s390/crypto: fix aes_s390 crypto module unload problem

If a machine has no hardware support for the xts-aes or ctr-aes algorithms
they are not registered in aes_s390_init. But aes_s390_fini unconditionally
unregisters the algorithms which causes crypto_remove_alg to crash.
Add two flag variables to remember if xts-aes and ctr-aes have been added.

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index b4dbade8ca24..46cae138ece2 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -725,6 +725,8 @@ static struct crypto_alg xts_aes_alg = {
         }
 };
 
+static int xts_aes_alg_reg;
+
 static int ctr_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
                            unsigned int key_len)
 {
@@ -846,6 +848,8 @@ static struct crypto_alg ctr_aes_alg = {
         }
 };
 
+static int ctr_aes_alg_reg;
+
 static int __init aes_s390_init(void)
 {
         int ret;
@@ -884,6 +888,7 @@ static int __init aes_s390_init(void)
                 ret = crypto_register_alg(&xts_aes_alg);
                 if (ret)
                         goto xts_aes_err;
+                xts_aes_alg_reg = 1;
         }
 
         if (crypt_s390_func_available(KMCTR_AES_128_ENCRYPT,
@@ -902,6 +907,7 @@ static int __init aes_s390_init(void)
                         free_page((unsigned long) ctrblk);
                         goto ctr_aes_err;
                 }
+                ctr_aes_alg_reg = 1;
         }
 
 out:
@@ -921,9 +927,12 @@ aes_err:
 
 static void __exit aes_s390_fini(void)
 {
-        crypto_unregister_alg(&ctr_aes_alg);
-        free_page((unsigned long) ctrblk);
-        crypto_unregister_alg(&xts_aes_alg);
+        if (ctr_aes_alg_reg) {
+                crypto_unregister_alg(&ctr_aes_alg);
+                free_page((unsigned long) ctrblk);
+        }
+        if (xts_aes_alg_reg)
+                crypto_unregister_alg(&xts_aes_alg);
         crypto_unregister_alg(&cbc_aes_alg);
         crypto_unregister_alg(&ecb_aes_alg);
         crypto_unregister_alg(&aes_alg);