crypto: arm64/aes-ccm - fix bugs in non-NEON fallback routine

Commit 5092fcf34908 ("crypto: arm64/aes-ce-ccm: add non-SIMD generic
fallback") introduced C fallback code to replace the NEON routines
when invoked from a context where the NEON is not available (i.e.,
from the context of a softirq taken while the NEON is already being
used in kernel process context)

Fix two logical flaws in the MAC calculation of the associated data.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Fixes: 5092fcf34908 ("crypto: arm64/aes-ce-ccm: add non-SIMD generic fallback")
Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 68b11aa690e476d1011c50480da444b8bde91479..986191e8c0583b64d112a2a7c4155811a5bca16e 100644 (file)
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -125,7 +125,7 @@ static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
                        abytes -= added;
                }
 
-               while (abytes > AES_BLOCK_SIZE) {
+               while (abytes >= AES_BLOCK_SIZE) {
                        __aes_arm64_encrypt(key->key_enc, mac, mac,
                                            num_rounds(key));
                        crypto_xor(mac, in, AES_BLOCK_SIZE);
@@ -139,8 +139,6 @@ static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
                                            num_rounds(key));
                        crypto_xor(mac, in, abytes);
                        *macp = abytes;
-               } else {
-                       *macp = 0;
                }
        }
 }