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jpp |
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From 185fbbfea732588187c81d1b2cafb3e1fae9eb77 Mon Sep 17 00:00:00 2001 |
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From: Clemens Lang <cllang@redhat.com> |
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Date: Thu, 17 Nov 2022 16:38:45 +0100 |
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Subject: [PATCH 2/2] kbkdf: Add explicit FIPS indicator for key length |
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NIST SP 800-131Ar2, section 8 "Deriving Additional Keys from |
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a Cryptographic Key" says that for KDFs defined in SP 800-108, "[t]he |
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length of the key-derivation key shall be at least 112 bits". It further |
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specifies that HMAC-based KDFs "with a key whose length is at least 112 |
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bits" are acceptable. |
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Add an explicit indicator for SP 800-108 KDFs that will mark shorter key |
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lengths as unapproved. The indicator can be queried from the EVP_KDF_CTX |
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object using EVP_KDF_CTX_get_params() with the |
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OSSL_KDF_PARAM_REDHAT_FIPS_INDICATOR |
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parameter. |
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Signed-off-by: Clemens Lang <cllang@redhat.com> |
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--- |
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providers/implementations/kdfs/kbkdf.c | 32 +++++++++++++++++++++----- |
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1 file changed, 26 insertions(+), 6 deletions(-) |
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diff --git a/providers/implementations/kdfs/kbkdf.c b/providers/implementations/kdfs/kbkdf.c |
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index a542f84dfa..93a8a10537 100644 |
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--- a/providers/implementations/kdfs/kbkdf.c |
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+++ b/providers/implementations/kdfs/kbkdf.c |
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@@ -365,18 +365,38 @@ static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[]) |
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OSSL_PARAM *p; |
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p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE); |
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- if (p == NULL) |
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- return -2; |
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+ if (p != NULL) |
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+ /* KBKDF can produce results as large as you like. */ |
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+ return OSSL_PARAM_set_size_t(p, SIZE_MAX); |
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+ |
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+#ifdef FIPS_MODULE |
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+ p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_REDHAT_FIPS_INDICATOR); |
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+ if (p != NULL) { |
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+ KBKDF *ctx = (KBKDF *)vctx; |
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+ int fips_indicator = EVP_KDF_REDHAT_FIPS_INDICATOR_APPROVED; |
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+ /* According to NIST Special Publication 800-131Ar2, Section 8: |
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+ * Deriving Additional Keys from a Cryptographic Key, "[t]he length of |
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+ * the key-derivation key [i.e., the input key] shall be at least 112 |
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+ * bits". */ |
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+ if (ctx->ki_len < EVP_KDF_FIPS_MIN_KEY_LEN) |
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+ fips_indicator = EVP_KDF_REDHAT_FIPS_INDICATOR_NOT_APPROVED; |
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+ return OSSL_PARAM_set_int(p, fips_indicator); |
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+ } |
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+#endif |
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- /* KBKDF can produce results as large as you like. */ |
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- return OSSL_PARAM_set_size_t(p, SIZE_MAX); |
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+ return -2; |
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} |
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static const OSSL_PARAM *kbkdf_gettable_ctx_params(ossl_unused void *ctx, |
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ossl_unused void *provctx) |
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{ |
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- static const OSSL_PARAM known_gettable_ctx_params[] = |
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- { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END }; |
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+ static const OSSL_PARAM known_gettable_ctx_params[] = { |
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+ OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), |
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+#ifdef FIPS_MODULE |
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+ OSSL_PARAM_int(OSSL_KDF_PARAM_REDHAT_FIPS_INDICATOR, NULL), |
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+#endif /* defined(FIPS_MODULE) */ |
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+ OSSL_PARAM_END |
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+ }; |
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return known_gettable_ctx_params; |
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} |
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-- |
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2.38.1 |
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