[PATCH] crypto: ecdsa - explicitly zeroize pub_key

[PATCH] crypto: ecdsa - explicitly zeroize pub_key

[Vladis Dronov]

The FIPS standard, as a part of the Sensitive Security Parameter area,
requires the FIPS module to provide methods to zeroise all the unprotected
SSP (Security Sensitive Parameters), i.e. both the CSP (Critical Security
Parameters), and the PSP (Public Security Parameters):

    A module shall provide methods to zeroise all unprotected SSPs and key
    components within the module.

This requirement is mentioned in the section AS09.28 "Sensitive security
parameter zeroisation – Levels 1, 2, 3, and 4" of FIPS 140-3 / ISO 19790.
This is required for the FIPS certification. Thus, add a public key
zeroization to ecdsa_ecc_ctx_deinit().

Signed-off-by: Vladis Dronov <vdronov@redhat.com>
---
 crypto/ecdsa.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
index 117526d15dde..e7f58ad5ac76 100644
--- a/crypto/ecdsa.c
+++ b/crypto/ecdsa.c
@@ -96,10 +96,12 @@ static int ecdsa_ecc_ctx_init(struct ecc_ctx *ctx, unsigned int curve_id)
 	return 0;
 }
 
-
 static void ecdsa_ecc_ctx_deinit(struct ecc_ctx *ctx)
 {
 	ctx->pub_key_set = false;
+
+	memzero_explicit(ctx->x, sizeof(ctx->x));
+	memzero_explicit(ctx->y, sizeof(ctx->y));
 }
 
 static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx)
-- 
2.49.0

Re: [PATCH] crypto: ecdsa - explicitly zeroize pub_key

[Ignat Korchagin]

Hi,

On Mon, Apr 14, 2025 at 3:11 PM Vladis Dronov <vdronov@redhat.com> wrote:
>
> The FIPS standard, as a part of the Sensitive Security Parameter area,
> requires the FIPS module to provide methods to zeroise all the unprotected
> SSP (Security Sensitive Parameters), i.e. both the CSP (Critical Security
> Parameters), and the PSP (Public Security Parameters):
>
>     A module shall provide methods to zeroise all unprotected SSPs and key
>     components within the module.
>
> This requirement is mentioned in the section AS09.28 "Sensitive security
> parameter zeroisation – Levels 1, 2, 3, and 4" of FIPS 140-3 / ISO 19790.
> This is required for the FIPS certification. Thus, add a public key
> zeroization to ecdsa_ecc_ctx_deinit().
>
> Signed-off-by: Vladis Dronov <vdronov@redhat.com>
> ---
>  crypto/ecdsa.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
> index 117526d15dde..e7f58ad5ac76 100644
> --- a/crypto/ecdsa.c
> +++ b/crypto/ecdsa.c
> @@ -96,10 +96,12 @@ static int ecdsa_ecc_ctx_init(struct ecc_ctx *ctx, unsigned int curve_id)
>         return 0;
>  }
>
> -
>  static void ecdsa_ecc_ctx_deinit(struct ecc_ctx *ctx)
>  {
>         ctx->pub_key_set = false;
> +
> +       memzero_explicit(ctx->x, sizeof(ctx->x));
> +       memzero_explicit(ctx->y, sizeof(ctx->y));

Isn't this already done with crypto_destroy_tfm()? Or am I missing something?

Ignat

>  }
>
>  static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx)
> --
> 2.49.0
>

Re: [PATCH] crypto: ecdsa - explicitly zeroize pub_key

[Vladis Dronov]

On Mon, Apr 14, 2025 at 5:53 PM Ignat Korchagin <ignat@cloudflare.com> wrote:
>
> Hi,
>
> On Mon, Apr 14, 2025 at 3:11 PM Vladis Dronov <vdronov@redhat.com> wrote:
> >
> > The FIPS standard, as a part of the Sensitive Security Parameter area,
> > requires the FIPS module to provide methods to zeroise all the unprotected
> > SSP (Security Sensitive Parameters), i.e. both the CSP (Critical Security
> > Parameters), and the PSP (Public Security Parameters):
> >
> >     A module shall provide methods to zeroise all unprotected SSPs and key
> >     components within the module.
> >
> > This requirement is mentioned in the section AS09.28 "Sensitive security
> > parameter zeroisation – Levels 1, 2, 3, and 4" of FIPS 140-3 / ISO 19790.
> > This is required for the FIPS certification. Thus, add a public key
> > zeroization to ecdsa_ecc_ctx_deinit().
> >
> > Signed-off-by: Vladis Dronov <vdronov@redhat.com>
> > ---
> >  crypto/ecdsa.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
> > index 117526d15dde..e7f58ad5ac76 100644
> > --- a/crypto/ecdsa.c
> > +++ b/crypto/ecdsa.c
> > @@ -96,10 +96,12 @@ static int ecdsa_ecc_ctx_init(struct ecc_ctx *ctx, unsigned int curve_id)
> >         return 0;
> >  }
> >
> > -
> >  static void ecdsa_ecc_ctx_deinit(struct ecc_ctx *ctx)
> >  {
> >         ctx->pub_key_set = false;
> > +
> > +       memzero_explicit(ctx->x, sizeof(ctx->x));
> > +       memzero_explicit(ctx->y, sizeof(ctx->y));
>
> Isn't this already done with crypto_destroy_tfm()? Or am I missing something?
>
> Ignat

Thank you for your input, Ignat, most appreciated.
Indeed, the memory for ecc_ctx is cleared with kfree_sensitive()
in crypto_destroy_tfm(), you are right. And people at FIPS LAB
seem to be okay with that (for now).

So, please disregard this patch, I'm sorry for the noise.

Best regards,
Vladis

>
> >  }
> >
> >  static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx)
> > --
> > 2.49.0
> >
>