Only honor the FIGETBSZ ioctl for regular files, directories, and symlinks
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From: Christoph Hellwig on 14 Jun 2010 10:10 On Mon, Jun 14, 2010 at 10:05:10AM -0400, Theodore Ts'o wrote: > FIGETBSZ has an ioctl number of _IO(0x00,2) == 2, which can conflict > with device driver ioctls. Let's avoid the potential for problems by > only honoring the ioctl number for files where this ioctl is likely > going to be useful: regular files, directories, and symlinks. > > Thanks to Johannes Stezenbach for pointing this consequence of commit > 19ba0559. ioctl operate on a file descriptor, so you never call them on symbolic links. > diff --git a/fs/ioctl.c b/fs/ioctl.c > index 2d140a7..5c61d69 100644 > --- a/fs/ioctl.c > +++ b/fs/ioctl.c > @@ -597,7 +597,10 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, > { > struct inode *inode = filp->f_path.dentry->d_inode; > int __user *p = (int __user *)arg; > - return put_user(inode->i_sb->s_blocksize, p); > + > + if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || > + S_ISLNK(inode->i_mode)) > + return put_user(inode->i_sb->s_blocksize, p); > } > > default: A comment explaining why we fall through here for special files is almost required. Without that the chance of breaking it during the next random cleanup are far too high. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: tytso on 14 Jun 2010 10:20
On Mon, Jun 14, 2010 at 10:07:30AM -0400, Christoph Hellwig wrote: > On Mon, Jun 14, 2010 at 10:05:10AM -0400, Theodore Ts'o wrote: > > FIGETBSZ has an ioctl number of _IO(0x00,2) == 2, which can conflict > > with device driver ioctls. Let's avoid the potential for problems by > > only honoring the ioctl number for files where this ioctl is likely > > going to be useful: regular files, directories, and symlinks. > > > > Thanks to Johannes Stezenbach for pointing this consequence of commit > > 19ba0559. > > ioctl operate on a file descriptor, so you never call them on > symbolic links. Oops, good point. > A comment explaining why we fall through here for special files is > almost required. Without that the chance of breaking it during the > next random cleanup are far too high. Sigh. I had fixed that, but I failed to save emacs buffer before creating commit. Will resend with both fixes. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |