crypto: skcipher - Avoid infinite loop when cipher fails selftest

When an skcipher constructed through crypto_givcipher_default fails
its selftest, we'll loop forever trying to construct new skcipher
objects but failing because it already exists.

The crux of the issue is that once a givcipher fails the selftest,
we'll ignore it on the next run through crypto_skcipher_lookup and
attempt to construct a new givcipher.

We should instead return an error to the caller if we find a
givcipher that has failed the test.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 19 insertions, 0 deletions

diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 94140b3..e11ce37 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -282,6 +282,25 @@ static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
 					  alg->cra_ablkcipher.ivsize))
 		return alg;
 
+	crypto_mod_put(alg);
+	alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
+				    mask & ~CRYPTO_ALG_TESTED);
+	if (IS_ERR(alg))
+		return alg;
+
+	if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+	    CRYPTO_ALG_TYPE_GIVCIPHER) {
+		if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
+			crypto_mod_put(alg);
+			alg = ERR_PTR(-ENOENT);
+		}
+		return alg;
+	}
+
+	BUG_ON(!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+		 CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
+					     alg->cra_ablkcipher.ivsize));
+
 	return ERR_PTR(crypto_givcipher_default(alg, type, mask));
 }