crypto: arm/aes-neonbs - fix usage of cbc(aes) fallback

Loading the module deadlocks since:
-local cbc(aes) implementation needs a fallback and
-crypto API tries to find one but the request_module() resolves back to
the same module

Fix this by changing the module alias for cbc(aes) and
using the NEED_FALLBACK flag when requesting for a fallback algorithm.

Fixes: 00b99ad ("crypto: arm/aes-neonbs - Use generic cbc encryption path")
Signed-off-by: Horia Geantă <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

arch/arm/crypto/aes-neonbs-glue.c

@@ -19,7 +19,7 @@ MODULE_AUTHOR("Ard Biesheuvel <[email protected]>");
 MODULE_LICENSE("GPL v2");
 
 MODULE_ALIAS_CRYPTO("ecb(aes)");
-MODULE_ALIAS_CRYPTO("cbc(aes)");
+MODULE_ALIAS_CRYPTO("cbc(aes)-all");
 MODULE_ALIAS_CRYPTO("ctr(aes)");
 MODULE_ALIAS_CRYPTO("xts(aes)");
 
@@ -191,7 +191,8 @@ static int cbc_init(struct crypto_skcipher *tfm)
 	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 	unsigned int reqsize;
 
-	ctx->enc_tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
+	ctx->enc_tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC |
+					     CRYPTO_ALG_NEED_FALLBACK);
 	if (IS_ERR(ctx->enc_tfm))
 		return PTR_ERR(ctx->enc_tfm);
 
@@ -441,7 +442,8 @@ static struct skcipher_alg aes_algs[] = { {
 	.base.cra_blocksize	= AES_BLOCK_SIZE,
 	.base.cra_ctxsize	= sizeof(struct aesbs_cbc_ctx),
 	.base.cra_module	= THIS_MODULE,
-	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
+	.base.cra_flags		= CRYPTO_ALG_INTERNAL |
+				  CRYPTO_ALG_NEED_FALLBACK,
 
 	.min_keysize		= AES_MIN_KEY_SIZE,
 	.max_keysize		= AES_MAX_KEY_SIZE,