[PATCH 06/22] elevate write count during entire ncp_ioctl()

From: Dave Hansen
Date: Fri Feb 09 2007 - 18:01:46 EST




Some ioctls need write access, but others don't. Make a helper
function to decide when write access is needed, and take it.

Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
---

lxc-dave/fs/ncpfs/ioctl.c | 55 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 54 insertions(+), 1 deletion(-)

diff -puN fs/ncpfs/ioctl.c~08-24-elevate-write-count-during-entire-ncp-ioctl fs/ncpfs/ioctl.c
--- lxc/fs/ncpfs/ioctl.c~08-24-elevate-write-count-during-entire-ncp-ioctl 2007-02-09 14:26:50.000000000 -0800
+++ lxc-dave/fs/ncpfs/ioctl.c 2007-02-09 14:26:50.000000000 -0800
@@ -14,6 +14,7 @@
#include <linux/ioctl.h>
#include <linux/time.h>
#include <linux/mm.h>
+#include <linux/mount.h>
#include <linux/highuid.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
@@ -260,7 +261,7 @@ ncp_get_charsets(struct ncp_server* serv
}
#endif /* CONFIG_NCPFS_NLS */

-int ncp_ioctl(struct inode *inode, struct file *filp,
+static int __ncp_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct ncp_server *server = NCP_SERVER(inode);
@@ -821,6 +822,58 @@ outrel:
return -EINVAL;
}

+static int ncp_ioctl_need_write(unsigned int cmd)
+{
+ switch (cmd) {
+ case NCP_IOC_GET_FS_INFO:
+ case NCP_IOC_GET_FS_INFO_V2:
+ case NCP_IOC_NCPREQUEST:
+ case NCP_IOC_SETDENTRYTTL:
+ case NCP_IOC_SIGN_INIT:
+ case NCP_IOC_LOCKUNLOCK:
+ case NCP_IOC_SET_SIGN_WANTED:
+ return 1;
+ case NCP_IOC_GETOBJECTNAME:
+ case NCP_IOC_SETOBJECTNAME:
+ case NCP_IOC_GETPRIVATEDATA:
+ case NCP_IOC_SETPRIVATEDATA:
+ case NCP_IOC_SETCHARSETS:
+ case NCP_IOC_GETCHARSETS:
+ case NCP_IOC_CONN_LOGGED_IN:
+ case NCP_IOC_GETDENTRYTTL:
+ case NCP_IOC_GETMOUNTUID2:
+ case NCP_IOC_SIGN_WANTED:
+ case NCP_IOC_GETROOT:
+ case NCP_IOC_SETROOT:
+ return 0;
+ default:
+ /* unkown IOCTL command, assume write */
+ WARN_ON(1);
+ }
+ return 1;
+}
+
+int ncp_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ int ret;
+
+ if (ncp_ioctl_need_write(cmd)) {
+ /*
+ * inside the ioctl(), any failures which
+ * are because of file_permission() are
+ * -EACCESS, so it seems consistent to keep
+ * that here.
+ */
+ if (mnt_want_write(filp->f_vfsmnt))
+ return -EACCES;
+ }
+ ret = __ncp_ioctl(inode, filp, cmd, arg);
+ if (ncp_ioctl_need_write(cmd))
+ mnt_drop_write(filp->f_vfsmnt);
+ return ret;
+}
+
#ifdef CONFIG_COMPAT
long ncp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
_
-
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