On 4/15/2018 6:51 PM, Martin Townsend wrote:
> On Sun, Apr 15, 2018 at 3:12 PM, Fabio Estevam <festevam@xxxxxxxxx> wrote:
>> From: Fabio Estevam <fabio.estevam@xxxxxxx>
>>
>> imx6ul and imx7 report the following error:
>>
>> caam_jr 2142000.jr1: 40000789: DECO: desc idx 7:
>> Protocol Size Error - A protocol has seen an error in size. When
>> running RSA, pdb size N < (size of F) when no formatting is used; or
>> pdb size N < (F + 11) when formatting is used.
>>
>> ------------[ cut here ]------------
>> WARNING: CPU: 0 PID: 1 at crypto/asymmetric_keys/public_key.c:148
>> public_key_verify_signature+0x27c/0x2b0
>>
>> This error happens because the signature contains 257 bytes, including
>> a leading zero as the first element.
>>
>> Fix the problem by stripping off the leading zero from input data
>> before feeding it to the CAAM accelerator.
>>
>> Fixes: 8c419778ab57e497b5 ("crypto: caam - add support for RSA algorithm")
>> Cc: <stable@xxxxxxxxxxxxxxx>
>> Reported-by: Martin Townsend <mtownsend1973@xxxxxxxxx>
>> Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
>> ---
>> Changes since v2:
>> - Check if the lenght is zero after calling caam_rsa_drop_leading_zeros()
>>
>> drivers/crypto/caam/caampkc.c | 45 +++++++++++++++++++++++++++++++++++--------
>> 1 file changed, 37 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/crypto/caam/caampkc.c b/drivers/crypto/caam/caampkc.c
>> index 7a897209..47467ff 100644
>> --- a/drivers/crypto/caam/caampkc.c
>> +++ b/drivers/crypto/caam/caampkc.c
>> @@ -166,6 +166,14 @@ static void rsa_priv_f3_done(struct device *dev, u32 *desc, u32 err,
>> akcipher_request_complete(req, err);
>> }
>>
>> +static void caam_rsa_drop_leading_zeros(const u8 **ptr, size_t *nbytes)
>> +{
>> + while (!**ptr && *nbytes) {
>> + (*ptr)++;
>> + (*nbytes)--;
>> + }
>> +}
>> +
>> static struct rsa_edesc *rsa_edesc_alloc(struct akcipher_request *req,
>> size_t desclen)
>> {
>> @@ -178,7 +186,36 @@ static struct rsa_edesc *rsa_edesc_alloc(struct akcipher_request *req,
>> int sgc;
>> int sec4_sg_index, sec4_sg_len = 0, sec4_sg_bytes;
>> int src_nents, dst_nents;
>> + const u8 *temp;
>> + void *buffer;
>> + size_t len;
>> +
>> + buffer = kzalloc(req->src_len, GFP_ATOMIC);
>> + if (!buffer)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + sg_copy_to_buffer(req->src, sg_nents(req->src),
>> + buffer, req->src_len);
>> + temp = (u8 *)buffer;
>> + len = req->src_len;
>>
>> + /*
>> + * Check if the buffer contains leading zeros and if
>> + * it does, drop the leading zeros
>> + */
>> + if (temp[0] == 0) {
>> + caam_rsa_drop_leading_zeros(&temp, &len);
>> + if (!len) {
>> + kfree(buffer);
>> + return ERR_PTR(-ENOMEM);
>> + }
>> +
>> + req->src_len = len;
>> + sg_copy_from_buffer(req->src, sg_nents(req->src),
>> + (void *)temp, req->src_len);
>> + }
>> +
>> + kfree(buffer);
>> src_nents = sg_nents_for_len(req->src, req->src_len);
>> dst_nents = sg_nents_for_len(req->dst, req->dst_len);
>>
>> @@ -683,14 +720,6 @@ static void caam_rsa_free_key(struct caam_rsa_key *key)
>> memset(key, 0, sizeof(*key));
>> }
>>
>> -static void caam_rsa_drop_leading_zeros(const u8 **ptr, size_t *nbytes)
>> -{
>> - while (!**ptr && *nbytes) {
>> - (*ptr)++;
>> - (*nbytes)--;
>> - }
>> -}
>> -
>> /**
>> * caam_read_rsa_crt - Used for reading dP, dQ, qInv CRT members.
>> * dP, dQ and qInv could decode to less than corresponding p, q length, as the
>> --
>> 2.7.4
>>
>
> Hi Fabio,
>
> just tried it and it works fine on my i.MX6UL board running linux-imx
> 4.9 (had to manually apply the patch as it doesn't have
> caam_rsa_drop_leading_zeros) so a
> Reviewed and Tested-By Martin Townsend
>
I've sent a fix that does not copy data back and forth, instead it counts the
leading zeros and ffwds the S/G.
Please check it works in your case.
Thanks,
Horia
