On Thu, Jun 17, 2021 at 04:08:15PM +1000, Michael Ellerman wrote:

Kees Cook keescook@chromium.org writes:

...

Fix typo in memcpy() where size should be CTR_RFC3686_NONCE_SIZE.

Fixes: 030f4e968741 ("crypto: nx - Fix reentrancy bugs") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org

Thanks.

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drivers/crypto/nx/nx-aes-ctr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/nx/nx-aes-ctr.c b/drivers/crypto/nx/nx-aes-ctr.c index 13f518802343..6120e350ff71 100644 --- a/drivers/crypto/nx/nx-aes-ctr.c +++ b/drivers/crypto/nx/nx-aes-ctr.c @@ -118,7 +118,7 @@ static int ctr3686_aes_nx_crypt(struct skcipher_request *req) struct nx_crypto_ctx *nx_ctx = crypto_skcipher_ctx(tfm); u8 iv[16];

• memcpy(iv, nx_ctx->priv.ctr.nonce, CTR_RFC3686_IV_SIZE);

• memcpy(iv, nx_ctx->priv.ctr.nonce, CTR_RFC3686_NONCE_SIZE); memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE); iv[12] = iv[13] = iv[14] = 0; iv[15] = 1;

Where IV_SIZE is 8 and NONCE_SIZE is 4.

And iv is 16 bytes, so it's not a buffer overflow.

But priv.ctr.nonce is 4 bytes, and at the end of the struct, so it reads 4 bytes past the end of the nx_crypto_ctx, which is not good.

But then immediately overwrites whatever it read with req->iv.

So seems pretty harmless in practice?

Right -- there's no damage done, but future memcpy() FORTIFY work alerts on this, so I'm going through cleaning all of these up. :)