[BLOCK] scsi_ioctl: file can be NULL from ioctl_by_bdev()

Signed-off-by: Jens Axboe <axboe@suse.de>

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index c2ac36dfe4f3a8253bba24933ab9f5b66634eb83..18de84c8ccd8bca5d1fafe8d0326cda0998cf87d 100644 (file)
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -190,16 +190,21 @@ 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))