On Wed, Oct 14, 2020 at 07:02:06PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Map xattr names originating at the client; from get/set/remove xattr.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> tools/virtiofsd/passthrough_ll.c | 101 ++++++++++++++++++++++++++++++-
> 1 file changed, 98 insertions(+), 3 deletions(-)
>
> diff --git a/tools/virtiofsd/passthrough_ll.c
> b/tools/virtiofsd/passthrough_ll.c
> index f5a33014f9..57ebe17ed6 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -2183,20 +2183,80 @@ static XattrMapEntry *parse_xattrmap(struct lo_data
> *lo)
> return res;
> }
>
> -static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
> +/*
> + * For use with getxattr/setxattr/removexattr, where the client
> + * gives us a name and we may need to choose a different one.
> + * Allocates a buffer for the result placing it in *out_name.
> + * If there's no change then *out_name is not set.
> + * Returns 0 on success
> + * Can return -EPERM to indicate we block a given attribute
> + * (in which case out_name is not allocated)
> + * Can return -ENOMEM to indicate out_name couldn't be allocated.
> + */
> +static int xattr_map_client(const struct lo_data *lo, const char
> *client_name,
> + char **out_name)
> +{
> + const XattrMapEntry *cur_entry;
> +
> + for (cur_entry = lo->xattr_map_list; ; cur_entry++) {
> + if ((cur_entry->flags & XATTR_MAP_FLAG_CLIENT) &&
> + (strstart(client_name, cur_entry->key, NULL))) {
> + if (cur_entry->flags & XATTR_MAP_FLAG_END_BAD) {
> + return -EPERM;
> + }
> + if (cur_entry->flags & XATTR_MAP_FLAG_END_OK) {
> + /* Unmodified name */
> + return 0;
> + }
> + if (cur_entry->flags & XATTR_MAP_FLAG_PREFIX) {
I am wondering why do have "END" substring in BAD and OK flags while
we don't have one in PREFIX flag. IOW, why not simply call these
flags as XATTR_MAP_FLAG_OK and XATTR_MAP_FLAG_BAD respectively.
> + *out_name = g_try_malloc(strlen(client_name) +
> + strlen(cur_entry->prepend) + 1);
Should we check for cur_entry->prepend to be NULL before we try to
allocate out_name. One could say.
"prefix:client:trusted.::". In that case we are not supposed to prefix
anything?
> + if (!*out_name) {
> + return -ENOMEM;
> + }
> + sprintf(*out_name, "%s%s", cur_entry->prepend, client_name);
> + return 0;
> + }
> + }
> + }
> +
> + /* Shouldn't get here - rules should have an END_* */
> + abort();
> +}
Thanks
Vivek
