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| author | Sasha Levin <sasha.levin@oracle.com> | 2015-01-28 20:30:43 -0600 |
|---|---|---|
| committer | Simon Shields <keepcalm444@gmail.com> | 2016-03-15 18:03:05 +1100 |
| commit | 9c6b633d3414bf49bb75a641a4f028bf0acf2254 (patch) | |
| tree | 2592383f5e50aeeed6119f9e9158d40a0d922757 /fs | |
| parent | c88f7bbd8026761a615c9969d186ffa2a1a3da3c (diff) | |
| download | kernel_samsung_smdk4412-9c6b633d3414bf49bb75a641a4f028bf0acf2254.tar.gz kernel_samsung_smdk4412-9c6b633d3414bf49bb75a641a4f028bf0acf2254.tar.bz2 kernel_samsung_smdk4412-9c6b633d3414bf49bb75a641a4f028bf0acf2254.zip | |
vfs: read file_handle only once in handle_to_path
We used to read file_handle twice. Once to get the amount of extra bytes, and
once to fetch the entire structure.
This may be problematic since we do size verifications only after the first
read, so if the number of extra bytes changes in userspace between the first
and second calls, we'll have an incoherent view of file_handle.
Instead, read the constant size once, and copy that over to the final
structure without having to re-read it again.
Change-Id: Ib05e5129629e27d5a05953098c5bc470fae40d2a
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fhandle.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/fhandle.c b/fs/fhandle.c index 6b088641f5b..c9e18f3ecc4 100644 --- a/fs/fhandle.c +++ b/fs/fhandle.c @@ -196,8 +196,9 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh, goto out_err; } /* copy the full handle */ - if (copy_from_user(handle, ufh, - sizeof(struct file_handle) + + *handle = f_handle; + if (copy_from_user(&handle->f_handle, + &ufh->f_handle, f_handle.handle_bytes)) { retval = -EFAULT; goto out_handle; |