crypto: api - Fix race condition in larval lookup (77dbd7a9) · Commits · e / devices / android_kernel_teracube_2e

crypto_larval_lookup should only return a larval if it created one. Any larval created by another entity must be processed through crypto_larval_wait before being returned. Otherwise this will lead to a larval being killed twice, which will most likely lead to a crash. Cc: stable@vger.kernel.org Reported-by:

Kees Cook <keescook@chromium.org> Tested-by:

Kees Cook <keescook@chromium.org> Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au>

crypto/api.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -34,6 +34,8 @@ EXPORT_SYMBOL_GPL(crypto_alg_sem);
		BLOCKING_NOTIFIER_HEAD(crypto_chain);
		EXPORT_SYMBOL_GPL(crypto_chain);

		static struct crypto_alg crypto_larval_wait(struct crypto_alg alg);

		struct crypto_alg crypto_mod_get(struct crypto_alg alg)
		{
		return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
		@@ -144,8 +146,11 @@ static struct crypto_alg crypto_larval_add(const char name, u32 type,
		}
		up_write(&crypto_alg_sem);

		if (alg != &larval->alg)
		if (alg != &larval->alg) {
		kfree(larval);
		if (crypto_is_larval(alg))
		alg = crypto_larval_wait(alg);
		}

		return alg;
		}