Re: [PATCH 15/25] ubifs: Add auth nodes to garbage collector journal head

From: Richard Weinberger
Date: Mon Aug 27 2018 - 16:52:02 EST


Am Mittwoch, 4. Juli 2018, 14:41:27 CEST schrieb Sascha Hauer:
> To be able to authenticate the garbage collector journal head add
> authentication nodes to the buds the garbage collector creates.
>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> ---
> fs/ubifs/gc.c | 37 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
> index ac3a3f7c6a6e..8feeeb12b6ed 100644
> --- a/fs/ubifs/gc.c
> +++ b/fs/ubifs/gc.c
> @@ -365,12 +365,13 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
>
> /* Write nodes to their new location. Use the first-fit strategy */
> while (1) {
> - int avail;
> + int avail, moved = 0;
> struct ubifs_scan_node *snod, *tmp;
>
> /* Move data nodes */
> list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
> - avail = c->leb_size - wbuf->offs - wbuf->used;
> + avail = c->leb_size - wbuf->offs - wbuf->used -
> + ubifs_auth_node_sz(c);
> if (snod->len > avail)
> /*
> * Do not skip data nodes in order to optimize
> @@ -378,14 +379,19 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
> */
> break;
>
> + ubifs_shash_update(c, c->jheads[GCHD].log_hash,
> + snod->node, snod->len);
> +
> err = move_node(c, sleb, snod, wbuf);
> if (err)
> goto out;
> + moved = 1;
> }
>
> /* Move non-data nodes */
> list_for_each_entry_safe(snod, tmp, &nondata, list) {
> - avail = c->leb_size - wbuf->offs - wbuf->used;
> + avail = c->leb_size - wbuf->offs - wbuf->used -
> + ubifs_auth_node_sz(c);
> if (avail < min)
> break;
>
> @@ -403,7 +409,32 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
> continue;
> }
>
> + ubifs_shash_update(c, c->jheads[GCHD].log_hash,
> + snod->node, snod->len);
> +
> err = move_node(c, sleb, snod, wbuf);
> + if (err)
> + goto out;
> + moved = 1;
> + }
> +
> + if (ubifs_authenticated(c) && moved) {
> + struct ubifs_auth_node *auth;
> +
> + auth = kmalloc(ubifs_auth_node_sz(c), GFP_NOFS);
> + if (!auth) {
> + err = -ENOMEM;
> + goto out;
> + }
> +
> + ubifs_prepare_auth_node(c, auth,
> + c->jheads[GCHD].log_hash);

ubifs_prepare_auth_node() does a crypto_shash_final(), check.
But the overall "hash life cycle" is not 100% clear to me.
For example, does move_nodes() assume that the hash is initialized
or is it allowed that an crypto_shash_update() happened before?

Thanks,
//richard