Commit 84a0b00a authored Aug 19, 2019 by Ard Biesheuvel Committed by Herbert Xu Aug 30, 2019

crypto: s5p - deal gracefully with bogus input sizes

The s5p skcipher driver returns -EINVAL for zero length inputs, which
deviates from the behavior of the generic ECB template, and causes fuzz
tests to fail. In cases where the input is not a multiple of the AES
block size (and the chaining mode is not CTR), it prints an error to
the kernel log, which is a thing we usually try to avoid in response
to situations that can be triggered by unprivileged users.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 735177ca

drivers/crypto/s5p-sss.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -2056,9 +2056,12 @@ static int s5p_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
		struct s5p_aes_ctx *ctx = crypto_ablkcipher_ctx(tfm);
		struct s5p_aes_dev *dev = ctx->dev;

		if (!req->nbytes)
		return 0;

		if (!IS_ALIGNED(req->nbytes, AES_BLOCK_SIZE) &&
		((mode & FLAGS_AES_MODE_MASK) != FLAGS_AES_CTR)) {
		dev_err(dev->dev, "request size is not exact amount of AES blocks\n");
		dev_dbg(dev->dev, "request size is not exact amount of AES blocks\n");
		return -EINVAL;
		}