ich777/linux_media
1
0
Fork 0
mirror of https://github.com/tbsdtv/linux_media.git synced 2025-07-23 04:33:26 +02:00
Code Issues Packages Projects Releases Wiki Activity

crypto: api - Fix race condition in crypto_spawn_alg

Browse Source 
The function crypto_spawn_alg is racy because it drops the lock
before shooting the dying algorithm.  The algorithm could disappear
altogether before we shoot it.

This patch fixes it by moving the shooting into the locked section.

Fixes: 6bfd48096f ("[CRYPTO] api: Added spawns")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu
2019-12-07 22:15:15 +08:00
parent 4a2abbc6b8
commit 73669cc556
3 changed files with 6 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
crypto/algapi.c
View File

@@ -679,22 +679,16 @@ EXPORT_SYMBOL_GPL(crypto_drop_spawn);
static struct crypto_alg *crypto_spawn_alg(struct crypto_spawn *spawn)
{
struct crypto_alg *alg;
struct crypto_alg *alg2;
down_read(&crypto_alg_sem);
alg = spawn->alg;
alg2 = alg;
if (alg2)
alg2 = crypto_mod_get(alg2);
if (alg && !crypto_mod_get(alg)) {
alg->cra_flags |= CRYPTO_ALG_DYING;
alg = NULL;
}
up_read(&crypto_alg_sem);
if (!alg2) {
if (alg)
crypto_shoot_alg(alg);
return ERR_PTR(-EAGAIN);
}
return alg;
return alg ?: ERR_PTR(-EAGAIN);
}
struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,