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Subject[PATCH] fs/fhandle.c: 'handle_to_path' function reorganization
Date
This reorganization:

Removes the exiting labels and adds direct return, once that
there is only one cleanup necessity.

Removes 'retval' and 'file_handle' prior assignments due this new
approach.

Adds 'size' and 'byte' variables to make the code cleaner and more
understandable.

Uses 'memdup_user' instead 'kmalloc' + 'copy_from_user'.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
---
fs/fhandle.c | 48 ++++++++++++++++++------------------------------
1 file changed, 18 insertions(+), 30 deletions(-)

diff --git a/fs/fhandle.c b/fs/fhandle.c
index 999ff5c..56b120d 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -166,47 +166,35 @@ out_err:
static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
struct path *path)
{
- int retval = 0;
+ int retval;
struct file_handle f_handle;
- struct file_handle *handle = NULL;
+ struct file_handle *handle;
+ unsigned int size, bytes;

/*
* With handle we don't look at the execute bit on the
* the directory. Ideally we would like CAP_DAC_SEARCH.
* But we don't have that
*/
- if (!capable(CAP_DAC_READ_SEARCH)) {
- retval = -EPERM;
- goto out_err;
- }
- if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) {
- retval = -EFAULT;
- goto out_err;
- }
- if ((f_handle.handle_bytes > MAX_HANDLE_SZ) ||
- (f_handle.handle_bytes == 0)) {
- retval = -EINVAL;
- goto out_err;
- }
- handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
- GFP_KERNEL);
- if (!handle) {
- retval = -ENOMEM;
- goto out_err;
- }
- /* copy the full handle */
- if (copy_from_user(handle, ufh,
- sizeof(struct file_handle) +
- f_handle.handle_bytes)) {
- retval = -EFAULT;
- goto out_handle;
- }
+ if (!capable(CAP_DAC_READ_SEARCH))
+ return -EPERM;
+
+ size = sizeof(struct file_handle);
+ if (copy_from_user(&f_handle, ufh, size))
+ return -EFAULT;
+
+ bytes = f_handle.handle_bytes;
+ if ((bytes > MAX_HANDLE_SZ) || (bytes == 0))
+ return -EINVAL;
+
+ size += bytes;
+ handle = memdup_user(ufh, size);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);

retval = do_handle_to_path(mountdirfd, handle, path);

-out_handle:
kfree(handle);
-out_err:
return retval;
}

--
1.8.4


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