From 98aaaec4a150c39219a8aaa68c3adc6eed443ea8 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 14 Mar 2019 17:45:18 +0100 Subject: compat_ioctl: reimplement SG_IO handling There are two code locations that implement the SG_IO ioctl: the old sg.c driver, and the generic scsi_ioctl helper that is in turn used by multiple drivers. To eradicate the old compat_ioctl conversion handler for the SG_IO command, I implement a readable pair of put_sg_io_hdr() /get_sg_io_hdr() helper functions that can be used for both compat and native mode, and then I call this from both drivers. For the iovec handling, there is already a compat_import_iovec() function that can simply be called in place of import_iovec(). To avoid having to pass the compat/native state through multiple indirections, I mark the SG_IO command itself as compatible in fs/compat_ioctl.c and use in_compat_syscall() to figure out where we are called from. As a side-effect of this, the sg.c driver now also accepts the 32-bit sg_io_hdr format in compat mode using the read/write interface, not just ioctl. This should improve compatiblity with old 32-bit binaries, but it would break if any application intentionally passes the 64-bit data structure in compat mode here. Steffen Maier helped debug an issue in an earlier version of this patch. Cc: Steffen Maier Cc: linux-scsi@vger.kernel.org Cc: Doug Gilbert Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Signed-off-by: Arnd Bergmann --- include/linux/blkdev.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f3ea78b0c91c..2c8cd22b176b 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -870,6 +870,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t, unsigned int, void __user *); extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t, struct scsi_ioctl_command __user *); +extern int get_sg_io_hdr(struct sg_io_hdr *hdr, const void __user *argp); +extern int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp); extern int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags); extern void blk_queue_exit(struct request_queue *q); -- cgit v1.2.3