Re: [PATCH] crypto: arm64/aes - fix handling sub-block CTS-CBC inputs

[Herbert Xu]

On Tue, Oct 02, 2018 at 10:22:15PM -0700, Eric Biggers wrote:
> From: Eric Biggers 
> 
> In the new arm64 CTS-CBC implementation, return an error code rather
> than crashing on inputs shorter than AES_BLOCK_SIZE bytes.  Also set
> cra_blocksize to AES_BLOCK_SIZE (like is done in the cts template) to
> indicate the minimum input size.
> 
> Fixes: dd597fb33ff0 ("crypto: arm64/aes-blk - add support for CTS-CBC mode")
> Signed-off-by: Eric Biggers 

Patch applied.  Thanks.
-- 
Email: Herbert Xu 
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH] crypto: arm64/aes - fix handling sub-block CTS-CBC inputs

[Ard Biesheuvel]

On 3 October 2018 at 07:22, Eric Biggers  wrote:
> From: Eric Biggers 
>
> In the new arm64 CTS-CBC implementation, return an error code rather
> than crashing on inputs shorter than AES_BLOCK_SIZE bytes.  Also set
> cra_blocksize to AES_BLOCK_SIZE (like is done in the cts template) to
> indicate the minimum input size.
>
> Fixes: dd597fb33ff0 ("crypto: arm64/aes-blk - add support for CTS-CBC mode")
> Signed-off-by: Eric Biggers 

Thanks Eric

Reviewed-by: Ard Biesheuvel 

> ---
>  arch/arm64/crypto/aes-glue.c | 13 +
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
> index 26d2b0263ba63..1e676625ef33f 100644
> --- a/arch/arm64/crypto/aes-glue.c
> +++ b/arch/arm64/crypto/aes-glue.c
> @@ -243,8 +243,11 @@ static int cts_cbc_encrypt(struct skcipher_request *req)
>
> skcipher_request_set_tfm(>subreq, tfm);
>
> -   if (req->cryptlen == AES_BLOCK_SIZE)
> +   if (req->cryptlen <= AES_BLOCK_SIZE) {
> +   if (req->cryptlen < AES_BLOCK_SIZE)
> +   return -EINVAL;
> cbc_blocks = 1;
> +   }
>
> if (cbc_blocks > 0) {
> unsigned int blocks;
> @@ -305,8 +308,11 @@ static int cts_cbc_decrypt(struct skcipher_request *req)
>
> skcipher_request_set_tfm(>subreq, tfm);
>
> -   if (req->cryptlen == AES_BLOCK_SIZE)
> +   if (req->cryptlen <= AES_BLOCK_SIZE) {
> +   if (req->cryptlen < AES_BLOCK_SIZE)
> +   return -EINVAL;
> cbc_blocks = 1;
> +   }
>
> if (cbc_blocks > 0) {
> unsigned int blocks;
> @@ -486,14 +492,13 @@ static struct skcipher_alg aes_algs[] = { {
> .cra_driver_name= "__cts-cbc-aes-" MODE,
> .cra_priority   = PRIO,
> .cra_flags  = CRYPTO_ALG_INTERNAL,
> -   .cra_blocksize  = 1,
> +   .cra_blocksize  = AES_BLOCK_SIZE,
> .cra_ctxsize= sizeof(struct crypto_aes_ctx),
> .cra_module = THIS_MODULE,
> },
> .min_keysize= AES_MIN_KEY_SIZE,
> .max_keysize= AES_MAX_KEY_SIZE,
> .ivsize = AES_BLOCK_SIZE,
> -   .chunksize  = AES_BLOCK_SIZE,
> .walksize   = 2 * AES_BLOCK_SIZE,
> .setkey = skcipher_aes_setkey,
> .encrypt= cts_cbc_encrypt,
> --
> 2.19.0
>

[PATCH] crypto: arm64/aes - fix handling sub-block CTS-CBC inputs

[Eric Biggers]

From: Eric Biggers 

In the new arm64 CTS-CBC implementation, return an error code rather
than crashing on inputs shorter than AES_BLOCK_SIZE bytes.  Also set
cra_blocksize to AES_BLOCK_SIZE (like is done in the cts template) to
indicate the minimum input size.

Fixes: dd597fb33ff0 ("crypto: arm64/aes-blk - add support for CTS-CBC mode")
Signed-off-by: Eric Biggers 
---
 arch/arm64/crypto/aes-glue.c | 13 +
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 26d2b0263ba63..1e676625ef33f 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -243,8 +243,11 @@ static int cts_cbc_encrypt(struct skcipher_request *req)
 
skcipher_request_set_tfm(>subreq, tfm);
 
-   if (req->cryptlen == AES_BLOCK_SIZE)
+   if (req->cryptlen <= AES_BLOCK_SIZE) {
+   if (req->cryptlen < AES_BLOCK_SIZE)
+   return -EINVAL;
cbc_blocks = 1;
+   }
 
if (cbc_blocks > 0) {
unsigned int blocks;
@@ -305,8 +308,11 @@ static int cts_cbc_decrypt(struct skcipher_request *req)
 
skcipher_request_set_tfm(>subreq, tfm);
 
-   if (req->cryptlen == AES_BLOCK_SIZE)
+   if (req->cryptlen <= AES_BLOCK_SIZE) {
+   if (req->cryptlen < AES_BLOCK_SIZE)
+   return -EINVAL;
cbc_blocks = 1;
+   }
 
if (cbc_blocks > 0) {
unsigned int blocks;
@@ -486,14 +492,13 @@ static struct skcipher_alg aes_algs[] = { {
.cra_driver_name= "__cts-cbc-aes-" MODE,
.cra_priority   = PRIO,
.cra_flags  = CRYPTO_ALG_INTERNAL,
-   .cra_blocksize  = 1,
+   .cra_blocksize  = AES_BLOCK_SIZE,
.cra_ctxsize= sizeof(struct crypto_aes_ctx),
.cra_module = THIS_MODULE,
},
.min_keysize= AES_MIN_KEY_SIZE,
.max_keysize= AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
-   .chunksize  = AES_BLOCK_SIZE,
.walksize   = 2 * AES_BLOCK_SIZE,
.setkey = skcipher_aes_setkey,
.encrypt= cts_cbc_encrypt,
-- 
2.19.0