| From | David Howells <> | Subject | [PATCH 59/73] unionmount: Override creds when copying up a file to correctly set ownership [ver #2] | Date | Tue, 21 Feb 2012 18:04:54 +0000 |
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Override the current creds when creating a file for copy up purposes so that the ownership of that file is set correctly.
Signed-off-by: David Howells <dhowells@redhat.com> ---
fs/union.c | 22 +++++++++++++++++++--- 1 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/fs/union.c b/fs/union.c index b8ee42d..264da49 100644 --- a/fs/union.c +++ b/fs/union.c @@ -556,28 +556,44 @@ int union_copyup_file(struct nameidata *nd, struct path *lower, struct dentry *dentry, size_t len) { struct path *parent = &nd->path; + const struct cred *saved_cred; + struct cred *override_cred; int error; BUG_ON(!mutex_is_locked(&parent->dentry->d_inode->i_mutex)); + override_cred = prepare_kernel_cred(NULL); + if (!override_cred) + return -ENOMEM; + + override_cred->fsuid = lower->dentry->d_inode->i_uid; + override_cred->fsgid = lower->dentry->d_inode->i_gid; + + saved_cred = override_creds(override_cred); + if (S_ISREG(lower->dentry->d_inode->i_mode)) { error = union_create_file(nd, lower, dentry); if (error) - return error; + goto out; error = union_copyup_data(lower, parent->mnt, dentry, len); } else if (S_ISLNK(lower->dentry->d_inode->i_mode)) { - return union_create_symlink(nd, lower, dentry); + error = union_create_symlink(nd, lower, dentry); + goto out; } else { /* Don't currently support copyup of special files, though in * theory there's no reason we couldn't at least copy up * blockdev, chrdev and FIFO files */ - return -EXDEV; + error = -EXDEV; + goto out; } if (error) /* Most likely error: ENOSPC */ vfs_unlink(parent->dentry->d_inode, dentry); +out: + revert_creds(saved_cred); + put_cred(override_cred); return error; }
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