Re: [PATCH] Fix floppy ioctl (which were broken in 2.4.0-test5)

From: Alain Knaff (Alain.Knaff@ltnb.lu)
Date: Sat Sep 16 2000 - 13:32:21 EST


>
>
>On Sat, 16 Sep 2000, Alain Knaff wrote:
>>
>> The following patch (against 2.4.0-test8) restores ioctl functionality,
>> which has been broken in 2.4.0-test6-pre7:
>
>No. Th epatch breaks things. You cannot use "permission" at that point,
>and the code was removed on purpose before. Nobody could tell what the
>point in the ugly code was.

Maybe because nobody had asked? N.B. Here is a revised edition, which
eliminates the problem alluded to (root mounts). If that still isn't
good enough (please tell me), I'll follow up with a patch that uses
the inode passed to fd_ioctl.

>
>Not applied.
>
> Linus

--- 2.4.0-test8/linux/drivers/block/floppy.c Mon Sep 11 20:09:28 2000
+++ linux/drivers/block/floppy.c Sat Sep 16 18:57:14 2000
@@ -3435,6 +3435,7 @@
 static int fd_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
                     unsigned long param)
 {
+#define FD_IOCTL_ALLOWED ((filp) && (filp)->private_data)
 #define OUT(c,x) case c: outparam = (const char *) (x); break
 #define IN(c,x,tag) case c: *(x) = inparam. tag ; return 0
 
@@ -3502,7 +3503,7 @@
                 return -EINVAL;
 
         /* permission checks */
- if (((cmd & 0x40) && !(filp->f_mode & 2)) ||
+ if (((cmd & 0x40) && !FD_IOCTL_ALLOWED) ||
             ((cmd & 0x80) && !capable(CAP_SYS_ADMIN)))
                 return -EPERM;
 
@@ -3708,6 +3709,8 @@
                 return -EIO;
         }
 
+ filp->private_data = (void*) 0;
+
         drive = DRIVE(inode->i_rdev);
         if (drive >= N_DRIVE ||
             !(allowed_drive_mask & (1 << drive)) ||
@@ -3774,6 +3777,13 @@
                         buffer_track = -1;
                 invalidate_buffers(MKDEV(FLOPPY_MAJOR,old_dev));
         }
+
+ /* Allow ioctls if we have write-permissions even if read-only open.
+ * Needed so that programs such as fdrawcmd still can work on write
+ * protected disks */
+ if ((filp->f_mode & 2) ||
+ (inode->i_sb && (permission(inode,2) == 0)))
+ filp->private_data = (void*) 8;
 
         if (UFDCS->rawcmd == 1)
                 UFDCS->rawcmd = 2;
-
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