Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release

1 files changed, 305 insertions, 0 deletions

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
new file mode 100644
index 000000000..c90d722c6
--- /dev/null
+++ b/mm/process_vm_access.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * linux/mm/process_vm_access.c
+ *
+ * Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
+ */
+
+#include <linux/compat.h>
+#include <linux/mm.h>
+#include <linux/uio.h>
+#include <linux/sched.h>
+#include <linux/compat.h>
+#include <linux/sched/mm.h>
+#include <linux/highmem.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+
+/**
+ * process_vm_rw_pages - read/write pages from task specified
+ * @pages: array of pointers to pages we want to copy
+ * @offset: offset in page to start copying from/to
+ * @len: number of bytes to copy
+ * @iter: where to copy to/from locally
+ * @vm_write: 0 means copy from, 1 means copy to
+ * Returns 0 on success, error code otherwise
+ */
+static int process_vm_rw_pages(struct page **pages,
+                               unsigned offset,
+                               size_t len,
+                               struct iov_iter *iter,
+                               int vm_write)
+{
+        /* Do the copy for each page */
+        while (len && iov_iter_count(iter)) {
+                struct page *page = *pages++;
+                size_t copy = PAGE_SIZE - offset;
+                size_t copied;
+
+                if (copy > len)
+                        copy = len;
+
+                if (vm_write)
+                        copied = copy_page_from_iter(page, offset, copy, iter);
+                else
+                        copied = copy_page_to_iter(page, offset, copy, iter);
+
+                len -= copied;
+                if (copied < copy && iov_iter_count(iter))
+                        return -EFAULT;
+                offset = 0;
+        }
+        return 0;
+}
+
+/* Maximum number of pages kmalloc'd to hold struct page's during copy */
+#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
+
+/**
+ * process_vm_rw_single_vec - read/write pages from task specified
+ * @addr: start memory address of target process
+ * @len: size of area to copy to/from
+ * @iter: where to copy to/from locally
+ * @process_pages: struct pages area that can store at least
+ *  nr_pages_to_copy struct page pointers
+ * @mm: mm for task
+ * @task: task to read/write from
+ * @vm_write: 0 means copy from, 1 means copy to
+ * Returns 0 on success or on failure error code
+ */
+static int process_vm_rw_single_vec(unsigned long addr,
+                                    unsigned long len,
+                                    struct iov_iter *iter,
+                                    struct page **process_pages,
+                                    struct mm_struct *mm,
+                                    struct task_struct *task,
+                                    int vm_write)
+{
+        unsigned long pa = addr & PAGE_MASK;
+        unsigned long start_offset = addr - pa;
+        unsigned long nr_pages;
+        ssize_t rc = 0;
+        unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
+                / sizeof(struct pages *);
+        unsigned int flags = 0;
+
+        /* Work out address and page range required */
+        if (len == 0)
+                return 0;
+        nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
+
+        if (vm_write)
+                flags |= FOLL_WRITE;
+
+        while (!rc && nr_pages && iov_iter_count(iter)) {
+                int pinned_pages = min(nr_pages, max_pages_per_loop);
+                int locked = 1;
+                size_t bytes;
+
+                /*
+                 * Get the pages we're interested in.  We must
+                 * access remotely because task/mm might not
+                 * current/current->mm
+                 */
+                mmap_read_lock(mm);
+                pinned_pages = pin_user_pages_remote(mm, pa, pinned_pages,
+                                                     flags, process_pages,
+                                                     NULL, &locked);
+                if (locked)
+                        mmap_read_unlock(mm);
+                if (pinned_pages <= 0)
+                        return -EFAULT;
+
+                bytes = pinned_pages * PAGE_SIZE - start_offset;
+                if (bytes > len)
+                        bytes = len;
+
+                rc = process_vm_rw_pages(process_pages,
+                                         start_offset, bytes, iter,
+                                         vm_write);
+                len -= bytes;
+                start_offset = 0;
+                nr_pages -= pinned_pages;
+                pa += pinned_pages * PAGE_SIZE;
+
+                /* If vm_write is set, the pages need to be made dirty: */
+                unpin_user_pages_dirty_lock(process_pages, pinned_pages,
+                                            vm_write);
+        }
+
+        return rc;
+}
+
+/* Maximum number of entries for process pages array
+   which lives on stack */
+#define PVM_MAX_PP_ARRAY_COUNT 16
+
+/**
+ * process_vm_rw_core - core of reading/writing pages from task specified
+ * @pid: PID of process to read/write from/to
+ * @iter: where to copy to/from locally
+ * @rvec: iovec array specifying where to copy to/from in the other process
+ * @riovcnt: size of rvec array
+ * @flags: currently unused
+ * @vm_write: 0 if reading from other process, 1 if writing to other process
+ *
+ * Returns the number of bytes read/written or error code. May
+ *  return less bytes than expected if an error occurs during the copying
+ *  process.
+ */
+static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
+                                  const struct iovec *rvec,
+                                  unsigned long riovcnt,
+                                  unsigned long flags, int vm_write)
+{
+        struct task_struct *task;
+        struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
+        struct page **process_pages = pp_stack;
+        struct mm_struct *mm;
+        unsigned long i;
+        ssize_t rc = 0;
+        unsigned long nr_pages = 0;
+        unsigned long nr_pages_iov;
+        ssize_t iov_len;
+        size_t total_len = iov_iter_count(iter);
+
+        /*
+         * Work out how many pages of struct pages we're going to need
+         * when eventually calling get_user_pages
+         */
+        for (i = 0; i < riovcnt; i++) {
+                iov_len = rvec[i].iov_len;
+                if (iov_len > 0) {
+                        nr_pages_iov = ((unsigned long)rvec[i].iov_base
+                                        + iov_len)
+                                / PAGE_SIZE - (unsigned long)rvec[i].iov_base
+                                / PAGE_SIZE + 1;
+                        nr_pages = max(nr_pages, nr_pages_iov);
+                }
+        }
+
+        if (nr_pages == 0)
+                return 0;
+
+        if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
+                /* For reliability don't try to kmalloc more than
+                   2 pages worth */
+                process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
+                                              sizeof(struct pages *)*nr_pages),
+                                        GFP_KERNEL);
+
+                if (!process_pages)
+                        return -ENOMEM;
+        }
+
+        /* Get process information */
+        task = find_get_task_by_vpid(pid);
+        if (!task) {
+                rc = -ESRCH;
+                goto free_proc_pages;
+        }
+
+        mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
+        if (!mm || IS_ERR(mm)) {
+                rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
+                /*
+                 * Explicitly map EACCES to EPERM as EPERM is a more
+                 * appropriate error code for process_vw_readv/writev
+                 */
+                if (rc == -EACCES)
+                        rc = -EPERM;
+                goto put_task_struct;
+        }
+
+        for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
+                rc = process_vm_rw_single_vec(
+                        (unsigned long)rvec[i].iov_base, rvec[i].iov_len,
+                        iter, process_pages, mm, task, vm_write);
+
+        /* copied = space before - space after */
+        total_len -= iov_iter_count(iter);
+
+        /* If we have managed to copy any data at all then
+           we return the number of bytes copied. Otherwise
+           we return the error code */
+        if (total_len)
+                rc = total_len;
+
+        mmput(mm);
+
+put_task_struct:
+        put_task_struct(task);
+
+free_proc_pages:
+        if (process_pages != pp_stack)
+                kfree(process_pages);
+        return rc;
+}
+
+/**
+ * process_vm_rw - check iovecs before calling core routine
+ * @pid: PID of process to read/write from/to
+ * @lvec: iovec array specifying where to copy to/from locally
+ * @liovcnt: size of lvec array
+ * @rvec: iovec array specifying where to copy to/from in the other process
+ * @riovcnt: size of rvec array
+ * @flags: currently unused
+ * @vm_write: 0 if reading from other process, 1 if writing to other process
+ *
+ * Returns the number of bytes read/written or error code. May
+ *  return less bytes than expected if an error occurs during the copying
+ *  process.
+ */
+static ssize_t process_vm_rw(pid_t pid,
+                             const struct iovec __user *lvec,
+                             unsigned long liovcnt,
+                             const struct iovec __user *rvec,
+                             unsigned long riovcnt,
+                             unsigned long flags, int vm_write)
+{
+        struct iovec iovstack_l[UIO_FASTIOV];
+        struct iovec iovstack_r[UIO_FASTIOV];
+        struct iovec *iov_l = iovstack_l;
+        struct iovec *iov_r = iovstack_r;
+        struct iov_iter iter;
+        ssize_t rc;
+        int dir = vm_write ? WRITE : READ;
+
+        if (flags != 0)
+                return -EINVAL;
+
+        /* Check iovecs */
+        rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
+        if (rc < 0)
+                return rc;
+        if (!iov_iter_count(&iter))
+                goto free_iov_l;
+        iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r,
+                                in_compat_syscall());
+        if (IS_ERR(iov_r)) {
+                rc = PTR_ERR(iov_r);
+                goto free_iov_l;
+        }
+        rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
+        if (iov_r != iovstack_r)
+                kfree(iov_r);
+free_iov_l:
+        kfree(iov_l);
+        return rc;
+}
+
+SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
+                unsigned long, liovcnt, const struct iovec __user *, rvec,
+                unsigned long, riovcnt, unsigned long, flags)
+{
+        return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
+}
+
+SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
+                const struct iovec __user *, lvec,
+                unsigned long, liovcnt, const struct iovec __user *, rvec,
+                unsigned long, riovcnt, unsigned long, flags)
+{
+        return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
+}