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-rw-r--r--fs/fuse/ioctl.c515
1 files changed, 515 insertions, 0 deletions
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
new file mode 100644
index 0000000000..726640fa43
--- /dev/null
+++ b/fs/fuse/ioctl.c
@@ -0,0 +1,515 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ */
+
+#include "fuse_i.h"
+
+#include <linux/uio.h>
+#include <linux/compat.h>
+#include <linux/fileattr.h>
+
+static ssize_t fuse_send_ioctl(struct fuse_mount *fm, struct fuse_args *args,
+ struct fuse_ioctl_out *outarg)
+{
+ ssize_t ret;
+
+ args->out_args[0].size = sizeof(*outarg);
+ args->out_args[0].value = outarg;
+
+ ret = fuse_simple_request(fm, args);
+
+ /* Translate ENOSYS, which shouldn't be returned from fs */
+ if (ret == -ENOSYS)
+ ret = -ENOTTY;
+
+ if (ret >= 0 && outarg->result == -ENOSYS)
+ outarg->result = -ENOTTY;
+
+ return ret;
+}
+
+/*
+ * CUSE servers compiled on 32bit broke on 64bit kernels because the
+ * ABI was defined to be 'struct iovec' which is different on 32bit
+ * and 64bit. Fortunately we can determine which structure the server
+ * used from the size of the reply.
+ */
+static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
+ size_t transferred, unsigned count,
+ bool is_compat)
+{
+#ifdef CONFIG_COMPAT
+ if (count * sizeof(struct compat_iovec) == transferred) {
+ struct compat_iovec *ciov = src;
+ unsigned i;
+
+ /*
+ * With this interface a 32bit server cannot support
+ * non-compat (i.e. ones coming from 64bit apps) ioctl
+ * requests
+ */
+ if (!is_compat)
+ return -EINVAL;
+
+ for (i = 0; i < count; i++) {
+ dst[i].iov_base = compat_ptr(ciov[i].iov_base);
+ dst[i].iov_len = ciov[i].iov_len;
+ }
+ return 0;
+ }
+#endif
+
+ if (count * sizeof(struct iovec) != transferred)
+ return -EIO;
+
+ memcpy(dst, src, transferred);
+ return 0;
+}
+
+/* Make sure iov_length() won't overflow */
+static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov,
+ size_t count)
+{
+ size_t n;
+ u32 max = fc->max_pages << PAGE_SHIFT;
+
+ for (n = 0; n < count; n++, iov++) {
+ if (iov->iov_len > (size_t) max)
+ return -ENOMEM;
+ max -= iov->iov_len;
+ }
+ return 0;
+}
+
+static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
+ void *src, size_t transferred, unsigned count,
+ bool is_compat)
+{
+ unsigned i;
+ struct fuse_ioctl_iovec *fiov = src;
+
+ if (fc->minor < 16) {
+ return fuse_copy_ioctl_iovec_old(dst, src, transferred,
+ count, is_compat);
+ }
+
+ if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
+ return -EIO;
+
+ for (i = 0; i < count; i++) {
+ /* Did the server supply an inappropriate value? */
+ if (fiov[i].base != (unsigned long) fiov[i].base ||
+ fiov[i].len != (unsigned long) fiov[i].len)
+ return -EIO;
+
+ dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
+ dst[i].iov_len = (size_t) fiov[i].len;
+
+#ifdef CONFIG_COMPAT
+ if (is_compat &&
+ (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
+ (compat_size_t) dst[i].iov_len != fiov[i].len))
+ return -EIO;
+#endif
+ }
+
+ return 0;
+}
+
+
+/*
+ * For ioctls, there is no generic way to determine how much memory
+ * needs to be read and/or written. Furthermore, ioctls are allowed
+ * to dereference the passed pointer, so the parameter requires deep
+ * copying but FUSE has no idea whatsoever about what to copy in or
+ * out.
+ *
+ * This is solved by allowing FUSE server to retry ioctl with
+ * necessary in/out iovecs. Let's assume the ioctl implementation
+ * needs to read in the following structure.
+ *
+ * struct a {
+ * char *buf;
+ * size_t buflen;
+ * }
+ *
+ * On the first callout to FUSE server, inarg->in_size and
+ * inarg->out_size will be NULL; then, the server completes the ioctl
+ * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
+ * the actual iov array to
+ *
+ * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
+ *
+ * which tells FUSE to copy in the requested area and retry the ioctl.
+ * On the second round, the server has access to the structure and
+ * from that it can tell what to look for next, so on the invocation,
+ * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
+ *
+ * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
+ * { .iov_base = a.buf, .iov_len = a.buflen } }
+ *
+ * FUSE will copy both struct a and the pointed buffer from the
+ * process doing the ioctl and retry ioctl with both struct a and the
+ * buffer.
+ *
+ * This time, FUSE server has everything it needs and completes ioctl
+ * without FUSE_IOCTL_RETRY which finishes the ioctl call.
+ *
+ * Copying data out works the same way.
+ *
+ * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
+ * automatically initializes in and out iovs by decoding @cmd with
+ * _IOC_* macros and the server is not allowed to request RETRY. This
+ * limits ioctl data transfers to well-formed ioctls and is the forced
+ * behavior for all FUSE servers.
+ */
+long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
+ unsigned int flags)
+{
+ struct fuse_file *ff = file->private_data;
+ struct fuse_mount *fm = ff->fm;
+ struct fuse_ioctl_in inarg = {
+ .fh = ff->fh,
+ .cmd = cmd,
+ .arg = arg,
+ .flags = flags
+ };
+ struct fuse_ioctl_out outarg;
+ struct iovec *iov_page = NULL;
+ struct iovec *in_iov = NULL, *out_iov = NULL;
+ unsigned int in_iovs = 0, out_iovs = 0, max_pages;
+ size_t in_size, out_size, c;
+ ssize_t transferred;
+ int err, i;
+ struct iov_iter ii;
+ struct fuse_args_pages ap = {};
+
+#if BITS_PER_LONG == 32
+ inarg.flags |= FUSE_IOCTL_32BIT;
+#else
+ if (flags & FUSE_IOCTL_COMPAT) {
+ inarg.flags |= FUSE_IOCTL_32BIT;
+#ifdef CONFIG_X86_X32_ABI
+ if (in_x32_syscall())
+ inarg.flags |= FUSE_IOCTL_COMPAT_X32;
+#endif
+ }
+#endif
+
+ /* assume all the iovs returned by client always fits in a page */
+ BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
+
+ err = -ENOMEM;
+ ap.pages = fuse_pages_alloc(fm->fc->max_pages, GFP_KERNEL, &ap.descs);
+ iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
+ if (!ap.pages || !iov_page)
+ goto out;
+
+ fuse_page_descs_length_init(ap.descs, 0, fm->fc->max_pages);
+
+ /*
+ * If restricted, initialize IO parameters as encoded in @cmd.
+ * RETRY from server is not allowed.
+ */
+ if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
+ struct iovec *iov = iov_page;
+
+ iov->iov_base = (void __user *)arg;
+ iov->iov_len = _IOC_SIZE(cmd);
+
+ if (_IOC_DIR(cmd) & _IOC_WRITE) {
+ in_iov = iov;
+ in_iovs = 1;
+ }
+
+ if (_IOC_DIR(cmd) & _IOC_READ) {
+ out_iov = iov;
+ out_iovs = 1;
+ }
+ }
+
+ retry:
+ inarg.in_size = in_size = iov_length(in_iov, in_iovs);
+ inarg.out_size = out_size = iov_length(out_iov, out_iovs);
+
+ /*
+ * Out data can be used either for actual out data or iovs,
+ * make sure there always is at least one page.
+ */
+ out_size = max_t(size_t, out_size, PAGE_SIZE);
+ max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
+
+ /* make sure there are enough buffer pages and init request with them */
+ err = -ENOMEM;
+ if (max_pages > fm->fc->max_pages)
+ goto out;
+ while (ap.num_pages < max_pages) {
+ ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+ if (!ap.pages[ap.num_pages])
+ goto out;
+ ap.num_pages++;
+ }
+
+
+ /* okay, let's send it to the client */
+ ap.args.opcode = FUSE_IOCTL;
+ ap.args.nodeid = ff->nodeid;
+ ap.args.in_numargs = 1;
+ ap.args.in_args[0].size = sizeof(inarg);
+ ap.args.in_args[0].value = &inarg;
+ if (in_size) {
+ ap.args.in_numargs++;
+ ap.args.in_args[1].size = in_size;
+ ap.args.in_pages = true;
+
+ err = -EFAULT;
+ iov_iter_init(&ii, ITER_SOURCE, in_iov, in_iovs, in_size);
+ for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+ c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
+ if (c != PAGE_SIZE && iov_iter_count(&ii))
+ goto out;
+ }
+ }
+
+ ap.args.out_numargs = 2;
+ ap.args.out_args[1].size = out_size;
+ ap.args.out_pages = true;
+ ap.args.out_argvar = true;
+
+ transferred = fuse_send_ioctl(fm, &ap.args, &outarg);
+ err = transferred;
+ if (transferred < 0)
+ goto out;
+
+ /* did it ask for retry? */
+ if (outarg.flags & FUSE_IOCTL_RETRY) {
+ void *vaddr;
+
+ /* no retry if in restricted mode */
+ err = -EIO;
+ if (!(flags & FUSE_IOCTL_UNRESTRICTED))
+ goto out;
+
+ in_iovs = outarg.in_iovs;
+ out_iovs = outarg.out_iovs;
+
+ /*
+ * Make sure things are in boundary, separate checks
+ * are to protect against overflow.
+ */
+ err = -ENOMEM;
+ if (in_iovs > FUSE_IOCTL_MAX_IOV ||
+ out_iovs > FUSE_IOCTL_MAX_IOV ||
+ in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
+ goto out;
+
+ vaddr = kmap_local_page(ap.pages[0]);
+ err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr,
+ transferred, in_iovs + out_iovs,
+ (flags & FUSE_IOCTL_COMPAT) != 0);
+ kunmap_local(vaddr);
+ if (err)
+ goto out;
+
+ in_iov = iov_page;
+ out_iov = in_iov + in_iovs;
+
+ err = fuse_verify_ioctl_iov(fm->fc, in_iov, in_iovs);
+ if (err)
+ goto out;
+
+ err = fuse_verify_ioctl_iov(fm->fc, out_iov, out_iovs);
+ if (err)
+ goto out;
+
+ goto retry;
+ }
+
+ err = -EIO;
+ if (transferred > inarg.out_size)
+ goto out;
+
+ err = -EFAULT;
+ iov_iter_init(&ii, ITER_DEST, out_iov, out_iovs, transferred);
+ for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
+ c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
+ if (c != PAGE_SIZE && iov_iter_count(&ii))
+ goto out;
+ }
+ err = 0;
+ out:
+ free_page((unsigned long) iov_page);
+ while (ap.num_pages)
+ __free_page(ap.pages[--ap.num_pages]);
+ kfree(ap.pages);
+
+ return err ? err : outarg.result;
+}
+EXPORT_SYMBOL_GPL(fuse_do_ioctl);
+
+long fuse_ioctl_common(struct file *file, unsigned int cmd,
+ unsigned long arg, unsigned int flags)
+{
+ struct inode *inode = file_inode(file);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (!fuse_allow_current_process(fc))
+ return -EACCES;
+
+ if (fuse_is_bad(inode))
+ return -EIO;
+
+ return fuse_do_ioctl(file, cmd, arg, flags);
+}
+
+long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ return fuse_ioctl_common(file, cmd, arg, 0);
+}
+
+long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
+}
+
+static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff,
+ unsigned int cmd, void *ptr, size_t size)
+{
+ struct fuse_mount *fm = ff->fm;
+ struct fuse_ioctl_in inarg;
+ struct fuse_ioctl_out outarg;
+ FUSE_ARGS(args);
+ int err;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.fh = ff->fh;
+ inarg.cmd = cmd;
+
+#if BITS_PER_LONG == 32
+ inarg.flags |= FUSE_IOCTL_32BIT;
+#endif
+ if (S_ISDIR(inode->i_mode))
+ inarg.flags |= FUSE_IOCTL_DIR;
+
+ if (_IOC_DIR(cmd) & _IOC_READ)
+ inarg.out_size = size;
+ if (_IOC_DIR(cmd) & _IOC_WRITE)
+ inarg.in_size = size;
+
+ args.opcode = FUSE_IOCTL;
+ args.nodeid = ff->nodeid;
+ args.in_numargs = 2;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+ args.in_args[1].size = inarg.in_size;
+ args.in_args[1].value = ptr;
+ args.out_numargs = 2;
+ args.out_args[1].size = inarg.out_size;
+ args.out_args[1].value = ptr;
+
+ err = fuse_send_ioctl(fm, &args, &outarg);
+ if (!err) {
+ if (outarg.result < 0)
+ err = outarg.result;
+ else if (outarg.flags & FUSE_IOCTL_RETRY)
+ err = -EIO;
+ }
+ return err;
+}
+
+static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode)
+{
+ struct fuse_mount *fm = get_fuse_mount(inode);
+ bool isdir = S_ISDIR(inode->i_mode);
+
+ if (!fuse_allow_current_process(fm->fc))
+ return ERR_PTR(-EACCES);
+
+ if (fuse_is_bad(inode))
+ return ERR_PTR(-EIO);
+
+ if (!S_ISREG(inode->i_mode) && !isdir)
+ return ERR_PTR(-ENOTTY);
+
+ return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir);
+}
+
+static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff)
+{
+ fuse_file_release(inode, ff, O_RDONLY, NULL, S_ISDIR(inode->i_mode));
+}
+
+int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa)
+{
+ struct inode *inode = d_inode(dentry);
+ struct fuse_file *ff;
+ unsigned int flags;
+ struct fsxattr xfa;
+ int err;
+
+ ff = fuse_priv_ioctl_prepare(inode);
+ if (IS_ERR(ff))
+ return PTR_ERR(ff);
+
+ if (fa->flags_valid) {
+ err = fuse_priv_ioctl(inode, ff, FS_IOC_GETFLAGS,
+ &flags, sizeof(flags));
+ if (err)
+ goto cleanup;
+
+ fileattr_fill_flags(fa, flags);
+ } else {
+ err = fuse_priv_ioctl(inode, ff, FS_IOC_FSGETXATTR,
+ &xfa, sizeof(xfa));
+ if (err)
+ goto cleanup;
+
+ fileattr_fill_xflags(fa, xfa.fsx_xflags);
+ fa->fsx_extsize = xfa.fsx_extsize;
+ fa->fsx_nextents = xfa.fsx_nextents;
+ fa->fsx_projid = xfa.fsx_projid;
+ fa->fsx_cowextsize = xfa.fsx_cowextsize;
+ }
+cleanup:
+ fuse_priv_ioctl_cleanup(inode, ff);
+
+ return err;
+}
+
+int fuse_fileattr_set(struct mnt_idmap *idmap,
+ struct dentry *dentry, struct fileattr *fa)
+{
+ struct inode *inode = d_inode(dentry);
+ struct fuse_file *ff;
+ unsigned int flags = fa->flags;
+ struct fsxattr xfa;
+ int err;
+
+ ff = fuse_priv_ioctl_prepare(inode);
+ if (IS_ERR(ff))
+ return PTR_ERR(ff);
+
+ if (fa->flags_valid) {
+ err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS,
+ &flags, sizeof(flags));
+ if (err)
+ goto cleanup;
+ } else {
+ memset(&xfa, 0, sizeof(xfa));
+ xfa.fsx_xflags = fa->fsx_xflags;
+ xfa.fsx_extsize = fa->fsx_extsize;
+ xfa.fsx_nextents = fa->fsx_nextents;
+ xfa.fsx_projid = fa->fsx_projid;
+ xfa.fsx_cowextsize = fa->fsx_cowextsize;
+
+ err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR,
+ &xfa, sizeof(xfa));
+ }
+
+cleanup:
+ fuse_priv_ioctl_cleanup(inode, ff);
+
+ return err;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 12:28:27 +0000