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From: Tyler Hicks on 20 May 2010 19:50
Lower filesystems that only implement unlocked_ioctl aren't being
passed ioctl calls because eCryptfs only checked for
lower_file->f_op->ioctl and returned -ENOTTY if it was NULL.

eCryptfs shouldn't implement ioctl(), since it doesn't require the BKL.
Instead, unlocked_ioctl() should be used and vfs_ioctl() can be called
on the lower file since it handles locking, if necessary. This requires
vfs_ioctl() to be exported.

Also implements compat_ioctl() function by simply passing the call on
to the lower filesystem's compat_ioctl() function.

Reported-by: James Dupin <james.dupin(a)gmail.com>
Signed-off-by: Tyler Hicks <tyhicks(a)linux.vnet.ibm.com>
---
fs/ecryptfs/file.c | 56 ++++++++++++++++++++++++++++++++-------------------
fs/ioctl.c | 4 +-
include/linux/fs.h | 1 +
3 files changed, 38 insertions(+), 23 deletions(-)

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index e7440a6..4632ac8 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -294,12 +294,40 @@ static int ecryptfs_fasync(int fd, struct file *file, int flag)
return rc;
}

-static int ecryptfs_ioctl(struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg);
+static long
+ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long rc = -ENOTTY;
+ struct file *lower_file = NULL;
+
+ if (ecryptfs_file_to_private(file))
+ lower_file = ecryptfs_file_to_lower(file);
+ if (lower_file)
+ rc = vfs_ioctl(lower_file, cmd, arg);
+ return rc;
+}
+
+#ifdef CONFIG_COMPAT
+static long
+ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long rc = -ENOTTY;
+ struct file *lower_file = NULL;
+
+ if (ecryptfs_file_to_private(file))
+ lower_file = ecryptfs_file_to_lower(file);
+ if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
+ rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
+ return rc;
+}
+#endif

const struct file_operations ecryptfs_dir_fops = {
.readdir = ecryptfs_readdir,
- .ioctl = ecryptfs_ioctl,
+ .unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ecryptfs_compat_ioctl,
+#endif
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
@@ -315,7 +343,10 @@ const struct file_operations ecryptfs_main_fops = {
.write = do_sync_write,
.aio_write = generic_file_aio_write,
.readdir = ecryptfs_readdir,
- .ioctl = ecryptfs_ioctl,
+ .unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ecryptfs_compat_ioctl,
+#endif
.mmap = generic_file_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
@@ -324,20 +355,3 @@ const struct file_operations ecryptfs_main_fops = {
.fasync = ecryptfs_fasync,
.splice_read = generic_file_splice_read,
};
-
-static int
-ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
- unsigned long arg)
-{
- int rc = 0;
- struct file *lower_file = NULL;
-
- if (ecryptfs_file_to_private(file))
- lower_file = ecryptfs_file_to_lower(file);
- if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
- rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
- lower_file, cmd, arg);
- else
- rc = -ENOTTY;
- return rc;
-}
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 7faefb4..549b8e9 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -34,8 +34,7 @@
*
* Returns 0 on success, -errno on error.
*/
-static long vfs_ioctl(struct file *filp, unsigned int cmd,
- unsigned long arg)
+long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int error = -ENOTTY;

@@ -57,6 +56,7 @@ static long vfs_ioctl(struct file *filp, unsigned int cmd,
out:
return error;
}
+EXPORT_SYMBOL(vfs_ioctl);

static int ioctl_fibmap(struct file *filp, int __user *p)
{
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 44f35ae..d862c81 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1922,6 +1922,7 @@ extern char * getname(const char __user *);
/* fs/ioctl.c */

extern int ioctl_preallocate(struct file *filp, void __user *argp);
+extern long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);

/* fs/dcache.c */
extern void __init vfs_caches_init_early(void);
--
1.7.0.1

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