From 580e295178402d14bbf598a5702f8e01fc59dbaa Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 12 Mar 2019 22:12:46 -0700 Subject: [PATCH] crypto: arm64/gcm-aes-ce - fix no-NEON fallback code 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: # v4.19+ Signed-off-by: Eric Biggers Reviewed-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm64/crypto/ghash-ce-glue.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c index 791ad422c427..089b09286da7 100644 --- a/arch/arm64/crypto/ghash-ce-glue.c +++ b/arch/arm64/crypto/ghash-ce-glue.c @@ -473,9 +473,11 @@ static int gcm_encrypt(struct aead_request *req) 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, @@ -485,9 +487,9 @@ static int gcm_encrypt(struct aead_request *req) 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, pmull_ghash_update_p64); @@ -609,7 +611,7 @@ static int gcm_decrypt(struct aead_request *req) 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; -- 2.30.2