6.4-stable review patch. If anyone has any objections, please let me know.
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From: Herbert Xu herbert@gondor.apana.org.au
[ Upstream commit 9ae4577bc077a7e32c3c7d442c95bc76865c0f17 ]
The function crypto_drop_spawn expects to be called in process context. However, when an instance is unregistered while it still has active users, the last user may cause the instance to be freed in atomic context.
Fix this by delaying the freeing to a work queue.
Fixes: 6bfd48096ff8 ("[CRYPTO] api: Added spawns") Reported-by: Florent Revest revest@chromium.org Reported-by: syzbot+d769eed29cc42d75e2a3@syzkaller.appspotmail.com Reported-by: syzbot+610ec0671f51e838436e@syzkaller.appspotmail.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Tested-by: Florent Revest revest@chromium.org Acked-by: Florent Revest revest@chromium.org Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- crypto/algapi.c | 16 ++++++++++++++-- include/crypto/algapi.h | 3 +++ 2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/crypto/algapi.c b/crypto/algapi.c index 5e7cd603d489c..4fe95c4480473 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -17,6 +17,7 @@ #include <linux/rtnetlink.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/workqueue.h>
#include "internal.h"
@@ -74,15 +75,26 @@ static void crypto_free_instance(struct crypto_instance *inst) inst->alg.cra_type->free(inst); }
-static void crypto_destroy_instance(struct crypto_alg *alg) +static void crypto_destroy_instance_workfn(struct work_struct *w) { - struct crypto_instance *inst = (void *)alg; + struct crypto_instance *inst = container_of(w, struct crypto_instance, + free_work); struct crypto_template *tmpl = inst->tmpl;
crypto_free_instance(inst); crypto_tmpl_put(tmpl); }
+static void crypto_destroy_instance(struct crypto_alg *alg) +{ + struct crypto_instance *inst = container_of(alg, + struct crypto_instance, + alg); + + INIT_WORK(&inst->free_work, crypto_destroy_instance_workfn); + schedule_work(&inst->free_work); +} + /* * This function adds a spawn to the list secondary_spawns which * will be used at the end of crypto_remove_spawns to unregister diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index 016d5a302b84a..bd3a99b0106bf 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -12,6 +12,7 @@ #include <linux/cache.h> #include <linux/crypto.h> #include <linux/types.h> +#include <linux/workqueue.h>
/* * Maximum values for blocksize and alignmask, used to allocate @@ -83,6 +84,8 @@ struct crypto_instance { struct crypto_spawn *spawns; };
+ struct work_struct free_work; + void *__ctx[] CRYPTO_MINALIGN_ATTR; };