diff options
| -rw-r--r-- | fs/fuse/file.c | 72 |
1 files changed, 66 insertions, 6 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 9242d294fe90..8b984a2cebbd 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -13,6 +13,7 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/module.h> +#include <linux/compat.h> static const struct file_operations fuse_direct_io_file_operations; @@ -1628,6 +1629,58 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov, } /* + * 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(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 iovec *iov, size_t count) +{ + size_t n; + u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT; + + for (n = 0; n < count; n++) { + if (iov->iov_len > (size_t) max) + return -ENOMEM; + max -= iov->iov_len; + } + 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 @@ -1808,18 +1861,25 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) goto out; - err = -EIO; - if ((in_iovs + out_iovs) * sizeof(struct iovec) != transferred) - goto out; - - /* okay, copy in iovs and retry */ vaddr = kmap_atomic(pages[0], KM_USER0); - memcpy(page_address(iov_page), vaddr, transferred); + err = fuse_copy_ioctl_iovec(page_address(iov_page), vaddr, + transferred, in_iovs + out_iovs, + (flags & FUSE_IOCTL_COMPAT) != 0); kunmap_atomic(vaddr, KM_USER0); + if (err) + goto out; in_iov = page_address(iov_page); out_iov = in_iov + in_iovs; + err = fuse_verify_ioctl_iov(in_iov, in_iovs); + if (err) + goto out; + + err = fuse_verify_ioctl_iov(out_iov, out_iovs); + if (err) + goto out; + goto retry; } |