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 - 14:32:21 EDT

  • Next message: Alain Knaff: "Re: bug in blkdev <-> VFS interaction. (oops) (fwd)"

    >
    >
    >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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