From: Eric Biggers ebiggers@google.com
commit 580e295178402d14bbf598a5702f8e01fc59dbaa upstream.
The arm64 gcm-aes-ce algorithm is failing the extra crypto self-tests following my patches to test the !may_use_simd() code paths, which previously were untested. The problem is that in the !may_use_simd() case, an odd number of AES blocks can be processed within each step of the skcipher_walk. However, the skcipher_walk is being done with a "stride" of 2 blocks and is advanced by an even number of blocks after each step. This causes the encryption to produce the wrong ciphertext and authentication tag, and causes the decryption to incorrectly fail.
Fix it by only processing an even number of blocks per step.
Fixes: c2b24c36e0a3 ("crypto: arm64/aes-gcm-ce - fix scatterwalk API violation") Fixes: 71e52c278c54 ("crypto: arm64/aes-ce-gcm - operate on two input blocks at a time") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Eric Biggers ebiggers@google.com Reviewed-by: Ard Biesheuvel ard.biesheuvel@linaro.org Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/crypto/ghash-ce-glue.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/arm64/crypto/ghash-ce-glue.c +++ b/arch/arm64/crypto/ghash-ce-glue.c @@ -418,9 +418,11 @@ static int gcm_encrypt(struct aead_reque put_unaligned_be32(2, iv + GCM_IV_SIZE);
while (walk.nbytes >= (2 * AES_BLOCK_SIZE)) { - int blocks = walk.nbytes / AES_BLOCK_SIZE; + const int blocks = + walk.nbytes / (2 * AES_BLOCK_SIZE) * 2; u8 *dst = walk.dst.virt.addr; u8 *src = walk.src.virt.addr; + int remaining = blocks;
do { __aes_arm64_encrypt(ctx->aes_key.key_enc, @@ -430,9 +432,9 @@ static int gcm_encrypt(struct aead_reque
dst += AES_BLOCK_SIZE; src += AES_BLOCK_SIZE; - } while (--blocks > 0); + } while (--remaining > 0);
- ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg, + ghash_do_update(blocks, dg, walk.dst.virt.addr, &ctx->ghash_key, NULL);
@@ -553,7 +555,7 @@ static int gcm_decrypt(struct aead_reque put_unaligned_be32(2, iv + GCM_IV_SIZE);
while (walk.nbytes >= (2 * AES_BLOCK_SIZE)) { - int blocks = walk.nbytes / AES_BLOCK_SIZE; + int blocks = walk.nbytes / (2 * AES_BLOCK_SIZE) * 2; u8 *dst = walk.dst.virt.addr; u8 *src = walk.src.virt.addr;