* [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode
@ 2023-06-13 16:17 Mahmoud Adam
2023-06-14 9:50 ` Herbert Xu
2023-06-23 8:22 ` Herbert Xu
0 siblings, 2 replies; 4+ messages in thread
From: Mahmoud Adam @ 2023-06-13 16:17 UTC (permalink / raw)
To: herbert; +Cc: davem, linux-crypto, linux-kernel, Mahmoud Adam
check if rsa public exponent is odd and check its value is between
2^16 < e < 2^256.
FIPS 186-5 DSS (page 35)[1] specify that:
1. The public exponent e shall be selected with the following constraints:
(a) The public verification exponent e shall be selected prior to
generating the primes, p and q, and the private signature exponent
d.
(b) The exponent e shall be an odd positive integer such that:
2^16 < e < 2^256.
[1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5.pdf
Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
---
crypto/rsa.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/crypto/rsa.c b/crypto/rsa.c
index c50f2d2a4d06..c79613cdce6e 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -205,6 +205,32 @@ static int rsa_check_key_length(unsigned int len)
return -EINVAL;
}
+static int rsa_check_exponent_fips(MPI e)
+{
+ MPI e_max = NULL;
+
+ /* check if odd */
+ if (!mpi_test_bit(e, 0)) {
+ return -EINVAL;
+ }
+
+ /* check if 2^16 < e < 2^256. */
+ if (mpi_cmp_ui(e, 65536) <= 0) {
+ return -EINVAL;
+ }
+
+ e_max = mpi_alloc(0);
+ mpi_set_bit(e_max, 256);
+
+ if (mpi_cmp(e, e_max) >= 0) {
+ mpi_free(e_max);
+ return -EINVAL;
+ }
+
+ mpi_free(e_max);
+ return 0;
+}
+
static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
@@ -232,6 +258,11 @@ static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
return -EINVAL;
}
+ if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
return 0;
err:
@@ -290,6 +321,11 @@ static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
return -EINVAL;
}
+ if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
return 0;
err:
--
2.40.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode
2023-06-13 16:17 [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode Mahmoud Adam
@ 2023-06-14 9:50 ` Herbert Xu
2023-06-14 11:59 ` Stephan Mueller
2023-06-23 8:22 ` Herbert Xu
1 sibling, 1 reply; 4+ messages in thread
From: Herbert Xu @ 2023-06-14 9:50 UTC (permalink / raw)
To: Mahmoud Adam; +Cc: davem, linux-crypto, linux-kernel, Stephan Mueller
On Tue, Jun 13, 2023 at 04:17:31PM +0000, Mahmoud Adam wrote:
> check if rsa public exponent is odd and check its value is between
> 2^16 < e < 2^256.
>
> FIPS 186-5 DSS (page 35)[1] specify that:
> 1. The public exponent e shall be selected with the following constraints:
> (a) The public verification exponent e shall be selected prior to
> generating the primes, p and q, and the private signature exponent
> d.
> (b) The exponent e shall be an odd positive integer such that:
> 2^16 < e < 2^256.
>
> [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5.pdf
>
> Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
> ---
> crypto/rsa.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/crypto/rsa.c b/crypto/rsa.c
> index c50f2d2a4d06..c79613cdce6e 100644
> --- a/crypto/rsa.c
> +++ b/crypto/rsa.c
> @@ -205,6 +205,32 @@ static int rsa_check_key_length(unsigned int len)
> return -EINVAL;
> }
>
> +static int rsa_check_exponent_fips(MPI e)
> +{
> + MPI e_max = NULL;
> +
> + /* check if odd */
> + if (!mpi_test_bit(e, 0)) {
> + return -EINVAL;
> + }
> +
> + /* check if 2^16 < e < 2^256. */
> + if (mpi_cmp_ui(e, 65536) <= 0) {
> + return -EINVAL;
> + }
> +
> + e_max = mpi_alloc(0);
> + mpi_set_bit(e_max, 256);
> +
> + if (mpi_cmp(e, e_max) >= 0) {
> + mpi_free(e_max);
> + return -EINVAL;
> + }
> +
> + mpi_free(e_max);
> + return 0;
> +}
> +
> static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
> unsigned int keylen)
> {
> @@ -232,6 +258,11 @@ static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
> return -EINVAL;
> }
>
> + if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
> + rsa_free_mpi_key(mpi_key);
> + return -EINVAL;
> + }
> +
> return 0;
>
> err:
> @@ -290,6 +321,11 @@ static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
> return -EINVAL;
> }
>
> + if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
> + rsa_free_mpi_key(mpi_key);
> + return -EINVAL;
> + }
> +
> return 0;
>
> err:
> --
> 2.40.1
Cc Stephan Mueller
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode
2023-06-14 9:50 ` Herbert Xu
@ 2023-06-14 11:59 ` Stephan Mueller
0 siblings, 0 replies; 4+ messages in thread
From: Stephan Mueller @ 2023-06-14 11:59 UTC (permalink / raw)
To: Mahmoud Adam, Herbert Xu; +Cc: davem, linux-crypto, linux-kernel
Am Mittwoch, 14. Juni 2023, 11:50:52 CEST schrieb Herbert Xu:
Hi Herbert,
> On Tue, Jun 13, 2023 at 04:17:31PM +0000, Mahmoud Adam wrote:
> > check if rsa public exponent is odd and check its value is between
> > 2^16 < e < 2^256.
> >
> > FIPS 186-5 DSS (page 35)[1] specify that:
> >
> > 1. The public exponent e shall be selected with the following constraints:
> > (a) The public verification exponent e shall be selected prior to
> > generating the primes, p and q, and the private signature exponent
> > d.
> >
> > (b) The exponent e shall be an odd positive integer such that:
> > 2^16 < e < 2^256.
> >
> > [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5.pdf
> >
> > Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Ciao
Stephan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode
2023-06-13 16:17 [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode Mahmoud Adam
2023-06-14 9:50 ` Herbert Xu
@ 2023-06-23 8:22 ` Herbert Xu
1 sibling, 0 replies; 4+ messages in thread
From: Herbert Xu @ 2023-06-23 8:22 UTC (permalink / raw)
To: Mahmoud Adam; +Cc: davem, linux-crypto, linux-kernel
On Tue, Jun 13, 2023 at 04:17:31PM +0000, Mahmoud Adam wrote:
> check if rsa public exponent is odd and check its value is between
> 2^16 < e < 2^256.
>
> FIPS 186-5 DSS (page 35)[1] specify that:
> 1. The public exponent e shall be selected with the following constraints:
> (a) The public verification exponent e shall be selected prior to
> generating the primes, p and q, and the private signature exponent
> d.
> (b) The exponent e shall be an odd positive integer such that:
> 2^16 < e < 2^256.
>
> [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-5.pdf
>
> Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
> ---
> crypto/rsa.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-06-13 16:17 [PATCH] crypto: rsa - allow only odd e and restrict value in FIPS mode Mahmoud Adam
2023-06-14 9:50 ` Herbert Xu
2023-06-14 11:59 ` Stephan Mueller
2023-06-23 8:22 ` Herbert Xu
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