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authorHerbert Xu <herbert@gondor.apana.org.au>2009-08-31 15:56:54 +1000
committerHerbert Xu <herbert@gondor.apana.org.au>2009-08-31 15:56:54 +1000
commit2bf2901669a564b402cd0e40eb3f941c391e64c4 (patch)
tree2c4d23726c2dbb7624108b6865aea6ebb1d6403e /crypto
parenta367b17f34e1280270a6b577c11d5ecff093f9ae (diff)
downloadlinux-2bf2901669a564b402cd0e40eb3f941c391e64c4.tar.gz
crypto: api - Do not displace newly registered algorithms
We have a mechanism where newly registered algorithms of a higher priority can displace existing instances that use a different implementation of the same algorithm with a lower priority. Unfortunately the same mechanism can cause a newly registered algorithm to displace itself if it depends on an existing version of the same algorithm. This patch fixes this by keeping all algorithms that the newly reigstered algorithm depends on, thus protecting them from being removed. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/algapi.c77
1 files changed, 63 insertions, 14 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c
index 6a98076d9d2..feb77e4bbb4 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -81,16 +81,35 @@ static void crypto_destroy_instance(struct crypto_alg *alg)
crypto_tmpl_put(tmpl);
}
+static struct list_head *crypto_more_spawns(struct crypto_alg *alg,
+ struct list_head *stack,
+ struct list_head *top,
+ struct list_head *secondary_spawns)
+{
+ struct crypto_spawn *spawn, *n;
+
+ if (list_empty(stack))
+ return NULL;
+
+ spawn = list_first_entry(stack, struct crypto_spawn, list);
+ n = list_entry(spawn->list.next, struct crypto_spawn, list);
+
+ if (spawn->alg && &n->list != stack && !n->alg)
+ n->alg = (n->list.next == stack) ? alg :
+ &list_entry(n->list.next, struct crypto_spawn,
+ list)->inst->alg;
+
+ list_move(&spawn->list, secondary_spawns);
+
+ return &n->list == stack ? top : &n->inst->alg.cra_users;
+}
+
static void crypto_remove_spawn(struct crypto_spawn *spawn,
- struct list_head *list,
- struct list_head *secondary_spawns)
+ struct list_head *list)
{
struct crypto_instance *inst = spawn->inst;
struct crypto_template *tmpl = inst->tmpl;
- list_del_init(&spawn->list);
- spawn->alg = NULL;
-
if (crypto_is_dead(&inst->alg))
return;
@@ -106,25 +125,55 @@ static void crypto_remove_spawn(struct crypto_spawn *spawn,
hlist_del(&inst->list);
inst->alg.cra_destroy = crypto_destroy_instance;
- list_splice(&inst->alg.cra_users, secondary_spawns);
+ BUG_ON(!list_empty(&inst->alg.cra_users));
}
-static void crypto_remove_spawns(struct list_head *spawns,
- struct list_head *list, u32 new_type)
+static void crypto_remove_spawns(struct crypto_alg *alg,
+ struct list_head *list,
+ struct crypto_alg *nalg)
{
+ u32 new_type = (nalg ?: alg)->cra_flags;
struct crypto_spawn *spawn, *n;
LIST_HEAD(secondary_spawns);
+ struct list_head *spawns;
+ LIST_HEAD(stack);
+ LIST_HEAD(top);
+ spawns = &alg->cra_users;
list_for_each_entry_safe(spawn, n, spawns, list) {
if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)
continue;
- crypto_remove_spawn(spawn, list, &secondary_spawns);
+ list_move(&spawn->list, &top);
}
- while (!list_empty(&secondary_spawns)) {
- list_for_each_entry_safe(spawn, n, &secondary_spawns, list)
- crypto_remove_spawn(spawn, list, &secondary_spawns);
+ spawns = &top;
+ do {
+ while (!list_empty(spawns)) {
+ struct crypto_instance *inst;
+
+ spawn = list_first_entry(spawns, struct crypto_spawn,
+ list);
+ inst = spawn->inst;
+
+ BUG_ON(&inst->alg == alg);
+
+ list_move(&spawn->list, &stack);
+
+ if (&inst->alg == nalg)
+ break;
+
+ spawn->alg = NULL;
+ spawns = &inst->alg.cra_users;
+ }
+ } while ((spawns = crypto_more_spawns(alg, &stack, &top,
+ &secondary_spawns)));
+
+ list_for_each_entry_safe(spawn, n, &secondary_spawns, list) {
+ if (spawn->alg)
+ list_move(&spawn->list, &spawn->alg->cra_users);
+ else
+ crypto_remove_spawn(spawn, list);
}
}
@@ -258,7 +307,7 @@ found:
q->cra_priority > alg->cra_priority)
continue;
- crypto_remove_spawns(&q->cra_users, &list, alg->cra_flags);
+ crypto_remove_spawns(q, &list, alg);
}
complete:
@@ -330,7 +379,7 @@ static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
list_del_init(&alg->cra_list);
- crypto_remove_spawns(&alg->cra_users, list, alg->cra_flags);
+ crypto_remove_spawns(alg, list, NULL);
return 0;
}