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Diffstat (limited to 'block/scsi_ioctl.c')
-rw-r--r--block/scsi_ioctl.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 6e7db2e79f42..cc72210687eb 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -21,6 +21,7 @@
 #include <linux/string.h>
 #include <linux/module.h>
 #include <linux/blkdev.h>
+#include <linux/capability.h>
 #include <linux/completion.h>
 #include <linux/cdrom.h>
 #include <linux/slab.h>
@@ -46,7 +47,7 @@ EXPORT_SYMBOL(scsi_command_size);
 
 static int sg_get_version(int __user *p)
 {
-	static int sg_version_num = 30527;
+	static const int sg_version_num = 30527;
 	return put_user(sg_version_num, p);
 }
 
@@ -190,16 +191,21 @@ static int verify_command(struct file *file, unsigned char *cmd)
 		safe_for_write(GPCMD_SET_STREAMING),
 	};
 	unsigned char type = cmd_type[cmd[0]];
+	int has_write_perm = 0;
 
 	/* Anybody who can open the device can do a read-safe command */
 	if (type & CMD_READ_SAFE)
 		return 0;
 
+	/*
+	 * file can be NULL from ioctl_by_bdev()...
+	 */
+	if (file)
+		has_write_perm = file->f_mode & FMODE_WRITE;
+
 	/* Write-safe commands just require a writable open.. */
-	if (type & CMD_WRITE_SAFE) {
-		if (file->f_mode & FMODE_WRITE)
-			return 0;
-	}
+	if ((type & CMD_WRITE_SAFE) && has_write_perm)
+		return 0;
 
 	/* And root can do any command.. */
 	if (capable(CAP_SYS_RAWIO))
@@ -233,7 +239,7 @@ static int sg_io(struct file *file, request_queue_t *q,
 	if (verify_command(file, cmd))
 		return -EPERM;
 
-	if (hdr->dxfer_len > (q->max_sectors << 9))
+	if (hdr->dxfer_len > (q->max_hw_sectors << 9))
 		return -EIO;
 
 	if (hdr->dxfer_len)