next;
|
|
}
|
|
|
|
up_write(&mm->mmap_sem);
|
|
return retval;
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
|
|
{
|
|
struct shmid_kernel *shp = it;
|
|
char *format;
|
|
|
|
#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
|
|
#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
|
|
|
|
if (sizeof(size_t) <= sizeof(int))
|
|
format = SMALL_STRING;
|
|
else
|
|
format = BIG_STRING;
|
|
return seq_printf(s, format,
|
|
shp->shm_perm.key,
|
|
shp->id,
|
|
shp->shm_perm.mode,
|
|
shp->shm_segsz,
|
|
shp->shm_cprid,
|
|
shp->shm_lprid,
|
|
is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
|
|
shp->shm_perm.uid,
|
|
shp->shm_perm.gid,
|
|
shp->shm_perm.cuid,
|
|
shp->shm_perm.cgid,
|
|
shp->shm_atim,
|
|
shp->shm_dtim,
|
|
shp->shm_ctim);
|
|
}
|
|
#endif
|