Add two new file operations that are identical to ->read and ->write except that they can also safely take kernel pointers using the uptr_t type.
Signed-off-by: Christoph Hellwig <[email protected]> --- fs/internal.h | 4 ++-- fs/read_write.c | 18 ++++++++++++++---- include/linux/fs.h | 3 +++ 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 242f2845b3428b..b6777a47b05163 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -189,9 +189,9 @@ int do_statx(int dfd, const char __user *filename, unsigned flags, static inline void set_fmode_can_read_write(struct file *f) { if ((f->f_mode & FMODE_READ) && - (f->f_op->read || f->f_op->read_iter)) + (f->f_op->read || f->f_op->read_uptr || f->f_op->read_iter)) f->f_mode |= FMODE_CAN_READ; if ((f->f_mode & FMODE_WRITE) && - (f->f_op->write || f->f_op->write_iter)) + (f->f_op->write || f->f_op->write_uptr || f->f_op->write_iter)) f->f_mode |= FMODE_CAN_WRITE; } diff --git a/fs/read_write.c b/fs/read_write.c index e7f36b15683049..24ffbf3cbda243 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -430,7 +430,9 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; - if (file->f_op->read) { + if (file->f_op->read_uptr) { + ret = file->f_op->read_uptr(file, KERNEL_UPTR(buf), count, pos); + } else if (file->f_op->read) { mm_segment_t old_fs = get_fs(); set_fs(KERNEL_DS); @@ -485,7 +487,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; - if (file->f_op->read) + if (file->f_op->read_uptr) + ret = file->f_op->read_uptr(file, USER_UPTR(buf), count, pos); + else if (file->f_op->read) ret = file->f_op->read(file, buf, count, pos); else if (file->f_op->read_iter) ret = new_sync_read(file, buf, count, pos); @@ -530,7 +534,10 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; - if (file->f_op->write) { + if (file->f_op->write_uptr) { + ret = file->f_op->write_uptr(file, KERNEL_UPTR((void *)buf), + count, pos); + } else if (file->f_op->write) { mm_segment_t old_fs = get_fs(); set_fs(KERNEL_DS); @@ -592,7 +599,10 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_ if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; file_start_write(file); - if (file->f_op->write) + if (file->f_op->write_uptr) + ret = file->f_op->write_uptr(file, + USER_UPTR((char __user *)buf), count, pos); + else if (file->f_op->write) ret = file->f_op->write(file, buf, count, pos); else if (file->f_op->write_iter) ret = new_sync_write(file, buf, count, pos); diff --git a/include/linux/fs.h b/include/linux/fs.h index fac6aead402a98..d8fc3015f5a197 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -39,6 +39,7 @@ #include <linux/fs_types.h> #include <linux/build_bug.h> #include <linux/stddef.h> +#include <linux/uptr.h> #include <asm/byteorder.h> #include <uapi/linux/fs.h> @@ -1830,6 +1831,8 @@ struct file_operations { ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + ssize_t (*read_uptr) (struct file *, uptr_t, size_t, loff_t *); + ssize_t (*write_uptr) (struct file *, uptr_t, size_t, loff_t *); int (*iopoll)(struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); -- 2.26.2
