| // 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) |
| { |
| ssize_t ret = fuse_simple_request(fm, args); |
| |
| /* Translate ENOSYS, which shouldn't be returned from fs */ |
| if (ret == -ENOSYS) |
| ret = -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 |
| 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, WRITE, 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[0].size = sizeof(outarg); |
| ap.args.out_args[0].value = &outarg; |
| 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); |
| 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_atomic(ap.pages[0]); |
| err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr, |
| transferred, in_iovs + out_iovs, |
| (flags & FUSE_IOCTL_COMPAT) != 0); |
| kunmap_atomic(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, READ, 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[0].size = sizeof(outarg); |
| args.out_args[0].value = &outarg; |
| args.out_args[1].size = inarg.out_size; |
| args.out_args[1].value = ptr; |
| |
| err = fuse_send_ioctl(fm, &args); |
| 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 user_namespace *mnt_userns, |
| 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; |
| } |