allow userspace to modify scsi command filter on per device basis

This patch exports the per-gendisk command filter to user space through
sysfs, so it can be changed by the system administrator.
All users of the old cmd filter have been converted to use the new one.

Original patch from Peter Jones.

Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 10 insertions, 30 deletions

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index ea0edd1b2e76..f7abccaffaec 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -182,8 +182,9 @@ static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
 			 int tablesize);
 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 			   Sg_request * srp);
-static ssize_t sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
-			    int blocking, int read_only, Sg_request ** o_srp);
+static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
+			const char __user *buf, size_t count, int blocking,
+			int read_only, Sg_request **o_srp);
 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 			   unsigned char *cmnd, int timeout, int blocking);
 static int sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
@@ -204,7 +205,6 @@ static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
 static Sg_request *sg_add_request(Sg_fd * sfp);
 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 static int sg_res_in_use(Sg_fd * sfp);
-static int sg_allow_access(unsigned char opcode, char dev_type);
 static int sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len);
 static Sg_device *sg_get_dev(int dev);
 #ifdef CONFIG_SCSI_PROC_FS
@@ -544,7 +544,7 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 		return -EFAULT;
 	blocking = !(filp->f_flags & O_NONBLOCK);
 	if (old_hdr.reply_len < 0)
-		return sg_new_write(sfp, buf, count, blocking, 0, NULL);
+		return sg_new_write(sfp, filp, buf, count, blocking, 0, NULL);
 	if (count < (SZ_SG_HEADER + 6))
 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
 
@@ -621,8 +621,9 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 }
 
 static ssize_t
-sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
-	     int blocking, int read_only, Sg_request ** o_srp)
+sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
+		 size_t count, int blocking, int read_only,
+		 Sg_request **o_srp)
 {
 	int k;
 	Sg_request *srp;
@@ -678,8 +679,7 @@ sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
 		sg_remove_request(sfp, srp);
 		return -EFAULT;
 	}
-	if (read_only &&
-	    (!sg_allow_access(cmnd[0], sfp->parentdp->device->type))) {
+	if (read_only && (!blk_verify_command(file, cmnd))) {
 		sg_remove_request(sfp, srp);
 		return -EPERM;
 	}
@@ -799,7 +799,7 @@ sg_ioctl(struct inode *inode, struct file *filp,
 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
 				return -EFAULT;
 			result =
-			    sg_new_write(sfp, p, SZ_SG_IO_HDR,
+			    sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 					 blocking, read_only, &srp);
 			if (result < 0)
 				return result;
@@ -1048,7 +1048,7 @@ sg_ioctl(struct inode *inode, struct file *filp,
 
 			if (copy_from_user(&opcode, siocp->data, 1))
 				return -EFAULT;
-			if (!sg_allow_access(opcode, sdp->device->type))
+			if (!blk_verify_command(filp, &opcode))
 				return -EPERM;
 		}
 		return sg_scsi_ioctl(filp, sdp->device->request_queue, NULL, p);
@@ -2506,26 +2506,6 @@ sg_page_free(struct page *page, int size)
 #define MAINTENANCE_IN_CMD 0xa3
 #endif
 
-static unsigned char allow_ops[] = { TEST_UNIT_READY, REQUEST_SENSE,
-	INQUIRY, READ_CAPACITY, READ_BUFFER, READ_6, READ_10, READ_12,
-	READ_16, MODE_SENSE, MODE_SENSE_10, LOG_SENSE, REPORT_LUNS,
-	SERVICE_ACTION_IN, RECEIVE_DIAGNOSTIC, READ_LONG, MAINTENANCE_IN_CMD
-};
-
-static int
-sg_allow_access(unsigned char opcode, char dev_type)
-{
-	int k;
-
-	if (TYPE_SCANNER == dev_type)	/* TYPE_ROM maybe burner */
-		return 1;
-	for (k = 0; k < sizeof (allow_ops); ++k) {
-		if (opcode == allow_ops[k])
-			return 1;
-	}
-	return 0;
-}
-
 #ifdef CONFIG_SCSI_PROC_FS
 static int
 sg_idr_max_id(int id, void *p, void *data)